,illu/ration3 ,a special color recon/ruction ( ! eruption ( ! volcano ,loki on ! ,jovian satellite ,io4 ,! picture 0 tak5 by ,voyag] #a f a range ( ab\t half a million kilomet]s4 ,p-#baccd;,c ,,nasa ,,sp-#dci ,illu/ration3 ,voyage ,to ,jupit] ,voyage ,to ,jupit] ,david ,morrison & ,jane ,samz ,illu/ration3 ,,nasa ,sci5tific & ,te*nical ,in=mation ,bran* #aihj ,national ,a]onautics & ,space ,adm9i/ration ,wa%+ton1 ,,dc ,= sale by ! ,sup]9t5d5t ( ,docum5ts ,u4,s4 ,gov]nm5t ,pr9t+ ,(fice1 ,wa%+ton1 ,d4,c4 #bjdjb ,libr>y ( ,congress ,catalog ,c>d ,numb] #hj-fjjabf ,,=eword ,few missions ( planet>y exploration h provid$ su* rew>ds ( insight & surprise z ! ,voyag] flybys ( ,jupit]4 ,^? :o 7 =tunate en\gh to be ) ! sci5ce teams dur+ ^? weeks w long rememb] ! exp]i5ce2 x 0 l be+ 9 ! cr['s ne/ ( a %ip dur+ l&fall & passage ?r\gh an ar*ipelago ( /range isl&s4 ,we _h kn[n t ,jupit] w\ld be rem>kable1 = man _h be5 /udy+ x = c5turies1 b we 7 f> f prep>$ = ! torr5t ( new in=mation t ! ,voyag]s p\r$ back to ,e>?4 ,"s ( ! _s ( excitem5t & connection is captur$ 9 ?is volume4 ,its s5ior au?or 0 a memb] ( ! ,imag+ ,team4 ,x is n common t a p]son c bo? 8d sci5ce0 at ! lead+ edge & also pres5t s vivid an inside picture ( a rem>kable mom5t 9 ! hi/ory ( space exploration4 ,april #cj1 #aihj ,?omas ,a4 ,mut* ,associate ,adm9i/rator ,(fice ( ,space ,sci5ce ,,introduction ,! two ,voyag] enc\nt]s ) ,jupit] 7 p]iods unp>allel$ 9 degree & div]sity ( discov]y4 ,we _h1 ( c\rse1 expect$ a numb] ( discov]ies because we _h nev] be=e be5 able to /udy 9 detail ! atmosph]ic motions on a planet t is a giant sp9n+ sph]e ( hydrog5 & helium1 nor _h we ev] obs]v$ planet-siz$ objects su* z ! ,jovian satellites ,ganym$e & ,calli/o1 :i* are half wat]-ice4 ,we _h nev] be5 s close to a ,moon-siz$ satellite su* z ,io1 :i* 0 kn[n to be disp]s+ sodium ?r\gh\t its ,jovian neighborhood & 0 ?\ght to be g5]at+ a "o-million-amp]e electrical curr5t t 9 "s way results 9 billions ( watts ( radio emission f ,jupit]4 ,! clos] ,voyag] came to ,jupit] ! m app>5t x became t ! sci5tific ri*ness ( ! ,jovian sy/em 0 go+ to greatly exce$ ev5 our mo/ optimi/ic expectations4 ,! gr[+ realization among ,voyag] sci5ti/s ( ! weal? ( discov]y is app>5t 9 _! comm5ts1 discussions1 & reports z rec\nt$ by ! au?ors 9 _! descriptions ( ! two enc\nt]s4 ,al?\gh _m ( ! discov]ies occurr$ 9 ! few weeks ar\nd ea* enc\nt]1 !y 71 ( c\rse1 ! result ( m ?an ^? few weeks ( ef=t4 ,9 fact1 plann+ />t$ a decade e>li]1 & ! ,voyag] team ( eng9e]s & sci5ti/s _h be5 design+1 build+1 & plann+ = ! enc\nt]s = sev5 ye>s4 ,! ,pione] spacecraft made ! fir/ reconnaissance ( ,jupit] 9 #aigc-aigd1 provid+ key sci5tific results on :i* ,voyag] c\ld build1 & discov]ies f cont9u+ gr\nd-bas$ obs]vations sugge/$ specific ,voyag] /udies4 ,voyag] is itself j ! second phase ( exploration ( ! ,jovian sy/em4 ,x w be foll[$ by ! ,galileo program1 :i* w directly probe ,jupit]'s atmosph]e & provide long-t]m obs]vations ( ! ,jovian sy/em f an orbit+ spacecraft4 ,9 ! meantime1 ! ,voyag] spacecraft w cont9ue _! j\rney to ,saturn1 & possibly ,uranus & ,neptune1 planets ev5 m remote f ,e>? & ab\t :i* we "k ev5 less ?an we knew ( ,jupit] be=e #aigi4 ,z is cle>ly illu/rat$ 9 ?is rec\nt+ ( ! voyage to ,jupit]1 sci5tific endeavors are human endeavors2 j z ,galileo c\ld n h =ese5 ! advancem5t 9 our k initiat$ by 8 discov]ies ( ! f\r ,jovian moons 9 #afaj1 nei!r c we fully compreh5d ! sci5tific h]itage t our exploration ( space is provid+ future g5]ations4 ,april #aihj ,edw>d ,c4 ,/one ,voyag] ,project ,sci5ti/ ,,ackn[l$gem5t ,! au?ors are grateful to ! _m memb]s ( ! ,voyag] ,project team :o n only made ?is hi/oric mission ( exploration possible b also took "t f _! busy s*$ules to (f] u assi/ance1 in=mation1 & enc\ragem5t 9 ! prep>ation ( ?is book4 ,among _m too num]\s to "n individually1 we p>ticul>ly ?ank ,e4 ,c4 ,/one1 ,a4 ,l4 ,lane1 ,c4 ,h4 ,/embridge1 ,r4 ,a4 ,mills1 ,e4 ,montoya1 ,m4 ,a4 ,mitz1 & ,b4 ,a4 ,smi?1 ,l4 ,sod]blom1 & _! colleagues on ! ,voyag] ,imag+ ,team4 ,we are grateful to ,f4 ,e4 ,bri/[1 ,d4 ,l4 ,bane1 ,l4 ,j4 ,pi]i & especially ,j4 ,j4 ,van d] ,w\de = _! assi/ance 9 obta9+ optimum v]sions ( ! photographs pr9t$ "h4 ,c4 ,b4 ,pil*] & ,i4 de ,pat] k9dly made available _! gr\ndbas$ pictures ( ! ,jovian magnetosph]e4 ,_m colleagues h read & provid$ helpful comm5ts on p>ts ( ! manuscript1 among !m ,g4 ,a4 ,briggs1 ,s4 ,a4 ,coll9s1 ,s4 ,cruik%ank1 ,j4 ,d\ghty1 ,a4 ,l4 ,gu91 ,a4 ,l4 ,lane1 ,r4 ,a4 ,mills1 ,e4 ,montoya1 ,e4 ,c4 ,/one1 ,j4 ,l4 ,w>d1 & especially ,c4 ,r4 ,*apman4 ,,cont5ts ,=eword v ,introduction vii ,ackn[l$gm5t ix ,*apt] #a4 ,! ,jovian ,sy/em #a ,*apt] #b4 ,pione]s to ,jupit] #aa ,*apt] #c4 ,! ,voyag] ,mission #bc ,*apt] #d4 ,sci5ce & ,sci5ti/s #cc ,*apt] #e4 ,! ,voyage to ,jupit]--,gett+ ,!re #dg ,*apt] #f4 ,! ,fir/ ,enc\nt] #fc ,*apt] #g4 ,! ,second ,enc\nt]3 ,m ,surprises ,f ! 8,l&0 ( ! ,giant #ic ,*apt] #h4 ,jupit]--,k+ ( ! ,planets #aag ,*apt] #i4 ,f\r ,new ,worlds #aci ,*apt] #aj4 ,return to ,jupit] #afi ,app5dix ,a4 ,pictorial ,maps ( ! ,galilean ,satellites #agg ,app5dix ,b4 ,voyag] ,sci5ce ,teams #aie ,app5dix ,c4 ,voyag] ,managem5t ,team #aig ,additional ,read+ #aii ,illu/ration3 ,jupit] is ! l>ge/ planet 9 ! sol> sy/em--a gase\s _w z l>ge z #acjj ,e>?s1 m>k$ by alt]nat+ b&s ( color$ cl\ds & a dazzl+ complexity ( /orm sy/ems4 ,! ,voyag] mission gave u our fir/ close look at ?is spectacul> planet4 ,p-#bajhe ,,*apt] #a ,,! ,,jovian ,,sy/em ,introduction ,9 ! ,sun's necklace ( planets1 "o gem f> out%9es ! re/3 ,jupit]4 ,l>g] ?an all ! o!r planets & satellites comb9$1 ,jupit] is a true giant4 ,if intellig5t be+s exi/ on planets circl+ ne>by />s1 x is probable t ,jupit] is ! only memb] ( our planet>y sy/em !y c detect4 ,!y c see ! ,sun wobble 9 its motion ) a twelve-ye> p]iod z ,jupit] circles x1 pull+ fir/ "o way1 !n ! o!r ) ! p[]ful tug ( its gravity4 ,if a/ronom]s on "s di/ant worlds put telescopes 9 orbit above _! atmosph]es1 !y might ev5 be able to detect ! sunlight reflect$ f ,jupit]4 ,b all ! o!r planets--includ+ t9y inconspicu\s ,e>?--w\ld be hopelessly lo/ 9 ! gl>e ( our />1 ! ,sun4 ,jupit] is out/&+ among planets n only = its size1 b also = its sy/em ( orbit+ bodies4 ,) fifte5 kn[n satellites1 & probably sev]al m too small to h be5 detect$1 x =ms a sort ( m9iature sol> sy/em4 ,if we c\ld und]/& h[ ! ,jovian sy/em =m$ & evolv$1 we c\ld unlock vital clues to ! beg9n+ & ultimate fate ( ! entire sol> sy/em4 ,anci5t peoples all ov] ! _w recogniz$ ,jupit] z "o ( ! brighte/ w&]+ lights 9 _! skies4 ,only ,v5us is bright]1 b ,v5us1 always a morn+ or ev5+ />1 nev] rules ov] ! d>k midnight skies z ,jupit] (t5 does4 ,9 ,greek & ,roman my?ology ! planet 0 id5tifi$ ) ! mo/ p[]ful ( ! gods & "l ( ! heav5s--! ,greek ,zeus2 ! ,roman ,jupit]4 ,z befits ! k+ ( ! heav5s1 ! planet ,jupit] moves at a sl[ & /ately pace4 ,twelve ye>s are requir$ = ,jupit] to complete "o orbit ar\nd ! ,sun4 ,= ab\t six mon?s ( ea* ye>1 ,jupit] %9es d[n on u f ! night sky1 m brightly & /eadily ?an any />4 ,dur+ ! late #aigjs x 0 a w9t] object1 b 9 #aihj x w dom9ate ! spr+ skies1 becom+ a summ] 8/>0 ab\t #aihb4 ,e>ly ,discov]ies ,ev5 se5 ?r\gh a small telescope or pair ( b9ocul>s1 ,jupit] looks l a real _w1 display+ a fa9tly b&$ disk q unlike ! t9y1 brilliant image ( a />4 ,x also reveals ! brighte/ memb]s ( its satellite family z />like po9ts spread out along a /raight l9e ext5d$ ea/-we/ ?r\gh ! planet4 ,!re are f\r ( ^! planet-siz$ moons2 ) _! orbits se5 edge-on f ,e>?1 !y seem to move con/antly back & =?1 *ang+ _! configuration h\rly4 ,9 ,janu>y #afaj1 9 8 fir/ attempt to apply ! newly inv5t$ telescope to a/ronomy1 ,galileo discov]$ ! f\r l>ge satellites ( ,jupit]4 ,he correctly int]pret$ _! motion z be+ t ( objects circl+ ,jupit]--e/abli%+ ! fir/ cle> pro( ( cele/ial motion ar\nd a c5t] o!r ?an ! ,e>?4 ,! discov]y ( ^! satellites play$ an important role 9 support+ ! ,cop]nican revolution t =m$ ! basis = mod]n a/ronomy4 ,a few decades lat] ! satellites ( ,jupit] 7 us$ to make ! fir/ measurem5t ( ! spe$ ( light4 ,obs]v]s foll[+ _! motions _h le>n$ t ! satellite clock seem$ to run sl[ :5 ,jupit] 0 f> f ,e>? & to spe$ up :5 ! two planets 7 clos] toge!r4 ,9 #afge ! ,dani% a/ronom] ,ole ,roem] expla9$ t ?is *ange 0 due to ! f9ite velocity ( light3 ,! satellites only seem$ to run sl[ at l>ge di/ances because ! light com+ f !m took long] to rea* ,e>?4 ,kn[+ ! dim5sions ( ! orbits ( ,e>? & ,jupit] & ! am\nt ( ! delay 7ab\t fifte5 m9utes71 ,roem] 0 able to calculate "o ( ! mo/ fundam5tal con/ants ( ! physical univ]se--! spe$ ( light 7ab\t #cjj #jjj kilomet]s p] second74 ,illu/ration3 ,galileo's notes summ>iz+ 8 fir/ obs]vations ( ! ,jovian satellites ,io1 ,europa1 ,ganym$e1 & ,calli/o 9 ,janu>y #afaj 7 made on a piece ( scrat* pap] conta9+ ! draft ( a lett] pres5t+ a telescope to ! ,doge 9 ,v5ice4 ,^! obs]vations 7 ! result ( ,galileo's fir/ attempt to apply ! telescope to a/ronomical rese>*4 ,! f\r great moons ( ,jupit] are call$ ! ,galilean satellites aft] _! discov]]4 ,_! individual names--,io1 ,europa1 ,ganym$e1 & ,calli/o--7 propos$ by ,simon ,m>ius1 a contempor>y & rival ( ,galileo4 7,m>ius claim$ to h discov]$ ! satellites a few weeks be=e ,galileo did1 b mod]n s*ol>s t5d to discr$it 8 claim47 ,io1 ,europa1 ,ganym$e1 & ,calli/o are names ( lov]s ( ! god ,jupit] 9 ,greco-,roman my?ology4 ,s9ce ,jupit] 0 n at all %y ab\t tak+ lov]s1 !re are en\gh su* names = ! o!r elev5 ,jovian satellites1 z well z = ^? yet to be discov]$4 ,9 ! c5tury foll[+ ,galileo's dea?1 improvem5ts 9 telescopes made x possible to measure ! size ( ,jupit] & to note t x bulg$ at ! equator4 ,! equatorial diamet] is kn[n today to be #adb #hjj kilomet]s1 :ile f pole to pole ,jupit] measures only #acc #ejj kilomet]s4 ,= comp>ison1 ! diamet] ( ! ,e>? is #ab #ijj kilomet]s1 only ab\t "o-t5? z great1 & ! flatt5+ ( ,e>? is also mu* small] 7less ?an "o p]c5t74 ,by measur+ ! orbits ( ! satellites & apply+ ! laws ( planet>y motion discov]$ by ,johannes ,kepl] & ,isaac ,newton1 a/ronom]s 7 also able to det]m9e ! total mass ( ,jupit]--ab\t #b #aj tons1 or #cah times ! mass ( ! ,e>?4 ,once ! size & mass are kn[n1 x is possible to calculate ano!r fundam5tal prop]ty ( a planet--its d5sity4 ,! d5sity1 :i* is ! mass divid$ by ! volume1 provides important clues to ! composition & int]ior /ructure ( a planet>y body4 ,! d5sity ( ,e>?1 a body compos$ prim>ily ( rocky & metallic mat]ials1 is #e4f times ! d5sity ( wat]4 ,! mass ( ,jupit] is #cah times t ( ,e>?2 its volume is #acag times t ( ,e>?4 ,?us ,jupit]'s d5sity is sub/antially l[] ?an ,e>?'s1 am\nt+ to #a4cd times ! d5sity ( wat]4 ,f ?is l[ d5sity1 x 0 evid5t long ago t ,jupit] 0 n j a big bro!r ( ,e>? & ! o!r rocky planets 9 ! inn] sol> sy/em4 ,r1 ,jupit] is ! prototype ( ! giant1 gas-ri* planets ,jupit]1 ,saturn1 ,uranus1 & ,neptune4 ,^! giant planets mu/1 f _! l[ d5sity1 h a composition fundam5tally diff]5t f t ( ,m]cury1 ,v5us1 ,e>?1 ,moon1 & ,m>s4 ,jupit] ,?r\gh ! ,telescope ,jupit] is a beautiful sight se5 ) ! nak$ eye on a cle> night1 b only ?r\gh a telescope does x beg9 to reveal its magnific5ce4 ,! mo/ prom95t features are alt]nat+ light & d>k b&s1 runn+ p>allel to ! equator & subtly %ad$ 9 tones ( blue1 yell[1 br[n1 & orange4 ,h[ev]1 ^! b&s are n ! planet's only conspicu\s m>k+s4 ,9 #affd ! ,engli% a/ronom] ,rob]t ,hooke fir/ report$ see+ a l>ge oval spot on ,jupit]1 & additional spots 7 not$ z telescopes improv$4 ,z ! planet rotates on its axis1 su* spots are c>ri$ across ! disk & c be us$ to measure ,jupit]'s spe$ ( rotation4 ,! giant planet sp9s s fa/ t a ,jovian day is less ?an half z long z a day on ,e>?1 av]ag+ j "u t5 h\rs4 ,dur+ ! n9ete5? c5tury1 obs]v]s us+ increas+ly sophi/icat$ telescopes 7 able to see m complex detail 9 ! b& /ructure1 ) wisps1 /reaks1 & fe/oons t v>i$ 9 int5sity & color f ye> to ye>4 ,fur!rmore1 obs]vations reveal$ ! rem>kable fact t n all p>ts ( ! planet rotate ) ! same p]iod2 ne> ! equator ! app>5t l5g? ( a ,jovian day is sev]al m9utes %ort] ?an ! av]age day at high] latitudes4 ,x is ?us app>5t t ,jupit]'s surface is n solid1 & a/ronom]s came to realize t !y 7 look+ at a turbul5t kaleidoscope ( %ift+ cl\ds4 ,al?\gh ! face ( ,jupit] is always *ang+1 "s spots & o!r cl\d features survive = ye>s at a "t1 mu* long] ?an d ! l>ge/ /orms on ,e>?4 ,! record = longevity goes to ! ,great ,r$ ,spot4 ,?is gigantic r$ oval1 l>g] ?an ! planet ,e>?1 0 fir/ se5 m ?an ?ree c5turies ago4 ,f decade to decade x has *ang$ 9 size & color1 & = ne>ly fifty ye>s 9 ! late eighte5? c5tury no sight+s 7 report$1 b s9ce ab\t #ahdj ! ,great ,r$ ,spot has be5 ! mo/ prom95t feature on ! disk ( ,jupit]4 ,illu/ration3 ,?is gr\nd-bas$ photograph ( ,jupit] %[+ ! ,great ,r$ ,spot 9 ! s\!rn hemisph]e 0 tak5 ) ! ,catal9a ,obs]vatory's #fa-;in* telescope 9 ,decemb] #aiff4 ,x 0 n until ! tw5tie? c5tury t ! composition ( ! atmosph]e ( ,jupit] c\ld be measur$4 ,9 #aije spectra ( ! planet reveal$ ! pres5ce ( gases t absorb /rongly at r$ & infr>$ wavel5g?s2 ?irty ye>s lat] ^! 7 id5tifi$ z ammonia & me?ane4 ,^! two poison\s gases are ! simple/ *emical comp\nds ( hydrog5 comb9$ ) nitrog5 & c>bon1 respectively4 ,9 ! atmosph]e ( ,e>? !y are n /able1 because oxyg51 :i* is highly active *emically1 de/roys !m4 ,! exi/5ce ( me?ane & ammonia on ,jupit] demon/rat$ t free oxyg5 c\ld n be pres5t & t ! atmosph]e 0 dom9at$ by hydrog5--a r$uc+1 r ?an oxidiz+1 condition4 ,subsequ5tly1 hydrog5 0 id5tifi$ spectroscopically4 ,al?\gh mu* m abundant ?an me?ane or ammonia1 hydrog5 is h>d] to detect4 ,9 ! #aidjs & #aiejs ! ,g]man-,am]ican a/ronom] ,rup]t ,wildt us$ all ! available data to d]ive a picture ( ,jupit] t is /ill g5]ally accept$4 ,he not$ t bo? ! l[ total d5sity & ! obs]v$ pres5ce ( hydrog5-ri* comp\nds 9 ! atmosph]e 7 consi/5t ) a bulk composition simil> to t ( ! ,sun & />s4 ,?is 8cosmic composition0 is dom9at$ by ! two simple/ elem5ts1 hydrog5 & helium1 :i* toge!r make up ne>ly #ii p]c5t ( all ! mat]ial 9 ! univ]se4 ,wildt hypo!siz$ t ! giant planets1 because ( _! l>ge size1 _h succe$$ 9 reta9+ ?is primordial composition1 :]eas ! hydrog5 & helium _h escap$ f ! small] inn] planets4 ,he also us$ 8 k ( ! prop]ties ( hydrog5 & helium to calculate :at ! int]ior /ructure ( ,jupit] might be l1 conclud+ t ! planet is mo/ly liquid or gas4 ,wildt sugge/$ t !re probably 0 a core ( solid mat]ial deep 9 ! int]ior1 b t mu* ( ,jupit] is fluid--extremely visc\s & compress$ deep bel[ ! visible atmosph]e1 b /ill n solid4 ,! atmosph]e se5 f above is j ! ?91 topmo/ lay] ( an ocean ( gases ?\s&s ( kilomet]s ?ick4 ,rec5t ,e>?-,bas$ ,/udies ( ,jupit] ,9 ! pa/1 a great deal ( planet>y rese>* 0 basically descriptive1 consi/+ ( visual obs]vations & photography4 ,beg9n+ 9 ! #aifjs1 a new g5]ation ( planet>y sci5ti/s began to apply ! te*niques ( mod]n a/rophysics & geophysics to ! /udy ( ! sol> sy/em4 ,inspir$ 9 "p by ! develop+ space programs ( ! ,unit$ ,/ates & ! ,soviet ,union1 sci5ti/s began to ask m quantitative que/ions3 ,:at are ! surfaces & atmosph]es made (8 ,:at are ! temp]atures & w9d spe$s8 ,exactly :at quantities ( diff]5t elem5ts & isotopes are pres5t8 ,& h[ c ^! new data be us$ to inf] ! orig9 & evolution ( ! planets8 ,illu/ration3 ,! major features ( ,jupit] are %[n 9 s*ematic =m4 ,! planet is a b&$ disk ( turbul5t cl\ds2 all its /ripes are p>allel to ! bulg+ equator4 ,l>ge dusky gray regions surr\nd ea* pole4 ,d>k] gray or br[n /ripes call$ belts int]m+le ) light]1 yell[-:ite /ripes call$ zones4 ,_m ( ! belts & zones are p]man5t features t h be5 nam$4 ,"o feature ( p>ticul> note is ! ,great ,r$ ,spot1 an enigmatic oval l>g] ?an ! planet ,e>?1 :i* 0 fir/ se5 m ?an ?ree c5turies ago4 ,dur+ ! ye>s ! spot has *ang$ 9 size & color1 & x escap$ detection entirely = ne>ly fifty ye>s 9 ! #agjjs4 ,h[ev]1 s9ce ! mid-n9ete5? c5tury ! ,great ,r$ ,spot has be5 ! mo/ prom95t feature on ! face ( ,jupit]4 #bice ,n ,nor? pol> region ,nor? nor? nor? temp]ate belt ,nor? nor? temp]ate zone ,nor? nor? temp]ate belt ,nor? temp]ate zone ,nor? temp]ate belt ,nor? tropical zone ,nor? equatorial belt ,equatorial zone equatorial b& ,s\? equatorial belt ,n4 compon5t ,s4 compon5t ,s\? tropical zone ,great ,r$ ,spot ,s\? temp]ate belt ,s\? temp]ate zone ,s\? s\? temp]ate belt ,s\? s\? temp]ate zone ,s\? pol> region ,s ,wildt _h already sugge/$ ! basic gases 9 ! atmosph]e ( ,jupit]3 prim>ily hydrog5 & helium1 ) mu* small] quantities ( ammonia & me?ane4 ,undetect$ b possibly also pres5t 7 nitrog51 neon1 argon1 & wat] vapor4 ,! abundance ( helium 0 p>ticul>ly a problem2 al?\gh x 0 presumably ! second-rank+ gas aft] hydrog51 x has no spectral features 9 visible light & its pres5ce rema9$ only a hypo!sis1 unconfirm$ by obs]vation4 ,al?\gh ! pres5ce ( a gas c usually be inf]r$ f spectroscopy1 solids or liquids _c normally be detect$ 9 ?is way4 ,?us ! composition ( ,jupit]'s cl\ds c\ld n be det]m9$ directly4 ,h[ev]1 ! pres5ce ( ammonia gas provid$ an important clue4 ,at ! temp]atures expect$ 9 ! upp] atmosph]e ( ! planet1 ammonia gas mu/ freeze to =m t9y cry/als ( ammonia ice1 j z wat] vapor 9 ! ,e>?'s atmosph]e freezes to =m cirrus cl\ds4 ,mo/ inve/igators agre$ t ! high cl\ds cov]+ mu* ( ,jupit] mu/ be ammonia cirrus4 ,b ammonia cry/als are :ite1 s ! pres5ce ( ?is mat]ial provides no explanation = ! _m colors se5 on ,jupit]4 ,additional mat]ials mu/ be pres5t--p]haps color$ organic comp\nds1 produc$ 9 small am\nts by ! action ( sunlight on ! atmosph]e4 ,because ,jupit] is five times f>!r f ! ,sun ?an is ! ,e>?1 a giv5 area on ,jupit] receives only ab\t f\r p]c5t z mu* sol> heat+ z does a comp>able area on ,e>?4 ,?us ,jupit] is cold] ?an ,e>?2 ev5 ?\gh x may be w>m deep bel[ its blanket ( cl\ds1 ,jupit] pres5ts a frigid face4 ,illu/ration3 ,^! blue filt] photographs ( ,jupit] 7 tak5 at ,mauna ,kea ,obs]vatory1 ,hawaii4 ,!y %[ *anges on ,jupit]'s surface betwe5 #aigc & #aigh1 ) ! dates ( ! obs]vations4 ,illu/ration3 ,july #be1 #aigc ,illu/ration3 ,octob] #e1 #aigd ,illu/ration3 ,octob] #b1 #aige ,illu/ration3 ,novemb] #bj1 #aigf4 ,illu/ration3 ,janu>y #bh1 #aigh4 ,illu/ration3 ,decemb] #ai1 #aigh4 ,! developm5t ( a new sci5ce1 infr>$ a/ronomy1 9 ! #aifjs made x possible to measure ^! l[ temp]atures directly4 ,9 ! case ( a cl\dy planet l ,jupit]1 ! infr>$ emission evid5t at v>i\s wavel5g?s orig9ates at diff]5t dep?s 9 ! atmosph]e4 ,x is a g5]al prop]ty ( any mix$1 convect+ atmosph]e t ! temp]ature v>ies ) dep?2 ! rate ( v>iation dep5ds only on ! composition ( ! atmosph]e1 ! gravity ( ! planet1 & ! pres5ce or abs5ce ( cond5sible mat]ials to =m cl\ds4 ,on ,jupit] x is ab\t #a4i ,c w>m] = ea* kilomet] ( desc5t ?r\gh ! atmosph]e4 ,?us1 al?\gh ! ammonia cl\ds are v cold1 a little above -#agc ,c1 if "o goes deep en\gh "o c rea* temp]atures t are q com=table4 ,) a v>iation ( #a4i ,c p] kilomet]1 t]re/rial 8room temp]ature0 w\ld be rea*$ ab\t #ajj kilomet]s bel[ ! cl\ds4 ,to measure ! total en]gy radiat$ by a planet1 x is necess>y to utilize infr>$ radiation at wavel5g?s m ?an "o hundr$ times long] ?an ! wavel5g?s ( visible light4 ,ev5 :5 detectors 7 develop$ t c\ld measure su* radiation1 x 0 impossible to obs]ve cele/ial s\rces su* z ,jupit] because ( ! opacity ( ! t]re/rial atmosph]e4 ,ev5 a t9y am\nt ( wat] vapor 9 our own atmosph]e c block our view ( long-wave infr>$4 ,to make ! requir$ measurem5ts1 x is necess>y to c>ry a telescope to v high altitudes1 above all b a fraction ( a p]c5t ( ! (f5d+ wat] vapor4 ,9 ! late #aifjs a ,le>-,jet airplane 0 equipp$ ) a telescope & made available by ,,nasa to a/ronom]s to c>ry out long-wave infr>$ obs]vations f above #ii p]c5t ( ! t]re/rial wat] vapor4 ,9 #aifi ,frank ,l[ ( ! ,univ]sity ( ,arizona & 8 colleagues us$ ?is sy/em to make a rem>kable discov]y3 ,jupit] 0 radiat+ m heat ?an x receiv$ f ! ,sun6 ,repeat$ obs]vations demon/rat$ t betwe5 two & ?ree times z mu* en]gy emanat$ f ! planet z 0 absorb$4 ,?us ,jupit] mu/ h an int]nal heat s\rce2 9 effect1 x %9es by its own p[] z well z by reflect$ sunlight4 ,!oretical /udies sugge/ t ! heat is primordial1 ! remnant ( an inc&esc5t proto-,jupit] t =m$ f\r & "o-half billion ye>s ago4 ,illu/ration3 ,images ( ,jupit] 9 visible light 7bel[7 & five-micromet] infr>$ light %[ ! planet's *>act]i/ic belts & zones4 ,! infr>$ image reveals areas t emit l>ge am\nts ( !rmal en]gy4 ,! s\rce ( ! en]gy is ?\ght to be breaks 9 ! ,jovian cl\d cov]1 :i* all[ inve/igators a glimpse ( ! deep regions ( ! atmosph]e4 ,"o ( ! my/]ies ( ,jupit] conc]ns its heat balance3 ,! planet appe>s to radiate m heat ?an x receives f ! ,sun4 ,p-#bjieg ,illu/ration3 ,jupit] 9 visible light4 ,at ! same "t t ! int]nal heat s\rce on ,jupit] 0 be+ reveal$ ) long-wave airborne infr>$ telescopes1 a new discov]y 0 be+ made f %ort-wave infr>$ obs]vations4 ,! cl\ds ( ,jupit] are too cold to emit any detectable !rmal radiation at a wavel5g? ( #e micromet]s 7ab\t t5 times ! wavel5g? ( gre5 light74 ,nev]!less1 images ( ,jupit] at #e micromet]s reveal$ a few small spots :]e l>ge am\nts ( !rmal en]gy 7 be+ emitt$4 ,! s\rces ( ! en]gy appe>$ to be holes or breaks 9 ! cl\ds1 :]e x 0 possible to see deep] into hott] regions4 ,! discov]y ( ^! hot spots op5$ ! possibility ( prob+ deep regions ( ! ,jovian atmosph]e t _h previ\sly be5 beyond ! rea* ( direct inve/igation4 ,! ,jovian ,magnetosph]e ,! discov]y ( planet>y magnetosph]es began 9 #aiei :5 ! fir/ ,u4,s4 ,explor] satellite detect$ ! radiation belts ar\nd ! ,e>?4 ,nam$ = ,james ,van ,all5 ( ! ,univ]sity ( ,i[a1 ^: geig]-c\nt] in/rum5t abo>d ,explor] #a fir/ measur$ !m1 ^! belts are regions 9 :i* *>g$ atomic p>ticles--prim>ily electrons & protons--are trapp$ by ! magnetic field ( ! ,e>?4 ,!y are "o manife/ation ( ! t]re/rial magnetosph]e--a l>ge1 dynamic region ar\nd ! ,e>? 9 :i* ! magnetic field ( our planet int]acts ) /reams ( *>g$ p>ticles emanat+ f ! ,sun4 ,at almo/ ! same "t t ! t]re/rial magnetosph]e 0 be+ discov]$ by artificial satellites1 a/ronom]s 7 f9d+ evid5ce to sugge/ simil> ph5om5a ar\nd ,jupit]4 ,radio a/ronomy is a bran* ( sci5ce t measures radiation f cele/ial bodies at radio frequ5cies1 :i* correspond to wavel5g?s mu* long] ?an ^? ( visible or infr>$ light4 ,all planets emit weak !rmal radio radiation1 b 9 ! late #aiejs inve/igators f\nd t ,jupit] 0 a mu* /rong] long-wave radio s\rce ?an w\ld be expect$ = a planet ) its temp]ature4 ,?is radiation bore ! signature ( high]-en]gy processes4 ,physici/s _h se5 simil> emissions produc$ 9 syn*rotron electron accel]ators1 huge ma*9es 9 :i* electrons are :irl$ ar\nd at ne>ly ! spe$ ( light s t !y c be us$ = exp]im5ts 9 nucle> physics4 ,! ,russian !ori/ ,i4 ,s4 ,%klovsky id5tifi$ ! ,jovian radio radiation z also result+ f ! syn*rotron process1 due to spiral+ electrons trapp$ 9 ! planet's magnetic field4 ,f ! int5sity & spectrum ( ! obs]v$ syn*rotron radiation1 x 0 cle> t bo? ! magnetic field ( ! planet & ! en]gy ( *>g$ p>ticles 9 its ,van ,all5 belts 7 mu* great] ?an 0 ! case = ,e>?4 ,us+ radio telescopes ( high s5sitivity1 a/ronom]s det]m9$ ! approximate /r5g? & ori5tation ( ! magnetic field ( ,jupit]4 ,al?\gh !y 7 able to measure syn*rotron radiation only f ! inn]mo/ p>ts ( ! ,jovian magnetosph]e1 !y c\ld inf] t ! total volume occupi$ by ! magnetosph]e 0 enorm\s4 ,if our eyes 7 s5sitive to magnetosph]ic emissions1 ,jupit] w\ld look m ?an twice ! diamet] ( ! full moon 9 ! sky4 ,all f\r ,galilean satellites orbit )9 ! magnetosph]e ( ,jupit]2 9 contra/1 our ,moon lies well outside ! t]re/rial magnetosph]e4 ,/rik+ evid5ce ( ! int]action ( ! satellites & ! magnetosph]e 0 provid$ :5 x 0 f\nd t ! inn]mo/ l>ge satellite--,io--actually affects ! bur/s ( radio /atic produc$ by ,jupit]4 ,only :5 ,io is at c]ta9 places 9 its orbit are ^! /rong bur/s detect$4 ,!ori/s sugge/$ t electric curr5ts fl[+ betwe5 ! satellite & ! planet might be responsible = ?is effect4 ,! ,jovian ,satellites ,= ne>ly ?ree c5turies aft] _! discov]y 9 #afaj1 ! only kn[n moons ( ,jupit] 7 ! f\r l>ge ,galilean satellites4 ,9 #ahib ,e4 ,e4 ,b>n>d1 an ,am]ican a/ronom]1 f\nd a mu* small] fif? satellite orbit+ v close to ! planet1 & betwe5 #aijd & #aigd eight additional satellites 7 f\nd f> outside ! orbits ( ! ,galilean satellites4 ,! out] satellites are q fa9t & presumably no m ?an a few t5s ( kilomet]s 9 diamet]1 & all h orbits t are mu* less regul> ?an ^? ( ! five inn] satellites4 ,f\r ( !m revolve 9 a retrograde direction1 opposite to t ( ! inn] satellites & ,jupit] itself4 ,9 #aige ! ,int]national ,a/ronomical ,union assum$ ! responsibility = assign+ names to ! non-,galilean satellites ( ,jupit]4 ,foll[+ tradition1 !y nam$ ! inn] satellite ,amal!a = ! %e-goat t suckl$ ! "y god ,jupit]4 ,! out] eight 7 nam$ = lov]s ( ,jupit]3 ,l$a1 ,himalia1 ,lysi!a1 ,el>a1 ,ananke1 ,c>me1 ,pasiphae1 & ,s9ope4 ,= ! non-,galilean satellites1 ! 8e0 end+ is res]v$ = satellites ) retrograde orbits2 ^? ) normal orbits h names t end 9 8a40 ,because !y are s l>ge1 ! ,galilean satellites h attract$ ! mo/ att5tion f a/ronom]s4 ,m ?an fifty ye>s ago l>ge telescopes 7 us$ to e/imate _! sizes1 & a c>eful s]ies ( measurem5ts ( _! light v>iation %[$ t all f\r always keep ! same face po9t$ t[>d ,jupit]1 j z our ,moon always turns ! same face t[>d ,e>?4 ,also1 ! subtle gravitational p]turbations !y ex]t on ea* o!r 7 us$ to det]m9e ! approximate mass ( ea*4 ,illu/ration3 ,! patt]n ( ! ,galilean satellites *anges f h\r to h\r1 z se5 f ,e>?4 ,view$ edge-on1 ! ne>ly circul> orbits produce an app>5t back & =? motion ) respect to ,jupit]4 ,^! images recreate ! k9ds ( obs]vations fir/ made by ,galileo 9 #afaj4 ,calli/o1 ! out]mo/ ,galilean satellite1 is l>g] ?an ! planet ,m]cury4 ,x also has ! l[e/ reflectivity1 or alb$o1 ( ! f\r1 sugge/+ t its surface may be compos$ ( "s r d>k1 colorless rock4 ,calli/o takes j ov] two weeks to orbit once ar\nd ,jupit]4 ,ganym$e1 :i* requires only sev5 days = "o orbit1 is ! l>ge/ satellite 9 ! ,jovian sy/em1 be+ only slightly small] ?an ! planet ,m>s4 ,its alb$o is mu* high] ?an t ( ,calli/o1 or ( ! rocky planets su* z ,m]cury1 ,m>s1 or ! ,moon4 ,9 #aiga a/ronom]s fir/ measur$ ! infr>$ spectrum ( reflect$ sunlight f ,ganym$e & f\nd ! *>act]i/ic absorptions ( wat] ice1 indicat+ t ?is satellite is p>tially cov]$ ) highly reflective sn[ or ice4 ,europa1 :i* is slightly small] ?an ! ,moon1 circles ,jupit] 9 half ! "t requir$ by ,ganym$e4 ,its surface reflects ab\t sixty p]c5t ( ! incid5t sunlight1 & ! infr>$ spectrum %[s prom95t absorptions due to wat] ice2 ,europa appe>s to be almo/ entirely cov]$ ) ice4 ,h[ev]1 its color 9 ! visible & ultraviolet "p ( ! spectrum is n t ( ice1 s "s o!r mat]ial mu/ also be pres5t4 ,io1 inn]mo/ ( ! ,galilean satellites1 is ! same size z our ,moon4 ,x orbits ! planet 9 #db h\rs1 half ! p]iod ( ,europa4 ,l ,europa1 x has a v high reflectivity1 b1 unlike ,europa1 x has no spectral absorptions indicative ( wat] ice4 ,be=e ,voyag]1 id5tification ( ! surface mat]ial on ,io pres5t$ a major problem to planet>y a/ronom]s4 ,:5 ! sizes & masses ( ^! satellites 7 measur$1 a/ronom]s c\ld calculate _! d5sities4 ,! inn] two1 ,io & ,europa1 bo? h d5sities ab\t ?ree times t ( wat]--ne>ly ! same z ! d5sity ( ! ,moon1 or ( rocks 9 ! cru/ ( ! ,e>?4 ,calli/o & ,ganym$e h d5sities only half z l>ge1 f> too l[ to be consi/5t ) a rocky composition4 ,! mo/ plausible alt]native to rock is a composition t includes ice z a major compon5t4 ,calculations %[$ t if ^! satellites 7 compos$ ( rock & ice1 approximately equal quantities ( ea* 7 requir$ to acc\nt = ! measur$ d5sity4 ,?us ! two out] ,galilean satellites 7 ?\ght to repres5t a new k9d ( sol> sy/em object1 z l>ge z "o ( ! t]re/rial planets1 b compos$ 9 l>ge "p ( ice4 ,9 #aigc ! att5tion ( a/ronom]s 0 dramatically drawn to ,io :5 ,rob]t ,br[n ( ,h>v>d ,univ]sity detect$ ! fa9t yell[ gl[ ( sodium f ! region ( space surr\nd+ x4 ,x seem$ t ?is satellite _h an atmosph]e1 compos$ ( ! metal sodium6 ,cont9u$ obs]vations %[$1 h[ev]1 t ?is 0 n an atmosph]e 9 ! usual s5se ( ! ^w4 ,! gas atoms 7 n b\nd gravitationally to ,io1 b cont9u\sly escap$ f x to =m a gigantic cl\d envelop+ ! orbit ( ! satellite4 ,fras] ,fanale & ,d5nis ,matson ( ! ,calte* ,jet ,propulsion ,laboratory sugge/$ t bomb>dm5t ( ,io by high-en]gy p>ticles f ! ,jovian ,van ,all5 belts 0 knock+ (f atoms ( sodium by a process call$ sputt]+1 releas+ ^! atoms & all[+ !m to exp& outw>d to =m ! obs]v$ sodium cl\d4 ,no "o anticipat$ !n t p[]ful volcanic eruptions on ,io might also be contribut+ to ?is rem>kable gas cl\d4 ,illu/ration3 ,! ,galilean satellites 9 orbit ar\nd ,jupit]1 along ) ! out] satellites1 con/itute a m9iature sol> sy/em4 ,"h !y are %[n relative to ! size ( ,m]cury & t ( ! ,moon4 ,! portrayal ( _! int]nal & ext]nal composition is bas$ on !oretical models t prec$$ ! ,voyag] flybys4 ,,pc-#agjed;,,ac ,illu/ration3 ,?is image ( ,io's ext5d$ sodium cl\d 0 tak5 ,febru>y #ai1 #aigg1 at ! ,jet ,propulsion ,laboratory's ,table ,m\nta9 ,obs]vatory4 ,a picture ( ,jupit]1 draw+s ( ! orbital geometry1 & ,io's disk 7! small circle on ! left7 are includ$ = p]spective4 ,! sodium cl\d image has be5 process$ = removal ( sky backgr\nd1 in/rum5tal effects1 & ! l4 ,?is photograph demon/rates t ! cl\d is highly elongat$ & t m sodium prec$es ,io 9 its orbit ?an trails x4 ,p-#bjjdg ,?is picture ( ! satellites 0 develop$ j z ! fir/ space probe rea*$ ! ,jovian sy/em4 ,9 ! next *apt] we describe ! ,pione] program by :i* sci5ti/s rea*$ out across ne>ly a million kilomet]s ( space to explore ,jupit]1 its magnetosph]e1 & its sy/em ( satellites4 ,illu/ration3 ,pione] #aj 0 laun*$ on ,m>* #b1 #aigb1 at #h3di p4m4 f ,cape ,canav]al1 ,florida4 ,a p[]ful ,atlas-,c5taur rocket s]v$ z ! laun* vehicle1 :i* propell$ ! space probe to its goal ne>ly a billion kilomet]s away4 ,! beauty ( ! night laun* 0 enhanc$ by ! rumbl+ ?und] & fla%+ lightn+ ( a ne>by /orm4 ,,*apt] #b ,,pione]s ,,to ,,jupit] ,rea*+ = ! ,out] ,planets ,s9ce ! beg9n+ ( ! ,space ,age1 sci5ti/s _h dream$ ( s5d+ probes to ,jupit] & its family ( satellites4 ,initially1 robot spacecraft 7 limit$ to /udy+ ! ,e>? & its ,moon4 ,9 #aifb1 h[ev]1 ! fir/ true int]planet>y explor]1 ,m>9] #b1 succe$$ 9 escap+ ! ,e>?-,moon sy/em & cross+ #ajj million kilomet]s ( space to enc\nt] ,v5us1 /udy+ ,e>?'s si/] planet at close range us+ half a doz5 sci5tific in/rum5ts4 ,by ! mid #aifjs a ,u4,s4 planet>y spacecraft _h also fl[n to ,m>s1 !re _h be5 a second flyby ( ,v5us1 & an ambiti\s program 0 "u way = two m flybys ( ,m>s 9 #aifi1 foll[$ by a ,m>s orbit] 9 #aiga4 ,bas$ on ?is success ) ! inn] planets1 ,,nasa sci5ti/s & eng9e]s began to plan s]i\sly to meet ! *all5ge ( ! out] sol> sy/em4 ,n only ,jupit]1 b ,saturn & ev5 ,uranus & ,neptune1 7 consid]$ z possible t>gets4 ,h[ev]1 ! di/ances betwe5 ! out] planets are s va/ t _m ye>s ( flight w\ld be requir$ = a spacecraft to rea* !m1 ev5 us+ ! mo/ p[]ful rocket boo/]s !n contemplat$4 ,if a cauti\s exploration program 7 foll[$1 inve/igat+ "o planet at a "t be=e design+ ! next mission1 x w\ld be well into ! tw5ty-fir/ c5tury be=e ev5 a fir/ reconnaissance ( ! sol> sy/em c\ld be a*iev$4 ,a way to bridge ! space betwe5 planets 9 a m effici5t1 economical mann] 0 ne$$4 ,9 ! late #aifjs cele/ial me*anicians--sci5ti/s :o /udy ! motions ( planets & spacecraft--began to solve problems pos$ by ! imm5sity ( ! out] sol> sy/em4 ,if a spacecraft is aim$ to fly close to a planet 9 j ! "r way1 x c be accel]at$ by ! gravity ( ! planet to high] spe$s ?an c\ld ev] be obta9$ by direct laun* f ,e>?4 ,if a second1 m di/ant planet is 9 ! correct alignm5t1 ! gravity boo/ giv5 by ! fir/ enc\nt] c spe$ ! craft on to ! second4 ,jupit]1 ) its huge size & /rong gravitational pull1 c\ld be us$ z ! fulcrum = a s]ies ( missions to ,saturn1 ,uranus1 ,neptune1 & ev5 di/ant ,pluto4 ,9 addition1 ! e>ly #aihjs w\ld (f] an exceptional opportunity1 "o repeat$ only ab\t once e two c5turies4 ,at t "t1 all f\r giant planets w\ld be 9 approximate alignm5t1 s t gravity-assi/ maneuv]s c\ld be done sequ5tially4 ,a s+le spacecraft1 aft] be+ boo/$ f ,jupit] to ,saturn1 c\ld use ! accel]ation ( ,saturn to cont9ue to ,uranus1 & 9 turn c\ld be accel]at$ all ! way out to ,neptune4 ,su* an ambiti\s1 multiplanet mission 0 nam$ ! ,gr& ,t\r4 ,! fir/ ess5tial /ep 9 ! ,gr& ,t\r 0 a flyby ( ,jupit]4 ,h[ev]1 ?is planet is t5 times f>!r away f ,e>? ?an ,v5us or ,m>s4 ,9 addition1 !re 7 two pot5tially le?al haz>ds t _h n be5 fac$ be=e 9 int]planet>y flights3 ! a/]oid belt & ! ,jovian magnetosph]e4 ,! fir/ dang] 0 pres5t$ by ! _m ?\s&s ( a/]oids t occupy a belt betwe5 ! orbits ( ,m>s & ,jupit]4 ,! l>ge/ a/]oid1 ,c]es1 0 discov]$ 9 #ahja & 0 initially ?\ght to be ! 8miss+ planet0 sometimes hypo!siz$ z ly+ betwe5 ,jupit] & ,m>s4 ,h[ev]1 ,c]es is only #ajjj kilomet]s 9 diamet]1 too small to des]ve ! title ( planet4 ,hundr$s m ( ^! m9or planets 7 discov]$ dur+ ! n9ete5? c5tury1 & by ! #aifjs m ?an #cjjj _h well-det]m9$ orbits4 ,mo/ 7 only a few t5s ( kilomet]s 9 diamet]1 & a/ronom]s e/imat$ t #ej #jjj exi/$ t 7 #a kilomet] or m 9 diamet]4 ,any spacecraft to ,jupit] w\ld h to cross ?is conge/$ region ( space4 ,ev5 #ej #jjj m9or bodies spread ?r\gh ! volume ( space occupi$ by ! a/]oid belt w\ld pres5t little direct dang]1 al?\gh a *ance collision ) an uncatalogu$ object 0 always possible4 ,mu* m s]i\s 0 ! possibility t ^! l>g] objects 7 accompani$ by l>ge am\nts ( debris1 f ! size ( b\ld]s d[n to microscopic du/1 t 7 undetectable f ,e>?4 ,collisions ) pebble-siz$ /ones c\ld easily de/roy a spacecraft4 ,! only way to evaluate ?is dang] 0 to g !re & f9d out h[ mu* small debris 0 pres5t4 ,a second dang] 0 pos$ by ,jupit] itself4 ,9 ord] to use ! gravity boo/ ( ,jupit] to spe$ on to ano!r planet1 a spacecraft w\ld h to fly r close to ! giant4 ,b ?is w\ld mean pass+ "r ?r\gh ! regions ( en]getic *>g$ p>ticles surr\nd+ ! planet4 ,"s e/imates ( ! numb] & en]gy ( ^! p>ticles indicat$ t ! delicate electronic bra9s ( a spacecraft w\ld be damag$ be=e x c\ld p5etrate ?is region4 ,aga91 only by go+ !re c\ld ! dang] be evaluat$ prop]ly4 ,! ,pione] ,jupit] ,mission ,9 #aifi ! ,u4,s4 ,congress approv$ ! ,pione] ,jupit] ,mission to provide a reconnaissance ( int]planet>y space betwe5 ,e>? & ,jupit] & a fir/ close look at ! giant planet itself4 ,! ,project 0 assign$ by ,,nasa to ! ,ames ,rese>* ,c5t] 9 ,m\nta9 ,view1 ,cali=nia4 ,! prim>y objectives 7 def9$ by ,,nasa3 ,explore ! int]planet>y m$ium beyond ! orbit ( ,m>s4 ,inve/igate ! nature ( ! a/]oid belt1 assess+ possible haz>ds to missions to ! out] planets4 ,explore ! environm5t ( ,jupit]1 includ+ its inn] magnetosph]e4 ,! ,pione] spacecraft 0 design$ = economy & reliability1 bas$ on previ\s exp]i5ce at ,ames ) ,pione]s #f ?r\gh #i1 all ( :i* _h prov5 !mselves by ye>s ( successful measurem5t ( ! int]planet>y m$ium ne> ! ,e>?4 ,unlike ! ,m>9] class ( spacecraft be+ us$ to inve/igate ,v5us & ,m>s1 ! ,pione] craft rotat$ cont9u\sly ar\nd an axis po9t$ t[>d ! ,e>?4 ,?is sp9n+ design 0 extremely /able1 l ! :eels ( a fa/-mov+ bicycle1 & requir$ less elaborate guidance ?an a nonsp9n+ craft4 ,9 addition1 ! sp9 provid$ an ideal base = measurem5ts ( en]getic p>ticles & magnetic fields 9 space1 s9ce ! motion ( ! spacecraft itself swept ! view+ direction ar\nd ! sky & all[$ data to be acquir$ rapidly f _m diff]5t directions4 ,! only major disadvantage ( a sp9n+ spacecraft is t x does n all[ a /abiliz$ plat=m on :i* to m\nt cam]as or o!r in/rum5ts t require exact po9t+4 ,?us ! spacecraft design 0 optimiz$ = measurem5ts ( p>ticles & fields 9 int]planet>y space & 9 ! ,jovian magnetosph]e1 b _h limit$ capability = obs]vations ( ! planet & its satellites4 ,z f9ally assembl$1 ! ,pione] ,jupit] spacecraft _h a mass ( #beh kilograms4 ,"o hundr$ =ty watts ( electrical p[] at ,jupit] 7 suppli$ by f\r radioisotope !rmoelectric g5]ators 7,r,t,gs71 :i* turn$ heat f ! radioactive decay ( plutonium into electricity4 ,! laun* vehicle = ! flight to ,jupit] 0 an ,atlas-,c5taur rocket1 equipp$ ) an additional solid-propellant ?ird /age4 ,?is p[]ful rocket c\ld accel]ate ! spacecraft to a spe$ ( #ea #ejj kilomet]s p] h\r1 suffici5t to escape ! ,e>? & make ! billion-kilomet] trip to ,jupit] 9 j ov] two ye>s4 ,! specific sci5tific inve/igations to be c>ri$ out on ,pione] 7 select$ competitively 9 #aifi f proposals submitt$ by sci5ti/s f ,u4,s4 univ]sities1 indu/ry1 & ,,nasa laboratories1 & also f abroad4 ,elev5 sep>ate in/rum5ts w\ld be fl[n1 9 addition to two exp]im5ts t w\ld make use ( ! spacecraft itself4 ,?ree complete ,pione] spacecraft1 ) _! payloads ( #be kilograms ( sci5tific in/rum5ts1 7 built3 "o z a te/ vehicle & two = laun* to ,jupit]4 ,"o ( ^!--! te/ vehicle--is n[ on display at ! ,national ,air & ,space ,museum 9 ,wa%+ton4 ,! fir/ opportunity to laun*--! op5+ ( ! 8laun* w9d[0--0 on ,febru>y #bg1 #aigb4 ,h[ev]1 x 0 n until %ortly aft] d>k on ,m>* #b t all sy/ems 7 ready1 & ,pione] #aj began its hi/oric trip to ,jupit]4 ,pione] #aj 0 ! fir/ human artifact laun*$ ) suffici5t en]gy to escape ! sol> sy/em entirely4 ,fitt+ly1 ! craft c>ri$ a message design$ = any possible ali5 a/ronauts :o might1 9 ! di/ant future1 f9d ! d]elict ,pione] 9 ! va/ness ( int]/ell> space4 ,a small plaque fa/5$ to ! spacecraft told ! "t & planet f :i* x _h be5 laun*$1 & c>ri$ a symbolic greet+ f humanity to ! cosmos4 ,illu/ration3 ,two id5tical ,pione] spacecraft 7 design$ & fabricat$ by ,,trw ,sy/ems ,gr\p at _! ,r$ondo ,bea*1 ,cali=nia facility4 ,ea* weigh$ only ab\t #bfj kilograms1 yet c>ri$ elev5 highly sophi/icat$ in/rum5ts capable ( op]at+ unatt5d$ = _m ye>s 9 space4 ,data sy/ems on bo>d controll$ ! in/rum5tation1 receiv$ & process$ comm&s1 & transmitt$ in=mation across ! va/ di/ance to ,e>?4 ,! second ,pione] 0 to wait m ?an a ye> be=e laun*4 ,by foll[+ f> beh9d ,pione] #aj1 its trajectory--9 p>ticul> h[ deeply x p5etrat$ ! radiation belts dur+ ,jupit] flyby--c\ld be modifi$1 dep5d+ on ! fate ( ! fir/ spacecraft4 ,at dusk on ,april #e1 #aigc1 ,pione] #aa bla/$ f ! laun* pad at ,cape ,canav]al & foll[$ its pr$ecessor on ! long1 lonely j\rney into ! out] sol> sy/em4 ,flight to ,jupit] ,)9 a few h\rs ( laun*1 ea* ,pione] spacecraft %$ ! %r\d t _h protect$ x & unfurl$ booms support+ ! sci5ce in/rum5ts & ! ,,rtg p[] g5]ators4 ,aft] ea* craft _h be5 c>efully track$ & precise orbits calculat$1 small onbo>d rockets 7 comm&$ to fire to correct its trajectory = exactly ! desir$ flyby at ,jupit]4 ,pione] #aj 0 t>get$ to fly by ! planet at a m9imum di/ance ( #c ,jupit] radii 7,r,j7 f ! c5t]1 or #b ,r,j 7ab\t #adj #jjj kilomet]s7 above ! cl\ds4 ,?is close passage1 inside ! orbit ( ,io1 all[$ ! craft to pass beh9d bo? ,io & ,jupit] z se5 f ,e>?1 s t its radio beam c\ld probe bo? ! planet & its inn]mo/ l>ge satellite4 ,pione] #aa 0 int5d$ to fly ev5 clos] to ,jupit]1 b ! exact t>get+ options 7 held op5 until aft] ! ,pione] #aj enc\nt]4 ,on ,pione] #aj1 all in/rum5ts appe>$ to be work+ well z ! craft pass$ ! orbit ( ,m>s 9 ,june #aigb1 j #ig days aft] laun*4 ,at ?is po9t1 z x head$ into unexplor$ space1 x truly became a pione]4 ,9 mid-,july x began to ent] ! a/]oid belt1 & sci5ti/s & eng9e]s anxi\sly wat*$ = signs ( increas+ p>ticulate matt]4 ,pione] #aj c>ri$ two in/rum5ts design$ to measure small p>ticles 9 space4 ,"o1 ) an effective area ( ab\t #j4f squ>e met]s1 measur$ ! direct impact ( du/ gra9s z small z "o-billion? ( a gram4 ,! o!r look$ = l>g]1 m di/ant gra9s by measur+ sunlight reflect$ f !m4 ,to ! surprise ( _m1 !re 0 little increase 9 ! rate ( du/ impacts record$ z ! craft p5etrat$ m & m deeply into ! belt4 ,at ab\t #djj million kilomet]s f ! ,sun1 ne> ! middle ( ! belt1 !re appe>$ to be an increase 9 ! numb] ( l>g] p>ticles detect$ optically1 b n to a level t pos$ any haz>d4 ,9 ,febru>y #aigc ! spacecraft em]g$ unsca!d f ! a/]oid belt1 hav+ demon/rat$ t ! mu*-fe>$ conc5tration ( small debris 9 ! belt did n exi/4 ,! pa?way 0 op5 to ! out] sol> sy/em6 ,on ,novemb] #bf1 #aigc1 ! long-await$ enc\nt] ) ,jupit] began4 ,on t date1 at a di/ance ( #f4d million kilomet]s f ! planet1 in/rum5ts on bo>d ,pione] #aj detect$ a sudd5 *ange 9 ! int]planet>y m$ium z ! spacecraft cross$ ! po9t--! b[ %ock--at :i* ! magnetic pres5ce ( ,jupit] fir/ becomes evid5t4 ,at ! b[ %ock1 ! en]getic p>ticles ( ! sol> w9d are sudd5ly sl[$ z !y approa* ,jupit]4 ,at noon ! next day1 ,pione] #aj ent]$ ! ,jovian magnetosph]e at a di/ance ( #if ,r,j f ! planet4 ,z ! spacecraft hurtl$ inw>d t[>d regions ( increas+ magnetic field /r5g? & *>g$ plasma p>ticles1 ! in/rum5ts design$ to look at ,jupit] began to play _! role4 ,a simple l9e-scan cam]a t c\ld build up an image f _m individual brightness scans 7l a newspap] picture transmitt$ by wire7 obta9$ its fir/ pictures ( ! planet1 & ultraviolet & infr>$ photomet]s prep>$ to obs]ve x also4 ,by ,decemb] #b1 :5 ! spacecraft _h cross$ ! orbit ( ,calli/o1 ! out]mo/ ( ! l>ge ,galilean satellites1 ! l9e-scan images 7 ne>ly equal 9 quality to ! be/ telescopic photos tak5 previ\sly1 & z ea* h\r pass$ !y improv$ 9 resolution4 ,ne> close/ approa*1 ,pione] #aj transmitt$ p>tial frames ( ,jupit] t repres5t$ a ?reefold improvem5t ov] any ,e>?-bas$ pictures ev] tak54 ,illu/ration3 ,! a/]oid belt is a region betwe5 ,m>s & ,jupit] t is populat$ by ?\s&s ( m9or planets1 mo/ only a few kilomet]s 9 diamet]4 ,be=e #aigj1 "s !ori/s sugge/$ t l>ge quantities ( abrasive du/ might damage spacecraft pass+ ?r\gh ! a/]oid belt4 ,pione] #aj prov$ t ?is dang] 0 n pres5t1 ?us op5+ ! way to ! out] sol> sy/em4 ,e>? at enc\nt] ,e>? at laun* ,jupit] at enc\nt] ,jupit] at laun* ,a/]oid belt ,t5sion increas$ z ! spacecraft plung$ deep] into ! radiation belts ( ,jupit]4 ,w\ld x survive ! bla/ ( x-rays & gamma-rays induc$ 9 e "p ( ! craft by ! electrons & ions trapp$ by ! magnetic field ( ,jupit]8 ,sev]al ( ! in/rum5ts measur+ ! *>g$ p>ticles climb$ to full scale & saturat$4 ,o!rs ne>$ _! limits b1 z anxi\s sci5ti/s wat*$ ! data be+ s5t back1 ! levels flatt5$ (f4 ,mean:ile1 ! spacecraft itself began to feel ! effects ( ! radiation1 & occasional spuri\s comm&s 7 g5]at$4 ,sev]al plann$ high-resolution images ( ,jupit] & its satellites 7 lo/ because ( ^! false signals4 ,b aga9 ! sy/em /abiliz$1 & no m problems occurr$ z1 j pa/ noon on ,decemb] #c1 #aigc1 ,pione] #aj rea*$ its close/ po9t to ,jupit]1 #acj #jjj kilomet]s above ! ,jovian cl\d tops4 ,pione] _h pass$ its mo/ dem&+ te/ ) fly+ colors1 & at a news conf]5ce at ,ames1 ,,nasa ,planet>y ,program ,director ,rob]t ,kraem] pron\nc$ ! mission 8#ajj p]c5t successful40 ,he add$1 8,we s5t ,pione] (f to tweak a dragon's tail1 & x did t & m4 ,x gave x a really good yank1 & x manag$ to survive40 ,! ,project ,sci5ce ,*ief pron\nc$ x 8! mo/ excit+ day ( my life10 & mo/ ( ! hundr$s ( sci5ti/s & eng9e]s :o p>ticipat$ 9 ! enc\nt] probably agre$ ) him4 ,pione] #aa cont9u$ to foll[ /eadily1 em]g+ f ! a/]oid belt 9 ,m>* #aigd4 ,bas$ on ! p]=mance & f9d+s ( ,pione] #aj1 x 0 decid$ to s5d ,pione] #aa /ill clos] to ,jupit]1 b on a m incl9$ trajectory4 ,on ,april #ai ?ru/]s on ! spacecraft fir$ to move ! ,pione] #aa aimpo9t j #cd #jjj kilomet]s above ! cl\ds ( ,jupit]4 ,9 us+ ! ,pione] #aj data to assess ! haz>d to ,pione] #aa1 sci5ti/s _h to consid] ?ree aspects ( ! *>g$ p>ticle environm5t4 ,fir/ 0 ! en]gy di/ribution ( ! p>ticles3 ,! mo/ en]getic pres5t$ ! mo/ dang]4 ,second 0 ! flux1 ! rate at :i* p>ticles /ruck ! craft4 ,?ird 0 ! total radiation dose4 ,"o c make an analogy ) a box+ mat*4 ,! en]gy di/ribution tells y h[ h>d ! bl[s ( y\r oppon5t are4 ,! flux is a measure ( h[ _m times a m9ute he hits y1 & ! total dose measures h[ _m bl[s l&4 ,! spacecraft reacts j l a box]2 ! crucial "q is h[ mu* total dose x absorbs4 ,en\gh radiation bl[s1 & ! sy/em is knock$ out4 ,! trajectory *os5 = ,pione] #aa result$ 9 high] flux1 s9ce ! craft prob$ m deeply into ,jupit]'s inn] magnetosph]e ?an _h ,pione] #aj4 ,b by mov+ at a high angle across ! equatorial regions :]e ! flux is highe/1 ! total dose c\ld be kept bel[ t exp]i5c$ by ,pione] #aj4 ,pione] #aa ent]$ ! ,jovian magnetosph]e on ,novemb] #bf1 #aigd1 j a ye> aft] its pr$ecessor4 ,close/ approa* took place on ,decemb] #b4 ,z ) ,pione] #aj1 ! radiation dose tax$ ! spacecraft to its limit4 ,aga9 spuri\s comm&s 7 issu$1 ?is "t affect+ ! infr>$ radiomet] m ?an ! imag+ sy/em4 ,! craft flew at high latitude ov] ! nor? pol> region ( ,jupit]1 an area nev] se5 f ,e>?1 & return$ sev]al excell5t high-resolution pictures4 ,once m ! little ,pione]s _h succe$$ aga9/ ! odds 9 op5+ ! way to ! giant planets4 ,illu/ration3 ,pione] #aj & #aa enc\nt]s ) ,jupit] are %[n z view$ f ! cele/ial ,nor? ,pole4 ,pione] #aj swung ar\nd ! giant planet 9 ! c\nt]clockwise direction1 :ile ,pione] #aa foll[$ a clockwise approa*4 ,9 ?is view1 ,jupit] rotates c\nt]clockwise4 ,pione] #aa ,pione] #aj ,calli/o ,ganym$e ,europa ,io ,amal!a ,foll[+ _! enc\nt]s ) ,jupit]1 bo? ,pione] spacecraft return$ to _! normal r\t9e ( measur+ ! int]planet>y m$ium4 ,pione] #aj _h ga9$ spe$ f ! gravity field ( ,jupit] & became ! fir/ craft to a*ieve ! velocity ne$$ to escape f ! sol> sy/em4 ,pione] #aa1 h[ev]1 _h us$ ! pull ( ,jupit] to b5d its trajectory inw>d1 aim+ x across ! sol> sy/em t[>d ,saturn4 ,foll[+ ! successes at ,jupit]1 ,,nasa ann\nc$ t ,pione] #aa w\ld be t>get$ = a close flyby ( ,saturn five ye>s lat]1 :i* 0 successfully c>ri$ out 9 ,septemb] #aigi4 ,9 e>ly #aihj1 f> beyond _! design lifetimes1 bo? spacecraft 7 /ill p]=m+ beautifully4 ,illu/ration3 ,9 ?is view ( ,jupit]1 ! ,great ,r$ ,spot is prom95t & ! %ad[ ( ,io trav]ses ! planet>y disk4 ,! gross morphology ( ! belts & zones1 ) /ructures %[+ turbul5ce & convective cells 9 ! middle latitudes1 is cle>ly se54 ,! small :ite spots surr\nd$ by d>k r+s1 se5 ma9ly 9 ! s\!rn hemisph]e1 indicate regions ( int5se v]tical convective activity1 some:at simil> to cumulonimbus or ?und]cl\ds4 ,jupit] ,results ,! sci5tific results ( ! ,pione] flybys ( ,jupit] 7 _m & v>i$4 ,z is always ! case1 "s old que/ions 7 answ]$ & new problems 7 rais$ by ! spacecraft data4 ,highlights ( ^! results are summ>iz$ bel[4 ,photographs ( ,jupit]4 ,! l9e-scan imag+ sy/ems ( ,pione] return$ "s rem>kable pictures ( ! planet dur+ ! two enc\nt]s1 %[+ individual features z small z #ejj kilomet]s across4 ,9 addition1 ! ,pione]s 7 able to look at ,jupit] f angles nev] obs]vable f ,e>?4 ,"o ( ! discov]ies made f ^! pictures 0 ! great v>iety ( cl\d /ructures ne> ! b\nd>ies betwe5 ! light zones & d>k belts4 ,_m individual cl\d patt]ns sugge/$ ris+ & fall+ air4 ,! convolut$ swirls evid5t 9 ^! regions appe>$ to be ! result ( dynamic motions2 un=tunately1 ) only ! few 8snap%ots0 obta9$ dur+ ! h\rs ( ! flyby1 ! actual motions ( ^! cl\ds c\ld n be foll[$4 ,!rmal ,emission4 ,9 ! ye> ! ,pione] ,project 0 begun1 a/ronom]s on ,e>? _h measur$ t ,jupit] emitt$ m heat ?an x absorb$ f ! ,sun4 ,f ! ,e>? ^! measurem5ts c\ld be made only ( ! sunlit "p ( ! planet2 nei!r ! night side nor ! poles c\ld be se54 ,"o ( ! ma9 objectives ( ! ,pione] flybys 0 to det]m9e ! heat budget accurately f temp]ature measurem5ts at _m po9ts on bo? ! sunlit & ! night sides4 ,! ,pione] data confirm$ ! pres5ce ( a heat s\rce 9 ,jupit] & suppli$ a quantitative e/imate ( its magnitude4 ,! global effective temp]ature 0 f\nd to be -#adh ,c1 to a precision ( #c degrees4 ,?is temp]ature implies t ,jupit] radiates #a4i times z mu* heat z x receives f ! ,sun4 ,! correspond+ int]nal heat s\rce is #aj watts4 ,surpris+ly1 ! poles 7 z w>m z ! equator2 app>5tly1 ! atmosph]e is v effici5t at transf]r+ sol> heat absorb$ ne> ! equator up to high latitudes1 or p]haps ! int]nal compon5t ( ! heat comes pref]5tially f ! pol> regions4 ,helium 9 ! ,atmosph]e4 ,! ,pione] infr>$ exp]im5t made ! fir/ measurem5t ( ! am\nt ( helium on ,jupit]4 ,! ratio ( ! numb] ( helium atoms to ! numb] ( hydrog5 atoms 0 f\nd to be ,he_/,h #j4ad #j4jh4 ,?is is consi/5t ) ! kn[n sol> ratio ( ,he_/,h #j4aa4 ,measurem5ts ( helium 9 ! upp] atmosph]e 7 also made by ! ultraviolet exp]im5t4 ,illu/ration3 ,"o ( ! be/ ,pione] images ( ,jupit] 0 obta9$ at a range ( #ede #jjj kilomet]s by ,pione] #aa4 ,/ructure )9 ! ,great ,r$ ,spot & ! surr\nd+ belts & zones c be se54 ,!re 0 mu* less turbul5t cl\d activity r\nd ! spot at ! "t ( ! ,pione] flybys ?an 0 se5 five ye>s lat] by ! ,voyag] cam]as4 ,illu/ration3 ,pione] #aj confirm$ !oretical models ( ,jupit] t sugge/ ! planet is ne>ly all liquid1 ) a v small core & an extremely deep atmosph]e4 ,! liquid int]ior see!s ) int]nal heat en]gy1 :i* is transf]r$ f deep )9 ! planet to its out] regions4 ,! temp]ature at ! c5t] may be #cj #jjj ,k4 ,s9ce ! temp]ature at ! cl\d tops is ar\nd -#abc ,c1 !re is a l>ge range ( temp]atures )9 ! planet4 ,di/ance 7km7 ,visible cl\ds ,hydrog5 gas ,cl\d tops ,ammonia cry/als ,ammonium hydrosulfide cry/als ,ice cry/als ,wat] droplets -#abc ,c ,transp>5t atmosph]e ,hydrog5_/,helium gas #gj #jjj ,transition zone #aihj ,c #fj #jjj ,liquid hydrog5 #ej #jjj #aa #jjj ,c ,transition zone #c million atmosph]es pressure #dj #jjj ,liquid metallic hydrog5 #cj #jjj #bj #jjj ,possible 8sea0 ( helium #aj #jjj #cj #jjj ,k ,possible solid core #j ,,pione] ,,sci5ce ,,inve/igations ,project ,sci5ti/3 ,j4 ,h4 ,wolfe1 ,,nasa ,ames ,inve/igation ,pr9cipal ,inve/igator ,prim>y ,objectives ,magnetic fields ,e4 ,j4 ,smi?1 ,,jpl ,measurem5t ( ! magnetic field ( ,jupit] & det]m9ation ( ! /ructure ( ! magnetosph]e4 ,magnetic fields ,n4 ,f4 ,ness1 ,,nasa ,measurem5t ( ! magnetic 7,pione] #aa only7 ,godd>d field ( ,jupit] & det]m9ation ( ! /ructure ( ! magnetosph]e4 ,plasma analyz] ,j4 ,h4 ,wolfe1 ,,nasa ,ames ,measurem5t ( l[-en]gy electrons & ions1 det]m9ation ( ! /ructure ( ! magnetosph]e4 ,*>g$ p>ticle ,j4 ,a4 ,simpson1 ,u4 ,det]m9ation ( ! composition ,*icago numb]1 en]gy1 & composition ( en]getic *>g$ p>ticles 9 ! ,jovian magnetosph]e4 ,cosmic ray en]gy ,f4 ,b4 ,mc,donald1 ,,nasa ,measurem5t ( numb] & spectra ,godd>d en]gy ( v high en]gy *>g$ p>ticles 9 space4 ,jovian *>g$ ,j4 ,a4 ,van ,all51 ,u4 ,measurem5t ( numb] & p>ticles ,i[a en]gy di/ribution ( en]getic *>g$ p>ticles & det]m9ation ( magnetosph]ic /ructure4 ,jovian trapp$ ,r4 ,walk] ,fillius1 ,,uc ,measurem5t ( numb] & radiation ,san ,diego en]gy di/ribution ( en]getic *>g$ p>ticles & det]m9ation ( magnetosph]ic /ructure4 ,a/]oid-meteoroid ,r4 ,k4 ,sob]man1 ,obs]vation ( solid a/ronomy ,g5]al ,electric p>ticles 7du/ & l>g]7 9 ! vic9ity ( ! spacecraft4 ,meteoroid detection ,w4 ,h4 ,k9>d1 ,,nasa ,detection ( v small ,langley solid p>ticles t /rike ! spacecraft4 ,cele/ial me*anics ,j4 ,d4 ,&]son1 ,,jpl ,measurem5t ( ! masses ( ,jupit] & ! ,galilean satellites ) high precision4 ,ultraviolet photometry ,d4 ,l4 ,judge1 ,u4 ,measurem5t ( ultraviolet ,s\!rn ,cali=nia emissions ( ! ,jovian atmosph]e & f circumsatellite gas cl\ds4 ,imag+ ,t4 ,gehrels1 ,u4 ,arizona ,reconnaissance imag+ ( photopol>imetry ,jupit] & its satellites2 /udy ( atmosph]ic dynamics4 ,jovian infr>$ ,g4 ,mn*1 ,calte* ,measurem5t ( ,jovian !rmal /ructure temp]ature & heat budget2 det]m9ation ( helium to hydrog5 ratio4 ,s-,b& occultation ,a4 ,j4 ,kliore1 ,,jpl ,probes ( /ructure ( ,jovian atmosph]e & ionosph]e4 ,atmosph]ic ,/ructure4 ,sev]al ,pione] inve/igations yield$ in=mation on ! v>iation ( atmosph]ic temp]ature & pressure 9 ! regions above ! ammonia cl\ds4 ,ne> ! equator1 at a level :]e ! atmosph]ic pressure is ! same z t on ! surface ( ! ,e>? 7#a b>71 ! temp]ature is -#ajh ,c4 ,ab\t #aej kilomet]s high]1 :]e ! pressure drops to #j4a b>1 is ! m9imum atmosph]ic temp]ature ( ab\t -#afe ,c4 ,above ?is po9t ! temp]ature rises aga91 rea*+ ab\t -#abc ,c ne> a pressure level ( #j4jc b>4 ,presumably ?is temp]ature rise is due to absorption ( sunlight by a ?9 haze ( du/ p>ticles 9 ! upp] atmosph]e ( ,jupit]4 ,int]nal ,/ructure4 ,! measurem5ts ( ! am\nt ( helium1 ( ! gravitational field1 & ( ! size ( ! int]nal heat s\rce on ,jupit] greatly cl>ifi$ sci5ti/s' und]/&+ ( ! deep int]ior ( ! planet4 ,calculations %[$ t ! core ( ,jupit] mu/ be s hot t hydrog5 _c become solid1 b mu/ rema9 a fluid ?r\gh\t ! int]ior4 ,ev5 at great dep?s1 !re=e1 ,jupit] does n h a solid surface4 ,! !ory t ! ,great ,r$ ,spot 0 ! result ( int]actions ) a surface feature bel[ ! cl\ds ?us became unt5able4 ,:atev] its exact nature1 ! ,r$ ,spot mu/ be a /rictly atmosph]ic ph5om5on4 ,magnetic ,field4 ,pione] data %[$ t ! magnetic field ( ,jupit] has a dipol> nature1 l t ( ! ,e>?1 b #bjjj times /rong]4 ,! calculat$ surface fields measur$ ab\t #d gauss1 comp>$ to a field ( ab\t #j4e gauss on ! ,e>?4 ,! axis ( ! magnetic field 0 tilt$ #aa degrees ) respect to ! rotation axis1 & x 0 (fset by ab\t #aj #jjj kilomet]s 7#j4a ,r,j7 f ! c5t] ( ! planet4 ,illu/ration3 ,pione]s #aj & #aa did n obta9 v detail$ pictures ( ! satellites ( ,jupit]4 ,! be/ view 0 ( ,ganym$e1 :i* %[$ a surface ( contra/+ light & d>k spots ( unkn[n nature4 ,illu/ration3 ,a less detail$ image ( ,europa cle>ly reveals ! illum9at$ cresc5t b supplies little in=mation ab\t ! surface ( ?is ice-cov]$ satellite4 ,satellite ,atmosph]es4 ,two exp]im5ts yield$ excit+ new in=mation on possible atmosph]es ( ! ,galilean satellites4 ,fir/ 0 an occultation1 9 :i* ! ,pione] #aj spacecraft 0 t>get$ to pass beh9d ,io z se5 f ,e>?4 ,at ! mom5ts j be=e ! spacecraft disappe>$1 & j aft] reem]g5ce f beh9d ! satellite1 ! radio signal 0 influ5c$ by a ?9 lay] ( ioniz$ gas1 9 :i* ! electrons _h be5 /ripp$ f ! atoms by absorb$ sunlight or by o!r processes4 ,! ionosph]e ?us discov]$ _h a peak d5sity ( ab\t #fj #jjj electrons p] cubic c5timet]4 ,9 addition1 a v ext5d$ f>-ultraviolet gl[1 probably due to atomic hydrog51 0 f\nd ne> ! orbit ( ,io by ! ultraviolet photomet]4 ,masses ( ,jupit] & ,its ,satellites4 ,precise radio track+ ( ! ,pione]s z !y coa/$ pa/ ,jupit] & its satellites reveal$ t ,jupit] is ab\t "o p]c5t heavi] ?an _h be5 anticipat$1 & sev]al satellites 7 f\nd to h masses t diff] by m ?an t5 p]c5t f values det]m9$ previ\sly4 ,^! improvem5ts 9 k ( ! masses 7 requir$ to a*ieve ! close satellite flybys be+ plann$ = lat] missions4 ,illu/ration3 ,! ,pione] spacecraft c>ri$ ?is plaque on ! j\rney beyond ! sol> sy/em1 be>+ data t tell :]e & :5 ! human species liv$ & t convey details ( our biological =m4 ,:5 ,pione] #aj flew by ,jupit] x acquir$ suffici5t k9etic en]gy to c>ry x completely out ( ! sol> sy/em4 ,"s "t betwe5 "o & t5 billion ye>s f n[1 ! probe may pass ?r\gh ! planet>y sy/em ( a remote /ell> neighbor1 "o ( ^: planets may h evolv$ intellig5t life4 ,if ! spacecraft is detect$ & !n inspect$1 ,pione]'s message w rea* across ! eons to communicate its greet+4 ,! ,inn] ,magnetosph]e4 ,a great deal ( ! sci5tific emphasis ( ! ,pione] missions 0 direct$ at *>act]iz+ ! p>ticles & fields 9 ! inn] magnetosph]e1 ! region 9 :i* *>g$ p>ticles are trapp$ 9 /able orbits4 ,! ,pione]s f\nd t x ext5d$ to ab\t #be ,r,j1 well beyond ! orbit ( ,calli/o4 ,)9 ?is region1 in/rum5ts on ! spacecraft record$ ! numb]s & en]gy ( electrons1 protons1 & ions4 ,! electrons rea*$ a maximum conc5tration ne> #c ,r,j1 & _! numb]s rema9$ almo/ con/ant f !re 9 t[>d ! planet4 ,! maximum conc5tration ( protons obs]v$ by ,pione] #aj 0 at #c4d ,r,j1 a little inside ! orbit ( ,io4 ,pione] #aa p5etrat$ deep] & f\nd ano!r maximum1 ab\t tw5ty times high]1 at #a4i ,r,j2 at ?is di/ance1 #aj million en]getic protons hit ea* squ>e c5timet] ( ! spacecraft e second4 ,x 0 believ$ t ! gap betwe5 ^! two peaks 0 due to t9y ,amal!a1 ! inn]mo/ satellite1 :i* orbits at #b4e ,r,j4 ,app>5tly ?is satellite sweeps up ! p>ticles z x circles ,jupit]4 ,ano!r l>ge dip 9 ! proton di/ribution 0 attribut$ to sweep+ by ,io1 ) small] effects se5 ne> ! orbits ( ,europa & ,ganym$e4 ,!re 0 an additional small effect at #a4h ,r,j1 lat] f\nd by ,voyag] to be due to ,jupit]'s r+ & its f\rte5? satellite4 ,! ,out] ,magnetosph]e4 ,f ab\t #be ,r,j outw>d to its b\nd>y ne> #ajj ,r,j1 ! ,jovian magnetosph]e is a complex & dynamic place4 ,beyond ab\t #fj ,r,j1 bo? ,pione]s f\nd ! b\nd>y to be highly un/able1 app>5tly bl[n 9 & out by v>iations 9 ! pressure ( ! sol> w9d1 :i* consi/s ( *>g$ p>ticles fl[+ outw>d f ! ,sun4 ,9 ?is region conc5trations ( ,jovian p>ticles are sometimes se5 t rival ! inn] magnetosph]e 9 int5sity4 ,betwe5 #fj ,r,j & #be ,r,j1 a region sometimes call$ ! middle magnetosph]e1 ! p>ticle motions are m ord]$1 & = ! mo/ "p electrons & protons are c>ri$ along ) ! planet's rotation by its magnetic field4 ,ne> ! equatorial plane1 ! fl[ ( ^! p>ticles produces an electric curr5t circl+ ! planet1 & ?is curr5t 9 turn g5]ates its own magnetic field1 :i* approa*es 9 /r5g? t ( ,jupit] itself4 ,occasionally ! out] magnetosph]e collapses d[n to ab\t #fj ,r,j1 & en]getic p>ticles are squirt$ f ! middle region into space2 ^! bur/s ( ,jovian p>ticles c sometimes be detect$ z f> away z ,e>?4 ,at ! same "t t ,pione] sci5ti/s 7 analyz+ _! results & develop+ new concepts ( ! ,jupit] sy/em1 a new team ( inve/igators _h be5 select$ = ! next mission to ,jupit]4 ,f ab\t #aige on1 att5tion %ift$ f ,pione] to its successor--,voyag]4 ,illu/ration3 ,! ,voyag] spacecraft are among ! mo/ sophi/icat$1 automatic1 & indep5d5t robots ev] s5t to explore ! planets4 ,ea* craft has a mass ( "o ton & is dom9at$ by ! #c4g-met]-diamet] :ite ant5na us$ = radio communication ) ,e>?4 ,"h ,voyag] und]goes f9al te/s 9 a space simulator *amb]4 #cgc-gafb;,,ac ,,*apt] #c ,,! ,,voyag] ,,mission ,g5esis ( ,voyag] ,voyag] _h its orig9 9 ! ,out] ,planets ,gr& ,t\r1 a plan to s5d spacecraft to all ! planets ( ! out] sol> sy/em4 ,9 #aifi1 ! same ye> 9 :i* ! ,pione] ,project receiv$ ,congressional approval1 ,,nasa began to design ! ,gr& ,t\r4 ,at ! same "t1 ! ,space ,sci5ce ,bo>d ( ! ,national ,academy ( ,sci5ces complet$ a /udy call$ 8,! ,out] ,sol> ,sy/em10 *air$ by ,james ,van ,all5 ( ! ,univ]sity ( ,i[a1 :i* recomm5d$ t ! ,unit$ ,/ates und]take an exploration program3 #a4 ,to conduct exploratory inve/igations ( ! appe>ance1 size1 mass1 magnetic prop]ties1 & dynamics ( ea* ( ! out] planets & _! major satellites2 #b4 ,to det]m9e ! *emical & isotopic composition ( ! atmosph]es ( ! out] planets2 #c4 ,to det]m9e :e!r biologically important organic sub/ances exi/ 9 ^! atmosph]es & to *>act]ize ! l[] atmosph]ic environm5ts 9 t]ms ( biologically significant p>amet]s2 #d4 ,to describe ! motions ( ! atmosph]es ( ! major planets & to *>act]ize _! temp]ature-d5sity-composition /ructure2 #e4 ,to make a detail$ /udy = ea* ( ! out] planets ( ! ext]nal magnetic field & respective p>ticle population1 associat$ radio emissions1 & magnetosph]ic p>ticle-wave int]actions2 #f4 ,to det]m9e ! mode ( int]action ( ! sol> w9d ) ! out] planets1 includ+ ! int]action ( ! satellites ) ! planets' magnetosph]es2 #g4 ,to inve/igate ! prop]ties ( ! sol> w9d & ! int]planet>y magnetic field at great di/ances f ! ,sun at bo? l[ & high sol> latitudes1 & to se>* = ! out] b\nd>y ( ! sol> w9d fl[2 #h4 ,to attempt to obta9 ! composition1 en]gy spectra1 & fluxes ( cosmic rays 9 int]/ell> space1 free ( ! modulat+ effects ( ! sol> w9d4 ,! report also not$ t 8exceptionally favorable a/ronomical opportunities occur 9 ! late #aigjs = multiplanet missions10 & t 8pr(essional res\rces = full utilization ( ! out]-sol>-sy/em mission opportunities 9 ! #aigjs & #aihjs are amply available )9 ! sci5tific community1 & !re is a widespread eag]ness to p>ticipate 9 su* missions40 ,an additional ,academy /udy1 *air$ by ,francis ,s4 ,johnson ( ! ,univ]sity ( ,texas at ,dallas & publi%$ 9 #aiga1 0 ev5 m specific3 8,an ext5sive /udy ( ! out] sol> sy/em is recogniz$ by u to be "o ( ! major objectives ( space sci5ce 9 ?is decade4 ,?is endeavor is made p>ticul>ly excit+ by ! r>e opportunity to explore sev]al planets & satellites 9 "o mission us+ long-liv$ spacecraft & exi/+ propulsion sy/ems4 ,we recomm5d t ,m>9]-class spacecraft be develop$ & us$ 9 ,gr& ,t\r missions = ! exploration ( ! out] planets 9 a s]ies ( f\r laun*es 9 ! late #aigjs40 ,?us ! /age 0 set to initiate ! ,out] ,planets ,gr& ,t\rs4 ,,nasa's timetable call$ = dual laun*es to ,jupit]1 ,saturn1 & ,pluto 9 #aigf & #aigg1 & dual laun*es to ,jupit]1 ,uranus1 & ,neptune 9 #aigi1 at a total co/ ov] ! decade ( ! #aigjs ( ab\t #gej million4 ,a necess>y /ep 0 to obta9 f ! sci5tific community ! be/ possible set ( in/rum5ts to fly on ! spacecraft4 ,foll[+ its initial int]nal /udies1 ,,nasa turn$ = its detail$ sci5tific plann+ to an op5 competition 9 :i* any sci5ti/ or sci5tific organization 0 invit$ to propose an inve/igation4 ,9 ,octob] #aigj ,,nasa issu$ an 8,invitation = ,p>ticipation 9 ! ,mission ,developm5t = ,gr& ,t\r ,missions to ! ,out] ,sol> ,sy/em10 & a ye> lat] x _h select$ ab\t a doz5 teams ( sci5ti/s to =mulate specific objectives = ^! missions4 ,at ! same "t1 an advanc$ spacecraft eng9e]+ design 0 c>ri$ out by ! ,calte* ,jet ,propulsion ,laboratory 7,,jpl71 & /udies 7 also support$ by indu/rial contractors4 ,9 fiscal ye> #aigb1 plans call$ = an appropriation by ,congress ( #cj million to fund ^! developm5ts1 lead+ t[>d a fir/ laun* 9 #aigf4 ,ev5 z ! sci5tific & te*nical problems ( ! ,gr& ,t\r 7 be+ solv$1 h[ev]1 political & budget>y difficulties int]v5$4 ,! ,gr& ,t\r 0 an ambiti\s & exp5sive concept1 design$ 9 ! en?usiasm ( ! ,apollo ye>s4 ,9 ! alt]$ national climate t foll[$ ! fir/ mann$ lun> l&+s1 ! ,unit$ ,/ates began to pull back f major commitm5ts 9 space4 ,! lat] ,apollo l&+s 7 cancel$1 & 9 fiscal ye> #aigb only #aj million ( ! #cj million ne$$ to complete ,gr& ,t\r designs 0 appropriat$4 ,x sudd5ly became necess>y to re/ructure ! exploration ( ! out] planets to con=m to m mode/ space budgets4 ,illu/ration3 ,! orig9al plan = ! ,out] ,planets ,gr& ,t\r envisag$ dual laun*es to ,jupit]1 ,saturn1 & ,pluto 9 ! mid-#aigjs1 & dual laun*es to ,jupit]1 ,uranus1 & ,neptune 9 #aigi4 ,h[ev]1 political & budget>y con/ra9ts alt]$ ! plan1 & ! ,voyag] mission to ,jupit] & ,saturn1 ) an optional enc\nt] ) ,uranus1 0 =mulat$ to replace x4 ,"h ! orig9al ,gr& ,t\r trajectories f ,e>? to ! out] planets are %[n4 ,p-#ajfab;,,ac ,r$esign ( ! ,mission ,! new mission concept t replac$ ! ,gr& ,t\r dropp$ ! objectives ( explor+ ! out] ?ree planets--,uranus1 ,neptune1 & ,pluto4 ,9 ?is way ! lifetime ( ! mission 0 greatly %ort5$1 plac+ less /r+5t dem&s on ! reliability ( ! millions ( compon5ts t g into a spacecraft4 ,limit+ ! mission to ,jupit] & ,saturn also reliev$ problems associat$ ) spacecraft p[]1 & ) communicat+ effectively ov] di/ances ( m ?an #b billion kilomet]s4 ,! total co/ ( ! new mission 0 e/imat$ at #bej million1 only a ?ird ( t previ\sly plann$ = ! ,gr& ,t\r4 ,because x 0 bas$ on ! prov5 ,m>9] spacecraft design1 ! new mission 0 initially nam$ ,m>9] ,jupit] ,saturn1 or ,,mjs2 9 #aigg ! "n 0 *ang$ to ,voyag]4 ,9 ,janu>y #aigb ! ,presid5t's propos$ fiscal ye> #aigc budget includ$ #aj million specifically designat$ = ,voyag]2 aft] au?orization & appropriation by ,congress1 ! (ficial beg9n+ ( ,voyag] 0 set = ,july #a1 #aigb4 ,) approval ( ! new mission app>5tly assur$ 9 ! ,congress1 ,,nasa issu$ an 8,ann\ncem5t ( ,flight ,opportunity0 to select ! sci5tific in/rum5ts to be c>ri$ on ,voyag]4 ,sev5ty-sev5 proposals 7 receiv$2 #ca f gr\ps ( sci5ti/s ) designs = in/rum5ts1 & #df f individuals desir+ to p>ticipate 9 ,,nasa-=m$ teams4 ,( ^! #gg proposals1 #bd 7 f ,,nasa laboratories1 #dh 7 f sci5ti/s 9 v>i\s ,u4,s4 univ]sities & indu/ry1 & #e 7 f =eign s\rces4 ,aft] ext5sive review1 #bh proposals 7 accept$3 #i = in/rum5ts & #ai = individual p>ticipation4 ,! newly select$ ,pr9cipal ,inve/igators & ,team ,lead]s met = ! fir/ "t at ,,jpl j be=e ,*ri/mas1 #aigb4 ,to coord9ate all ! sci5ce activity ( ! ,voyag] mission1 ,,nasa & ,,jpl select$ ,edw>d ,/one ( ,calte*1 a di/+ui%$ exp]t on magnetosph]ic physics1 to s]ve z ,project ,sci5ti/4 ,! team assembl$ 9 #aigb by ,,jpl & its indu/rial contractors includ$ m ?an a ?\s& highly tra9$ eng9e]s1 sci5ti/s1 & te*nical manag]s :o assum$ responsibility = ! awesome task ( build+ ! mo/ sophi/icat$ unmann$ spacecraft ev] design$ & laun*+ x across ! f>!/ rea*es ( ! sol> sy/em4 ,at ! head ( ! organization 0 ! ,project ,manag]1 ,h>ris 7,bud7 ,s*urmei]4 ,lat]1 ,s*urmei] 0 succe$$ by ,john ,casani1 ,rob]t ,p>ks1 & ,ray ,heacock4 ,?is team _h only f\r ye>s to turn ! pap] concepts into h>dw>e1 ready to deliv] to ,k5n$y ,space ,c5t] = laun* 9 ! summ] ( #aigg4 ,illu/ration3 ,project ,sci5ti/ ,edw>d ,c4 ,/one ,illu/ration3 ,project ,manag] ,h>ris 7,bud7 ,s*urmei] ,! ,objectives ( ,voyag] ,voyag] is "o ( ! mo/ ambiti\s planet>y space missions ev] und]tak54 ,voyag] #a1 :i* enc\nt]$ ,jupit] on ,m>* #e1 #aigi1 0 to inve/igate ,jupit]1 its l>ge satellites ,io1 ,ganym$e1 & ,calli/o1 & t9y ,amal!a2 ,saturn1 its r+s1 & sev]al ( its satellites--includ+ ,titan1 ! l>ge/ satellite 9 ! sol> sy/em4 ,voyag] #b1 :i* arriv$ at ,jupit] on ,july #i1 #aigi1 0 to exam9e ,jupit]1 ,europa1 ,ganym$e1 ,calli/o1 & ,saturn & sev]al ( its satellites1 aft] :i* x 0 to be hurl$ on t[>d an enc\nt] ) ! ,uranian sy/em 9 #aihf4 ,bo? spacecraft 7 also design$ to /udy ! int]planet>y m$ium & its int]actions ) ! sol> w9d4 ,sci5tific objectives z well z ! orbital positions ( ! planets & satellites influ5c$ ! *oice ( spacecraft trajectories1 :i* 7 design$ to provide close flybys ( all f\r ( ,jupit]'s ,galilean satellites & six ( ,saturn's satellites--featur+ a v close approa* to ,titan--& occultations ( ! ,sun & ,e>? by ,jupit]1 ,saturn1 ,titan1 & ! r+s ( ,saturn4 ,h[ev]1 all ^! objectives c\ld n be accompli%$ by a s+le spacecraft4 ,no s+le pa? ?r\gh ! ,jupit] sy/em1 = in/ance1 c provide close flybys ( all f\r ,galilean satellites4 ,specifically1 a trajectory = ,voyag] #a t includ$ a close enc\nt] ) ,io preclud$ a close enc\nt] ) ,europa & did n all[ ! spacecraft ! option ( be+ t>get$ f ,saturn to ,uranus )\t hav+ to travel ?r\gh ! r+s ( ,saturn4 ,on ! o!r h&1 a trajectory t w\ld s5d ,voyag] #b on to ,uranus preclud$ n only a close enc\nt] ) ,io1 b also a close enc\nt] ) ,titan & ) ,saturn's r+s4 ,! alignm5t ( ! planets & _! satellites 0 su* t enc\nt] ) ,jupit] on or be=e ,april #d1 #aigi 0 necess>y = optimum inve/igation ( ,io1 b enc\nt] ) ,jupit] aft] ,june #ae1 #aigi 0 m&atory = a trajectory t w\ld ma9ta9 ! option to g on to ,uranus4 ,! latt] trajectory also all[$ ,voyag] #b to ma9ta9 a heal?i] di/ance f ,jupit]1 avoid+ ! full dose ( radiation t w\ld be exp]i5c$ by ,voyag] #a4 ,al?\gh ! two ,voyag] trajectories d h c]ta9 fundam5tal diff]5ces1 !y also h a great deal 9 common3 ,bo? spacecraft 7 design$ to /udy ! int]planet>y m$ium1 & bo? w\ld inve/igate ,jupit] & ,saturn & h close flybys ) sev]al ( _! major satellites4 ,also1 if x 7 decid$ n to s5d ,voyag] #b on to ,uranus1 ?is spacecraft c\ld be ret>get$ to a ,saturn trajectory simil> to t ( ,voyag] #a1 provid+ a close flyby ( ,titan & a clos] look at ! r+s4 ,! flight pa?s ( ,voyag] #a & ,voyag] #b complem5t ea* o!r--all[+ ! planets & "s ( ! satellites to be view$ f a numb] ( angles & ov] a long] p]iod ( "t ?an w\ld be possible ) only "o spaceprobe--yet ! trajectories 7 also design$ to be m or less capable ( duplicat+ ea* o!r's sci5tific inve/igations4 ,?is r$undancy helps to ensure1 s f> z is possible1 ! success ( ! mission4 ,! r$undancy built into ! mission is evid5t1 n only 9 ! design ( ! trajectories1 b 9 ! spacecraft !mselves4 ,voyag]s #a & #b are id5tical spacecraft4 ,9 addition1 _m crucial elem5ts are duplicat$ on ea*3 ,= example1 ! comput] comm& subsy/em 7,,ccs71 ! flight data subsy/em 7,,fds71 & ! attitude & articulation control subsy/em 7,,aacs7--:i* function z onbo>d control sy/ems--ea* h multiple reprogrammable digital comput]s4 ,9 addition1 ! ,,ccs1 :i* decodes comm&s f gr\nd control & c in/ruct o!r subsy/ems f its own memory1 conta9s duplicates = all its functional units4 ,! ,,aacs1 :i* controls ! spacecraft's /abilization & ori5tation1 has duplicate /> track]s & ,sun s5sors4 ,! communications sy/em conta9s two radio receiv]s & f\r transmitt]s1 two ea* to transmit bo? ,s-b& 7frequ5cy ( ab\t #bbie megah]tz7 & ,x-b& 7frequ5cy ( ab\t #hdah megah]tz74 ,illu/ration3 ,project ,manag] ,john ,casani ,! ,spacecraft ,! ,voyag] spacecraft are m sophi/icat$1 m automatic1 & m indep5d5t ?an 7 ! ,pione]s4 ,?is indep5d5ce is important because ! giant planets are s f> away t ! correction ( a malfunction by eng9e]s on ,e>? w\ld take h\rs to p]=m4 ,ev5 at 8ne>by0 ,jupit]1 radio signals take ab\t =ty m9utes to travel 9 "o direction betwe5 ! spacecraft & ,e>?4 ,saturn is ab\t twice z f> away z ,jupit]1 & ,uranus is twice z f> z ,saturn1 sl[+ communication ev5 m4 ,illu/ration3 ,ab\t ! same size & weight ( a subcompact c>1 ! ,voyag] spacecraft c>ry in/rum5ts = elev5 sci5ce inve/igations ( ! out] planets & _! satellites4 ,p[] to op]ate ! spacecraft is provid$ by ?ree radioisotope !rmoelectric g5]ators m\nt$ on "o boom2 o!r booms hold ! sci5ce scan plat=m & ! dual magnetomet]s4 ,high-ga9 directional ant5na ,magnetomet] ,ext5dable boom ,planet>y radio a/ronomy & plasma wave ant5na ,radioisotope !rmoelectric g5]ators ,plasma detector ,cosmic ray detector ,wide angle ,,tv ,n>r[ angle ,,tv ,,tv electronics ,ultraviolet spectromet] ,photopol>imet] ,infr>$ int]f]omet] spectromet] & radiomet] ,l[ en]gy *>g$ p>ticles ,?ru/]s ,electronic comp>tm5ts ,sci5ce in/rum5t calibration panel & %unt radiator ,propulsion fuel tank ,planet>y radio a/ronomy & plasma wave ant5na ,p]*$ atop ! ,c5taur /age ( ! laun* rocket1 ea* ,voyag] spacecraft has a mass ( #b tons 7#bjff kilograms71 divid$ ab\t equally betwe5 ! spacecraft prop] & ! propulsion module us$ = f9al accel]ation to ,jupit]4 ,! ,voyag] itself1 ) a mass ( #hae kilograms & typical dim5sions ( ab\t #c met]s1 is almo/ ! size & weight ( a subcompact c>--b enorm\sly m complex4 ,a bett] analogy might be made ) a l>ge electronic comput]--b no t]re/rial comput] 0 ev] ask$ to supply its own p[] s\rce & to op]ate unatt5d$ 9 ! vacuum ( space = up to a decade4 ,ea* ,voyag] spacecraft c>ries in/rum5ts = elev5 sci5ce inve/igations cov]+ visual1 infr>$1 & ultraviolet regions ( ! spectrum1 & o!r remote s5s+ /udies ( ! planets & satellites2 /udies ( radio emissions1 magnetic fields1 cosmic rays1 & l[] en]gy p>ticles2 plasma 7ioniz$ gases7 waves & p>ticles2 & /udies us+ ! spacecraft radios4 ,ea* ,voyag] has a sci5ce boom t holds high & l[ resolution ,,tv1 photopol>imet]1 plasma & cosmic ray detectors1 infr>$ spectromet] & radiomet]1 ultraviolet spectromet]1 & l[ en]gy *>g$ p>ticle detector2 9 addition1 ea* spacecraft has a planet>y radio a/ronomy & plasma wave ant5na & a long boom c>ry+ a l[- & a high-field magnetomet]4 ,communication ) ,e>? is c>ri$ out via a high-ga9 ant5na #c4g met]s 9 diamet]1 ) a small] l[-ga9 ant5na z backup4 ,! l>ge :ite di% ( ! high-ga9 ant5na dom9ates ! appe>ance ( ! spacecraft1 sett+ x (f f its pr$ecessors1 :i* 7 able to use mu* small] ant5nas to communicate ov] ! m mode/ di/ances t sep>ate ! planets ( ! inn] sol> sy/em4 ,al?\gh ! transmitt] p[] is only #bc watts--ab\t ! p[] ( a refrig]ator light bulb--?is sy/em is design$ to transmit data ov] a billion kilomet]s at ! enorm\s rate ( #aae #bjj bits p] second4 ,data c also be /or$ = lat] transmission to ,e>?2 an onbo>d digital tape record] has a capacity ( ab\t #ejj million 7#e #aj7 bits1 suffici5t to /ore ne>ly #ajj ,voyag] images4 ,illu/ration3 ,project ,manag] ,ray ,heacock ,illu/ration3 ,dur+ ! e>ly assembly /age1 te*nicians at ,calte*'s ,jet ,propulsion ,laboratory equip ,voyag]'s ext5dable boom ) l[- & high-field magnetomet]s t measure ! int5sity & direction ( ! out] planets' magnetic fields4 #cgc-gagi;,,bc ,radioisotope !rmoelectric g5]ator 7,r,t,gs71 r ?an sol> cells1 provide electricity = ! ,voyag] spacecraft4 ,! ,,rtg use radioactive plutonium oxide = ?is purpose4 ,z ! plutonium oxide decays1 x gives (f heat :i* is conv]t$ to electricity1 supply+ a total ( ab\t #dej watts to ! spacecraft at laun*4 ,?is p[] sl[ly decl9es z ! plutonium is us$ up1 ) less ?an #djj watts expect$ at ,saturn flyby five ye>s aft] laun*4 ,hydraz9e fuel is us$ to make mid-c\rse corrections 9 trajectory & to control ! spacecraft's ori5tation4 ,s9ce ! ,voyag]s mu/ fly ?r\gh ! inn] magnetosph]e ( ,jupit]1 x 0 imp]ative t ! h>dw>e sy/ems be able to )/& ! radiation f ,jovian *>g$ p>ticles4 ,! electronic microcircuits t =m ! he>t & bra9 ( ! spacecraft & its sci5tific in/rum5ts are especially susceptible to radiation damage4 ,?ree te*niques 7 us$ to 8h>d50 compon5ts aga9/ radiation3 #a4 ,special design us+ radiation-resi/ant mat]ials2 #b4 ,ext5sive te/+ to select ^? electronic compon5ts :i* come out ( ! manufactur+ process ) highe/ reliability2 & #c4 ,spot %ield+ ( especially s5sitive areas ) radiation-absorb+ mat]ials4 ,,voyag]',s ,,greet+s ,,to ,,! ,,univ]se ,! ,voyag] spacecraft w be ! ?ird & f\r? human artifacts to escape entirely f ! sol> sy/em4 ,pione]s #aj & #aa1 :i* prec$$ ,voyag] 9 out/ripp+ ! gravitational attraction ( ! ,sun1 bo? c>ri$ small metal plaques id5tify+ _! "t & place ( orig9 = ! b5efit ( any o!r spacef>]s t might f9d !m 9 ! di/ant future4 ,) ?is example be=e !m1 ,,nasa plac$ a m ambiti\s message abo>d ,voyag] #a & #b--;a k9d ( "t capsule1 int5d$ to communicate a /ory ( our _w to extrat]re/rials4 ,! ,voyag] message is c>ri$ by a phonograph record--a #ab-;in* gold-plat$ copp] disk conta9+ s\nds & images select$ to portray ! div]sity ( life & culture on ,e>?4 ,! cont5ts ( ! record 7 select$ = ,,nasa by a committee *air$ by ,c>l ,sagan ( ,cornell ,univ]sity4 ,dr4 ,sagan & 8 associates assembl$ #aae images & a v>iety ( natural s\nds1 su* z ^? made by surf1 w9d & ?und]1 birds1 :ales1 & o!r animals4 ,to ?is !y add$ musical selections f diff]5t cultures & eras1 & spok5 greet+s f ,e>?people 9 sixty languages1 & pr9t$ messages f ,presid5t ,c>t] & ,u4,n4 ,secret>y ,g5]al ,waldheim4 ,ea* record is encas$ 9 a protective alum9um jacket1 toge!r ) a c>tridge & ne$le4 ,in/ructions1 9 symbolic language1 expla9 ! orig9 ( ! spacecraft & indicate h[ ! record is to be play$4 ,! #aae images are encod$ 9 analog =m4 ,! rema9d] ( ! record is 9 audio1 design$ to be play$ at #af revolutions p] second4 ,x conta9s ! spok5 greet+s1 beg9n+ ) ,akkadian1 :i* 0 spok5 9 ,sum] ab\t six ?\s& ye>s ago1 & end+ ) ,wu1 a mod]n ,*9ese dialect4 ,foll[+ ! section on ! s\nds ( ,e>?1 !re is an eclectic #ij-m9ute selection ( music1 includ+ bo? ,ea/]n & ,we/]n classics & a v>iety ( e?nic music4 ,once ! ,voyag] spacecraft leave ! sol> sy/em 7by #aiij1 bo? w be beyond ! orbit ( ,pluto71 !y w f9d !mselves 9 empty space4 ,x w be =ty ?\s& ye>s be=e !y come )9 a light ye> ( a />1 call$ ,,ac #gi #chhh1 & millions ( ye>s be=e ei!r might make a close approa* to any o!r planet>y sy/em4 ,z ,c>l ,sagan has not$1 8,! spacecraft w be enc\nt]$ & ! record play$ only if !re are advanc$ spacef>+ civilizations 9 int]/ell> space4 ,b ! laun*+ ( ?is bottle into ! cosmic ocean says some?+ v hopeful ab\t life on ?is planet40 ,,languages ,,on ,,voyag] ,,record ,sum]ian ,akkadian ,hittite ,hebrew ,aramaic ,engli% ,portuguese ,cantonese ,russian ,?ai ,arabic ,r\manian ,fr5* ,burmese ,spani% ,indonesian ,ke*ua ,dut* ,g]man ,b5gali ,urdu ,h9di ,vietnamese ,s9halese ,greek ,lat9 ,japanese ,punjabi ,turki% ,wel% ,italian ,nguni ,so?o ,wu ,korean ,arm5ian ,poli% ,netali ,m&>9 ,gujorati ,ila 7,zambia7 ,nyanja ,sw$i% ,ukra9ian ,p]sian ,s]bian ,luganada ,amoy 7,m9 dialect7 ,m>a?i ,kannada ,telugu ,oriya ,hung>ian ,cze* ,raja/hani ,,s\nds ,,( ,,e>? ,,on ,,voyag] ,,record ,:ales ,planets 7music7 ,volcanoes ,mud pots ,ra9 ,surf ,crickets1 frogs ,birds ,hy5a ,elephant ,*impanzee ,wild dog ,foot/eps & he>tbeats ,laught] ,fire ,tools ,dogs1 dome/ic ,h]d+ %eep ,blacksmi? %op ,saw+ ,rivet] ,morse code ,%ips ,horse & c>t ,horse & c>riage ,tra9 :i/le ,tractor ,truck ,auto ge>s ,jet ,lift-(f ,saturn #e rocket ,kiss ,baby ,life signs--,,eeg1 ,,ekg ,puls>t ,,voyag] ,,record ,,photograph ,,index ,calibration circle ,sol> location map ,ma!matical def9itions ,physical unit def9itions ,sol> sy/em p>amet]s ,! ,sun ,sol> spectrum ,m]cury ,m>s ,jupit] ,e>? ,egypt1 ,r$ ,sea1 ,s9ai ,p59sula & ! ,nile ,*emical def9itions ,,dna /ructure ,,dna /ructure magnifi$ ,cells & cell division ,anatomy 7eight7 ,human sex organs ,diagram ( conception ,conception ,f]tiliz$ ovum ,fetus diagram ,fetus ,diagram ( male & female ,bir? ,nurs+ "m ,fa!r & daught] 7,malaysia7 ,gr\p ( *ildr5 ,diagram ( family ages ,family portrait ,diagram ( cont95tal drift ,/ructure ( ,e>? ,h]on ,isl& 7,great ,b>ri] ,reef ( ,au/ralia7 ,sea%ore ,snake ,riv] & ,gr& ,tetons ,s& dunes ,monum5t ,valley ,=e/ sc5e ) mu%rooms ,leaf ,fall5 leaves ,sequoia ,sn[flake ,tree ) daffodils ,fly+ insect ) fl[]s ,diagram ( v]tebrate evolution ,sea%ell 7,xancidae7 ,dolph9s ,s*ool ( fi% ,tree toad ,crocodile ,eagle ,wat]hold ,jane ,goodall & *imps ,sket* ( ,bu%m5 ,bu%m5 hunt]s ,man f ,guatemala ,danc] f ,bali ,&ean girls ,?ail& craftsman ,elephant ,old man ) be>d & glasses 7,turkey7 ,old man ) dog & fl[]s ,m\nta9 climb] ,ca?y ,rigby ,spr9t]s ,s*oolroom ,*ildr5 ) globe ,cotton h>ve/ ,grape pick] ,sup]m>ket ,und]wat] sc5e ) div] & fi% ,fi%+ boat ) nets ,cook+ fi% ,*9ese d9n] p>ty ,demon/ration ( lick+1 eat+ & dr9k+ ,great ,wall ( ,*9a ,h\se con/ruction 7,african7 ,con/ruction sc5e 7,ami% c\ntry7 ,h\se 7,africa7 ,h\se 7,new ,engl&7 ,mod]n h\se 7,cl\dcr(t1 ,new ,mexico7 ,h\se int]ior ) arti/ & fire ,taj ,mahal ,engli% city 7,ox=d7 ,bo/on ,,un ,build+1 day ,,un ,build+1 night ,sydney ,op]a ,h\se ,artisan ) drill ,factory int]ior ,museum ,x-ray ( h& ,woman ) microscope ,/reet sc5e1 ,asia 7,paki/an7 ,ru% h\r traffic1 ,india ,mod]n highway 7,i?aca7 ,gold5 ,gate ,bridge ,tra9 ,airplane 9 flight ,airport 7,toronto7 ,ant>ctic exp$ition ,radio telescope 7,we/]bork1 ,ne!rl&s7 ,radio telescope 7,arecibo7 ,page ( book 7,newton1 ,sy/em ( ! ,_w7 ,a/ronaut 9 space ,titan ,c5taur laun* ,sunset ) birds ,/r+ qu>tet 7,qu>tetto ,italiano7 ,viol9 ) music score 7,cavat9a7 ,,music ,,on ,,voyag] ,,record ,ba* ,br&5b]g ,conc]to ,numb] ,two1 ,fir/ ,movem5t 8,k9ds ( ,fl[]s0 ,javanese ,c\rt ,gamelan ,s5egalese ,p]cussion ,pygmy girls initiation song ,au/ralian ,horn & ,totem song 8,el ,cascabel0 ,lor5zo ,b>celata 8,johnny ,b4 ,goode0 ,*uck ,b]ry ,new ,gu9ea ,m5's ,h\se 8,depict+ ! ,cranes 9 ,_! ,ne/0 ,ba* ,p>tita ,numb] ,?ree = ,viol92 ,gavotte et ,rondeaus ,moz>t ,magic ,flute1 ,que5 ( ! ,night 7,aria ,numb] #ad7 ,*akrulo ,p]uvian ,pan ,pipes ,melan*oly ,blues ,az]baijan ,two ,flutes ,/rav9sky1 ,rite ( ,spr+1 ,conclusion ,ba* ,prelude & ,fugue ,numb] ,"o 9 ,c ,major f ! ,well ,temp]$ ,clavi]1 ,book ,two ,bee?ov5's ,fif? ,symphony1 ,fir/ ,movem5t ,bulg>ian ,%eph]dess ,song 8,izlel ,delyo ,hajdut90 ,navajo ,indian ,night ,*ant ,! ,fairie ,r\nd f ,pavans1 ,galli>ds1 ,alma9s ,melanesian ,pan ,pipes ,p]uvian ,woman's ,w$d+ ,song 8,fl[+ ,/reams0--,*9ese ,*'9 music 8,jaat ,kahan ,ho0--,indian ,raga 8,d>k ,0 ! ,night0 ,bee?ov5 ,/r+ ,qu>tet ,numb] #ac 8,cavat9a0 ,illu/ration3 ,ea* ,voyag] c>ries a message 9 ! =m ( a #ab-;in* gold-plat$ phonograph record4 ,! record1 toge!r ) a c>tridge & ne$le1 is fa/5$ to ! side ( ! spacecraft 9 a gold-anodiz$ alum9um case t also illu/rates h[ ! record is to be play$4 ,p-#aigbh ,,! ,,bra9s ,,( ,,! ,,voyag] ,,spacecraft#a ,! ,voyag] spacecraft _h great] indep5d5ce f ,e>?-bas$ controll]s & great] v]satility 9 c>ry+ out complex sequ5ces ( sci5tific measurem5ts ?an any ( _! pr$ecessors4 ,^! capabilities result$ f ?ree int]connect$ onbo>d comput] sy/ems3 ! ,,aacs 7attitude & articulation control subsy/em72 ! ,,fds 7flight data subsy/em72 & ! ,,ccs 7comput] comm& sy/em74 ,op]at+ f 8loads0 ( in/ructions transmitt$ e>li] f ,e>?1 ^! comput]s c\ld issue comm&s to ! spacecraft & ! sci5ce in/rum5ts & react automatically to problems or *anges 9 op]at+ conditions4 ,! complex sequ5ce ( sci5tific obs]vations & ! associat$ eng9e]+ functions 7 execut$ by ! spacecraft "u ! control ( an updatable program /or$ 9 ! ,,ccs by gr\nd comm&4 ,at appropriate times1 ! ,,ccs issu$ comm&s to ! ,,aacs = movem5t ( ! scan plat=m or spacecraft maneuv]s2 to ! ,,fds = *anges 9 in/rum5t configuration or telemetry rate2 or to num]\s o!r subsy/ems )9 ! spacecraft = specific actions4 ,! two id5tical 7r$undant7 #djif-^w memories )9 ! ,,ccs conta9$ bo? fix$ r\t9es 7ab\t #bhjj words7 & a v>iable section 7ab\t #abij words7 = *ang+ sci5ce sequ5c+ functions4 ,a s+le #abij-^w sci5ce sequ5ce load c\ld easily g5]ate #cjj #jjj discrete comm&s1 ?us provid+ significantly m sequ5c+ capability ?an w\ld be possible ?r\gh gr\nd comm&s4 ,a #abij-^w sequ5c+ load 9 ! ,,ccs controll$ bo? ! sci5ce & eng9e]+ functions ( ! spacecraft = a p]iod la/+ = day at close/ approa* & = up to #ajj days dur+ cruise4 ,ea* #abij-^w program 7or load7 0 built f specific sci5ce measurem5t units call$ l9ks4 ,"s l9ks 7 us$ repeat$ly 9 a loop+ cyclic 7l a comput] ,,d loop7 to p]=m ! same obs]vation num]\s times2 o!r l9ks t involv$ special measurem5t geometry or critical tim+ occurr$ only once4 ,ab\t #age sci5ce l9ks 7 def9$ = ! ,voyag] #a ,jupit] enc\nt]4 ,x took almo/ two ye>s to conv]t ! desir$ sci5ce objectives & measurem5ts fir/ into l9ks1 !n into a m9ute-by-m9ute timel9e = ! #ih-;day enc\nt] p]iod1 & f9ally into ! specific comput] in/ructions t c\ld be load$ into ! ,,ccs memory = t portion ( ! enc\nt] "t repres5t$ by a p>ticul> load4 ,! total ,voyag] #a ,jupit] enc\nt] p]iod us$ eighte5 sequ5ce memory loads1 supplem5t$ by ab\t #ajjj gr\nd comm&s to modify ! sequ5ces because ( *ang+ conditions or calibration requirem5ts4 ,= ! ,voyag] #b enc\nt]1 conc]n ab\t ! ail+ spacecraft receiv] limit$ ! numb] ( loads t c\ld be transmitt$1 p>ticul>ly :ile ! spacecraft 0 deep )9 ! ,jovian magnetosph]e1 :]e radiation effects caus$ ! receiv] frequ5cy to drift unpr$ictably4 ,h[ev]1 a c>eful r$esign ( ! plann$ sequ5ces p]mitt$ ! accompli%m5t ( v ne>ly ! orig9al set ( obs]vations ev5 ) ^! con/ra9ts4 ,all ?ree approa*es 7 requir$ on ! ,voyag] craft1 especially aft] ,pione] #aj & #aa demon/rat$ t ! radiation at ,jupit] 0 ev5 m int5se ?an _h be5 assum$ 9 e>ly design /udies4 ,! /eady /reams ( eng9e]+ & sci5tific data receiv$ on ,e>? are transmitt$ f ! receiv+ /ations ( ! ,deep ,space ,network 7,,dsn7 to ,,jpl1 :]e ! ,voyag] control functions are c5t]$4 ,!re1 doz5s ( te*nicians *eck & re*eck e subsy/em to se>* = ! slighte/ h9t ( malfunction4 ,9 case ( problems1 !re are ?ick notebooks ( in/ructions & racks ( precod$ comput] tapes ready to be us$ to correct any app>5t malfunction4 ,normally ,voyag] runs itself4 ,detail$ in/ructions are programm$ into its onbo>d comput]s & comm& sy/ems = deal+ ) su* pot5tial em]g5cies z a /uck valve 9 ! fuel sy/em1 loss ( ori5tation 9 ! /> track]s1 erratic gyroscope functions1 failure ( radio communications1 or a ?\s& & "o o!r nightm>es4 ,! in/ructions = op]at+ ! sci5tific in/rum5ts are also /or$ on bo>d1 ) new blocks ( comm&s s5t up once e few days to replace ^? = tasks already complet$4 ,:e!r 9 ! calm ( cruise mode or ! int5se excitem5t ( a planet>y enc\nt]1 ! ,voyag] craft is alone 9 space1 cont9u\sly s5s+ & react+ to its environm5t1 ti$ by only a t5u\s ?read ( radio communication to ! anxi\s wat*]s back on ,e>?4 ,illu/ration3 ,project ,manag] ,rob]t ,p>ks ,,nasa ,,planet>y ,,missions ,spacecraft ,laun* ,de/9ation ,enc\nt] ,type ( ,date ,date ,enc\nt] ,m>9] #b #h_/bf_/fb ,v5us #ab_/ad_/fb flyby ,m>9] #d #aa_/bh_/fd ,m>s #g_/ad_/fe flyby ,m>9] #e #f_/ad_/fg ,v5us #aj_/ai_/fg flyby ,m>9] #f #b_/be_/fi ,m>s #g_/ca_/fi flyby ,m>9] #g #c_/bg_/fi ,m>s #h_/je_/fi flyby ,m>9] #i #e_/cj_/ga ,m>s #aa_/ac_/ga orbit] ,pione] #aj #c_/jc_/gb ,jupit] #ab_/jd_/gc flyby ,pione] #aa #d_/jf_/gc ,jupit] #ab_/jc_/gd flyby ,saturn #i_/ja_/gi flyby ,m>9] #aj #aa_/jc_/gc ,v5us #b_/je_/gd flyby ,m]cury #c_/bi_/gd flyby ,vik+ #a #h_/bj_/ge ,m>s #f_/ai_/gf orbit] #g_/bj_/gf l&] ,vik+ #b #i_/ji_/ge ,m>s #g_/jg_/gf orbit] #i_/jc_/gf l&] ,voyag] #a #h_/bj_/gg ,jupit] #c_/je_/gi flyby ,voyag] #b #i_/je_/gg ,jupit] #g_/ji_/gi flyby ,pione] ,v5us #e_/bj_/gh ,v5us #ab_/jd_/gh orbit] #h_/h_/gh ,v5us #ab_/ji_/gh probe ,illu/ration3 ,! ,voyag] scan plat=m conta9s sophi/icat$ in/rum5ts t ga!r data = ,voyag]'s remote s5s+ inve/igations4 ,five ( ! remote-s5s+ in/rum5ts--two ,,tv cam]as1 ! infr>$ spectromet]1 ! ultraviolet spectromet]1 & ! photopol>imet]--are m\nt$ toge!r on ! scan plat=m1 :i* c be po9t$ to almo/ any direction 9 space1 all[+ exact t>get+ ( ! obs]vations4 #cgc-gadf;,,bc ,,*apt] #d ,,sci5ce ,,& ,,sci5ti/s ,introduction ,!re are _m reasons = s5d+ spacecraft to ! planets1 b 9 ! f9al analysis1 we s5d our robot mess5g]s across ! va/ness ( space = ! sake ( sci5tific exploration4 ,sci5ce & exploration h always gone h& 9 h&1 :e!r 9 ! transcont95tal j\rney ( ,lewis & ,cl>k or ! ,pacific voyages ( ,capta9 ,james ,cook4 ,9 ?is c5tury1 z exploration has become m & m dep5d5t on advances 9 te*nology1 ! sci5tific elem5t has atta9$ increas$ prom95ce4 ,! greate/ legacy ( ! ,,nasa ,planet>y ,program is ! k x has provid$ ( ! o!r worlds t %>e our corn] ( ! univ]se4 ,despite ! c5tral role ( sci5ce 9 motivat+ missions to ! planets1 specific sci5tific consid]ations are n dom9ant dur+ mo/ ( ! developm5t ( a mission su* z ,voyag]4 ,! problem ( build+ a spacecraft & gett+ x to ! out] sol> sy/em is too dem&+4 ,( ! ton ( mass 9 a ,voyag] spacecraft1 ! sci5tific in/rum5ts make up only #aae kilograms 7ab\t elev5 p]c5t74 ,simil>ly1 ! co/ ( ^! in/rum5ts am\nts to only ab\t #aj p]c5t ( ! co/ ( ! spacecraft & laun* vehicle4 ,unless ! laun* & op]ation ( ! spacecraft are ne>ly p]fect1 !re c be no sci5tific return 9 any case2 ev5 ! mo/ sophi/icat$ package ( sci5tific in/rum5ts w n tell mu* ab\t ,jupit] if1 foll[+ laun*1 x re/s at ! bottom ( ! ,atlantic ,ocean4 ,b x is equally true t ! ultimate purpose ( ! mission is sci5tific discov]y1 & ,,nasa makes e ef=t to ensure t ! v be/ in/rum5ts are fl[n & t a broad sci5tific community is giv5 ! opportunity to p>ticipate 9 ea* mission4 ,a decade be=e ! #aigg laun*1 _m a/ronom]s & space sci5ti/s began _! involvem5t ) ! ,voyag] mission ?r\gh p>ticipation 9 /udy gr\ps conv5$ by ,,nasa & by ! ,national ,academy ( ,sci5ces4 ,!y came prim>ily f univ]sities1 b also 9 significant numb]s f ,,nasa laboratories1 f indu/ry1 & f abroad4 ,9 #aiga ! ,out] ,planets ,gr& ,t\rs mission def9ition gr\p c>ri$ out a "o-ye> f9al /udy ( ! mission t 0 to become ,voyag]4 ,a competition 0 held 9 #aigb to select ! ,voyag] flight in/rum5ts & sci5ce teams1 & a ?ird review /age foll[$ a ye> lat] to confirm ?is selection4 ,out ( ?is process em]g$ elev5 sci5ce inve/igations1 ) :i* m ?an "o hundr$ sci5ti/s 7 associat$4 ,9 ?is *apt] we look at ! in/rum5ts & ! p]sons :o design$ !m = ?is *all5g+ task4 ,direct & ,remote ,measurem5ts ,! div]se measurem5ts made by ,voyag] ( a planet & its environm5t c be divid$ into two broad categories1 usually call$ direct or 9 situ measurem5ts & remote s5s+ measurem5ts4 ,a direct measurem5t involves ! analysis ( ! imm$iate environm5t ( ! spacecraft2 remote measurem5ts c be made by analyz+ radiation f di/ant objects4 ,! direct measurem5t in/rum5ts on ,voyag] measure cosmic ray p>ticles1 l[ en]gy *>g$ p>ticles1 magnetic fields1 plasma p>ticles1 & plasma waves4 ,_! activity began imm$iately aft] laun*1 monitor+ ! ,e>? environm5t & !n int]planet>y space until ! magnetosph]e ( ,jupit] 0 rea*$ a few days be=e ! actual flyby4 ,long aft] ! flybys ( ,jupit] & ,saturn are complet$1 p>ticles & fields data c cont9ue to be acquir$ by ! ,voyag]s z !y spe$ outw>d into previ\sly unexplor$ regions ( space4 ,! remote s5s+ inve/igations are ess5tially a/ronomical 9 nature1 measur+ ! light reflect$ f or emitt$ by ! planet & its satellites4 ,on ,voyag]1 h[ev]1 ^! in/rum5ts f> out/rip _! t]re/rial c\nt]p>ts 9 capability4 ,prim>ily1 !y d]ive _! advantage f _! proximity to :at !y obs]ve--at its close/1 ,voyag] 0 m ?an a ?\s& times ne>] to ,jupit] ?an are ,e>?-bas$ telescopes2 & = ! /ill clos] satellite enc\nt]s1 ,voyag] 0 ne>ly t5 ?\s& times ne>] ?an a/ronom]s on ,e>?4 ,9 addition1 ,voyag] provid$ p]spectives1 su* z views ( ! night side ( ,jupit]1 t are impossible f ,e>?4 ,f9ally1 ^! in/rum5ts c\ld exploit ! full spectrum ( electromagnetic radiation )\t conc]n = ! opacity ( ! t]re/rial atmosph]e1 :i* re/ricts gr\nd-bas$ a/ronom]s to c]ta9 spectral w9d[s & blocks all obs]vation at o!r wavel5g?s4 ,five ( ! remote s5s+ in/rum5ts--! two ,,tv cam]as1 ! infr>$ spectromet]1 ! ultraviolet spectromet]1 & ! photopol>imet]--are m\nt$ toge!r on a scan plat=m4 ,?is plat=m c be po9t$ to almo/ any direction 9 space1 all[+ exact t>get+ ( ! obs]vations4 ,"o remote s5s+ in/rum5t1 ! planet>y radio a/ronomy receiv]1 is n on ! scan plat=m4 ,x measures long-wave radio emission )\t requir+ special po9t+4 ,illu/ration3 ,! fully deploy$ ,voyag] spacecraft is capable ( a wide v>iety ( direct & remote s5s+ measurem5ts4 ,! in/rum5ts & _! objectives 7 select$ _m ye>s be=e ! fir/ ,jupit] enc\nt]4 ,because ( ! exploratory nature ( ! ,voyag] mission1 e ef=t 0 made to fly v]satile in/rum5ts t c\ld yield valuable results no matt] :at ! nature ( ! ,jovian sy/em4 ,p-#ahhaa;,,ac ,n>r[ angle ,,tv ,wide angle ,,tv ,/e]able plat=m ,sci5ce in/rum5t boom ,plasma detector ,cosmic ray detector ,high-ga9 ant5na ,l[-ga9 ant5na ,ext5dable magnetomet] boom ,photopol>imet] ,l[ en]gy *>g$ p>ticles detector ,infr>$ int]f]omet] spectromet] & radiomet] ,ultraviolet spectromet] ,?ru/]s ,/> track]s ,radioisotope !rmoelectric g5]ators ,sci5ce in/rum5t calibration panel & %unt radiator ,?ru/]s ,planet>y radio a/ronomy & plasma wave ant5na ,illu/ration3 ,! sci5ce in/rum5t boom supports ! plasma p>ticle detector1 ! cosmic ray detector1 & ! l[ en]gy *>g$ p>ticle detector4 ,^! in/rum5ts began collect+ data imm$iately aft] laun*1 monitor+ ! ,e>? environm5t & !n int]planet>y space until ! magnetosph]e ( ,jupit] 0 rea*$ a few days be=e ! actual flyby4 #cec-biib;,,bc ,a f9al ,voyag] inve/igation did n fit into ?is patt]n ( direct v]sus remote s5s+ in/rum5ts4 ,9 fact1 x requir$ no special in/rum5t at all4 ,?is inve/igation deals ) radio sci5ce1 & x utilizes ! regul> communications l9k betwe5 ! spacecraft & ,e>? to d]ive ! masses ( ,jupit] & its satellites1 to probe ! atmosph]e ( ,jupit]1 & to /udy prop]ties ( ! int]planet>y m$ium4 ,illu/ration3 ,! ,voyag] ,imag+ ,sci5ce ,team ,imag+ ,! eyes ( ,voyag] are 9 its imag+ sy/em4 ,two television cam]as1 ea* ) a set ( color filt]s1 look at ! planets & _! satellites & transmit ?\s&s ( detail$ pictures to ,e>?4 ,! imag+ sy/em is probably ! mo/ v]satile & !re=e ! mo/ truly exploratory ( ! ,voyag] in/rum5ts4 ,no matt] :at is out !re1 ! imag+ sy/em w let u see x & h5ce1 we hope1 beg9 to und]/& its nature4 ,,voyag] ,,sci5ce ,,inve/igations ,project ,sci5ti/3 ,e4 ,c4 ,/one1 ,calte* ,inve/igation ,pr9cipal ,inve/igator ,prim>y ,objectives at or ,team ,lead] ,jupit] ,imag+ sci5ce ,b4 ,a4 ,smi?1 ,u4 ,arizona ,high resolution reconnaissance ov] l>ge phase angles2 measurem5t ( atmosph]ic dynamics2 det]m9ation ( geologic /ructure ( satellites2 se>* = r+s & new satellites4 ,infr>$ radiation ,r4 ,a4 ,hanel1 ,,nasa ,det]m9ation ( 7,,iris7 ,godd>d atmosph]ic composition1 !rmal /ructure1 & dynamics2 satellite surface composition & !rmal prop]ties4 ,ultraviolet ,a4 ,l4 ,broadfoot1 ,kitt ,measurem5t ( upp] spectroscopy ,peak ,obs]vatory atmosph]ic composition & /ructure2 auroral processes2 di/ribution ( ions & neutral atoms 9 ! ,jovian sy/em4 ,photopol>imetry ,c4 ,f4 ,lillie_/,c4 ,w4 ,measurem5t ( atmosph]ic ,hord1 ,u4 ,colorado a]osols2 satellite surface texture & sodium cl\d4 ,planet>y radio ,j4 ,w4 ,w>wick1 ,u4 ,det]m9ation ( a/ronomy ,colorado pol>ization & spectra ( radio frequ5cy emissions2 ,io radio modulation process2 plasma d5sities4 ,magnetic fields ,n4 ,f4 ,ness1 ,,nasa ,godd>d ,measurem5t ( plasma electron d5sities2 wave-p>ticle int]actions2 l[-frequ5cy wave emissions4 ,plasma p>ticles ,h4 ,s4 ,bridge1 ,,mit ,measurem5t ( magnetosph]ic ion & electron di/ribution2 sol> w9d int]action ) ,jupit]2 ions f satellites4 ,plasma waves ,f4 ,l4 ,sc>f1 ,,trw ,measurem5t ( plasma electron d5sities2 wave-p>ticle int]actions2 l[-frequ5cy wave emissions4 ,l[ en]gy *>g$ ,s4 ,m4 ,krimigis1 ,johns ,measurem5t ( ! p>ticles ,hopk9s ,u4 di/ribution1 composition1 & fl[ ( en]getic ions & electrons2 satellite-en]getic p>ticle int]actions4 ,cosmic ray p>ticles ,r4 ,e4 ,vogt1 ,calte* ,measurem5t ( ! di/ribution1 composition1 & fl[ ( high en]gy trapp$ nuclei2 en]getic electron spectra4 ,radio sci5ce ,v4 ,r4 ,e%leman1 ,measurem5t ( atmosph]ic ,/an=d ,u4 & ionosph]ic /ructure1 con/itu5ts1 & dynamics2 satellite masses4 ,unlike o!r ,voyag] in/rum5ts1 ! imag+ sy/em is n ! result ( a competition among proposals submitt$ by gr\ps ( sci5ti/s4 ,,nasa assign$ ! developm5t ( ! cam]as directly to ,,jpl1 to be integrat$ f ! beg9n+ ) ! design ( ! ,voyag] spacecraft & its subsy/ems4 ,! memb]s ( ! ,voyag] ,imag+ ,sci5ce ,team 7 select$1 z individuals1 on ! basis ( ! sci5tific /udies !y propos$ to c>ry out4 ,initially1 t5 memb]s ( ! ,imag+ ,sci5ce ,team 7 select$1 b by ! "t ( ! ,jupit] enc\nt]s1 ! team _h be5 exp&$ to #bb sci5ti/s4 ,illu/ration3 ,brad=d ,a4 ,smi?1 imag+ sci5ce ,team ,lead] ,! ,team ,lead] is ,brad=d ,a4 ,smi?1 a pr(essor 9 ! ,dep>tm5t ( ,planet>y ,sci5ce at ! ,univ]sity ( ,arizona4 ,smi? 0 involv$ 9 imag+ sci5ce on sev]al previ\s missions1 includ+ ,m>9]s #f & #g & ,vik+4 ,he 0 also active 9 gr\nd-bas$ photography ( ,jupit] at bo? ,new ,mexico ,/ate ,univ]sity & ,univ]sity ( ,arizona1 & he is a memb] ( ! team develop+ a planet>y cam]a = ! ,space ,telescope1 s*$ul$ = op]ation 9 ,e>? orbit 9 ! mid-#aihjs4 ,orig9ally1 ! ,deputy ,team ,lead] 0 ,ge(frey ,a4 ,briggs1 a "y ,briti%-born physici/ f ,,jpl4 ,h[ev]1 9 #aigg ,briggs took a position at ,,nasa ,headqu>t]s 9 ,wa%+ton & 0 replac$ by geologi/ ,laur5ce ,a4 ,sod]blom ( ! ,u4,s4 ,geological ,survey 9 ,flag/aff1 ,arizona4 ,an en]getic & articulate sci5ti/1 ,sod]blom1 ) 8 int]e/ 9 satellite geology1 complem5t$ ,smi?1 ^: p]sonal sci5tific int]e/s are direct$ m t[>d ! atmosph]e ( ,jupit]4 ,! objectives ( imag+ involv$ multicolor photography ( ,jupit] & its satellites4 ,bo? wide- & n>r[-angle cam]as 7 ne$$ to obta9 ! highe/ possible resolution :ile reta9+ ! capability to /udy global-scale features on ,jupit] & ! satellites4 ,9 normal photographic t]ms1 bo? cam]as us$ telephoto l5ses4 ,= ! wide-angle cam]a1 a focal l5g? ( #bjj millimet]s 0 select$1 giv+ a field ( view ( ab\t #c degrees4 ,?is field is simil> to t obta9$ ) a #djj-millimet] telephoto l5s on a #ce-millimet] cam]a4 ,! n>r[-angle ,voyag] cam]a has a focal l5g? ( #aejj millimet]s & field ( view ( #j4d degrees4 ,! cam]a optics are comb9ations ( mirrors & l5ses1 design$ = extreme /ability ( focus & = fre$om f di/ortion4 ,ea* cam]a has a rotat+ filt] :eel t c be us$ to select ! color ( ! light t rea*es ! cam]a4 ,= ! wide-angle cam]a1 ^! colors are cle>1 violet1 blue1 gre51 orange1 & ?ree special b&s = selective obs]vation 9 sodium light 7#ehi-nanomet] wavel5g?71 & 9 me?ane spectral l9es at #eda nanomet]s & #fah nanomet]s4 ,= ! n>r[-angle cam]a1 ! filt]s are cle>1 ultraviolet1 violet1 blue1 gre51 & orange4 ,to create a color picture1 ! cam]as are comm&$ to take1 9 rapid succession1 pictures ( ! same area 9 blue1 gre51 & orange light4 ,^! ?ree pictures c !n be recon/ruct$ on ,e>? into a 8true0 color image4 ,o!r comb9ations ( colors are us$ to inve/igate p>ticul> sci5tific problems & to det]m9e ! spectrum ( sunlight reflect$ f features on ,jupit] & its satellites4 ,! detector 9 ! cam]as is n photographic film b ! surface ( a sel5ium-sulfur vidicon television tube1 #aa millimet]s squ>e4 ,unlike mo/ comm]cial ,,tv cam]as1 ^! tubes are design$ = sl[-scan read\t1 provid+ #dh seconds to acquire ea* picture4 ,! %utt] spe$ c be v>i$ f a fraction ( a second 7= ,jupit] & ,io7 to _m m9utes 7= se>*es = fa9t features1 su* z aurorae on ! night side ( ,jupit]74 ,ea* picture consi/s ( _m numb]s1 ea* ( :i* repres5ts ! brightness ( a s+le picture elem5t1 or pixel1 on ! image4 ,!re are #fdj #jjj pixels 9 ea* ,voyag] image1 repres5t+ a squ>e image ( #hjj #hjj po9ts4 ,?is in=mation cont5t is m ?an twice t ( an ord9>y television picture1 :i* has only #ebj l9es4 ,= ea* pixel1 eight b9>y numb]s are requir$ to specify ! brightness2 ! total in=mation 9 a s+le image is ?us #h #fdj #jjj #e #abj #jjj bits4 ,ev5 at a transmission ( "o frame p] #dh seconds1 ! 8bit rate0 is m ?an #ajj #jjj bits p] second4 ,= comp>ison1 ! bit rate f ! fir/ spacecraft to ,m>s 7,m>9] #d7 0 ab\t #aj bits p] second1 requir+ a week to transmit #ba pictures1 ) a total in=mation cont5t equival5t to a s+le ,voyag] picture4 ,altoge!r1 ,voyag] took ne>ly #bj #jjj pictures at ea* ,jupit] enc\nt]1 repres5t+ #aj--;a hundr$ billion--bits ( in=mation4 ,illu/ration3 ,rudolph ,hanel1 infr>$ spectromet] ,pr9cipal ,inve/igator ,infr>$ ,spectromet] ,! infr>$ inve/igation on ,voyag] is bas$ on "o ( ! mo/ sophi/icat$ in/rum5ts ev] fl[n to ano!r planet4 ,9 ! pa/1 mo/ infr>$ in/rum5ts on planet>y spacecraft measur$ at only a few wavel5g?s1 b ,voyag] c>ries a true spectromet]1 capable ( measur+ at ne>ly #bjjj sep>ate wavel5g?s1 cov]+ ! spectrum f #d to #ej micromet]s4 ,twelve sci5ti/s1 l$ by ,pr9cipal ,inve/igator ,rudolph ,hanel ( ! ,,nasa ,godd>d ,space ,flight ,c5t] at ,gre5belt1 ,m>yl&1 propos$ ?is infr>$ in/rum5t4 ,hanel is an ackn[l$g$ _w lead] 9 infr>$ spectroscopy f space4 ,) 8 co-work]s at ,godd>d1 he has pione]$ 9 adapt+ ! extremely complex art ( int]f]ometric spectroscopy to ! rigors ( space flight4 ,8 spectromet]s h made _m /udies ( ! ,e>?'s atmosph]e f meteorological satellites1 & a ,hanel int]f]omet] flew successfully to ,m>s on ,m>9] #i4 ,! prim>y goals ( ! infr>$ spectromet] inve/igation are direct$ t[>d analysis ( ! composition & /ructure ( ! atmosph]e ( ,jupit]4 ,among ! molecules to be se>*$ = on ,jupit] 7 hydrog5 7,h71 helium 7,he71 me?ane 7,,*71 ammonia 7,,nh71 phosph9e 7,,ph71 wat] 7,h,o71 c>bon monoxide 7,,co71 simple comp\nds ( silicon & sulfur1 & a v>iety ( organic comp\nds consi/+ ( atoms ( c>bon & hydrog5 7e4g41 ,c,h1 ,c,h1 ,c,h74 ,9 addition to indicat+ ! abundance ( ^! con/itu5ts ( ! atmosph]e1 ! infr>$ spectra also conta9 in=mation on atmosph]ic /ructure1 t is1 on ! v>iation ( temp]ature & pressure ) altitude4 ,! pres5ce ( cl\ds or du/ lay]s c also be inf]r$ f ! %apes ( spectral l9es4 ,9 addition to its spectroscopy ( ,jupit]1 ! ,voyag] in/rum5t c\ld be us$ z a heat-measur+ device to map ! temp]atures ( bo? ! satellites & ! atmosph]e ( ,jupit]4 ,p>ticul>ly int]e/+ = ! satellites are measurem5ts ( ! surface cool+ & heat+ rates1 s9ce ^! rates reveal ! physical compactness ( ! surface1 easily di/+ui%+ betwe5 rock & s& or du/4 ,! infr>$ in/rum5t is a ,mi*elson int]f]omet] at ! focus ( a gold-plat$ telescope ( #ea-;c5timet] ap]ture4 ,! spectrum is n obta9$ directly1 by mov+ a prism or grat+1 b indirectly ?r\gh ! int]f]5ce effects ( light ( diff]5t wavel5g?s3 h5ce its "n1 an int]f]omet]4 ,! complex int]f]5ce patt]n g5]at$ by ! motion ( "o ( ! mirrors 9 ! light pa? is transmitt$ to ,e>?1 :]e comput] analysis is requir$ to trans=m x into a recognizable spectrum4 ,! entire in/rum5t1 :i* has a mass ( #bj kilograms1 is call$ ,,iris1 = infr>$ int]f]omet] spectromet]4 ,! developm5t ( ! infr>$ sy/em = ,voyag] pos$ _m problems4 ,,iris 0 design$ to cov] ! optimum spectral region = /udies ( ! atmosph]es ( ,jupit] & ,saturn4 ,h[ev]1 :5 x 0 decid$ 9 #aigd t an ext5d$ ,voyag] mission might also all[ a visit to ,uranus1 ,hanel & 8 colleagues realiz$ t _! in/rum5t _h s]i\s defici5cies = inve/igation ( t cold] & m di/ant planet1 & !y propos$ t a modifi$ ,,iris 7,,miris7 be sub/itut$ = ! orig9al design4 ,a cra% program 0 au?oriz$ to develop ,,miris 9 p>allel ) ,,iris1 & 9 e>ly #aigg1 z laun* approa*$1 x appe>$ t ! improv$ in/rum5t w\ld be ready4 ,problems occurr$ dur+ te/+1 h[ev]1 & = sev]al weeks 9 ,june & ,july ! decision hung 9 ! balance4 ,un=tunately1 !re simply 0 n en\gh "t to solve all ! problems2 bo? ,voyag]s 7 laun*$ c>ry+ ! orig9al ,,iris1 & ! f9al flight qualification ( ,,miris came 9 ,octob]1 ab\t six weeks aft] laun*4 ,) no o!r missions plann$ beyond ,saturn1 no alt]nate use = ,,miris has be5 f\nd2 x rema9s 8on ! %elf10 "o ( ! r>e cases :]e a te*nological gamble by ,,nasa did n pay (f4 ,illu/ration3 ,lyle ,broadfoot1 ultraviolet spectromet] ,pr9cipal ,inve/igator ,ultraviolet ,spectromet] ,a second spectroscopic in/rum5t on ! ,voyag] scan plat=m exam9es %ort-wave1 or ultraviolet1 radiation4 ,! ,pr9cipal ,inve/igator = ! ultraviolet spectromet] 7,,uvs7 is ,a4 ,lyle ,broadfoot ( ,kitt ,peak ,national ,obs]vatory 9 ,tucson1 ,arizona4 ,broadfoot's exp]tise lies 9 in/rum5tation = atmosph]ic rese>*1 & he 0 previ\sly ! ,pr9cipal ,inve/igator = a simil> ultraviolet in/rum5t on ! ,m>9] #aj mission to ,v5us & ,m]cury4 ,associat$ ) ,broadfoot 9 ! ,voyag] inve/igation are f\rte5 o!r sci5ti/s f ! ,unit$ ,/ates1 ,canada1 & ,france4 ,9 ! upp] atmosph]e ( a planet1 ! light] gases t5d to diffuse1 ris+ above _! heavi] neighbors1 & unusual *emical reactions take place z ! action ( sunlight breaks "s *emical bonds & /imulates ! =mation ( o!rs4 ,! /udy ( ^! t5u\s regions ( planet>y atmosph]es is call$ a]onomy4 ,_m ( ! exotic *emical processes t occur c be/ be /udi$ by exam9+ radiation ( v %ort wavel5g?1 & x is to ^! problems t mu* ( ! "w ( ! ,,uvs team is direct$4 ,! obs]vations are also s5sitive to special processes 9 ! ,jovian atmosph]e result+ f ! magnetosph]e4 ,at ! v top ( ! atmosph]e1 en]getic *>g$ p>ticles int]act+ ) ! atmosph]ic molecules produce ultraviolet aurorae t indicate ! location & nature ( ! bomb>d+ electrons & ions4 ,emissions f atoms 9 ! ext5d$ gas cl\ds ar\nd ,io & possibly ar\nd o!r satellites 7 also expect$ to be obs]vable4 ,! ultraviolet in/rum5t is a relatively /raight=w>d optical spectromet]1 adapt$ = use 9 space4 ,a diffraction grat+ disp]ses ! light into a spectrum1 & ! o!r optical elem5ts are gold-coat$ mirrors4 ,! field ( view is rectangul>1 ab\t #j4a degrees #j4i degrees4 ,an array ( s5sitive electronic detectors provides simultane\s measurem5ts 9 #abh wavel5g? *annels ov] a wavel5g? range f #ej to #agj nanomet]s4 ,photopol>imet] ,! f\r? scan-plat=m in/rum5t is design$ to measure ! brightness & pol>ization ( light ) high precision4 ,unlike ! imag+ sy/em1 h[ev]1 x c look at only a s+le po9t 7"o pixel7 at a "t2 ?us x sacrifices spatial capability 9 favor ( precision ( measurem5t4 ,! prime objectives ( ?is photopol>imet] are relat$ to /udy ( ! cl\ds ( ,jupit]4 ,dur+ ! developm5t /age = ?is in/rum5t1 ! ,pr9cipal ,inve/igator 0 ,*>les ,f4 ,lillie ( ! ,laboratory = ,atmosph]ic & ,space ,physics ( ! ,univ]sity ( ,colorado at ,b\ld]4 ,lat]1 ! ,pr9cipal ,inve/igator's role 0 assum$ by ,lillie's colleague1 ,*>les ,w4 ,hord1 a physici/ ) consid]able exp]i5ce 9 space missions1 prim>ily ) ultraviolet in/rum5ts4 ,f\r o!r sci5ti/s are ,co-,inve/igators on ! photopol>imet]4 ,! in/rum5t itself is ess5tially a small ,cassegra9 reflect+ telescope ( #ae-;c5timet] ap]ture4 ,two consecutive filt] :eels select ! color & pol>ization ( ! light1 :i* is !n detect$ & measur$ by a photomultipli] tube4 ,! entire photopol>imet] weighs j #b4e kilograms4 ,9 spite ( _! app>5t simplicity1 h[ev]1 ! ,voyag] photopol>imet]s 7 plagu$ ) tr\bles almo/ f ! mom5t ( laun*4 ,a succession ( me*anical failures on ,voyag] #a l$ to ! /ick+ fir/ ( ! pol>ization :eel & !n ( ! filt] :eel4 ,ev5 :5 repeat$ comm&s f ,e>? manag$ to free ! :eels1 _! behavior 0 erratic4 ,ultimately an electronic failure also took place1 lead+ to ! reluctant decision to %ut d[n ! ,voyag] #a photopol>imet]4 ,on ,voyag] #b1 simil> me*anical problems greatly re/rict$ ! ability ( ! in/rum5t to c>ry out its obs]vations4 ,! photopol>imet] ?us 0 unable to contribute its %>e to unravel+ ! my/]ies ( ,jupit] & its satellites4 ,illu/ration3 ,*>les ,w4 ,hord1 photopol>imet] ,pr9cipal ,inve/igator ,illu/ration3 ,james ,w4 ,w>wick1 planet>y radio a/ronomy ,pr9cipal ,inve/igator ,planet>y ,radio ,a/ronomy ,! f9al ,voyag] remote s5s+ in/rum5t is design$ to measure radio emission f ,jupit] & ,saturn ov] a wide range ( frequ5cies4 ,^! emissions1 :i* s\nd l hiss or /atic if play$ ?r\gh an audio receiv]1 result f int]actions ( *>g$ p>ticles 9 ! magnetosph]es & ionosph]es ( ! giant planets4 ,! planet>y radio a/ronomy 7,,pra7 ,pr9cipal ,inve/igator is ,james ,w4 ,w>wick1 an a/ronom] 9 ! ,dep>tm5t ( ,a/ro-,geophysics ( ! ,univ]sity ( ,colorado at ,b\ld]4 ,elev5 colleagues f ! ,unit$ ,/ates & ,france p>ticipate z ,co-,inve/igators4 ,w>wick has be5 /udy+ ,jupit] long] ?an any o!r ,voyag] ,pr9cipal ,inve/igator4 ,he has monitor$ its radio emissions s9ce ! #aifjs1 & he play$ a c5tral role 9 ! discov]y t ,io influ5c$ ^! emissions4 ,jupit] emits _m k9ds ( radio radiation1 rang+ f bl& !rmal emission at %ort 7c5timet]7 wavel5g?s1 to syn*rotron emission f en]getic electrons at int]m$iate 7decimet]7 wavel5g?s1 to erratic1 extremely int5se bur/s at long 7met] & decamet]7 wavel5g?s4 ,! orig9 ( ^! latt]1 non!rmal emissions con/itutes "o ( ! major unsolv$ problems ( ! ,jovian sy/em1 &1 m g5]ally1 ( ! physics ( plasmas4 ,"o ( ! mo/ important advantages ( ! ,voyag] ,,pra = /udy+ ,jovian radio emission lies 9 its proximity to ,jupit] & h5ce its ability to locate ! s\rces ( diff]5t k9ds ( radio bur/s4 ,! ,,pra in/rum5t consi/s ( an ant5na & a radio receiv]4 ,! ant5na is made up ( two ?9 metal poles1 ea* #aj met]s long1 ext5d$ f ! spacecraft aft] laun* at an angle ( #ij degrees to ea* o!r4 ,^! are electrically connect$ to two receiv]s ( extremely high s5sitivity & broad frequ5cy response3 f #a4b kiloh]tz to #dj4e megah]tz4 ,! ,,pra c op]ate 9 a numb] ( modes1 dep5d+ on ! measurem5ts desir$4 ,at its l[e/ level ( activity1 x monitors int5sity 9 all #aih b&s & transmits ! data at #bff bits p] second4 ,9 its highe/ mode1 :]e se>*es are made = v>iations ) v %ort "t scales1 ! data rate goes up to #ajh #jjj bits p] second1 ess5tially ! same z t requir$ by imag+4 ,9 fact1 ! high-rate ,,pra data actually use an imag+ frame z a display =m1 & occasionally ?r\gh\t ! mission an unfamili> look+ 8image0 0 transmitt$ t 0 actually a block ( ,,pra data--a portrait ( electrical ev5ts 9 ! ,jovian atmosph]e & magnetosph]e t only ,w>wick & 8 colleagues c\ld int]pret4 ,illu/ration3 ,norman ,f4 ,ness1 magnetomet] ,pr9cipal ,inve/igator ,illu/ration3 ,voyag]'s #ac-met]-long magnetomet] boom is %[n fully ext5d$4 ,9 space1 "u z]o gravity conditions1 ! triangul> epoxy glass ma/ spirals f its h\s+ & provides a rigid support = two magnetomet] in/rum5ts--"o at ! end ( ! boom & ano!r at ab\t ! midpo9t4 #bfj-aha ,magnetomet] ,! fir/ ( ! direct s5s+ in/rum5ts to be discuss$ is ! magnetomet]1 design$ to measure ! magnetic fields surr\nd+ ! spacecraft4 ,su* measurem5ts c be int]pret$ to yield ! intr9sic fields ( ,jupit] & its satellites & to *>act]ize1 9 conjunction ) data f p>ticle & plasma in/rum5ts1 ! processes tak+ place 9 ! magnetosph]e ( ! planet4 ,! ,pr9cipal ,inve/igator = ?is in/rum5t is ,norman ,f4 ,ness ( ! ,,nasa ,godd>d ,space ,flight ,c5t]4 ,ness is an int5se1 competitive sci5ti/ ) a great deal ( previ\s exp]i5ce 9 spacecraft magnetomet]s1 prim>ily on bo>d ,e>? satellites4 ,ness is also ! only ,voyag] ,pr9cipal ,inve/igator :o has previ\s exp]i5ce at ,jupit]2 he 0 ,pr9cipal ,inve/igator on "o ( ! two magnetomet] in/rum5ts fl[n on ,pione] #aa4 ,= ! ,voyag] inve/igation1 ,ness is jo9$ by f\r colleagues f ,godd>d & "o f ,g]many4 ,! magnetomet] in/rum5t consi/s ( two sy/ems3 a high-field magnetomet] & a l[-field magnetomet]4 ,ea* sy/em conta9s two id5tical ?ree-axis magnetomet]s t measure ! int5sity & direction ( ! magnetic field4 ,! l[-field sy/em requires isolation f magnetic fields induc$ by electric circuits 9 ! spacecraft itself4 ,to a*ieve ?is isolation1 x is m\nt$ on ! l>ge/ compon5t ( ,voyag]--a #ac-met] boom1 ab\t z long z ! wid? ( a typical city h\se lot4 ,?is boom 0 coil$ tightly 9 a cani/] dur+ laun*2 lat]1 :5 ! package 0 op5$1 x uncurl$ & ext5d$ automatically4 ,by us+ two magnetomet]s1 ,ness & 8 colleagues are able to correct = ! residual artificial magnetic fields t rea* ev5 #ac met]s f ! ma9 spacecraft4 ,! dynamic range ext5ds f a maximum field ( #bj gauss d[n to #b #aj gauss--a factor ( "o billion4 ,! fields c be measur$ z frequ5tly z #ag times p] second4 ,! total mass1 exclusive ( ! #ac-met] boom1 is #e4f kilograms4 ,illu/ration3 ,h]b]t ,s4 ,bridge1 plasma p>ticle ,pr9cipal ,inve/igator ,plasma ,p>ticles ,plasma is ! t]m giv5 to a 8gas0 ( *>g$ p>ticles2 ! electrons & protons are sep>ate1 yet !re are equal numb]s ( ea*1 produc+ a z]o net *>ge4 ,if ! velocities ( ! electrons & protons are less ?an ab\t #j4a p]c5t ( ! spe$ ( light1 !y c be measur$ by ! ,voyag] plasma in/rum5t2 if _! en]gies are high]1 !y are measur$ by "o ( ! o!r two p>ticle in/rum5ts--! l[ en]gy *>g$ p>ticle 7,,lecp7 detector or ! cosmic ray detector4 ,! plasma in/rum5t1 l ! magnetomet]1 0 design$ to provide basic data on ! p>ticles & fields environm5t ( ,voyag]4 ,! ,pr9cipal ,inve/igator = ! plasma in/rum5t is ,h]b]t ,s4 ,bridge ( ! ,massa*usetts ,in/itute ( ,te*nology 9 ,cambridge1 ,massa*usetts4 ,an exp]i5c$ space physici/1 ,bridge has fl[n simil> in/rum5ts on _m ,e>? satellites & planet>y probes4 ,he also holds ! position ( ,director ( ! ,laboratory = ,space ,exp]im5ts at ,,mit4 ,on ! ,voyag] exp]im5t1 he is jo9$ by "o ,g]man & t5 ,u4,s4 ,co-,inve/igators4 ,! objectives ( ! plasma inve/igation are direct$ t[>d /udy ( bo? ! int]planet>y m$ium & ! ,jovian magnetosph]e4 ,at ,jupit]1 ,bridge expect$ to det]m9e ! plasma populations & processes 9 ! inn] & out] regions ( ! magnetosph]e & 9 ! plasma tail t ext5ds beyond ,jupit]1 mu* z a comet tail is bl[n outw>d by ! sol> w9d4 ,! d5sities & temp]ature ( electrons 7 measur$1 & _! orig9s det]m9$3 ,"s orig9ate ne> ,jupit] & diffuse outw>d ?r\gh ! magnetosph]e2 o!rs d]ive f ! sol> w9d4 ,! plasma in/rum5t1 ) a mass ( #i4i kilograms1 0 design$ to view 9 two directions3 "o t[>d ! ,e>? & ,sun1 prim>ily to /udy ! sol> w9d1 & ! o!r sideways1 look+ t[>d ! direction plasma w\ld fl[ if x 7 caught up 9 ! rotat+ ,jovian magnetic field4 ,if x is desir$ to look 9 o!r directions1 ! entire spacecraft mu/ be tipp$1 a maneuv] t 0 c>ri$ out sev]al times ne> ,jupit]4 ,! detectors directly s5se ! fl[ ( electrons1 protons1 & alpha p>ticles 7helium nucleii1 made up ( two protons & two neutrons ea*74 ,analysis ( ! en]gy spectra c also yield data on positive ions ( high] mass4 ,illu/ration3 ,fr$]ick ,l4 ,sc>f1 plasma wave ,pr9cipal ,inve/igator ,plasma ,waves ,! plasma wave inve/igation on ,voyag] 0 a late addition to ! sci5tific payload4 ,x 0 select$ to broad5 ! capability ( ! mission to /udy a wide v>iety ( plasma processes4 ,because ( ! electrically *>g$ nature ( ! plasma1 x responds to en]gy inputs 9 ways t ord9>y gas _c4 ,"o ( ^! modes ( response yields plasma waves1 :i* are oscillations 9 d5sity & electric field t g5]ally cov] ! audio range ( frequ5cies4 ,measurem5t ( su* waves *>act]izes ! d5sity & temp]ature ( ! local plasma surr\nd+ ! spacecraft1 & x also all[s remote s5s+ detection ( di/ant ev5ts f ! plasma waves !y produce4 ,! plasma wave ,pr9cipal ,inve/igator is physici/ ,fr$]ick ,l4 ,sc>f ( ! ,,trw ,def5se & ,space ,sy/ems ,gr\p ( ,r$ondo ,bea*1 ,cali=nia--he is ! only ,voyag] ,pr9cipal ,inve/igator to come f indu/ry4 ,sc>f has be5 associat$ ) _m p>ticles & fields inve/igations 9 ! t]re/rial magnetosph]e1 al?\gh he is bett] kn[n z a !ori/ ?an z an exp]im5t]4 ,a memb] ( ! ,space ,sci5ce ,bo>d ( ! ,national ,academy ( ,sci5ces1 he is famili> 9 ,wa%+ton z an eloqu5t advocate ( space physics--! /udy ( plasma-physical processes 9 ! space environm5t4 ,! plasma wave in/rum5t %>es ) ! planet>y radio a/ronomy inve/igation a pair ( #aj-met]-long ant5nas4 ,:]eas ! ,,pra uses ^! z electric ant5nas to detect radio radiation1 ! plasma wave sy/em uses !m to detect directly ! oscillations 9 ! plasma ne> ! spacecraft4 ,waves are measur$ ov] a broad frequ5cy range1 f #aj h]tz 7a bit deep] ?an ! l[e/ bass note we c he>7 to #ef kiloh]tz 7ab\t ?ree times high] ?an ! highe/ pit* to :i* ! human e> responds74 ,! in/rum5t electronics h a total mass ( only #a4d kilograms4 ,l[ ,en]gy ,*>g$ ,p>ticles ,*>g$ p>ticles ) en]gies great] ?an a few ?\s& electron volts are n easily measur$ by a plasma in/rum5t su* z t design$ by ,h]b ,bridge4 ,in/ead1 ^! fa/] mov+ p>ticles1 ) spe$s up to a few p]c5t ! spe$ ( light1 are ! subject ( a pair ( ,voyag] in/rum5ts call$ collectively ! ,,lecp1 or l[ en]gy *>g$ p>ticle in/rum5t4 ,l ! o!r p>ticles & fields inve/igation1 ! ,,lecp is design$ to provide basic data on plasma-physical processes 9 ! ,jovian magnetosph]e & ! sol> w9d1 & on _! int]actions4 ,! ,pr9cipal ,inve/igator = ! ,,lecp inve/igation is ,/amatios ,mike ,krimigis1 a ,greek-born physici/ f ,johns ,hopk9s ,univ]sity4 ,krimigis has p>ticipat$ 9 a numb] ( satellite /udies ( ! t]re/rial magnetosph]e1 & he n[ s]ves z ,head ( ,space ,physics & ,in/rum5tation at ! ,johns ,hopk9s ,appli$ ,physics ,laboratory4 ,he is jo9$ 9 ?is inve/igation by "o ,g]man & five ,u4,s4 ,co-,inve/igators4 ,! ,,lecp in/rum5t consi/s ( two subsy/ems4 ,! fir/1 call$ ! l[ en]gy magnetosph]ic p>ticle analyz]1 is optimiz$ = measurem5t ( p>ticles )9 ! ,jovian magnetosph]e1 ) high s5sitivity ov] a broad dynamic range4 ,measurem5ts ( electrons1 protons1 & o!r positive ions c be c>ri$ out1 det]m9+ ! en]gy & composition ( individual p>ticles4 ,! total en]gy ranges cov]$ are #aj kiloelectron volts 7ke,v7 to #aa million electron volts 7,me,v7 = electrons & #ae ke,v to #aej ,me,v = protons & ions4 ,illu/ration3 ,/amatios ,mike ,krimigis1 l[ en]gy *>g$ p>ticle ,pr9cipal ,inve/igator ,! second ,,lecp subsy/em is a l[ en]gy *>g$ p>ticle telescope1 design$ to op]ate :]e ! d5sity ( *>g$ p>ticles is l[1 su* z 9 int]planet>y space or ! out] magnetosph]e ( ,jupit]4 ,= protons & positive ions1 ! en]gy range is f #ej ke,v to #dj ,me,v p] nucleon4 ,! en]gy & species resolution is aga9 suffici5t to det]m9e ! composition1 bo? *emical & isotopic1 ( _m ions enc\nt]$4 ,9 ord] to provide directional discrim9ation ev5 on a spacecraft ( fix$ ori5tation1 bo? ,,lecp subsy/ems are m\nt$ on a mov+ plat=m t /eps ?r\gh eight positions 9 a "t t c be comm&$ to v>y f #dh seconds to #dh m9utes4 ,! mass ( ! in/rum5t & its plat=m is #f4g kilograms4 ,cosmic ,rays ,! sol> sy/em is con/antly bomb>d$ by extremely en]getic *>g$ p>ticles4 ,^! are call$ cosmic rays1 al?\gh !y are p>ticles1 n photons--8rays0 are only produc$ :5 ! p>ticles /rike some?+1 su* z ! molecules ( ! ,e>?'s atmosph]e1 & give up _! en]gy 9 a fla% ( x-rays & gamma-rays4 ,"o ( ! ,voyag] in/rum5ts is design$ to /udy ^! galactic cosmic rays1 p>ticul>ly to look f beyond ! orbit ( ,saturn1 :]e ! cosmic ray p>ticles w be less affect$ by ! sol> magnetic field & sol> w9d ?an !y are ne> ,e>?4 ,! cosmic ray ,pr9cipal ,inve/igator is ,ro*us ,e4 ,vogt ( ! ,cali=nia ,in/itute ( ,te*nology4 ,vogt has measur$ cosmic rays f ! gr\nd1 f balloons1 & f spacecraft = _m ye>s4 ,dur+ #aigg & #aigh he s]v$ z ,*ief ,sci5ti/ at ,,jpl1 & !n assum$ ! job ( direct+ ! physics1 ma!matics1 & a/ronomy programs at ,calte*4 ,among 8 six ,co-,inve/igators is ,ed ,/one1 ! ,voyag] ,project ,sci5ti/4 ,because ! cosmic ray in/rum5t 0 n direct$ pr9cipally t[>d measurem5ts ( ! ,jovian sy/em1 x is describ$ only briefly4 ,l ! ,,lecp1 x is design$ to det]m9e ! en]gy & composition ( individual electrons & positive ions4 ,= electrons1 ! en]gy range is f #c to #aaj ,me,v1 & = ions f #a to #ejj ,me,v p] nucleon2 ! correspond+ velocities are f ab\t #aj p]c5t to #ii p]c5t ( ! spe$ ( light4 ,= ! positive ions1 composition c be det]m9$ = elem5ts f hydrog5 to iron4 ,at ,jupit]1 ?is sy/em c\ld be us$ to det]m9e ! nature ( ! r>e p>ticles accel]at$ to v high en]gies 9 ! ,jovian magnetosph]e4 ,radio ,sci5ce ,! f9al ,voyag] sci5ce inve/igation is 9 ! field ( radio sci5ce4 ,no special in/rum5t 0 requir$ = ?is /udy2 r1 ,,nasa select$ memb]s ( a ,radio ,sci5ce ,team :o propos$ inve/igations t c\ld be c>ri$ out us+ ! already exi/+ spacecraft telecommunication sy/em4 ,! radio sci5ce ,team ,lead] is ,von ,r4 ,e%leman ( ! ,c5t] = ,radio ,a/ronomy at ,/an=d ,univ]sity4 ,e%leman is a rad> physici/ :o has be5 int]pret+ spacecraft radio occultation data s9ce ! fir/ su* probe 0 c>ri$ out :5 ,m>9] #d pass$ beh9d ,m>s 9 #aifd4 ,! ,deputy ,team ,lead] is ,g4 ,leon>d ,tyl]1 a colleague ( ,e%leman's at ,/an=d4 ,!re are five o!r radio team memb]s1 f\r ( !m f ,,jpl4 ,! radio sci5ce inve/igations are divid$ into two gr\ps4 ,! fir/ deals ) ! atmosph]e ( ,jupit]4 ,dur+ ! ,voyag] flybys1 ! spacecraft pass$ beh9d ! planet z se5 f ,e>?1 & ! radio signal 0 dimm$ by ! atmosph]e be=e x 0 f9ally ext+ui%$4 ,dur+ an occultation1 ! propagation ( ! radio waves is sl[$ d[n by passage ?r\gh ! neutral atmosph]e & is spe$$ up by passage ?r\gh ! electrically *>g$ ionosph]e4 ,because ( ! extreme /ability ( ! gr\nd-bas$ & spacecraft radio transmitt]s1 x is possible to measure ^! %ifts 9 ! signal ) high precision4 ,! %ifts are proportional to electron d5sity = ! ionosph]e1 & to gas d5sity = ! atmosph]e4 ,f a c>eful /udy ( ! int]actions ( ! transmitt$ beam ) ! ,jovian atmosph]e1 ,e%leman & 8 colleagues c recon/ruct a temp]ature-pressure pr(ile ( ! ionosph]e & ! upp] atmosph]e ( ,jupit]4 ,! same approa* c be us$ to se>* = t5u\s atmosph]es on ! satellites4 ,! second area ( /udy is 9 ! field ( cele/ial me*anics4 ,! frequ5cy /ability ( ! communications sy/em p]mits measurem5ts ( ! spe$ ( ! spacecraft1 relative to ,e>?1 to a precision ( "o "p 9 sev]al million4 ,by c>eful track+1 gravitational p]turbations on ! spacecraft c be detect$ & us$ to measure ! gravitational fields1 & h5ce ! masses1 ( ,jupit] & its satellites4 ,illu/ration3 ,ro*us ,e4 ,vogt1 cosmic ray ,pr9cipal ,inve/igator ,illu/ration3 ,von ,r4 ,e%leman1 radio sci5ce ,team ,lead] ,^! sci5tific in/rum5ts & _! objectives 7 select$ _m ye>s be=e ! fir/ ,jupit] enc\nt] 9 ,m>* #aigg4 ,because ,voyag] 0 an exploratory mission1 e ef=t 0 made to fly v]satile in/rum5ts t c\ld yield valuable results no matt] :at ! nature ( ! ,jovian sy/em4 ,9 addition1 ! ,voyag] spacecraft control sy/em p]mitt$ ! in/rum5ts to receive comm&s f ,e>? to adju/ _! s5sitivities & obs]v+ sequ5ces 9 response to new in=mation4 ,by ! spr+ ( #aigg1 all ! in/rum5ts 7 complet$1 ready to be in/all$ 9 ! ,voyag] spacecraft = te/+ & laun*4 ,illu/ration3 ,! fir/ picture to capture cresc5t ,e>? & cresc5t ,moon 9 ! same frame 0 tak5 by ,voyag] #a1 ! second-laun*$ spacecraft1 on ,septemb] #ah1 #aigg1 at a di/ance ( #ab million kilomet]s f ,e>?4 ,on ! ,e>? ea/]n ,asia1 ! we/]n ,pacific1 & "p ( ! ,arctic c be se54 ,s9ce ! ,moon is mu* less reflective ?an ! ,e>?1 ,,jpl image processors bright5$ ! lun> image by a factor ( ?ree to ensure t bo? ,e>? & ,moon 7 visible on ?is pr9t4 ,p-#aihia;,c ,,*apt] #e ,,! ,,voyage ,,to ,,jupit]--,,gett+ ,,!re ,laun* ,on ,augu/ #bj1 #aigg1 exactly two ye>s aft] ! laun* ( ! ,vik+ spacecraft to ,m>s1 ! fir/ ( ! ,voyag]s--actually ,voyag] #b--0 boo/$ into space at #aj3bi a4m4 ,,edt1 less ?an five m9utes aft] ! laun* w9d[ op5$ on ! fir/ day ( ! ?irty-day laun* p]iod4 ,sixte5 days lat]1 at #h3ef a4m4 ,,edt on ,labor ,day1 ,septemb] #e1 #aigg1 ,voyag] #a 0 hurl$ into space on a %ort]1 fa/] trajectory ?an its tw91 zipp+ pa/ ! orbit ( ! ,moon only t5 h\rs aft] laun*4 ,ultimately1 ,voyag] #a e>n$ its title by ov]tak+ ,voyag] #b z bo? spacecraft j\rney$ ?r\gh ! a/]oid belt1 to arrive at ,jupit] f\r mon?s ahead ( ,voyag] #b4 ,! ,voyag]s lift$ (f f ,laun* ,complex #da1 ,air ,=ce ,ea/]n ,te/ ,range1 ,k5n$y ,space ,c5t]1 ,cape ,canav]al1 ,florida1 atop ! giant ,titan ,,iii-,e_/,c5taur rocket4 ,x 0 ! la/ "t su* a laun* vehicle 0 s*$ul$ to be us$1 z1 accord+ to plan1 ! ,space ,%uttle w\ld take ov] 9 ! #aihjs4 ,?us ! laun*+ ( ! two ,voyag]s signifi$ bo? an end & a beg9n+3 a once-9-a-lifetime opportunity to explore1 9 only #h ye>s' "t1 p]haps fifte5 major bodies ( ! out] sol> sy/em4 ,b long be=e ev5 ! fir/ ,voyag] 0 to make its close/ approa* to ,jupit]--9 fact1 ev5 be=e ,voyag] #b 0 (f ! laun* pad--!re 7 problems to ov]come4 ,9 e>ly ,augu/ #aigg1 ab\t ?ree weeks be=e laun*1 failures 9 ! attitude & articulation control subsy/em 7,,aacs7 & ! flight data subsy/em 7,,fds71 two ( ! spacecraft's ?ree ma9 comput] subsy/ems1 prev5t$ ! ,,vgr#gg-b spacecraft1 orig9ally s*$ul$ = laun* on ,augu/ #bj1 f becom+ ,voyag] #b4 ,in/ead1 ! 8sp>e0 spacecraft ,,vgr#gg-c 0 sub/itut$1 becom+ ,voyag] #b ^u laun* ,augu/ #bj1 & ,,vgr#gg-b1 aft] prop] repairs1 became ,voyag] #a4 ,m9or problems cont9u$ "r up to laun*4 ,! l[ en]gy *>g$ p>ticle in/rum5t fail$ & _h to be replac$1 & z late z ,t m9us five m9utes !re 0 a halt 9 ! c\ntd[n to *eck on a /uck valve4 ,unlike a j9x$ dress rehe>sal1 :i* is said to 8assure0 an op5+-night success1 ,voyag] #b's prelaun* problems 7 a port5t ( difficulties to come4 ,! ,voyag] #b laun* 0 witness$ by ?\s&s z ! spacecraft asc5d$ gracefully into ! blue ,florida sky1 accompani$ by ! deep-?roat$ rumbl+s ( its rocket1 e*o+ = miles across ! bea*es & scrub =e/s ( ,cape ,canav]al4 ,! ,titan-,c5taur p]=mance 0 ne>ly flawless1 & ,voyag] #b quickly a*iev$ an accurate trajectory t[>d ,jupit]4 ,h[ev]1 ev5 :ile ! eng9es 7 /ill fir+1 ! spacecraft began to exp]i5ce a baffl+ s]ies ( problems t w\ld absorb ! att5tion ( hundr$s ( p]sons f ,pasad5a to ,wa%+ton1 ,d4,c41 = ! next sev]al weeks until !y 7 br\ght "u control4 ,dur+ ! fir/ m9utes ( flight1 !re seem$ to be two difficulties ) ! ,,aacs4 ,! fir/ 0 a problem ) "o ( ! ?ree /abiliz+ gyroscopes1 b =tunately1 ! gyroscope began op]at+ normally )\t int]v5tion f ! gr\nd4 ,! o!r problem appe>$ to be ) "o ( ! ,,aacs comput]s2 ! spacecraft swit*$ to a backup comput] dur+ ! ,titan burn1 & initial data transmissions 7 incomplete4 ,e>ly analysis seem$ to indicate t an ev5t dur+ ! laun* itself1 r ?an a faulty spacecraft comput] sy/em1 0 ! cause ( ! data loss4 ,at fir/1 on ,augu/ #bc1 (ficials suspect$ t p]haps ! spacecraft _h be5 bump$ by ! rocket motor "o h\r aft] lift(f & aga9 ab\t sev5te5 h\rs lat]1 :5 telemetry signals indicat$ t ! spacecraft _h be5 jolt$4 ,h[ev]1 by ! next day1 flight eng9e]s det]m9$ t electronic gyrations 9 ! ,,aacs seem$ to h caus$ ! difficulty4 ,illu/ration3 ,! ,titan-,c5taur rocket us$ to laun* ,voyag] /ood z tall z a #ae-/ory build+ & weigh$ ne>ly #gjj tons4 ,"h ! rocket waits = laun* at ,k5n$y ,space ,c5t]1 ) ! ,voyag] spacecraft enclos$ 9 ! :ite protective %r\d at ! top4 ,p-#aidga;,a ,)9 an h\r aft] laun*1 ,voyag] #b's sci5ce scan plat=m boom 0 to h be5 fully ext5d$ & lock$4 ,in/ructions to deploy 7 giv51 & ! boom mov$ outw>d2 h[ev]1 !re 0 no signal to indicate t ! boom 0 actually lock$ 9 place4 ,ef=ts to comm& ! boom to move into ! lock$ position 7 ?w>t$ by ! spacecraft4 ,! fir/ maneuv] design$ to try to lock ! boom 0 abort$ by ! comput] comm& subsy/em 7,,ccs7 :5 ! ,,aacs errone\sly indicat$ t x 0 9 tr\ble4 ,?ree days lat] ano!r maneuv] 0 s*$ul$ to reprogram ! faulty comput] 9 ! ,,aacs1 to align ! ,sun s5sors1 & to try to lock ! sci5ce boom4 ,to provide a direct *eck ( ! boom position1 ! scan plat=m 0 turn$ s t ! ,,tv cam]as c\ld see ! spacecraft4 ,c>eful measurem5t ( ^! pictures v]ifi$ t ! boom 0 )9 degree ( full deploym5t1 b /ill !re 0 no indication t x 0 lock$ into place4 ,ultimately1 x 0 decid$ t ! s5sor to signal actuation ( ! lock 0 at fault1 & t ! boom itself 0 almo/ c]ta9ly fully ext5d$ & op]ational4 ,because ( ! po/laun* problems ( ,voyag] #b1 ! laun* ( ,voyag] #a 0 delay$ twice--f ,septemb] #a to ,septemb] #c & !n to ,septemb] #e--;9 ord] to inspect ,voyag] #a's sci5ce boom & to try to prev5t a repetition ( ,voyag] #b's problems4 ,an extra spr+ 0 atta*$ to ! sci5ce boom to assure its full ext5sion4 ,f9ally1 z if to make up = ! tr\bles ( ! fir/ laun*1 ,voyag] #a's laun* 0 bo? 8flawless & accurate40 ,all laun* & po/laun* ev5ts w5t smoo?ly4 ,! laun* w9d[ op5$ at #h3ef a4m4 ,,edt1 & ,voyag] took (f promptly at #h3ef3ja4 ,! booms & ant5nas deploy$ & lock$ 9 ! fir/ h\rs aft] laun*2 all in/rum5ts s*$ul$ to be on 7 on & work+ well4 ,,! ,,titan_/,,c5taur ,,laun* ,,vehicle ,! two ,voyag] spacecraft 7 c>ri$ into space & accel]at$ t[>d ,jupit] by ! ,titan ,,iii-,e ,c5taur rocket1 ! l>ge/ laun* vehicle 9 ! ,,nasa ars5al aft] ! retirem5t ( ! ,saturn rockets 9 #aige4 ,! ,titan & ,c5taur vehicles 7 orig9ally develop$ sep>ately & h be5 us$ ) o!r rocket /ages = _m ,,nasa laun*es4 ,!y 7 fir/ comb9$ = ! two ,vik+ laun*es to ,m>s 9 #aige1 & ?is p[]ful f\r-/age laun* vehicle 0 us$ aga9 9 #aigg = ,voyag]4 ,! ,titan_/,c5taur /&s ne>ly #ej met]s tall1 ab\t ! height ( a fifte5-/ory build+4 ,fully fuel$1 x weighs ne>ly #gjj tons4 ,at take(f1 ! ?ru/ ( ! two solid-propellant ,/age-#j motors is ab\t #aj4g million newtons4 ,^! motors1 :i* burn = #abb seconds1 use p[d]$ alum9um z fuel & ammonium p]*lorate z oxidiz]4 ,toge!r1 !y h a mass ( #ejj tons4 ,! fir/ /age ( ! liquid propellant core ( ! ,titan rocket ignites ab\t #aab seconds aft] take(f4 ,! propellant is hydraz9e z fuel & nitrog5 tetroxide z oxidiz]4 ,! fir/ /age is #c met]s 9 diamet] & #bj met]s tall4 ,fuel$1 x has a mass ( #acj tons4 ,! motor provides a ?ru/ ( #b4e million newtons = a duration ( #adf seconds4 ,ab\t #d4c m9utes aft] take(f ! ,titan ,/age ,,ii liquid propellant motor beg9s to fire1 & ! fir/ /age is sep>at$ & falls back into ! ,atlantic4 ,! second /age is #c met]s 9 diamet] & m ?an #g met]s long1 ) a fuel$ mass ( #ce tons4 ,! s+le liquid fuel motor burns = #baj seconds ) a ?ru/ ( half a million newtons4 ,dur+ ! second /age burn1 ! %r\d cov]+ ! ,voyag] spacecraft is jettison$4 ,! ,c5taur & ,titan vehicles sep>ate #h m9utes into ! flight1 & ! ,c5taur ma9 eng9e beg9s its burn4 ,! ,c5taur is ne>ly #bj met]s tall & #c met]s 9 diamet]1 ) a mass ( #ag tons4 ,! motors h a ?ru/ ( almo/ #bjj #jjj newtons1 op]at+ on ! mo/ p[]ful *emical fuels kn[n3 liquid oxyg5 & liquid hydrog54 ,! ,c5taur burns = only #a m9ute & #cf seconds z x atta9s ,e>? p>k+ orbit2 ! eng9e !n %uts d[n z ! vehicle beg9s a half-h\r coa/+ p]iod t c>ries x ne>ly half way ar\nd ! ,e>?4 ,dur+ ?is "t1 c>eful track+ ( ! spacecraft supplies ! data ne$$ = ,e>?-bas$ comput]s to calculate ! prop] "t to leave p>k+ orbit & />t ! long trip t[>d ,jupit]4 ,ab\t #ej m9utes aft] lift(f1 f a position high above ! ,indian ,ocean1 ! second burn ( ! ,c5taur ma9 eng9e beg9s4 ,six m9utes ( additional ?ru/ provides en\gh en]gy to break out ( ,e>?'s orbit4 ,! ,voyag] !n sep>ates f ! ,c5taur = a f9al boo/ t[>d ,jupit]4 ,! solid rocket motor 9 ! spacecraft propulsion module 7act+ z f9al /age ( ?is five-/age laun* sequ5ce7 fires = #de seconds at a ?ru/ ( #fh #jjj newtons4 ,j an h\r aft] lift(f1 ! ,voyag] spacecraft is on its way1 coa/+ on an orbit t[>d ,jupit] at a spe$ ( m ?an #aj kilomet]s p] second4 ,illu/ration3 ,! ,voyag] spacecraft is dom9at$ by ! l>ge #c4g-met]-diamet] ant5na us$ = communication ) ,e>?4 ,"h ! spacecraft und]goes f9al te/s be=e laun*4 ,! sci5ce in/rum5t scan plat=m is fold$ aga9/ ! spacecraft on ! "r2 ! ?ree cyl9d]s on ! left are ! ,,rtg p[] s\rces4 #bfj-ajh;,,bc ,illu/ration3 ,voyag] #b 0 ! fir/ ( ! spacecraft to be laun*$1 on ,augu/ #bj1 #aigg1 propell$ into space 9 a ,titan_/,c5taur rocket4 ,p-#aidej;,,ac ,! ,fir/ ,ye> ,is ! ,r\ghe/ ,dur+ ! autumn ( #aigg ,voyag] #b1 & to a less] ext5t ,voyag] #a1 cont9u$ to plague controll]s ) erratic actions4 ,?ru/]s fir$ at inappropriate times1 data modes %ift$1 in/rum5t filt] & analyz] :eels became /uck1 & ! v>i\s comput] control sy/ems occasionally ov]rode gr\nd comm&s4 ,app>5tly1 ! spacecraft h>dw>e 0 work+ prop]ly1 b ! comput]s on bo>d display$ c]ta9 traits t seem$ almo/ humanly p]v]se--& p]haps a little psy*otic4 ,9 g5]al1 ^! reactions 7 ! result ( programm+ too mu* s5sitivity into ! spacecraft sy/ems1 result+ 9 panic ov]-reaction by ! onbo>d comput]s to m9or fluctuations 9 ! environm5t4 ,ultimately1 "p ( ! programm+ _h to be rewritt5 on ,e>? & !n transmitt$ to ! ,voyag]s1 to calm !m d[n s t !y w\ld ignore m9or p]turbations1 yet /ill be ready to p]=m automatic sequ5ces requir$ to protect ! spacecraft f major ?reats4 ,mean:ile1 h[ev]1 m s]i\s problems 7 develop+4 ,on ,febru>y #bc1 #aigh1 dur+ a s]ies ( movem5ts or slews1 ,voyag] #a's scan plat=m sl[$ & /opp$ be=e complet+ ! maneuv]4 ,?is failure caus$ a great deal ( conc]n1 s9ce ! scan plat=m h\ses ! optical in/rum5ts t are crucial to ! obs]vation ( ! ,jovian sy/em--! ultraviolet spectromet]1 ! ,,iris1 ! photopol>imet]1 & ! two ,,tv cam]as4 ,at ,,jpl1 te/s 7 run on a pro(-te/ model--an exact copy ( ! ,voyag] spacecraft--to try to f9d out :y ,voyag] #a's scan plat=m _h become /uck4 ,on ,m>* #ag1 ,voyag] #a's scan plat=m 0 te/$--,,jpl eng9e]s in/ruct$ ! plat=m to move sl[ly = a %ort di/ance1 & ,voyag] respond$ z ord]$4 ,fur!r te/s 7 conduct$ on ,m>* #bc4 ,?is "t ! scan plat=m 0 ord]$ to execute a sequ5ce ( f\r slews1 mov+ away f ! "p ( ! sky :]e ! orig9al failure _h occurr$ & end+ ) ! position t x w\ld be mo/ useful to leave ! plat=m 9--j 9 case ! plat=m %\ld become /uck aga94 ,on ,april #d ! scan plat=m 0 comm&$ to p]=m a sequ5ce ( #ch slews1 & fifty m slews 7 p]=m$ on ,april #e4 ,all 7 successful4 ,yet eng9e]s 7 /ill hesitant to =ce ! plat=m to move ?r\gh ! region :]e x _h orig9ally /uck1 & ext5sive discussions 7 held to det]m9e if ! ,jupit] obs]vations c\ld be c>ri$ out )\t risk+ a return to ! dang] area4 ,x 0 argu$1 h[ev]1 t full mobility ( ! scan plat=m really 0 requir$1 & on ,may #ca comm&s 7 s5t to maneuv] ! scan plat=m ?r\gh ! dang] region4 ,x mov$ normally3 ,! scan plat=m 0 op]at+ prop]ly aga94 ,aft] additional slew+ te/s 7 run 9 mid-,june1 ! scan plat=m 0 pron\nc$ fit = op]ation4 ,eng9e]s suspect$ t ! mat]ial caught 9 ! plat=m ge>s mu/ h be5 cru%$ or mov$ out ( ! way by ! cont9u$ slew+1 all[+ ! plat=m to move once m4 ,illu/ration3 ,voyag] #a 0 laun*$ on ,septemb] #e1 #aigg4 ,! laun* 0 delay$ #e days to make la/-m9ute adju/m5ts to avoid ! po/laun* difficulties exp]i5c$ by ,voyag] #b4 ,p-#aidhj;,,ac ,an ev5 m s]i\s crisis soon endang]$ ! ,voyag] #b spacecraft4 ,9 late ,novemb] #aigg1 ! ,s-b& radio receiv] began los+ amplifi] p[] 9 its high-ga9 mode1 s ! solid-/ate amplifi] 0 swit*$ to its l[-p[] position4 ,no fur!r problems 7 not$ until ,april #e1 #aigh1 :5 ,voyag] #b's prim>y radio receiv] sudd5ly fail$1 & %ock$ eng9e]s discov]$ t ! backup receiv] 0 also faulty4 ,! tr\ble 0 detect$ aft] ,voyag]'s comput] comm& subsy/em direct$ ! spacecraft to swit* f ! prim>y radio receiv] to ! backup receiv]4 ,?is comm& 0 issu$ z "p ( a special protection sequ5ce3 ,if ! prim>y radio receiv] receives no comm&s f ,e>? = sev5 days1 ! backup receiv] is swit*$ on in/ead2 if ! second>y receiv] 9 turn receives no in/ructions ov] a twelve-h\r p]iod1 ! sy/em rev]ts to ! ma9 receiv]4 ,:51 on ,april #e1 ,voyag] #b's radio reception 0 swit*$ f ! prim>y to ! second>y receiv]1 flight eng9e]s f\nd t !y 7 unable to communicate ) ! spacecraft--! second>y receiv]'s track+ loop capacitor 0 malfunction+4 ,t meant t ! second>y receiv] c\ld n foll[ a *ang+ signal frequ5cy s5t out f ,e>?4 ,! frequ5cies ( signals transmitt$ f ,e>? are affect$ by ! ,doppl] effect--j z ! sir5 on a fire eng9e seems fir/ to rise 9 pit* z ! truck approa*es1 !n falls z ! truck spe$s away1 s ! frequ5cy ( signals transmitt$ f ,e>? fluctuates ) ! ,e>?'s rotation z ! ,deep ,space ,network's radio ant5nas move t[>d or away f ! spacecraft4 ,! eng9e]s _h to wait until ! prim>y radio receiv] 0 swit*$ back on be=e !y c\ld communicate ) ! spacecraft4 ,once ! prim>y receiv] 0 on1 ,voyag] #b began receiv+ in/ructions f ,e>?1 b approximately ?irty m9utes lat]1 !re 0 an app>5t p[] surge 9 ! receiv]4 ,! fuses blew4 ,!re 0 no rec\rse4 ,! ma9 receiv] _h fail$2 its loss 0 p]man5t4 ,x rema9$ = ! eng9e]s to devise a way to communicate ) ! slightly deaf spacecraft4 ,illu/ration3 ,ea* ,voyag] spacecraft foll[s a billion-kilomet] pa? to ,jupit]4 ,except = m9or ?ru/] fir+s to a*ieve small trajectory corrections1 ea* ,voyag] coa/s f ,e>? to ,jupit]1 guid$ by ! gravitational pull ( ! ,sun4 ,at ,jupit]1 ! p[]ful tug ( ! giant planet deflects ! spacecraft & spe$s !m up1 imp>t+ an extra kick to s5d !m on _! way t[>d ,saturn4 ,voyag] #a ,voyag] #b ,jupit]-,saturn-,uranus ,sun ,e>? #h_/bj_/gg ,e>? #i_/a_/gg ,m>s #h_/bj_/gg ,jupit] #h_/bj_/gg ,jupit] #c_/e_/gi ,jupit] #g_/i_/gi ,saturn #h_/bj_/gg ,saturn #aa_/ac_/hj ,saturn #h_/bg_/ha ,uranus #h_/bj_/gg ,uranus #a_/cj_/hf ,because ! swit*+ ( ! radio receiv]s 0 /ill controll$ by ! special protection sequ5ce discuss$ e>li]1 flight eng9e]s w\ld h to wait = sev5 days--until ,april #ac--;be=e !y c\ld attempt communication ) ! spacecraft aga94 ,dur+ t week special proc$ures 7 e/abli%$ & rehe>s$ s t comm&s c\ld be s5t to ,voyag] 9 ! %ort "t t ! backup receiv] w\ld be on4 ,on ,?ursday1 ,april #ac1 #aigh1 ! sev5 days 7 up & ! spacecraft %\ld h %ift$ f ! dead ma9 receiv] to ! sick backup sy/em4 ,!re 0 j a twelve-h\r 8w9d[0 9 :i* to re/ore communication4 ,at ab\t #c3cj a4m4 ,,p/ ! ,madrid track+ /ation ( ! ,deep ,space ,network s5t its fir/ ord] to ! spacecraft1 approximately #dgd million kilomet]s away4 ,almo/ an h\r lat]1 ^w arriv$ f ,voyag] t ! comm& _h be5 accept$4 7,"o-way light "t = a signal to travel ! di/ance f ,e>? to ,voyag] at t "t 0 almo/ #bg m9utes47 ,elat$ flight controll]s w5t ahead & transmitt$ n9e h\rs ( comm&s to ! spacecraft4 ,voyag] #b 0 successfully comm&$ aga9 on ,april #ah & ,april #bf4 ,! ,april #bf comm&s includ$ a c\rse *ange maneuv] t 0 execut$ prop]ly on ,may #c4 ,on ,june #bc1 ,voyag] #b 0 programm$ = a backup automatic mission at ,saturn 9 ! ev5t t ! second>y radio receiv] %\ld also fail4 ,^! backup mission in/ructions w\ld op]ate all ! sci5ce exp]im5ts1 b only a m9imum am\nt ( data w\ld be return$1 s9ce ! scan plat=m w\ld only be programm$ to move ?r\gh ?ree positions r ?an ?\s&s z x w\ld 9 normal op]ation4 ,in/ructions = a backup m9imum automatic enc\nt] at ,jupit] 7 transmitt$ to ,voyag] #b 9 two segm5ts1 ! second ( ^! on ,octob] #ab1 #aigh4 ,) ! backup in/ructions record$ on bo>d ! spacecraft1 ,voyag] p]sonnel felt _! fe>s p>tially allay$4 ,if ,voyag] #b's second>y radio receiv] fail$1 ! spacecraft w\ld /ill obta9 "s sci5ce data at ,jupit] & ,saturn4 ,b t w\ld mean t !re w\ld be no mission beyond ,saturn2 our fir/ opportunity to explore ,uranus1 its satellites1 its newly discov]$ r+ sy/em1 & possibly ev5 to get a look at ,neptune1 w\ld n come 9 ?is c5tury4 ,ano!r major conc]n affect+ bo? ,voyag] spacecraft 0 ! prop] managem5t ( hydraz9e fuel res]ves4 ,hydraz9e is us$ by ! ?ru/]s on ! ,voyag]s = /abilization ( ! spacecraft & = trajectory correction maneuv]s 7,,tcm74 ,ea* ,voyag] 0 load$ ) #aje kilograms ( hydraz9e budget$ = use on ! long flight to ,jupit]1 ,saturn1 & beyond4 ,because ( ! excell5t p]=mance ( ! laun* rockets1 bo? ,voyag]s requir$ less hydraz9e ?an anticipat$ = _! f9al boo/ into prop] trajectory t[>d ,jupit]1 & at fir/ x look$ z ?\gh bo? spacecraft w\ld h pl5ty ( propellant to sp>e4 ,*>les ,e4 ,kolhase1 ,manag] ( ,mission ,analysis & ,eng9e]+ = ! ,voyag] ,project1 lat] expla9$ ! situation3 8,voyag] #a %\ld h be5 laun*$ ,septemb] #a4 ,_h x be5 laun*$ on ,septemb] #a--;& ,i'm glad x wasn't--! maneuv] to correct ! trajectory = a ,titan flyby w\ld h requir$ a *ange 9 velocity ( #ajj-aaj met]s p] second--an enorm\s maneuv]--& we w\ld h _h a propellant m>g9 = go+ on to ,saturn ( p]haps #d4e kilograms4 ,b1 by laun*+ on ! fif? ( ,septemb] we increas$ our m>g9 to #bc kilograms4 ,=tunately1 = e laun* date t w5t by1 t velocity *ange maneuv] 0 %r9k+ at a rate ( #aj met]s p] second p] day4 ,n[1 a #a met] p] second *ange uses ab\t a p\nd ( hydraz9e ab\t #j4e kilogram4 ,s :5 we laun*$ on ! fif? ( ,septemb]1 n[ we sudd5ly _h #dj p\nds ( hydraz9e excess ov] :at we w\ld h _h if we _h laun*$ on ! fir/ ( ,septemb]4 ,z a result1 ,voyag] #a is 9 great %ape z f> z hydraz9e is conc]n$40 ,,! ,,deep ,,space ,,network ,a vital compon5t ( ! ,voyag] ,mission is ! communications sy/em l9k+ ! spacecraft ) controll]s & sci5ti/s on ,e>?4 ,! ability to communicate ) spacecraft ov] ! va/ di/ances to ! out] planets1 & p>ticul>ly to return ! enorm\s am\nts ( data collect$ by sophi/icat$ cam]as & spectromet]s1 dep5ds 9 l>ge "p on ! transmitt]s & receiv]s ( ! ,deep ,space ,network 7,,dsn71 op]at$ = ,,nasa by ,,jpl4 ,! orig9al network ( ^! receiv+ /ations 0 e/abli%$ 9 #aieh to provide r\nd-!-_w track+ ( ! fir/ ,u4,s4 satellite1 ,explor] #a4 ,by ! late #aigjs1 ! ,,dsn _h evolv$ into a sy/em ( l>ge ant5nas1 l[-noise receiv]s1 & high-p[] transmitt]s at sites /rategically locat$ on ?ree cont95ts4 ,f ^! sites ! data are =w>d$ 7(t5 us+ t]re/rial communications satellites7 to ! mission op]ations c5t] at ,,jpl4 ,! ?ree ,,dsn /ations are locat$ 9 ! ,mohave des]t at ,gold/one1 ,cali=nia2 ne> ,madrid1 ,spa92 & ne> ,canb]ra1 ,au/ralia4 ,ea* location is equipp$ ) two #bf-met] /e]able ant5nas & a s+le giant /e]able di% #fd met]s 9 diamet]1 ) approximately ! collect+ area ( a football field4 ,9 addition1 ea* is equipp$ ) transmitt+1 receiv+1 & data h&l+ equipm5t4 ,! transmitt]s 9 ,spa9 & ,au/ralia h #ajj-kil[att p[]1 :ile ! #fd-met] ant5na at ,gold/one has a #djj-kil[att transmitt]4 ,mo/ comm&s to ,voyag] are s5t f ,gold/one1 b all ?ree /ations require ! highe/ quality receiv]s to p]mit cont9u\s record+ ( ! data /reams p\r+ 9 f ! spacecraft4 ,s9ce ! mid-#aifjs1 ! ,,dsn's /&>d frequ5cy has be5 ,s-b& 7#bbie megah]tz74 ,voyag] introduces a new1 high] frequ5cy telemetry l9k at ,x-b& 7#hdah megah]tz74 ,! ,x-b& signal c c>ry m in=mation ?an ,s-b& ) simil> p[] transmitt]s1 b x requires m exact ant5na p]=mance4 ,9 addition1 ! ,x-b& signal is absorb$ by t]re/rial cl\ds &1 especially1 ra94 ,=tunately1 all ?ree ,,dsn /ations are 9 dry climates1 b dur+ enc\nt]s ! wea!r =eca/s on ,e>? become items ( crucial conc]n if preci\s data are n to be lo/ by /orm int]f]5ce4 ,z a result ( ! developm5t ( l>g] ant5nas & improv$ electronics1 ! ,,dsn comm& capabilities & telemetry data rates h increas$ dramatically ov] ! ye>s4 ,= example1 9 #aife ,m>9] #d transmitt$ f ,m>s at a rate ( only #h bits ( in=mation p] second4 ,9 #aifi1 ,m>9]s #f & #g transmitt$ picture data f ,m>s at #af #bjj bits p] second4 ,m>9] #aj1 9 #aigc1 a*iev$ #aag #bjj bits p] second f ,m]cury4 ,voyag] op]ates at a simil> rate f ,jupit]1 ab\t six times f>!r away4 ,_m ( ^! improvem5ts 9 data transmission result f *anges 9 ! ,,dsn r ?an 9 ! spacecraft transmitt]s4 ,problems ) hydraz9e managem5t develop$1 h[ev]4 ,voyag] #a's fir/ trajectory correction maneuv] a*iev$ only #hj p]c5t ( ! requir$ spe$ *ange4 ,exhau/ plumes f ! ?ru/]s app>5tly /ruck "p ( ! spacecraft1 caus+ a #bj p]c5t loss 9 velocity4 ,t be+ ! case1 ,voyag] might require m fuel ?an _h be5 expect$ to complete ! mission4 ,! extra fuel requirem5ts did n ?reat5 ,voyag] #a itself1 s9ce x held ample fuel to rea* ,saturn2 ! conc]n 0 = ,voyag] #b1 :]e ! effective loss ( fuel might be en\gh to jeop>dize ! ,uranus mission4 ,illu/ration3 ,project memb]s4 ,illu/ration3 ,project memb]s4 ,because ( ! plume imp+em5t problem on ,voyag] #a1 ,voyag] #b's fir/ trajectory correction maneuv] 0 adju/$ to all[ = ! possibility ( a #bj p]c5t loss 9 ?ru/4 ,! ,voyag] #b maneuv] 0 successful1 b controll]s felt t additional action 0 requir$ to cons]ve fuel4 ,"o way to save 0 by r$uc+ requirem5ts on control ( ! spacecraft ori5tation4 ,less control fuel w\ld be ne$$ if ! already m9iscule pressure ex]t$ on ! spacecraft by ! sol> w9d c\ld be r$uc$4 ,flight eng9e]s at ,,jpl calculat$ t ! pressure w\ld be r$uc$ if ! spacecraft 7 tipp$ upside d[n2 h[ev]1 to accompli% ?is1 ! spacecraft w\ld h to be /e]$ by a new set ( guide />s4 ,by reprogramm+ ! attitude control sy/em x 0 f\nd possible to sub/itute ! nor!rn />1 ,d5eb1 9 ! con/ellation ( ,cygnus1 = ! orig9al ref]5ce />1 ,canopus1 9 ! s\!rn con/ellation ( ,c>9a4 ,) ?is *ange1 z well z readju/m5t ( ,voyag] #b's trajectory ne> ,jupit]1 inflight consumption ( hydraz9e 0 r$uc$ significantly4 ,9 late ,augu/ #aigh bo? ,voyag]s 7 reprogramm$ to ensure bett] sci5ce results at ,jupit] enc\nt]2 = example1 ! reprogramm+ w\ld prev5t imag+ 7,,tv7 photographs f blurr+ :5 ! tape record] 0 op]at+4 ,by e>ly ,novemb]1 flight crews _h begun tra9+ ex]cises to rehe>se = ! ,voyag] #a flyby ( ,jupit] on ,m>* #e1 #aigi4 ,a ne> enc\nt] te/ 0 p]=m$ on ,decemb] #ab-ad1 #aigh3 a complete run?r\gh ( ,voyag] #a's #ci-;h\r ne> enc\nt] p]iod1 :i* w\ld take place ,m>* #c-e1 #aigi4 ,p>ticipants includ$ ! flight team1 ! ,deep ,space ,network track+ /ations1 ! sci5ti/s1 & ! spacecraft itself4 ,results3 ,voyag] & ! ,voyag] team 7 all ready = ! enc\nt]4 ,mean:ile1 ! spacecraft 7 busy return+ sci5tific data to ,e>?4 ,te*nically1 ! ,voyag]s 7 9 ! cruise phase ( ! mission--a p]iod t1 = ,voyag] #b1 w\ld la/ until ,april #bd1 #aigi1 & = ,voyag] #a1 until ,janu>y #d1 #aigi1 :5 ea* spacecraft w\ld ent] its respective obs]vatory phase4 ,cruise ,phase ,sci5ce ,9 ! fir/ few days aft] laun*1 ! spacecrafts' in/rum5ts 7 turn$ on & calibrat$2 v>i\s te/s = ea* in/rum5t w\ld cont9ue to be p]=m$ ?r\gh\t ! cruise phase4 ,?is p]iod pres5t$ a great opportunity = ! ,voyag]s to /udy ! int]planet>y magnetic fields1 sol> fl>es1 & ! sol> w9d4 ,9 addition1 ultraviolet & infr>$ radiation /udies ( ! sky 7 p]=m$4 ,9 mid-,septemb] #aigg ! television cam]as on ,voyag] #a record$ a numb] ( photographs ( ! ,e>? & ,moon4 ,a photograph tak5 ,septemb] #ah captur$ bo? cresc5t ,moon & cresc5t ,e>?4 ,x 0 ! fir/ "t ! two cele/ial bodies _h ev] be5 photograph$ toge!r4 ,9 ,novemb] bo? ,voyag]s cross$ ! orbit ( ,m>s1 ent]+ ! a/]oid belt a mon? lat]4 ,on ,decemb] #ae1 at a di/ance ( ab\t #agj million kilomet]s f ,e>?1 ,voyag] #a f9ally spe$$ pa/ its sl[] tw94 ,! j\rney ?r\gh ! a/]oid belt 0 long b unev5tful3 ,voyag] #a em]g$ safely 9 ,septemb] #aigh1 & ,voyag] #b 9 ,octob]4 ,unlike ,pione]s #aj & #aa1 ! ,voyag]s c>ri$ no in/rum5ts to look at debris 9 ! a/]oid belt4 ,by ,april bo? spacecraft 7 already halfway to ,jupit] &1 ab\t two mon?s lat]1 ,voyag] #a1 /ill approximately #bfe million kilomet]s f ,jupit]1 began return+ photographs ( ! planet t %[$ consid]able detail1 al?\gh less ?an c\ld be obta9$ ) telescopes on ,e>?4 ,bo? ! imag+ 7,,tv7 & ! planet>y radio a/ronomy in/rum5ts began obs]v+ ,jupit]1 &1 by ,octob] #b1 #aigh1 (ficials ann\nc$ t 8! pol>ization *>act]i/ics ( ,jupit]'s radio emissions h be5 def9$4 ,9 ! high frequ5cies1 !re is consi/5t "r-h& circul> pol>ization1 :ile 9 ! l[ frequ5cies1 !re is a consi/5t left-h& circul> pol>ization4 ,?is 0 an unexpect$ result40 ,9 addition to sci5tific /udies ( ! int]planet>y m$ium & a fir/ look at ,jupit]1 ! plasma wave in/rum5t1 :i* /udies waves ( *>g$ p>ticles ov] a range ( frequ5cies t includes audio frequ5cies1 0 able to record ! s\nd ( ! spacecraft ?ru/]s fir+1 z hydraz9e fuel is decompos$ & eject$ into space4 ,! s\nd 0 describ$ z be+ 8some:at l a #e-;gallon c be+ hit ) a lea!r-wrapp$ mallet40 ,on ,decemb] #aj1 #aigh1 #hc million kilomet]s f ,jupit]1 ,voyag] #a took photographs t surpass$ ! be/ photographs ev] tak5 f gr\nd-bas$ telescopes1 & sci5ti/s 7 anxi\sly await+ ! />t ( cont9u\s cov]age ( ! rapidly *ang+ cl\d =ms4 ,^! pictures1 toge!r ) data f sev]al gr\nd-bas$ obs]vatories1 7 c>efully scrut9iz$ by a team ( sci5ti/s at ,,jpl to select ! f9al t>gets 9 ! atmosph]e ( ,jupit] to be /udi$ at high resolution dur+ ! flyby4 ,! obs]vatory phase ( ,voyag] #a's j\rney to ,jupit] 0 ab\t to beg94 ,illu/ration3 ,z ,voyag] #a approa*$ ,jupit]1 ! resolution ( ! images /eadily improv$4 ,9 ,octob] #aigh1 at a di/ance ( ab\t #abe million kilomet]s1 ! image 0 less cle> ?an w\ld be obta9$ ) an ,e>?-bas$ telescope4 ,p-#bjgij ,illu/ration3 ,by ,decemb] #aj1 ! spacecraft _h mov$ to a di/ance ( #he million kilomet]s1 & ! resolution 0 ab\t #bjjj kilomet]s1 comp>able to ! be/ telescopic images4 ,p-#bjhbi;,c ,illu/ration3 ,on ,janu>y #i1 #aigi 7c71 at a di/ance ( #ed million kilomet]s1 ! image surpass$ all gr\nd-bas$ views & approa*$ ! resolution ( ! ,pione] #aj & #aa photos4 ,p-#bjibf;,c ,illu/ration3 ,9 ?is1 tak5 ,janu>y #bd at a di/ance ( #dj million kilomet]s1 ! resolution exce$$ #ajjj kilomet]s4 ,p-#bjide;,c ,! ,obs]vatory ,phase ,! obs]vatory phase1 orig9ally s*$ul$ to />t on ,decemb] #ae1 #aigh1 eighty days be=e enc\nt]1 0 po/pon$ until ,janu>y #d1 #aigi1 to provide ! flight team a holiday-season break4 ,= ! next two mon?s1 ,voyag] w\ld c>ry out a long-t]m sci5tific /udy--a 8"t hi/ory0--( ,jupit]1 its satellites1 & its magnetosph]e4 ,on ,janu>y #f1 ,voyag] #a began photograph+ ,jupit] e two h\rs--ea* "t tak+ a s]ies ( f\r photographs ?r\gh diff]5t color filt]s z "p ( a long-duration /udy ( l>ge-scale atmosph]ic processes1 s sci5ti/s c\ld /udy ! *ang+ cl\d patt]ns on ,jupit]4 ,ev5 ! fir/ ( ^! pictures %[$ t ! atmosph]e 0 dynamic 8) m convective /ructure ?an _h previ\sly be5 ?\ght40 ,p>ticul>ly /rik+ 7 ! *anges 9 ! planet1 especially ne> ! ,great ,r$ ,spot1 t _h tak5 place s9ce ! ,pione] flybys 9 #aigc & #aigd4 ,jupit] 0 we>+ a new face = ,voyag]4 ,9 mid-,janu>y1 photos ( ,jupit] 7 already be+ prais$ = 8%[+ exceptional details ( ! planet's multicolor$ b&s ( cl\ds40 ,/ill #dg million kilomet]s f ! giant1 ,voyag] #a _h by n[ tak5 m ?an #ejj photographs ( ,jupit]4 ,movem5ts ( cl\d patt]ns 7 becom+ m obvi\s2 fea!ry /ructures seem$ pa9t$ across "s ( ! b&s t encircle ! planet2 swirl+ features 7 huddl$ ne> ! ,great ,r$ ,spot4 ,! satellites 7 also beg9n+ to look m l worlds1 ) a few bright spots visible on ,ganym$e & d>k r$ poles & a bright equatorial region cle>ly se5 on ,io :5 x pass$ once ea* orbit across ! turbul5t face ( ,jupit]4 ,f ,janu>y #cj to ,febru>y #c1 ,voyag] s5t back "o photograph ( ,jupit] e #if seconds ov] a #ajj-;h\r p]iod4 ,us+ a total ( ?ree diff]5t color filt]s1 ! spacecraft ?us produc$ "o color picture e #d m9utes1 9 ord] to make a 8movie0 cov]+ t5 ,jovian 8days40 ,to receive ^! pictures1 s5t back ov] ! high-rate ,x-b& transmitt]1 ! ,deep ,space ,network's #fd-met] ant5nas provid$ r\nd-!-clock cov]age4 ,voyag] #a 0 ready = its f> enc\nt] phase4 ,illu/ration3 ,! ,galilean satellites ( ,jupit] fir/ began to %[ z t9y worlds1 n m]e po9ts ( light1 z ! ,voyag] #a obs]vatory phase began4 ,9 ?is view tak5 ,janu>y #ag1 #aigi1 at a range ( #dg million kilomet]s1 ! diff]+ sizes & surface reflectivities 7alb$os7 ( ,ganym$e 7"r c5t]7 & ,europa 7top "r7 are cle>ly visible4 ,! view ( ,jupit] is unusual 9 t ! ,great ,r$ ,spot is n easily visible1 b c j be se5 at ! "r edge ( ! planet4 ,mo/ pictures select$ = publication include ! photog5ic ,r$ ,spot4 ,p-#bjich;,c ,f> ,enc\nt] ,phase ,by e>ly ,febru>y ,jupit] loom$ too l>ge 9 ! n>r[-angle cam]a to be photograph$ 9 "o piece2 #b #b ?ree-color 7violet1 orange1 gre57 sets ( pictures 7 tak5 = ! next two weeks2 by ,febru>y #ba1 ,jupit] _h gr[n too l>ge ev5 = t1 & #c #c sets 7 s*$ul$ to beg94 ,:5 ^! sets ( pictures are pa/$ toge!r to =m a s+le picture1 ! result is call$ a mosaic4 ,illu/ration3 ,by ,febru>y #a1 #aigi1 ,voyag] #a 0 only #cj million kilomet]s f ,jupit]1 & ! resolution ( ! imag+ sy/em correspond$ to ab\t #fjj kilomet]s at ! cl\d tops ( ! giant planet4 ,at ?is "t1 a great deal ( unexpect$ complexity became app>5t ar\nd ! ,r$ ,spot1 & movie sequ5ces cle>ly %[$ ! cl\d motions1 includ+ ! app>5t six-day rotation ( ! ,r$ ,spot4 ,p-#bjiic;,c ,illu/ration3 ,"o ( ! mo/ spectacul> planet>y photographs ev] tak5 0 obta9$ on ,febru>y #ac z ,voyag] #a cont9u$ its approa* to ,jupit]4 ,by ?is "t1 at a range ( #bj million kilomet]s1 ,jupit] loom$ too l>ge to fit )9 a s+le n>r[-angle imag+ frame4 ,pass+ 9 front ( ! planet are ! inn] two ,galilean satellites4 ,io1 on ! left1 already %[s brightly color$ patt]ns on its surface1 :ile ,europa1 on ! "r1 is a bl& ice-cov]$ _w4 ,! scale ( all ( ^! objects is huge by t]re/rial /&>ds2 ,io & ,europa are ea* ! size ( our ,moon1 & ! ,r$ ,spot is l>g] ?an ! ,e>?4 ,p-#bajhb;,c ,:ile ! imag+ exp]im5ts 7 9 ! limelight1 ! o!r sci5tific in/rum5ts _h also begun to conc5trate on ! ,jovian sy/em4 ,! ultraviolet spectromet] _h be5 scann+ ! region eight times a day2 ! infr>$ spectromet] 7,,iris7 sp5t #a h\rs a day analyz+ infr>$ emissions f v>i\s longitudes 9 ,jupit]'s atmosph]e2 ! planet>y radio a/ronomy & plasma wave in/rum5ts look$ = radio bur/s f ,jupit] & = plasma di/urbances 9 ! region2 ! photopol>imet] _h begun se>*+ = ! edge ( ,io's sodium torus2 & a wat* 0 begun = ! b[ %ock--! out] b\nd>y ( ! ,jovian magnetosph]e4 ,on ,febru>y #aj1 ,voyag] #a cross$ ! orbit ( ,s9ope1 ,jupit]'s out]mo/ satellite4 ,yet ! spacecraft ev5 !n _h a long way to g--/ill #bc million kilomet]s f ,jupit]1 b clos+ 9 on ! planet at ne>ly a million kilomet]s a day4 ,a week lat]1 t>get$ photographs ( ,calli/o began to provide cov]age ( ! satellite all ar\nd its orbit2 simil> photos ( ,ganym$e began on ,febru>y #be4 ,mean:ile excitem5t 0 build+4 ,z e>ly z ,febru>y #h & #i1 delight ) ! mission & anticipation ( ! results ( ! enc\nt] 9 ,m>* 7 already evid5t4 ,g>ry ,e4 ,hunt1 f ! ,laboratory = ,planet>y ,atmosph]es1 ,univ]sity ,college1 ,london1 a memb] ( ! ,imag+ ,team1 discuss+ ! appe>ance ( ,jupit]'s atmosph]e z se5 by ,voyag] dur+ ! previ\s mon?1 said 8,x seems to be f> m photog5ic n[ ?an x did dur+ ! ,pione] enc\nt]s2 ,i'm m ?an delight$ by x--x's an incr$ible /ate ( affairs4 ,!re are inf9itely m details ?an ev] imag9$40 ,illu/ration3 ,! ,voyag] ,project 0 op]at$ f ! ,jet ,propulsion ,laboratory manag$ = ,,nasa by ! ,cali=nia ,in/itute ( ,te*nology4 ,locat$ 9 ! hills above ,pasad5a1 ,cali=nia1 ,,jpl is ! ma9 c5t] = ,u4,s4 exploration ( ! sol> sy/em4 ,,jb#agbdi;,,bc ,illu/ration3 ,! ,voyag] ,,tv cam]as d n take color pictures directly z d comm]cial cam]as4 ,in/ead1 a color image is recon/ruct$ on ! gr\nd f ?ree sep>ate mono*romatic images1 obta9$ ?r\gh color filt]s & transmitt$ sep>ately to ,e>?4 ,!re are a numb] ( possible filt] comb9ations1 b ! mo/ ne>ly 8true0 color is obta9$ ) orig9als photograph$ 9 blue 7#dhj nanomet]s71 gre5 7#efe nanomet]s71 & orange 7#eij nanomet]s7 light4 ,be=e ^! c be comb9$1 ! individual frames mu/ be regi/]$1 correct+ = any *ange 9 spacecraft position or po9t+ betwe5 exposures4 ,(t51 only "p ( a sc5e is conta9$ 9 all ?ree orig9al pictures4 ,%[n "h is a recon/ruction ( a plume on ,jupit]1 photograph$ on ,m>* #a1 #aigi4 ,! colors us$ to pr9t ! ?ree sep>ate frames c be se5 cle>ly 9 ! nonov]lapp+ areas4 ,= o!r pictures 9 ?is book1 ! nonov]lapp+ p>tial frames are omitt$4 ,p-#baaib ,! pictures f ,voyag] are 8cle>ly spectacul>10 said ,lonne ,lane1 ,assi/ant ,project ,sci5ti/ = ,jupit]4 8,we're gett+ ev5 bett] results ?an we _h anticipat$4 ,we h se5 new ph5om5a 9 bo? optical & radio emissions4 ,we h def9itely se5 ?+s t are diff]5t--9 at lea/ 9 "o case1 unanticipat$--& are begg+ = answ]s we hav5't got40 ,!re 0 already1 /ill almo/ a mon? f enc\nt]1 a /rong feel+ ( accompli%m5t among ! sci5ti/s & eng9e]s2 !y _h done a difficult task & x has be5 successful4 ,by ! la/ week ( ,febru>y #aigi1 ! att5tion ( ?\s&s ( individuals 0 focus$ on ! activities at ,,jpl4 ,sci5ti/s _h arriv$ f univ]sities & laboratories ar\nd ! c\ntry & f abroad1 _m br++ graduate /ud5ts or faculty colleagues to assi/ !m4 ,eng9e]s & te*nicians f ,,jpl contractors jo9$ ,,nasa (ficials z ! ,pasad5a motels fill$ up4 ,special badges 7 issu$ & res]v$ p>k+ areas set aside = ! ,voyag] influx4 ,tw5ty-f\r h\rs a day1 lights burn$ 9 ! flight control rooms1 ! sci5ce (fices1 ! comput] areas1 & ! photo process+ labs4 ,9 ord] to protect ^? ) critical tasks to p]=m f ! fri5dly di/raction ( ! new arrivals1 special comput]-controll$ locks 7 plac$ on doors1 & security (fic]s began to patrol ! halls4 ,by ! end ( ! mon? ! press _h begun to arrive4 ,amid accel]at+ excitem5t1 ! ,voyag] #a enc\nt] 0 ab\t to beg94 ,illu/ration3 ,! small]-scale cl\ds on ,jupit] t5d to be m irregul> ?an ! l>ge ovals & plumes4 ,at ! l[] "r1 "o ( ! ?ree l>ge :ite ovals cle>ly %[s int]nal /ructure1 ) ! swirl+ cl\d patt]n indicat+ c\nt]clockwise1 or anticyclonic1 fl[4 ,a small] anticyclonic :ite feature ne> ! c5t] is surr\nd$ by a d>k1 cl\d-free b& :]e "o c see to great] dep?s 9 ! atmosph]e4 ,?is photo 0 tak5 ,m>* #a f a di/ance ( #d million kilomet]s4 ,p-#baahc;,c ,,*apt] #f ,,! ,,fir/ ,,enc\nt] ,! ,giant ,is ,full ( ,surprises ,! ,voyag] #a enc\nt] took place at #d3db a4m4 ,,p/1 ,m>* #e1 #aigi4 ,ab\t six h\rs be=e1 :ile ! spacecraft cont9u$ to hurtle on t[>d ,jupit]1 ov]fl[ cr[ds _h p\r$ out ( ,beckman ,auditorium on ! campus ( ! ,cali=nia ,in/itute ( ,te*nology4 ,!re _h be5 a symposium entitl$ ,jupit] & ! ,m9d ( ,man4 ,m ?an "o face t ev5+ _h turn$ to look t[>d ! ,pasad5a night1 = !re1 glitt]+ aga9/ ! fabric ( ! sky1 0 ! 8/>0 ( ! %[--a planet s huge t ! ,e>? w\ld be b a blemi% on its ,great ,r$ ,spot4 ,"o might h tri$ to imag9e ,voyag] #a1 l>ge by spacecraft /&>ds1 rapidly clos+ 9 on ,jupit]--a pesky1 inve/igative 8mosquito0 buzz+ ar\nd ! ,jovian sy/em4 ,mean:ile1 at ,,jpl1 pictures tak5 by ,voyag] #a 7 fla%+ back e #dh seconds1 pictures t 7 already reveal+ m & m ( ,jupit]'s atmosph]e & w\ld soon disclose f\r new worlds--! ,galilean satellites4 ,! enc\nt] 0 almo/ at h&4 #d3db a4m4--,voyag] #a _h made its close/ approa* to ,jupit] #cg m9utes e>li]4 ,only n[ 7 ! signals t _h be5 s5t out f ! spacecraft at #d3je a4m4 rea*+ ! ,e>?4 ,b ! mom5t ( close/ enc\nt] did n h ! same impact a l&+ w\ld h _h4 ,al?\gh ! *ampagne w\ld fl[ lat] = ^? :o _h work$ s long & h>d on ?is successful mission1 !re 0 none n[4 ,9 ! press room !re 7 j f\r c(feepots work+ ov]time to help keep ! press al]t4 ,9 ! sci5ce areas1 focus _h %ift$ to ! satellite enc\nt]s1 :i* w\ld /ret* ov] ! next #bd h\rs2 mean:ile1 a few p]sons tri$ to cat* a little sleep at _! desks be=e ! fir/ closeups ( ,io came 94 ,! in/ant ( enc\nt] came 444 & w5t 444 ) no screams1 no ,new ,ye>'s noisemak]s4 ,all ! excitem5t ( ! mission lay bo? beh9d 444 & ahead4 ,?ursday1 ,febru>y #bb4 ,! enc\nt] activity 0 kick$ (f 9 ,wa%+ton1 ,d4,c41 by a press conf]5ce at ,,nasa ,headqu>t]s4 ,aft] introductory /atem5ts by ,,nasa & ,,jpl (ficials1 "s ( ! sci5tific results f ! obs]vatory & f> enc\nt] phases 7 pres5t$4 ,bo? ! plasma wave & ! planet>y radio a/ronomy in/rum5ts _h detect$ v-l[-frequ5cy radio emission t g5]ally increas$ 9 int5sity :5ev] ei!r ! nor? or s\? magnetic pole ( ,jupit] tipp$ t[>d ! spacecraft4 ,! plasma wave exp]im5t _h also detect$ radiation t seem$ to come f a region ei!r ne> or beyond ! orbit ( ,io--p]haps ev5 z f> z ! out] magnetosph]e4 ,9 addition1 ,fr$]ick ,l4 ,sc>f1 ,pr9cipal ,inve/igator = ! plasma wave in/rum5t1 releas$ a record+ ( ! ion s\nd waves creat$ by #e to #aj kilovolt en]gy protons travel+ up/ream f ,jupit]4 ,james ,w>wick1 ,pr9cipal ,inve/igator ( ! radio a/ronomy inve/igation1 en?usia/ically report$ ! detection ( a /rik+ new l[-frequ5cy radiation f ,jupit]1 at wavel5g?s ( t5s ( kilomet]s4 ,su* radio waves _c p5etrate ! ionosph]e ( ! ,e>?1 & ?us _h nev] be5 detect$ be=e4 ,because ( _! huge scale1 ^! bur/s probably did n orig9ate at ,jupit] itself1 b 9 magnetosph]ic regions above ! planet--p]haps 9 association ) ! high-d5sity plasma torus associat$ ) ,io4 ,w>wick comm5t$ t 8only f ! magnific5t p]spective ( ! ,voyag] z x approa*es ,jupit] h we be5 able to get ?is complete picture40 ,illu/ration3 ,! ,voyag] #a enc\nt] ) ,jupit] took place dur+ a little m ?an #dh h\rs1 f ! inb\nd to ! outb\nd cross+ ( ! orbit ( ,calli/o4 ,?is figure %[s ! spacecraft pa? z x w\ld be se5 f above ! nor? pole ( ,jupit]4 ,close/ approa* to ,jupit] 0 #cej #jjj kilomet]s4 ,! close flybys ( ,io1 ,ganym$e1 & ,calli/o all took place z ! spacecraft 0 outb\nd4 ,voyag] #a trajectory ,laun* date #i_/e_/gg ,jupit] arrival date #c_/e_/gi ,satellite close/ approa* ,sun occultation ,e>? occultation ,io ,ganym$e ,p]iapsis ,calli/o ,amal!a ,europa ,ano!r unexpect$ result 0 ann\nc$ by ,lyle ,broadfoot1 ,pr9cipal ,inve/igator = ! ultraviolet spectromet] inve/igation4 ,! sci5ti/s _h expect$ to f9d v weak ultraviolet emissions on ! sunlit side ( ,jupit]1 caus$ by sunlight be+ scatt]$ f hydrog5 & helium 9 ,jupit]'s upp] atmosph]e4 8,in/ead we are see+ a spectacul> auroral display4 ,!re are two features ( ! emission--! auroral emission :i* comes f ! planet & a second type ( emission :i* appe>s to come f a radiat+ torus or %ell ar\nd ! planet at ! orbit ( ,io4 ,! spectral cont5t ( ^! two radiat+ s\rces is di/9ctly diff]5t4 ,:at we f9d is t ! auroral emission f ,jupit]'s atmosph]e is s /rong t x completely dom9ates ! emission spectrum ev5 on ! sunlit side ( ! atmosph]e40 8,n s9ce ,m>9] #d c>ri$ its ,,tv cam]a to ,m>s fifte5 ye>s ago h we be5 less prep>$--h we be5 less c]ta9 ( :at we are ab\t to see ov] ! next two weeks10 said ,brad=d ,smi?1 ,imag+ ,team ,lead]4 ,he m5tion$ ! "t-lapse 8rotation movie10 9 :i* ! colorful planet spun ?r\gh t5 full ,jupit] days2 t9y images ( ! satellites pass$ across ,jupit]'s face z ?\gh be+ :ipp$ along by ! rotation ( ! giant4 ,a week or s e>li]1 :5 ?is film _h be5 %[n = ! fir/ "t to ! full ,imag+ ,team1 x provid$ an occasion = good-humor$ rivalry betwe5 planet p & satellite p1 ) jokes ab\t ! satellites gett+ 9 ! way ( ! important /udies ( ,jupit]4 ,= ! next few days1 ! imag+ focus rema9$ on ,jupit]2 x %ift$ to ,io1 ,ganym$e1 & ,calli/o1 z ea* 0 pass$ 9 turn aft] close/ approa* to ! planet4 ,tuesday1 ,febru>y #bg4 7,range to ,jupit]1 #g4a million kilomet]s74 ,at a di/ance ( #ffj million kilomet]s f ,e>?1 )9 #ij ,jovian radii 7,r,j7 ( ,jupit]1 ,voyag] #a 0 prep>$ to beg9 ! enc\nt] ) ! planet's magnetosph]e4 ,on ! previ\s day ! spacecraft _h cross$ ! po9t1 at #ajj ,r,j1 at :i* ,pione]s #aj & #aa _h f\nd ! b[ %ock1 ! fir/ indication ( ! magnetosph]ic b\nd>y4 ,! />t ( ,voyag]'s plunge into ! ,jovian magnetosph]e 0 ov]due1 & sci5ti/s anxi\sly wat*$ ! data f ! p>ticles & fields in/rum5ts1 look+ = ! fir/ indication ( disord]$ magnetic fields & alt]$ p>ticle d5sities t w\ld m>k ! b[ %ock4 ,app>5tly1 high] sol> w9d pressure1 associat$ ) increas$ sol> activity s9ce #aigd1 _h compress$ ! magnetosph]e1 b no "o c\ld pr$ict h[ /rong ?is compression might be4 ,,enc\nt] ,,di/ances ,,= ,,voyag] #a ,object ,range to ,c5t] at ,close/ ,be/ ,image ,resolution ,approa* 7kilomet]s7 7km p] l9e pair7 ,jupit] #cdi #jjj #h ,amal!a #dag #jjj #h ,io #ba #jjj #a ,europa #gcd #jjj #cc ,ganym$e #aae #jjj #b ,calli/o #abf #jjj #b ,= ! fir/ "t s9ce its discov]y1 ,lyle ,broadfoot & 8 ,,uvs colleagues sugge/$ a probable id5tification = ! unexpect$ ultraviolet emission ne> ! orbit ( ,io4 ,! mo/ likely c&idate 0 sulfur atoms ) two electrons remov$ 7,s ,,iii71 at an inf]r$ temp]ature p]haps z high z #bjj #jjj ,k4 ,an additional indication ( sulfur came f ,mike ,krimigis1 :o report$ t ! l[-en]gy *>g$ p>ticles in/rum5t _h detect$ bur/s ( sulfur ions /ream+ away f ,jupit] t _h app>5tly escap$ f ! inn] magnetosph]e4 ,no explanations 7 (f]$1 h[ev]1 = ! pres5ce ( l>ge am\nts ( ?is elem5t4 ,at ,,jpl1 a press room _h be5 op5$ 9 ,von ,k>man ,auditorium to accommodate ! hundr$ or s report]s expect$ to arrive4 ,to keep all ! int]e/$ p in=m$ ( ,voyag] progress1 frequ5t television reports 7 beam$ ov] clos$-circuit ,,tv ?r\gh\t ,,jpl4 ,f an 9-lab television /udio call$ ! ,blue ,room1 ,,jpl sci5ti/ ,al ,hibbs1 :o _h play$ a simil> role dur+ ! ,vik+ ,mission to ,m>s1 provid$ h\rly reports & int]view$ memb]s ( ! ,voyag] teams4 ,z ! pressure = con/ant comm5t>y & in/ant analysis increas$1 ,g>ry ,hunt ( ! ,imag+ ,team 0 also call$ on to ho/ activities 9 ! ,blue ,room1 :]e 8 ,briti% acc5t add$ an additional t\* ( class to ! op]ation4 ,z ! enc\nt] progress$1 ! ,,jpl television reports rea*$ a wid] audi5ce4 ,9 ! ,los ,angeles area1 ,,kcet ,public ,television began a nightly 8,jupit] ,wat*0 program1 ) ,dr4 ,hibbs z ho/4 ,dur+ ! enc\nt] days1 s]vice 0 ext5d$ to int]e/$ public television /ations ?r\gh\t ! nation4 ,9 ?is way1 t5s ( ?\s&s ( p]sons 7 able to exp]i5ce ! ?rill ( discov]y1 see+ ! closeup pictures ( ,jupit] & its satellites at ! same mom5t z ! sci5ti/s at ,,jpl saw !m1 & li/5+ to ! excit$ & frequ5tly awe/ruck comm5t>y z ! fir/ t5tative int]pretations 7 attempt$4 ,un=tunately1 ! comm]cial television networks did n make use ( ?is opportunity1 & ! greate/ cov]age available to mo/ ( ! c\ntry 0 a #ij-second comm5t>y on ! nightly network news4 ,w$nesday1 ,febru>y #bh4 7,range to ,jupit]1 #e4i million kilomet]s74 ,at #f3cc a4m41 at a range ( #hf ,r,j1 ,voyag] #a f9ally rea*$ ,jupit]'s b[ %ock4 ,b by #ab3bh p4m4 ! sol> w9d _h pu%$ ! magnetosph]e back t[>d ,jupit]1 & ,voyag] 0 once m outside1 back 9 ! sol> w9d4 ,n until ,m>* #b1 at a di/ance ( less ?an #de ,r,j1 w\ld ! spacecraft ent] ! magnetosph]e = ! f9al "t4 ,at #aa a4m4 ! fir/ daily brief+ to ! press 0 giv54 8,aft] ne>ly two mon?s ( atmosph]ic imag+ & p]haps a week or two ( satellite view+1 we're happily bewild]$10 said ,brad ,smi?4 ,! ,jovian atmosph]e is 8:]e our greate/ /ate ( confusion seems to exi/ "r at ! mom5t1 al?\gh ov] ! next sev]al days we may f9d t "s ( our smirk+ geology fri5ds w f9d !mselves 9 a simil> /ate4 ,i ?9k1 = ! mo/ "p1 we h to say t ! exi/+ atmosph]ic circulation models h all be5 %ot to hell by ,voyag]4 ,al?\gh ^! models c /ill expla9 "s ( ! co>se zonal fl[ patt]ns1 !y fail entirely 9 expla9+ ! detail$ behavior t ,voyag] is n[ reveal+40 ,x 0 ?\ght1 f ,pione] results1 t ,jupit]'s atmosph]e %[$ prim>ily horizontal or zonal fl[ ne> ! equatorial region1 b t ! zonal fl[ patt]n broke d[n at high latitudes4 ,b ,voyag] f\nd t 8zonal fl[ exi/s polew>d z f> z we c see40 ,smi? also %[$ a "t-lapse movie ( ,jupit] assembl$ f images obta9$ dur+ ! mon? ( ,janu>y4 ,once ea* rotation1 approximately e t5 h\rs1 a color picture _h be5 tak54 ,view$ consecutively1 ^! frames display$ ! complex cl\d motions on a s+le hemisph]e ( ,jupit]1 z !y w\ld be se5 f a fix$ po9t above ! equator ( ! planet4 ,! film reveal$ t cl\ds move ar\nd ! ,great ,r$ ,spot 9 a p]iod ( ab\t six days1 at spe$s ( p]haps #ajj met]s p] second4 ,! ,great ,r$ ,spot1 z well z _m ( ! small] spots t dot ! planet1 appe>$ to be rotat+ anticyclonically4 ,anticyclonic motion is *>act]i/ic ( high-pressure regions1 unlike t]re/rial /orms4 ,smi? not$ t 8,jupit] is f> m complex 9 its atmosph]ic motions ?an we _h ev] imag9$4 ,we are see+ a mu* m complicat$ fl[ ( cyclonic & anticyclonic vorticity1 circulation4 ,we see curr5ts :i* fl[ along & seem to int]act ) an ob/acle & turn ar\nd & fl[ back40 ,!re is a ,jovian jet /ream t is 8mov+ along at well ov] #ajj met]s p] second4 ,sev]al ( ^! curi\s little d>k features t appe> to be small br[n spots ne> ,jupit]'s nor? temp]ate region h be5 se5 to ov]take "o ano!r & gobble ea* o!r up4 ,& !n !y occasionally spit out a piece "h & !re z !y move along40 ,?ursday1 ,m>* #a4 7,range to ,jupit]1 #d4h million kilomet]s74 ,at #e a4m41 at a di/ance ( #ga ,r,j1 ,voyag] cross$ ! b[ %ock = ! ?ird "t1 cat*+ up ) ! contract+ magnetosph]e ( ! planet4 ,ab\t noon1 at #ff ,r,j1 ! spacecraft f9ally rea*$ ! b\nd>y ( ! magnetosph]e1 call$ ! magnetopause4 ,h]b]t ,bridge1 ! plasma in/rum5t ,pr9cipal ,inve/igator1 not$ t ! sol> w9d pressure z monitor$ by ,voyag] #b1 /ill betwe5 ! ,sun & ,jupit]1 _h be5 = sev]al days f two to five times great] ?an its level dur+ ! ,pione] #aj & #aa enc\nt]s4 ,presumably1 ?is high pressure 0 ! cause ( ! compress$ /ate ( ! magnetosph]e4 ,h[ev]1 9 ! previ\s few h\rs ! sol> pressure _h dropp$1 s ,bridge anticipat$ t ! ,jovian magnetosph]e might soon inflate & exp& outw>d4 ,illu/ration3 ,! s\!rn hemisph]e ( ,jupit] pres5ts a trem5d\s div]sity ( atmosph]ic /ructure & motion4 ,! ,great ,r$ ,spot rotates c\nt]clockwise 9 ab\t six days2 above & bel[ x high-spe$ jet /reams fl[ to ! "r & ! left1 :ile a complex1 dynamic cl\d patt]n develops 9 its wake4 ,?is picture 0 tak5 on ,febru>y #be1 :5 ,voyag] #a 0 #i million kilomet]s f ! planet4 ,p-#baaea;,c ,fr$ ,sc>f intrigu$ ! press ) a tape ( ! s\nds made by high-en]gy protons com+ up/ream f ,jupit]4 ,! plasma wave in/rum5t _h record$ ! noise ( ! protons1 mix$ ) ! noise ( ! spacecraft itself1 produc+ s\nd effects t s\nd$ some:at l a mixture ( s++ :ales1 a ,nor'ea/]1 & ! ,daytona #ejj4 ,at ! press brief+1 int]e/ 9 ! imag+ results began to %ift f ,jupit] t[>d ! satellites4 ,pictures ( ea* ( ! f\r big ,galilean moons reveal$ bright & d>k features z small z ab\t #bjj kilomet]s across4 ,un=tunately1 ?is resolution is n en\gh to be diagno/ic--! spots _c be int]pret$ 9 t]ms ( recognizable geological features1 su* z m\nta9s or crat]s4 ,today "o c\ld only speculate1 b tomorr[ or ! next day ! answ]s w\ld beg9 to come 94 ,deputy ,imag+ ,team ,lead] ,l>ry ,sod]blom convey$ 8 excitem5t ?r\gh a metaphor t w\ld be repeat$ _m times dur+ ! next week3 8,we're beg9n+ a /age 9 ?is mission :i* repres5ts1 ,i ?9k1 "o ( ! mo/ excit+ po9ts 9 man's sci5tific exploration ( ! sol> sy/em--9 ! next few days1 we'll explore f\r new worlds10 see+ 9 a few days' "t :at x took u c5turies to le>n ab\t o!r worlds 9 our sol> sy/em4 ,9 t]ms ( our exp]i5ce ) ! exploration ( ,m>s1 8x is ab\t #agjj ,,ad ?is morn+1 tomorr[ x w be ab\t #ahjj1 & x w be ab\t #aigf ! ye> ( ,vik+ by ,tuesday ev5+40 ,friday1 ,m>* #b4 7,range to ,jupit]1 #c4f million kilomet]s74 ,e>ly 9 ! morn+1 a twelvefold increase 9 sol> w9d pressure caus$ ano!r contraction ( ! magnetosph]e1 :i* 0 behav+ l a spr+1 compress+ 9 response to outside =ces4 ,z ! magnetopause b\nd>y mov$ rapidly inw>d1 x cross$ ! spacecraft at #ei ,r,j f ! planet4 ,an h\r lat] ! b[ %ock also fla%$ pa/1 & ,voyag] 0 once m 9 ! int]planet>y m$ium4 ,by noon re9flation ( ! magnetosph]e began aga92 ,voyag] cross$ ! b[ %ock = ! fif? & f9al "t at #ee ,r,j1 foll[$ by ?ree m magnetopause cross+s1 z ! magnetosph]ic b\nd>y flopp$ 9 & out betwe5 #de ,r,j & #ej ,r,j4 ,illu/ration3 ,a few days be=e enc\nt]1 ! ,voyag] images ( ! l>g] ,galilean satellites1 ,calli/o & ,ganym$e1 7 beg9n+ to %[ di/9ctive surfaces ) _m bright spots4 ,^! two pictures 7 tak5 on ,m>* #e at a range ( #h million kilomet]s2 ! resolution is ab\t #ajj kilomet]s4 ,al?\gh extremely tantaliz+1 ^! images 7 un9t]pretable1 because ! spots c\ld n be associat$ ) any recognizable geological features1 su* z m\nta9s or crat]s4 ,l a nak$-eye view ( ! ,moon1 ^! pictures seem$ to reveal m ?an 0 actually mean+ful4 ,p-#baahh;,c & ,p-#baaej;,c ,illu/ration3 ,ganym$e ,"s ,project (ficials began to worry ab\t ! contract$ /ate ( ! magnetosph]e4 ,! radiation 8h>d5+0 ( ,voyag] 0 c>ri$ out to protect aga9/ ! en]getic p>ticle fluxes obs]v$ by ,pione]s #aj & #aa4 ,"u ! new conditions1 w\ld ! p>ticles 9 ! inn] magnetosph]e be m conc5trat$ & p]haps increase ! radiation levels beyond ! design limits8 ,sci5ti/s ask$ h[ long ! compression might la/ & speculat$ ab\t h[ mu* en]gy might be pump$ into ! ,jovian radiation belts1 b only "t c\ld provide ! answ]s4 ,,voyag] #a ,,b[ ,,%ock 7,s7 ,,& ,,magnetopause 7,m7 ,,cross+s ,b\nd>y ,day ,di/ance 7,r,j7 ,inb\nd ,s #b_/bh #hf ,s #b_/bh #hb ,s #c_/ja #gb ,m #c_/ja #fg ,m #c_/jb #ei ,s #c_/jb #eh ,s #c_/jb #ef ,m #c_/jc #dg ,outb\nd ,m #c_/ac #aeh ,m #c_/ac #afc ,m #c_/ac #afe ,s #c_/af #aii ,s #c_/ah #bbg ,s #c_/ah #bbg ,s #c_/ai #bdj ,s #c_/bj #bef ,s #c_/bj #beh ,accurate record+ ( ! ,x-b& data be+ s5t f ,voyag] at #aae ?\s& bits p] second requir$ fairly cle> wea!r at ! track+ sites4 ,! ?ree ,deep ,space ,network 7,,dsn7 /ations 9 ,cali=nia1 ,spa91 & ,au/ralia are locat$ at normally dry sites4 ,h[ev]1 e>ly 9 ! morn+1 heavy ra9 at ! ,au/ralian site int]f]$ ) reception ( ! ,voyag] signal = f\rte5 m9utes4 ,=tunately1 ! loss occurr$ :5 ! ,,dsn track+ ( ! spacecraft 0 be+ swit*$ f ,gold/one1 ,cali=nia1 to ! ,au/ralian /ation4 ,mission control 0 able to ext5d ,gold/one cov]age = sev]al m9utes s t only ab\t ?ree m9utes' wor? ( data 0 lo/ completely4 ,a m positive ann\ncem5t 0 made at ! press conf]5ce t morn+ by ,donald ,%emansky ( ! ,ultraviolet ,spectroscopy ,team3 ! discov]y ( a high-en]gy torus ( d\bly ioniz$ sulfur 7,s ,,iii7 circl+ ,jupit] 9 ! region ( ,io's orbit4 8,we 7 surpris$ out ( our *airs to see a spectacul>ly bright emission 9 ! #fej-aajj ang/rom region1 imm$iately imply+ t we 7 look+ at a plasma t _h to be at a temp]ature ( ab\t #ajj #jjj degrees40 ,! sci5ti/s e/imat$ t ! d5sity ( ?is torus mu/ be at lea/ #ejj ions p] cubic c5timet]1 & t ! p[] ne$$ to keep ?is plasma at su* a high temp]ature mu/ be 9 ! neighborhood ( #ejj billion watts4 ,z ,al ,hibbs m5tion$ on 8,jupit] ,wat*0 t night1 #ejj billion watts ( p[] is ! total am\nt ( in/all$ g5]at+ capacity ( ! ,unit$ ,/ates4 ,saturday1 ,m>* #c4 7,range to ,jupit]1 #b4e million kilomet]s74 ,e>ly 9 ! morn+ ! f9al cross+ ( ! magnetopause took place at #dg ,r,j1 & ,voyag] f9ally jo9$ ! ,jovian sy/em4 ,at ! end ( ! day1 ! rapidly mov+ spacecraft cross$ ! orbit ( ,calli/o1 b t satellite itself 0 on ! f> side ( ! planet4 ,n until ! outb\nd cross+ ( its orbit on ,m>* #f w\ld closeup views ( ,calli/o be obta9$4 ,dur+ ! prec$+ night1 a sev]e summ] ?und]/orm 9 ,au/ralia aga9 caus$ a loss ( data4 ,a l9e ( /orms ov] ! track+ /ation block$ ! high-rate1 ,x-b& sci5ce data = ?ree h\rs & tw5ty m9utes4 ,attempts 7 made to save a "p ( ! data by comm&+ ! spacecraft to sl[ its transmission rate1 r l speak+ sl[ly to a p>tially deaf li/5]4 ,b by ! "t ! craft receiv$ ! signal & respond$1 ! /orms _h int5sifi$1 & no signal c\ld get ?r\gh4 ,closeups ( ! ,great ,r$ ,spot & an ext5d$ s]ies ( obs]vations ( ! gl[+ sodium cl\d ar\nd ,io 7 lo/4 ,a black-&-:ite movie assembl$ f photos obta9$ 9 ,janu>y & ,febru>y 0 %[n at ! press conf]5ce4 ,! movie 0 tak5 f obs]vatory phase pictures photograph$ 9 blue light4 ,f ^! pictures1 ! imag+ team 8put toge!r ?is s-call$ #8blue movie'10 said ,brad ,smi?1 introduc+ ! film4 ,! film %[$ *anges tak+ place 9 ,jupit]'s atmosph]e ov] a p]iod ( ab\t sev5ty ,jovian days4 ,ne> ! equator !re 7 8bright plumes float+ by--at high spe$ ! plumes seem to wave ar\nd1 some?+ l a flag wav+ 9 ! breeze40 ,f>!r nor?1 along ! edge ( ! nor? temp]ate zone1 "o c\ld see "o ( ! d>k ovals--8a r fuzzy "o w\ld move up1 cat* up ) ! "o j ahead ( x1 get /uck to ! outside & roll ar\nd on x = a :ile1 !n get eject$ a little lat]40 ,dr4 ,smi? also %[$ new closeup views ( ! region ar\nd ! ,r$ ,spot1 %[+ n only ! anticyclonic features b filam5t>y 8spaghettilike0 mat]ial :i* 0 rotat+ 9 a cyclonic direction1 indicat+ a l[-pressure region4 8,! filam5t>y mat]ial /ill seems to be r a my/]y--v difficult to see ! details ( ! motion40 ,b ! photographs 7 already %[+ :at seem$ to be /ream l9es 9 ! :ite ovals4 8,9 appe>ance ! :ite ovals seem to resemble ! ,r$ ,spot4 ,! /ream l9es are at lea/ sugge/ive ( div]g5t fl[1 t is1 mat]ial 9 ea* ( ^! spots :i* is upwell+ 9 ^! areas & !n mov+ out t5ds to g ar\nd 9 a c\nt]clockwise anticyclonic motion b may1 at ! same "t1 be sl[ly div]g+ outw>d40 ,illu/ration3 ,at a resolution ( ab\t #ajj kilomet]s a planet>y surface j beg9s to reveal its p]sonality4 ,io 0 photograph$ aga9/ ! disk ( ,jupit] on ,febru>y #bf1 f a di/ance ( ab\t #h million kilomet]s4 ,su* e>ly pictures :ett$ ! appetites ( ! ,voyag] sci5ti/s at ,,jpl z !y anxi\sly speculat$ ab\t :at !y w\ld f9d 9 clos] views ( ! surface ( ?is rem>kable satellite4 ,p-#baahe ,b_/,w ,! l>ge :ite ovals are ab\t =ty ye>s old4 ,dr4 ,smi? expla9$ h[ !y =m$3 ,betwe5 #aici & #aidj1 8:]e ^? ?ree :ite spots exi/ "r n[1 0 a r bright b& simil> to ! nor? temp]ate zone we see on ,jupit] "r n[4 ,9 t "t p]iod ( a ye> or s1 ?ree d>ki% spots =m$4 ,a d>k cl\d spread out at ea* "o ( ^? ?ree locations & j kept spread+ longitud9ally until ! :ite mat]ial cond5s$ betwe5 !m40 ,9 ! end1 ev]y?+ 0 d>k except = ! ?ree ovals1 :i* h p]si/$ ev] s9ce4 ,torr5ce ,johnson ( ! ,imag+ ,team comm5t$ on a photo ( ,io 9 :i* features resembl+ circul> crat]-type /ructures seem$ to be visible4 8,:atev] !y are1 ^? circul> features are approa*+ ! size ( ! ?+s t we w\ld call bas9s if !y 7 impact /ructures on o!r planets4 ,we don't really "k :e!r !y're impact /ructures4 ,!y h "s *>act]i/ics t look rem9isc5t ( impact /ructures4 ,!y c\ld be endog5ic--volcanic 9 orig9--or int]nally g5]at$ 9 "s o!r way40 ,johnson also %[$ ano!r photograph ( ,io1 ?is "o tak5 aga9/ black sky1 %[+ a 8/rik+ly diff]5t face0 look+1 p]haps1 l someone's nightm>e1 gl>+ back at ! intrud] f ,e>?4 ,"o huge feature--a 8bullseye0 or 8ho( pr9t0 on ,io--appe>$ to be approximately #ajjj kilomet]s long4 ,no "o _h ev] se5 su* a feature1 & ! imag+ sci5ti/s c\ld only speculate ab\t its significance4 ,illu/ration3 ,small-scale /ructures 9 ! jet /reams ( ,jupit]'s nor? tropical zone reveal details ( atmosph]ic circulation4 ,! small d>k oval ne> ! "r edge ( ! zone may (f] a glimpse deep into ,jupit]'s atmosph]e4 ,betwe5 ! regul>ly spac$ d>k ovals ne> ! bottom ( ! frame are m small-scale features t are be+ /udi$ = _! roles 9 ,jovian atmosph]ic activity4 ,! blue-gray regions along ! %e> l9e betwe5 ! equatorial zone & ! nor? equatorial belt also appe> to be w9d[s into ! deep] regions ( ! atmosph]e4 ,?is photo 0 tak5 ,febru>y #ai by ,voyag] #a f a di/ance ( #ad million kilomet]s4 ,p-#baafj;,c ,a few days e>li]1 someone _h po/$ 9 ! ,imag+ ,team area a quote f a #aige review pap] on ! ,jovian satellites by ,david ,morrison & ,joseph ,burns4 ,! section on ,io began1 8,io is "o ( ! mo/ intrigu+ objects 9 ! sol> sy/em40 ,?is /atem5t seem$ m & m appropriate z ,voyag] images improv$4 ,johnson ref]r$ to ?is day z equival5t to ! 8late #aifjs0 9 our /udy ( ! ,jovian satellites4 8,we c see mu* m cle>ly ?an ev] be=e1 b /ill n cle>ly en\gh to provide und]/&+ ( :at we are see+40 ,sunday1 ,m>* #d4 7,range to ,jupit]1 #a4b million kilomet]s74 ,at #d3cg a4m41 ! ne> enc\nt] phase began3 ,voyag] #a 0 almo/ !re6 ,9 ! press room1 someone tap$ a =tune cookie message to ! ,voyag] ,,tv monitor3 8,!re is a prospect ( a ?rill+ "t ahead = y40 ,pull$ by ! p[]ful gravity ( ,jupit]1 ! spacecraft 0 n[ on a curv$ pa? ?r\gh ! inn] ,jovian sy/em4 ,at #b p4m4 ,,p/1 x cross$ ! orbit ( ,ganym$e1 & lat] 9 ! aft]noon x pass$ )9 less ?an #b million kilomet]s ( ,europa1 provid+ ,voyag] #a's close/ look at ?is satellite4 ,dur+ ! aft]noon & ev5+1 a numb] ( views 7 obta9$ ( ,amal!a1 ! small inn] satellite1 at a range ( less ?an #ejj #jjj kilomet]s4 ,at #h p4m4 ! orbit ( ,europa 0 cross$1 & increas+ att5tion 0 drawn to ! com+ enc\nt] ) ,io4 ,at ab\t #g p4m4 a full-frame color sequ5ce ( ,io 0 receiv$ ) a resolution ( #af kilomet]s4 ,dur+ ! night1 z ,imag+ ,team memb]s scrat*$ _! heads try+ to prep>e a press release caption to int]pret ! peculi> /ructures se51 ! ,,jpl ,image ,process+ ,lab ru%$ to prep>e a color v]sion = release ! next day4 ,illu/ration3 ,! ,great ,r$ ,spot became m & m spectacul> z ,voyag] #a approa*$1 ) ea* day reveal+ new & intricate detail 9 ! cl\ds4 ,?is view 0 obta9$ on ,m>* #a at a di/ance ( #e million kilomet]s2 ! smalle/ features t c be made out are ab\t #ajj kilomet]s across4 ,to ! we/ ( ! ,great ,r$ ,spot is a region ( great turbul5ce1 & to ! s\? is "o ( ! ?ree :ite ovals4 ,p-#baahb;,c ,illu/ration3 ,l>ge br[n ovals 9 ! nor!rn hemisph]e ( ,jupit] are app>5tly regions 9 :i* an op5+ 9 ! upp]1 ammonia cl\ds reveals d>k] regions bel[4 ,?is oval1 ab\t ! same l5g? z ! diamet] ( ! ,e>?1 0 at latitude #ae,n4 ,features ( ?is sort are n r>e on ,jupit] & h an av]age lifetime ( "o to two ye>s4 ,above ! feature is ! pale orange nor? temp]ate belt1 b\nd$ on ! s\? by ! high-spe$ nor? temp]ate curr5t1 ) w9ds ( #abj met]s p] second4 ,! range to ,jupit] at ! "t ?is photograph 0 obta9$ on ,m>* #b 0 #d million kilomet]s1 ) ! smalle/ resolvable features be+ #ge kilomet]s across4 ,p-#baaid;,c ,illu/ration3 ,! be/ ,voyag] #a photos ( ,europa 7 obta9$ on ,m>* #d f a di/ance ( ab\t #b million kilomet]s4 ,?is view ( ! hemisph]e c5t]$ at ab\t #cjj longitude has a resolution ( ab\t #dj kilomet]s4 ,mo/ ( ! surface is bl& & highly reflective1 be+ compos$ almo/ entirely ( wat]-ice4 ,no crat]s result+ f meteoric impacts c be se54 ,! mo/ /rik+ visual features1 :i* set ,europa (f f ! o!r satellites1 are ! d>k /reaks1 z mu* z sev]al ?\s& kilomet]s long1 t cross ! surface4 ,j b>ely visible to ,voyag] #a1 ^! /reaks 7 dramatically app>5t to ,voyag] #b 9 its clos] flyby 9 ,july4 ,p-#babjh;,c ,once aga91 track+ /ation problems int]rupt$ ! smoo? fl[ ( data f ! spacecraft4 ,failure at ,madrid to ree/abli% ! correct receiv] frequ5cy aft] a spacecraft maneuv] result$ 9 ! loss ( #ec m9utes ( irreplaceable data2 an additional elev5 m9utes 7 lo/ an h\r lat]4 ,z ! fir/ problem 0 be+ correct$1 ! track+ ant5na became misalign$1 result+ 9 a noisy data return4 ,mean:ile1 only a few ( ! wat*]s at ,,jpl m\rn$ ! lo/ data1 s excit+ 7 ! o!r new results t kept p\r+ 94 8,= ! highlights ( ?is morn+ ,dr4 ,sod]blom w come up & %[ "s beautiful satellite pictures10 ,brad ,smi? ann\nc$ at ! daily press brief+4 ,l>ry ,sod]blom's excitem5t 0 h>d to conta94 8,today is probably go+ to turn out to be "o ( ! mo/ memorable days 9 our exploration program4 ,= ! planet>y geologi/s x's truly ,*ri/mas ,eve4 ,we see tonight ! beg9n+ ( ! exploration ( f\r new worlds4 ,we're rac+ ?r\gh "t & space at an incr$ible rate--! rate at :i* we are le>n+ ?+s is awe-inspir+ 9 itself40 ,calli/o 0 /ill too f> away to see well 8b ! ?+s we're see+ on ! clos] ?ree satellites h really got u *>g$ 9 anticipation40 ,ganym$e--8,:at c ,i say8 ,loops & swirls & incr$ible pat*es t are difficult n[ to haz>d a guess ab\t40 ,io--an e]ie-look+ r$1 orange1 & yell[ _w--8?is "o we've got all figur$ out4 ,laught] f ! press & applause4 ,x is cov]$ ) ?9 c&y %ells ( any?+ f sulfates & sulfur & salts to all k9ds ( /range ?+s40 ,! l[ en]gy *>g$ p>ticle in/rum5t _h discov]$ high-spe$ sulfur 9 ! out] ,jovian magnetosph]e1 t5 times z f> f ! planet z ! sulfur torus ar\nd ,io4 ,! high-spe$ sulfur1 :i* :izz$ by ,voyag] #a at #hjjj kilomet]s p] second1 0 fir/ detect$ z ! spacecraft cross$ ! magnetopause & ent]$ ! magnetosph]e4 ,app>5tly ?is sulfur _h pick$ up spe$ z x mov$ outw>d f ,io's torus1 b ! me*anism = ?is accel]ation 0 n kn[n4 ,roby ,vogt report$ t ! cosmic ray in/rum5t 0 detect+ two di/9ct gr\ps ( atoms clos] 9 to ! planet4 ,"o gr\p 0 app>5tly ( sol> composition 7d]iv$ f ! sol> w9d71 & ! o!r %[$ enhanc$ oxyg5 z well z sulfur4 ,! plasma in/rum5t _h also begun to measure sulfur 9 ! same =m 7,s ,,iii7 z t detect$ by ! ,,uvs 9 ! ,io torus4 ,:]e1 ! sci5ti/s ask$1 c\ld ! oxyg5 & sulfur be com+ f8 ,c\ld ,io be ! s\rce ( ^! atoms8 ,at "o po9t1 z que/ions f ! press became too detail$1 ask+ = 8in/ant analyses0 ( ! data1 ,dr4 ,smi? 0 prompt$ to make ! foll[+ /atem5t3 8,i want to say some?+ ab\t :at's go+ on "r n[ 9 ! imag+ area because we get a lot ( po9t$ que/ions4 ,we h a rem>kably good sy/em t is gett+ extremely good photographs4 ,n only are ! cam]as work+ well1 b ,jupit] & ! satellites are coop]at+ by %[+ a lot ( truly rem>kable detail4 ,& x may s\nd unpr(essional1 b a lot ( ! p up 9 ! ,imag+ ,team area are j /&+ ar\nd ) _! m\?s hang+ op5 wat*+ ! pictures come 91 & y don't l to te> y\rself away to g & />t look+ at numb]s on a pr9t\t4 ,we w d t1 b 9 ! meantime we're j caught up 9 ! excitem5t ( :at's go+ on40 ,:ile ! press brief+ 0 und]way1 betwe5 #aa3ch & #aa3ej a4m41 a special exp]im5t 0 be+ tri$ on bo>d ! ,voyag]4 ,z ! spacecraft pass$ ?r\gh ! plane ( ! equator ( ,jupit]1 x aim$ its n>r[-angle cam]a to a po9t 9 space halfway betwe5 ! cl\d tops & ! orbit ( ,amal!a & took a s+le1 elev5-m9ute exposure4 ,! purpose3 to se>* = a possible fa9t r+ ar\nd ,jupit]1 :i*1 if pres5t1 c\ld be/ be se5 by sight+ along ! plane ( ! equator4 ,! image appe>$ briefly on ! ,,tv monitors1 cle>ly %[+ some?+--a /range b& ( light--/reak+ across ! c5t] ( ! frame4 ,up 9 ! imag+ area1 analyses began at once to det]m9e if ! /range b& 7 really ! s\ght-= r+1 b x w\ld n be until ,m>* #g t ! id5tification w\ld be confirm$ & ! discov]y ann\nc$4 ,illu/ration3 ,! 8bullseye0 ( ,io 0 fir/ photograph$ at a range ( #b4h million kilomet]s on ,m>* #c1 & ?is color v]sion 0 releas$ on ,m>* #d4 ,at ! "t1 ,imag+ ,team sci5ti/s wrote t 8,! l>ge he>t-%ap$ feature ) a d>k spot ne> its c5t] c\ld be ,io's equival5t ( an impact bas9 su* z ,m>e ,ori5tale on ! ,moon4 ,its out] dim5sions are ab\t #hjj by #ajjj kilomet]s4 ,subsequ5t high-resolution cov]age %\ld reveal :e!r ! small d>k spots are impact crat]s1 or p]haps some?+ m exotic su* z volcanoes4 ,! r$di% color ( ,io has be5 attribut$ to sulfur 9 ! salts :i* are believ$ by "s to make up ! surface ( ,io40 ,x w\ld be ano!r week be=e ?is feature1 lat] nam$ 8,pele0 = ! ,hawaiian volcano goddess1 w\ld be recogniz$ z an active1 erupt+ volcano4 ,p-#baahg;,c ,monday1 ,m>* #e4 7,enc\nt] ,day4 ,m9imum range to ,jupit]1 #ghj #jjj kilomet]s2 spe$ ( spacecraft1 almo/ #ajj #jjj kilomet]s p] h\r74 ,_m celebrities1 includ+ ! ,gov]nor ( ,cali=nia1 sp5t ! night at ,,jpl to witness ! hi/oric occasion4 ,9 ,wa%+ton1 ,d4,c41 a special ,,tv monitor 0 set up 9 ! ,:ite ,h\se = ! ,presid5t & 8 family4 ,z late ,sunday night eas$ into ! e>ly morn+ ( enc\nt]1 closeup images ( ,jupit]1 look+ m l ab/ract art ?an l planet>y sci5ce1 fla%$ across ! ,,tv scre5s1 & v]bal images f> less wild ?an ! visuals f ,jupit] 7 he>d f comm5tators & f memb]s ( ! press4 8,are y sure ,van ,gogh didn't pa9t t80 8,t's n ,jupit]2 x looks l a closeup ( a salad40 8,!y're n %[+ u ,jupit]1 t's "s m$ical s*ool anatomy slide40 ,%ortly be=e close/ approa* to ,jupit]1 ,voyag] began its int5sive obs]vations ( ,io4 ,mu* ( ?is in=mation1 tak5 :ile ! ,au/ralian /ation 0 track+ ! spacecraft1 0 record$ on ,voyag]'s onbo>d tape-record] = playback lat] t day4 ,b ev5 be=e ! results ( t imag+ 7 kn[n1 ,l>ry ,sod]blom 0 call+ ,io 8"o ( ! mo/ spectacul> bodies 9 ! sol> sy/em40 ,z m & m vivid photos ( ,io appe>$ on ! monitors1 memb]s ( ! ,imag+ ,team 9 ! ,blue ,room buzz$ ) excitem5t4 8,?is is incr$ible40 8,! elem5t ( surprise is com+ up 9 e "o ( ^! frames40 8,i knew x w\ld be wild f :at we saw on approa* b to anticipate any?+ l ?is w\ld h requir$ "s sort ( heav5ly p]spective4 ,i ?9k ?is is incr$ible40 ,at #g3ce a4m4 ,voyag] 0 s*$ul$ to pass ?r\gh ! flux tube ( ,io1 ! region 9 :i* trem5d\s electric curr5ts 7 calculat$ to be fl[+ back & =? betwe5 ! satellite & ,jupit]4 ,norm ,ness sugge/$1 aft] exam9+ magnetomet] data1 t ,voyag] skirt$ ! edge ( ! flux tube1 & t ! curr5t 9 ! tube 0 ab\t "o million amps4 ,z ! flux tube results 7 receiv$1 *ampagne bottles began to pop 9 ! p>ticles & fields sci5ce (fices1 9 celebration ( ! successful passage ?r\gh ! inn] magnetosph]e4 ,mean:ile1 at #g3dg a4m41 close/ approa* to ,io occurr$1 at a range ( only #bb #jjj kilomet]s4 ,voyag] 0 #be #jjj times clos] to ?is satellite ?an 7 ! wat*]s on ,e>?4 ,at #h3ad a4m41 :ile /ill )9 #cj #jjj kilomet]s ( ,io1 ! spacecraft pass$ out ( sight beh9d ! edge ( ,jupit]4 ,all sci5tific data = ! next two h\rs & six m9utes 7 /or$ on ! onbo>d tape record] = lat] transmission to ,e>?4 ,mean:ile1 ! radio communication signal 0 us$ to probe ! atmosph]e ( ,jupit]1 yield+ a pr(ile ( electron d5sity 9 ! ionosph]e & ( ! gas pressure & temp]ature 9 ! upp] atmosph]e4 ,:ile out ( sight f ,e>?1 at #i3jg a4m41 ,voyag] plung$ into ! %ad[ ( ,jupit]4 ,z ! ,sun set on ! spacecraft1 ! ultraviolet in/rum5t us$ ! absorption ( sunlight to det]m9e ! composition & temp]ature ( ! upp] atmosph]e4 ,9 ! d>kness1 ! infr>$ ,,iris measur$ ! night-side temp]atures ( ! planet1 & long-exposure images 7 tak5 to se>* = aurora1 lightn+1 & fireballs 9 ! ,jovian atmosph]e4 ,at #aj3bj a4m41 ,voyag] reappe>$ f beh9d ,jupit] & radio contact 0 re/or$2 at #aa3bd a4m41 x em]g$ f %ad[ into sunlight1 spe$+ on t[>d enc\nt] ) ,ganym$e4 ,at #h a4m4 a special press conf]5ce 0 held to m>k ! successful ,jupit] flyby4 ,noel ,h9n]s1 ,associate ,adm9i/rator = ,space ,sci5ce & ! highe/ rank+ ,,nasa (ficial pres5t1 congratulat$ all ^? :o _h made ! ,voyag] ,mission a success4 ,! enc\nt] 0 ! 8culm9ation ( a fanta/ic am\nt ( d$ication & ef=t4 ,! result is a spectacul> feat ( te*nology & a beg9n+ ( a new era ( sci5ce = ! sol> sy/em4 ,j wat*+ ! data come 9 has be5 fanta/ic4 ,i _h a fe> t ?+s on ! satellites 7 go+ to look l ! lun> highl&s4 ,nature w9s aga94 ,if we're go+ to see exploration ( ?is nature occurr+ 9 ! #aihjs & #aiijs we mu/ cont9ue to exp\nd ! results ( :at we're f9d+ "h1 ! role ( exploration 9 ! hi/ory ( our c\ntry1 :at x means to u z a vigor\s national society40 ,z "t pass$1 x became app>5t t ,voyag] #a _h be5 affect$ by ,jupit]'s radiation environm5t4 ,! basic tim+--! ma9 clock on ! spacecraft--_h sl[$ d[n4 ,fir/ x sl[$ by #f4c seconds1 b by ,m>* #f x 0 f\nd to h sl[$ a total ( eight seconds4 ,9 addition1 ! two c5tral comput]s app>5tly got out ( syn*ronization bo? ) !mselves & ) ! flight data subsy/em4 ,on ,m>* #f x 0 report$ t ! spacecraft cam]as 7 %utt]+ "o frametime 7#dh seconds7 e>ly2 ?is 0 p>tly (fset by ! eight-second spacecraft 8ma/]clock0 sl[-d[n result+ 9 images 7accord+ to our clocks7 be+ photograph$ =ty seconds e>ly4 ,?is tim+ error result$ 9 ! cam]a tak+ "s pictures :ile ! scan plat=m 0 mov+1 caus+ "s blurr$ images4 ,a numb] ( ! highe/ resolution images ( ,io & ,ganym$e 7 s]i\sly degrad$ by ?is malfunction4 ,illu/ration3 ,:5 ! fir/ color close-up ( ,io 0 releas$1 ,imag+ ,team ,lead] ,brad ,smi? said t he _h se5 8bett] look+ pizzas02 h5ce ?is view1 tak5 ,m>* #d at a range ( ab\t #hfj #jjj kilomet]s1 became kn[n z 8! pizza picture40 ,! circul> feature 9 ! c5t] 7! piece ( pepp]oni7 0 lat] reveal$ to be ! active volcano ,prome!us1 b at ! "t ( its release ?is lovely b biz>re picture baffl$ sci5ti/s & press alike4 ,p-#badeg;,c ,at ! regul> #aa a4m4 press brief+1 ,brad ,smi? gl[$4 8,we're all recov]+ f :at ,i w\ld call ! mo/ excit+1 ! mo/ fasc9at+1 :at may ultimately prove to be ! mo/ sci5tifically rew>d+ mission 9 ! unmann$ space program4 ,! ,io pictures ?is morn+ 7 truly spectacul> & ! atmosph]e up 9 ! imag+ area 0 punctuat$ by :oops ( joy or amazem5t or bo?40 ,! new color photo ( ,io tak5 ! night be=e 0 releas$1 %[+ /range surface features 9 tones ( yell[1 orange1 & :ite4 ,! image defi$ description2 ! ,imag+ ,team us$ t]ms l 8grotesque10 8diseas$10 8gross10 8biz>re40 ,smi? introduc$ ! picture ) ! comm5t1 8,io looks bett] ?an a lot ( pizzas ,i've se540 ,l>ry ,sod]blom add$1 8,well1 y may recall t we told y ye/]day t :5 we flew by we'd figure all ?is out4 ,i hope y didn't believe x40 ,"o ?+ 0 c]ta93 ,!re 7 no impact crat]s on ,io4 ,unless ! satellites ( ,jupit] _h someh[ be5 %ield$ f ! meteoric impacts t crat]$ objects su* z ! ,moon1 ,m>s1 & ,m]cury1 ! abs5ce ( crat]s mu/ indicate ! pres5ce ( erosion or ( int]nal processes t de/roy or cov] up crat]s4 ,io did n look l a dead planet4 ,imag+ ,team memb] ,hal ,masursky1 look+ at ! 8pizza0 picture1 e/imat$ t ! surface ( ,io mu/ be no m ?an #ajj million ye>s old--t is1 "s ag5t mu/ h eras$ impact crat]s dur+ ! la/ #ajj million ye>s4 ,?is int]pretation dep5d$ on h[ (t5 crat]+ impacts occur on ,io4 ,no "o c\ld be sure t !re _h be5 any int]planet>y debris 9 ! ,jovian sy/em to impact ! surfaces ( ! satellites4 ,p]haps none ( !m w\ld be crat]$4 ,! =?com+ flybys ( ,ganym$e & ,calli/o w\ld soon provide ?is in=mation4 ,illu/ration3 ,! giant volcanic feature ,pele1 ab\t #ajjj kilomet]s across1 my/ifi$ ,voyag] sci5ti/s :5 ?is picture ( ,io 0 tak5 on ,m>* #e f a di/ance ( ab\t #djj #jjj kilomet]s4 ,! brilliant colors1 ! /range %apes ( ! surface deposits1 & ! abs5ce ( impact crat]s all te/ifi$ t ,io 0 unlike any _w previ\sly enc\nt]$ 9 ! exploration ( ! sol> sy/em4 ,p-#babbf;,c ,illu/ration3 ,z ,voyag] #a approa*$ ,io1 ! images ( ! surface became m & m spectacul>4 ,on ! morn+ ( ,m>* #e1 at a range ( #acj #jjj kilomet]s1 ?is picture 0 tak5 c5t]$ ne> longitude #cbj & latitude #aj,s4 ,! wid? ( ! picture is ab\t #ajjj kilomet]s 7! di/ance f ! ,mexican bord] to ! nor!rn edge ( ,cali=nia74 ,!re are no impact crat]s1 signify+ a geologically "y surface1 & ! d>k c5t] ) radiat+ r$ fl[s indicates rec5t volcanic activity ( "s sort4 ,p-#babgg;,c ,! close flyby ( ,ganym$e took place at #f3ec p4m41 at a range ( #aae #jjj kilomet]s4 ,dur+ ! prec$+ f\r h\rs1 photos reveal$ a surface cov]$ ) impact crat]s4 ,wat*+ ^! photos & supply+ comm5t>y = ! television li/5]s1 ,david ,morrison rem>k$1 8,:ile ,i'm delight$ to see crat]s1 x's j ! opposite ( :at ,i w\ld h expect$4 ,i 0 tell+ ev]yone a few days ago t ,i ?\ght ,io w\ld h pl5ty ( crat]s & t ,ganym$e1 because ( ! ice surface1 simply w\ld n be able to hold l>ge crat]s ov] geological "t4 ,s ?is is fasc9at+ & ?is is confus+--bo? :at has happ5$ on ,io to erase ! crat]s & :y ,ganym$e's surface is /rong en\gh to pres]ve !m40 ,j be=e close/ approa*1 at #f3ce p4m41 ! ultraviolet in/rum5t wat*$ z a bright /> pass$ beh9d ,ganym$e & reem]g$ t5 m9utes lat]4 ,no dimm+ t c\ld be attribut$ to an atmosph]e 0 se52 :5 ! data 7 analyz$ lat]1 sci5ti/s set an upp] limit = any gas on ?is satellite at "o-billion? ( ! atmosph]ic pressure at ! surface ( ! ,e>?4 ,z enc\nt] day drew to a close1 celebrations took place all ov] ,,jpl4 ,= _m1 h[ev]1 ! excitem5t 0 temp]$ by exhau/ion4 ,aft] #dh h\rs ( int5se activity1 sleep 0 imp]ative = "s4 ,b ! close approa* to ,calli/o 0 /ill to come1 z 0 an exam9ation ( ! data already receiv$4 ,illu/ration3 ,aft] its close flyby ( ,io1 ,voyag] #a head$ = ,ganym$e1 ! l>ge/ ( ! ,galilean satellites4 ,?is global view ( ,ganym$e1 tak5 on ,m>* #d at a range ( #b4f million kilomet]s1 %[s features z small z #ej kilomet]s across4 ,at ! "t1 ,voyag] sci5ti/s speculat$ t ! num]\s :ite spots 7 impact crat]s1 surr\nd$ 9 "s cases by icy ejecta blankets spla%$ onto ! surr\nd+ surface4 ,h[ev]1 _m n>r[ :ite /reaks1 especially ^? 9 ! l[] left quadrant1 promis$ new & excit+ geological features on ?is satellite4 ,p-#babjg;,c ,tuesday1 ,m>* #f4 ,voyag] 0 n[ rec$+ f ,jupit]1 accel]at$ on a new trajectory--"o t w\ld spe$ x on t[>d its ,novemb] #aihj enc\nt] ) ,saturn4 ,b fir/ came ! enc\nt] ) ,calli/o1 ) close/ approa* at #i3ej a4m41 at a range ( #abf #jjj kilomet]s4 ,! satellite 0 litt]$ ) crat]s & !re appe>$ "o huge 8bullseye0 patt]n t might h be5 ! result ( an impact4 ,z ! photos ( ,calli/o came 91 ,g>ry ,hunt describ$ ! sc5e 9 ! imag+ area3 8,! activity ar\nd ! monitors n[ is q incr$ible ) p caught brea?less by ! pictures com+ 94 ,e satellite we've se5 has be5 a diff]5t _w40 ,ask$ h[ he felt ab\t ! images ( ,jupit]'s atmosph]e1 he repli$1 8,i'm absolutely delight$ ) :at ,i've se51 & ,i'm delight$ ,voyag] #b is n f> beh9d s9ce ,i'm conv9c$ t we'll see yet ano!r face ( ,jupit] by !n4 ,! wea!r w h *ang$ by ,july40 ,at ! morn+ press brief+1 ! weal? ( new data began to be reveal$4 8,if ,jupit] _h ev] pos$ = ,monet1 x w\ld probably h turn$ out l ?is10 said ,brad ,smi? z he introduc$ "s enhanc$ 7exagg]at$7 color images t _h be5 specially process$ to %[ m detail 9 ! ,great ,r$ ,spot region4 ,inde$1 ^! photographs did look l pa9t+s ) ,jupit] display+ "s ( its be/ ab/ract art4 ,illu/ration3 ,z ,voyag] #a approa*$ ,ganym$e on ,m>* #e1 _m /range new surface features became visible4 ,9 ?is frame1 tak5 f a di/ance ( #bej #jjj kilomet]s & %[+ features z small z #e kilomet]s across1 ?ree di/9ct types ( t]ra9 are se53 polygons ( old d>k surface1 ext5sive areas ( light]1 y\ng] mat]ial1 & brilliant :ite ejecta patt]ns 7probably wat]-ice7 ar\nd fre% crat]s4 ,! bright rays 9 ! upp] "p ( ! picture are #cjj-ejj kilomet]s long2 at ! bottom are sev]al crat]s ) only fa9t1 mut$ ejecta patt]ns4 ,p-#babfb;,c ,illu/ration3 ,voyag] #a f\nd t ! surface ( ,ganym$e 0 geologically v complex4 ,?is frame1 tak5 ,m>* #e f a range ( #bej #jjj kilomet]s1 %[s a region ab\t #ajjj kilomet]s across c5t]$ ne> longitude #j & latitude #bj,s4 ,! surface displays _m crat]s1 "s 7probably ! y\ng] ones7 ) bright ray sy/ems4 ,bright groov$ b&s trav]se ! surface 9 v>i\s directions4 ,"o ( ^! b&s1 runn+ 9 a nor?-s\? direction 9 ! l[] left ( ! picture1 is (fset along a :ite l9e t may repres5t a fault4 ,ganym$e is ! only ,galilean satellite to %[ indications ( su* lat]al (fsets 9 ! cru/4 ,p-#babff ,! fir/ picture ( ,amal!a 0 %[n1 reveal+ an elongat$1 d>k1 r$di% object ab\t #bfe kilomet]s long4 ,smi? report$3 8,!re is actually "s /ructure t "o c see--a crat]--a c\ple ( bright features = :i* we h no int]pretation & "s o!r evid5ce ( crat]+4 ,x doesn't look l mu*1 b aft] all1 ,amal!a has nev] be5 se5 z any?+ m ?an a po9t ( light f ! ,e>?1 &1 9 fact1 !re are v few p t h ev5 se5 x z a po9t ( light4 ,i d\bt t m ?an "o a/ronom] out ( a hundr$ has actually se5 ,amal!a40 ,l>ry ,sod]blom introduc$ new photographs ( ! satellites4 ,io /ill %[$ no crat]s1 ev5 at high resolution4 ,! crat]s t 8%\ld0 h be5 on ,io 7 on ,ganym$e & ,calli/o4 ,ganym$e n only _h crat]s1 x _h fault l9es z well4 8,!re is transv]se motion along ^! faults4 ,?+s get (fset1 app>5tly1 = hundr$s ( kilomet]s4 ,s x's ! fir/ "t we've se5 major k9ds ( transv]se motion on ! surface ( ano!r planet40 ,ganym$e1 9 effect1 _h %[n evid5ce ( hav+ its own icy v]sion ( ! ,san ,&reas ,fault4 ,illu/ration3 ,amal!a 0 ?\ght to be ! inn]mo/ satellite ( ,jupit] until ,voyag] #b discov]$ t9y ,adra/ea 7#aigi;,j#a74 ,! ,voyag] #a cam]a reveal$ ,amal!a z an irregul> d>k r$di% object ) dim5sions ( #bgj #afj kilomet]s4 ,^! ?ree images h resolutions ( 7b7 #be kilomet]s2 7c7 #ac kilomet]s2 7d7 #h kilomet]s4 #bfj-ejc ,illu/ration3 ,obs]vation geometry = ,amal!a ,illu/ration3 7b7 ,illu/ration3 7c7 ,illu/ration3 7d7 ,al?\gh ,calli/o 0 heavily cov]$ ) crat]s up to #bjj kilomet]s 9 diamet]1 ,dr4 ,sod]blom comm5t$ on ! abs5ce ( l>g] impact bas9s4 ,p]haps !re 0 "o 9 ! huge bullseye feature2 h[ev]1 x 0 n a 8/&>d0 look+ bas9 l ^? on ! ,moon4 ,calli/o 0 8extremely smoo? & free ( any relief4 ,! /ructure ! bullseye1 if impact caus$1 %[s no relief2 ! limb does n %[ any relief2 maybe x's possible t ,calli/o _c support relief40 ,by ! next day1 ! geologi/s on ! ,imag+ ,team 7 becom+ m conv9c$ t ! ,calli/o 8bullseye0 0 ! froz5 remnant ( an enorm\s impact into ,calli/o's surface4 ,s9ce ,calli/o is compos$ 9 l>ge "p ( wat] & has an icy cru/1 ! team speculat$ t any rais$ features creat$ by ! impact w\ld ev5tually 8slide0 back into ! surface1 8& ! ripple m>ks f ! %ock wave caus$ by ! impact 7 froz50 into ! surface4 ,illu/ration3 ,calli/o 0 ! la/ ( ! ,galilean satellites to be /udi$ by ,voyag] #a4 ,9 ?is photo1 tak5 ,m>* #e f a di/ance ( #a4b million kilomet]s1 ) a resolution ( ab\t #be kilomet]s1 ! ext5sive crat]+ ( ! surface began to be app>5t4 ,ne> ! upp] left edge is ! l>ge impact bas9 ,valhalla2 ! num]\s light spots are crat]s #ajj kilomet]s or m 9 diamet]4 ,?is is ! same side ( ,calli/o t 0 photograph$ at high] resolution dur+ ! ,voyag] #a flyby ( ! satellite a day lat]4 ,p-#babhd;,c ,lyle ,broadfoot ann\nc$ t ! ultraviolet spectromet] _h detect$ v /rong auroral emission 9 ,jupit]'s nor? & s\? pol> regions4 ,! aurora seem$ to be caus$ prim>ily by ! excitation ( molecul> hydrog51 al?\gh "s atomic hydrog5 0 also detect$4 ,auroral emissions f helium atoms 7 n detect$4 ,illu/ration3 ,! l>ge/ anci5t impact bas9 on ,calli/o is call$ ,valhalla4 ,! c5tral light area is ab\t #fjj kilomet]s across4 ,surr\nd+ x is a set ( conc5tric l[ ridges1 look+ l froz5 ripple m>ks1 ext5d+ ab\t #aejj kilomet]s f ! c5t]4 ,?is picture 0 tak5 by ,voyag] #a on ,m>* #f at a range ( #cej #jjj kilomet]s4 ,p-#babhg;,c ,! ,,iris infr>$ measurem5ts requir$ m comput] process+ ?an o!r ,voyag] data1 & !re=e !y 7 n available until a day or two aft] ! obs]vations 7 made4 ,h[ev]1 ,rudy ,hanel already _h two new results to report4 ,fir/1 ! ,great ,r$ ,spot 0 ab\t #c ,c cool] ?an its surr\nd+s1 & ?is cool+ ext5d$ _m kilomet]s above ! cl\ds1 into ! ?9 upp] atmosph]e4 ,second1 ! !rmal emission f ,io 0 peculi>1 ) an unexpect$ %ape to ! spectrum4 ,t5tatively1 ,hanel sugge/$ !re might be "s hot spots on ! surface ( ! satellite4 ,jupit] has be5 full ( surprises1 b ! excitem5t 0 f> f ov]4 ,major discov]ies 7 yet to be made4 ,illu/ration3 ,voyag] #a discov]$ ! r+s ( ,jupit] on ,m>* #d 9 a s+le elev5-m9ute exposure ) ! n>r[-angle cam]a4 ,spacecraft motion dur+ ! "t exposure /reak$ ! picture1 z c be se5 f ! hairp9-l images ( ! />s4 7,! /> field 0 unusually ri*1 s9ce x happ5$ to include ! ,beehive /> clu/] 9 ,canc]47 ,! r+ image itself is a multiple exposure1 ) six sep>ate images side by side4 ,! r+ does n ext5d out ( ! "r side ( ! picture1 indicat+ t ?is image captur$ ! out] edge ( ! r+1 ab\t halfway betwe5 ! cl\d tops & ! orbit ( ,amal!a4 ,p-#babeh ,illu/ration3 ,cam]a ) fields ( view ,w$nesday1 ,m>* #g4 ,at ! press brief+1 ,brad ,smi? made a spectacul> ann\ncem5t3 8,?is morn+ ,i w\ld l to add yet ano!r important discov]y to be claim$ by ?is out/&+ mission--t ( a ?9 flat r+ ( p>ticles surr\nd+ ,jupit]4 ,?us ,jupit] n[ jo9s ,saturn & ,uranus to become ! ?ird planet ( our sol> sy/em kn[n to possess a planet>y r+ sy/em & leaves ,neptune z ! only memb] ( ! gr\p ( giant planets )\t a kn[n r+4 ,! discov]y ( ! r+ 0 unexpect$ 9 t ! curr5t !ory :i* treats long-t]m /ability ( planet>y r+s w\ld n pr$ict ! exi/5ce ( su* a r+ ar\nd ,jupit]4 ,! s+le ,voyag] cam]a image :i* record$ ! r+ 0 plann$ by ! ,voyag] ,imag+ ,team sev]al ye>s ago1 n really ) any great expectation ( a positive result1 b m = ! purpose ( provid+ a degree ( complet5ess to ,voyag]'s survey ( ! entire ,jupit] sy/em4 ,! obs]vation1 z plann$1 involv$ look+ (f to ! "r ( ! limb ( ,jupit] 9 ! planet's equatorial plane at ! exact mom5t t ! spacecraft w\ld be cross+ ! equatorial plane4 ,! image actually 0 tak5 at #af h\rs & #eb m9utes be=e enc\nt] f a di/ance ( ab\t #a4b million kilomet]s4 ,exposure "t 0 #aa4b m9utes4 ,we w]5't c]ta9 ( ! exact mom5t t we w\ld cross ! equatorial plane1 s we plann$ to op5 our %utt] & leave x op5 z we w5t ?r\gh40 ,illu/ration3 ,s9ce ! ,voyag] #a r+ photograph 0 tak5 exactly edge-on1 x 0 n possible to det]m9e ! wid? ( ! r+4 ,9 ?is arti/'s conception1 ! r+ is drawn z if x 7 ribbon-l1 ) v little wid?1 q unlike ! broad flat r+s ( ,saturn4 ,voyag] #b lat] %[$ ?is to h be5 a lucky guess4 ,p-#babei ,! image %[$ six exposures ( ! r+1 toge!r ) /reak$ trails ( backgr\nd />s4 ,smi? report$ t ! ?ickness ( ! r+ 0 less ?an #cj kilomet]s1 & t x ext5d$ to a po9t #abh #jjj kilomet]s f ! c5t] ( ,jupit]1 or #eg #jjj kilomet]s above ! cl\ds4 ,9 response to ?is discov]y1 sci5ti/s 7 eag]ly plann+ to alt] ! ,voyag] #b enc\nt] sequ5ce to try to obta9 additional in=mation on ! r+4 ,! newspap]s c>ri$ /ories ( ! r+ discov]y on ,?ursday1 ,m>* #h4 ,"o /ory 0 se5 by two ,univ]sity ( ,hawaii a/ronom]s1 ,eric ,beckl9 & ,g>e? ,wynn-,williams1 :o 7 obs]v+ at ,mauna ,kea ,obs]vatory1 at an altitude ( #dbjj met]s on ! ,big ,isl& ( ,hawaii4 ,)9 two days !y _h succe$$ 9 detect+ ! r+s by _! reflect$ sunlight1 at an infr>$ wavel5g? ( #b4b micromet]s1 provid+ a rapid confirmation ( ! ,voyag] discov]y4 ,z ! plasma measurem5ts f ! ,io flyby 7 analyz$1 an additional clue to ! orig9 ( sulfur & oxyg5 0 reveal$4 ,h]b ,bridge report$ ! detection ( sulfur dioxide 7,,s71 ! simple/ molecule compos$ ( ^! two atoms4 ,! high-resolution tape-record$ pictures ( ,io baffl$ imag+ sci5ti/s4 ,a numb] ( features look$ l volcanic fl[s2 toge!r ) ! abs5ce ( impact crat]s1 ^! features indicat$ a geologically active planet4 ,a c5tral po9t ( discussion 0 ! rec5t !oretical "w on ,io by ,/anton ,peale ( ! ,univ]sity ( ,cali=nia & two ,,nasa sci5ti/s1 ,pat ,cass5 & ,ray ,reynolds4 ,^! au?ors _h j publi%$ a pap] 9 ! ,m>* #b issue ( ,sci5ce %[+ h[ tidal heat+ f ,jupit]'s gravity c\ld melt ! int]ior ( ,io4 ,!y wrote t 8widespread & recurr5t surface volcanism might occur40 ,x began to look z if ! pr$iction _h be5 correct4 ,?ursday1 ,m>* #h4 ,! la/ ,voyag] #a press brief+ 0 held4 ,ea* speak] 0 allott$ only a few m9utes1 prompt+ ,l>ry ,sod]blom to preface 8 rem>ks by try+ to expla9 h[ difficult x 0 to describe f\r new planets--! ,galilean satellites--9 ! "t all[$4 8,torr5ce ,johnson 0 sitt+ ) me la/ night1 puzzl+4 ,he said1 #8,y "k1 ,l>ry1 x's sort ( l imag9+ we'd fl[n into ! sol> sy/em ! day be=e ye/]day1 & said1 8,!re's a ?+ we'll call ,m]cury1 & !re's ! ,moon1 & !re's ,e>?1 & !re's ,m>s4 ,n[ let's expla9 !m 9 t5 m9utes04'0 ,!re 0 ,calli/o1 ) ! highe/ d5sity ( crat]s ( any ,galilean satellite--! olde/ ( ! ,galilean surfaces--featur+ a huge 8bullseye0 t is 8! l>ge/ s+le contigu\s feature se5 s f> 9 ! sol> sy/em40 ,!re 0 ,ganym$e1 crat]$1 b also ov]run ) fault l9es t look$1 accord+ to "o p]son1 l 8tire tracks 9 ! des]t10 %[+ a surface t 8_h lat]ally slid--fault$ & %e>$ & %e>$ aga9--twi/$ & torn ap>t40 ,!re 0 ,io1 ! mo/ biz>re--! "o t sci5ti/s _h ?\ght w\ld be mo/ lun>like--%[+ a surface t _h app>5tly be5 8cook$ & /eam$ & fum$ out leav+ deposits all ov] ! surface mu* l y might see ar\nd a fum>ole at ,yell[/one ,national ,p>k4 ,! fact t ^! ?+s exhibit su* y\? makes x likely t ! planet is /ill volcanically active40 ,!re 0 ,europa1 ) huge l9e> features unlike ^? ( ! o!r ?ree ,galileans--,europa ! my/]y satellite1 wait+ = ! prob+ eyes ( ,voyag] #b to survey x 9 e>ly ,july4 ,ed ,/one summ$ x all up3 8,i ?9k we h _h almo/ a decade's wor? ( discov]y 9 ?is two-week p]iod1 & ,i ?9k t all ( ! p :o h be5 talk+ to y feel ! same saturation ( new in=mation :i* has occurr$4 ,& 9 fact1 we w probably be /udy+ x 9 great detail = at lea/ five ye>s40 ,ov] ! next day or s ! press pack$ up & w5t home4 ,! ,,tv monitors %[$ ! spacecraft's p>t+ glance at a cresc5t ,jupit]1 only h9t+ at ! va/ness ( space ,voyag] #a w\ld travel until its enc\nt] ) ,saturn 9 ! autumn ( #aihj4 ,maybe n[ !re w\ld be a relative calm t w\ld all[ ! sci5ti/s to beg9 analyz+ t 8decade's wor? ( data40 ,b ?+s 7 n to be calm j yet4 ,fire & ,brim/one ,at ab\t #e a4m4 on ,m>* #h1 ,voyag] _h tak5 a hi/oric picture4 ,look+ back at a cresc5t ,io f a di/ance ( #d4e million kilomet]s1 ! cam]a _h be5 us$ to obta9 a long-exposure view = ! spacecraft navigation team--"o t %[$ ! satellite aga9/ ! field ( backgr\nd />s4 ,dur+ ! day1 ,l9da ,morabito1 an optical navigation eng9e]1 began to "w ) ?is picture on h] comput]-controll$ image display4 ,%e not$ :at appe>$ to be a cresc5t cl\d1 ext5d+ beyond ! edge ( ,io4 ,b ,io has no atmosph]e1 s a cl\d ris+ hundr$s ( kilomet]s above ! surface did n seem to make s5se4 ,! next day1 work+ ) h] colleagues1 ,morabito elim9at$ all possibilities = ! new feature on ,io except ! obvi\s--a cl\d4 ,if x 7 a cl\d1 x mu/ be ! result ( an ongo+ volcanic eruption ( incr$ible viol5ce4 ,! picture 0 %[n to memb]s ( ! ,imag+ ,team1 :o agre$ ) ! id5tification4 ,b x 0 ,friday & ,brad ,smi? & ,l>ry ,sod]blom1 along ) mo/ ( ! o!r team memb]s1 _h left = ! week5d to try to get "s re/4 ,! picture w\ld h to wait two m days4 ,,highlights ,,( ,,! ,,voyag] #a ,,sci5tific ,,f9d+s#b ,atmosph]e ,uni=m w9d spe$s = cl\d features ) widely diff]5t size scales1 sugge/+ t mass motion & n wave motion is be+ obs]v$4 ,rapid =mation & spread+ ( bright cl\d mat]ial1 p]haps ! result ( di/urbances t trigg] convective activity4 ,a patt]n ( ea/-we/ w9ds 9 ! pol> regions1 previ\sly ?\ght to h be5 dom9at$ by convective upwell+ & d[nwell+4 ,anticyclonic motion ( mat]ial associat$ ) ! ,great ,r$ ,spot1 ) a rotational p]iod ( ab\t six days4 ,int]actions ( small] spots ) ! ,great ,r$ ,spot & ) ea* o!r4 ,auroral emissions 9 ! pol> regions1 bo? 9 ! ultraviolet 7:i* 7 n pres5t dur+ ! #aigc ,pione] enc\nt]7 & 9 ! visible4 ,cl\d-top lightn+ bolts1 simil> to t]re/rial sup]bolts1 & meteoritic fireballs4 ,a temp]ature inv]sion lay] 9 ! /ratosph]e & a temp]ature ( #afj ,k at ! level at :i* ! atmosph]ic pressure is #j4ja b>4 ,v /rong ultraviolet emission f ! disk1 indicat+ a !rmosph]ic temp]ature ( m ?an #ajjj ,k4 ,a hot 7#aajj ,k7 upp] ionosph]e on ! dayside t 0 n obs]v$ by ,pione] #aj1 sugge/+ !re may be l>ge temporal or spatial *anges4 ,an atmosph]ic composition ) volume fraction ( helium ( #j4aa #j4jc4 ,a sub/antially cold] atmosph]e above ! ,great ,r$ ,spot ?an 9 ! surr\nd+ regions4 ,satellites & ,r+s ,at lea/ eight curr5tly active volcanoes on ,io1 probably ! result ( tidal heat+ ( ! int]ior ( ! satellite1 ) plumes ext5d+ up to #bej kilomet]s above ! surface4 ,a l>ge hot spot on ,io ne> ! volcano ,loki t is ab\t #aej ,k w>m] ?an ! surr\nd+ surface4 ,num]\s int]sect+1 l9e> features on ,europa1 possibly due to cru/al crack+4 ,two di/9ct types ( t]ra91 crat]$ & groov$1 on ,ganym$e1 sugge/+ t ! entire ice-ri* cru/ 0 once "u t5sion4 ,an anci5t1 heavily crat]$ cru/ on ,calli/o1 ) ve/igial r+s ( enorm\s impact bas9s s9ce eras$ by fl[ ( ! ice-lad5 cru/4 ,! elliptical %ape ( ,amal!a 7#bgj #afj kilomet]s74 ,a fa9t r+ ( mat]ial ab\t ,jupit]1 ) an out] edge ( #abh #jjj kilomet]s f ! c5t] ( ! planet4 ,magnetosph]e ,an electrical curr5t ( m ?an a million amp]es fl[+ 9 ! magnetic flux tube l9k+ ,jupit] & ,io4 ,v /rong ultraviolet emissions f ioniz$ sulfur & oxyg5 9 ! ,io plasma torus1 indicat+ a hot 7hundr$ ?\s& degree7 plasma t evid5tly 0 n pres5t at ! "t ( ,pione] #aj enc\nt]4 ,plasma electron d5sities exce$+ #dejj p] cubic c5timet] 9 "s regions ( ! ,io plasma torus4 ,a cold1 corotat+ plasma inside #f ,r,j ) ions ( sulfur1 oxyg51 & sulfur dioxide4 ,high-en]gy trapp$ p>ticles inside #f ,r,j ) significantly enhanc$ abundances ( oxyg51 sodium1 & sulfur4 ,hot plasma ne> ! magnetopause pr$om9antly compos$ ( protons1 oxyg51 & sulfur4 ,jovian radio emission at kilomet] wavel5g?s1 :i* may be g5]at$ by plasma oscillations 9 ! ,io plasma torus4 ,corotat+ plasma fl[s unexpect$ly f> f ,jupit] 9 ! dayside out] magnetosph]e4 ,evid5ce sugge/+ a transition f clos$ magnetic field l9es to a ,jovian magnetotail at ab\t #be ,r,j f ,jupit]4 ,:i/l] emission int]pret$ z lightn+ :i/l]s f ! ,jovian atmosph]e4 #a;,adapt$ f a pap] by ,e4 ,c4 ,/one & ,a4 ,l4 ,lane 9 ! ,voyag] #a ,?irty-,day ,report4 #b;,adapt$ f a summ>y prep>$ by ,e4 ,c4 ,/one & ,a4 ,l4 ,lane = ! ,voyag] #a ,?irty-,day ,report4 ,illu/ration3 ,! dramatic discov]y ( active volcanoes on ,io 0 made by ,l9da ,morabito & h] colleagues f ?is navigation picture1 tak5 ,m>* #h at a range f ,io ( #d4e million kilomet]s4 ,on ! bright edge1 ! imm5se plume ( volcanic a% f ,pele 7,p7 rises ne>ly #cjj kilomet]s above ! surface4 ,at ! t]m9ator1 ! bord] betwe5 day & night on ,io1 a second small] cl\d f ! volcano ,loki 7,p7 cat*es ! sunlight4 ,^! two eruptions--captur$ on ?is s+le discov]y photograph--are mu* l>g] ?an ! l>ge/ t]re/rial volcanic eruption kn[n4 ,p-#bacjf ,b_/,w ,illu/ration3 ,once ! exi/5ce ( giant volcanic eruptions on ,io 0 recogniz$1 a reexam9ation ( ! ,voyag] #a enc\nt] pictures reveal$ _m m plumes4 ,^! two views ( ,prome!us 7,p7 7 f\nd by ,joseph ,vev]ka & ,rob]t ,/rom on ,m>* #ab :5 !y reproduc$ e>li] pictures4 ,illu/ration3 ,! plume is silh\ett$ aga9/ ! black space1 al?\gh x is also possible to see d>k 8feet0 :]e ! fall+ mat]ial rea*es ! surface4 ,p-#babie ,illu/ration3 ,! complex jets ( mat]ial are cle>ly se5 z d>k /reaks aga9/ ! light backgr\nd ( ! surface ( ,io4 ,! plume itself rose m ?an #ajj kilomet]s above ,io's surface4 ,p-#babid ,mean:ile1 new in=mation ab\t ,jupit] 0 releas$ to ! public4 ,a long-exposure 7?ree m9utes & twelve seconds7 image ( ! d>k side ( ! planet1 tak5 ) ! wide-angle cam]a :ile 9 ! %ad[ ( ! planet1 caught ,jupit] %[+ (f "s ,jovian 8fireworks40 ,a long1 broad1 :ite /reak across ! picture 0 a visible aurora1 ! l>ge/ aurora ev] se5--almo/ #bi #jjj kilomet]s long4 ,9 addition1 n9ete5 small] bright splot*es1 look+ insignificant by comp>ison1 7 9 reality 8sup]bolts0 ( lightn+4 ,s9ce huge electrical dis*>ges su* z lightn+ c1 "u ! "r circum/ances1 p[] *emical reactions t =m complex organic molecules1 ! discov]y ( lightn+ on ,jupit] c\ld h pr(\nd implications4 ,0 8lightn+-inspir$0 organic syn!sis go+ on 9 ,jupit]'s atmosph]e8 ,no "o knew4 ,return+ to ,,jpl on ,sunday night1 ,brad ,smi? got 8 fir/ look at ! ,morabito picture ( ! volcanic cl\d4 ,e>ly ,monday morn+1 o!r ,imag+ ,team sci5ti/s saw x4 ,z soon z ! ,,jpl comput]s 7 op]at+1 ,joseph ,vev]ka & ,rob]t ,/rom began work+ ) ! two int]active ,,tv t]m9als to look = evid5ce 9 o!r pictures ( ongo+ eruptions4 ,fa9t cl\ds or plumes w\ld n %[ up 9 normally process$ pictures1 b c\ld be br\ght out easily ) ! comput]-controll$ displays4 ,by midmorn+1 sev]al additional volcanic plumes _h be5 f\nd4 ,illu/ration3 ,l9da ,morabito %[s ! discov]y photo ( ! volcanic eruptions on ,io4 ,p-#bagah ,illu/ration3 ,! d>k side ( ,jupit] reveal$ _m surpris+ ph5om5a to ,voyag] #a4 ,a wide-angle view1 tak5 on ,m>* #e1 l$ to ! discov]y ( a d\ble auroral arc at nor?-pol> latitudes & num]\s fla%es ( lightn+ illum9at+ ! cl\ds dur+ ?is #c-m9ute1 #ab-second exposure1 tak5 at a range ( half a million kilomet]s4 #bfj-dfj ,mean:ile1 on ,m>* #aa1 ,john ,pe>l ( ! ,,iris team _h indep5d5tly drawn ! conclusion t volcanic activity mu/ be tak+ place on ,io4 ,he & ,rudy ,hanel f\nd evid5ce ( /rongly enhanc$ !rmal emission f p>ts ( ! satellite4 ,! mo/ prom95t 0 a s\rce ne>ly #bjj ,c hott] ?an its surr\nd+s4 ,on ,m>* #ab1 ,pe>l br\ght 8 new results to ! ,imag+ ,team1 & sure en\gh1 ! hot spot 0 locat$ ne> "o ( ! volcanic plumes6 ,a mon? lat]1 cont9u+ analysis ( ,,iris spectra yield$ id5tification ( sulfur dioxide 7,,s7 gas ov] ?is same erupt+ volcano4 ,at la/ a s\rce _h be5 locat$ = ! enigmatic sulfur & oxyg5 ions 9 ! magnetosph]e4 ,! volcanoes provid$ a ?read ) :i* to weave toge!r ! disp>ate data on ,io4 ,a few mon?s e>li] !re _h be5 a report ( a sudd5 bright5+ ( ,io 9 ! infr>$2 n[ x seem$ plausible t !rmal emission f an eruption 0 ! s\rce4 ,! ,voyag] ultraviolet exp]im5t]s _h be5 worry+ ov] ! s\rce ( ! int5se sulfur emissions !y _h se5 & _h be5 di/urb$ by ! *anges 9 ! gas cl\ds ar\nd ,io s9ce ! ,pione] #aj & #aa flybys2 n[ a v>iable s\rce = ^! gas cl\ds 0 id5tifi$4 ,9 addition1 ! crat]free surface & biz>re features se5 9 ! ,voyag] images c\ld be recogniz$ z ! product ( viol5t explosive eruptions on ,io4 ,x appe>$ t ,peale1 ,cass51 & ,reynolds _h f\nd1 9 _! !oretical calculations1 ! key to ! mo/ geologically active body ev] enc\nt]$ 9 ! sol> sy/em4 ,news ( ! discov]y 0 releas$ to ! press on ,monday1 ,m>* #ab4 ,dur+ ! next few days1 a total ( eight gigantic eruptions 7 locat$ 9 ! ,voyag] pictures ( ,io4 ,)9 a few weeks1 sci5ti/s all ov] ! _w 7 ?9k+ ) r5ew$ en]gy ab\t ?is incr$ible satellite4 ,) f\r new planet-siz$ satellites n[ photograph$1 !re 0 a sudd5 requirem5t = maps & = names to be assign$ to ! newly discov]$ features4 ,! maps 7 produc$ f ,voyag] images at ! ,a/rogeology ,bran* ( ! ,u4,s4 ,geological ,survey at ,flag/aff1 ,arizona4 ,! names1 propos$ by a gr\p ( sci5ti/s head$ by ,voyag] ,imag+ ,team memb]s ,tobias ,ow5 & ,hal ,masursky1 7 giv5 (ficial approval by ! ,int]national ,a/ronomical ,union 9 ,augu/4 ,= a "t1 a dual nom5clature p]si/$ = ! erupt+ volcanoes on ,io4 ,! eruption plumes 7 giv5 numb]s1 ,p1 ,p1 etc41 :ile ! volcanic features 7 giv5 names tak5 f ! my?ology ( fire & volcano leg5ds4 ,?us ! 8ho( pr9t0 ( ,io 0 call$ ,pele1 = ! ,hawaiian volcano goddess1 & ! #bhj-kilomet]-high plume associat$ ) x 0 call$ ,p4 ,by ! "t ( ! ,voyag] #b enc\nt]1 sci5ti/s _h prep>$ maps on :i* to plot _! new discov]ies4 ,:ile ! ,voyag] sci5ti/s fann$ out across ! _w to %>e _! f9d+s ) colleagues1 att5tion at ,,jpl turn$ to ,voyag] #b4 ,9 response to ! discov]ies ( ! fir/ enc\nt]1 *anges 7 requir$ 9 ! sequ5c+ ( sci5tific obs]vations = ,july4 ,voyag] #b1 /ill tr\bl$ by a faulty receiv]1 might require m coddl+ f ! spacecraft team ?an _h its si/] spacecraft1 n[ safely on ! way to ,saturn4 ,illu/ration3 ,! p>ticles ( ! r+s ( ,jupit] are /rong] reflectors ( r$ light ?an ( blue1 z c be se5 9 ?is view1 assembl$ f two images tak5 9 orange & violet light4 ,s9ce ! images 7 regi/]$ on ! r+s1 n ! planet1 ! bright b&s ( colors along ! edge ( ,jupit] are an artifact ( misalignm5t4 ,p-#baggi ,,*apt] #g ,,! ,,second ,,enc\nt]3 ,,m ,,surprises ,,f ,,! 8,,l&0 ,,( ,,! ,,giant ,approa*+ ,jupit] ,at ! beg9n+ ( ,july1 ! dry summ] heat _h return$ to ,pasad5a1 & s _h ! press4 ,! sci5ti/s _h come days or weeks e>li] to look at data be+ transmitt$ f ! second ,voyag] z x approa*$ ,jupit] & its satellites4 ,! mood at ,,jpl seem$ quiet] ?an x _h be5 9 ,m>* = ,voyag] #a1 al?\gh ! press room w\ld once aga9 be delug$ ) obs]v]s on ! day ( enc\nt]4 ,?is w\ld be our second good1 close look at ! ,jovian sy/em1 b x 0 to be no summ] r]un4 ,voyag] #b w\ld h a diff]5t view ( ea* _w1 &1 9 addition1 bo? ,io & ,jupit] _h und]gone *anges1 z ?\gh to ensure t no "o w\ld become bor$ & fall asleep 9 front ( a ,,tv monitor4 ,9 a s5se1 ?is enc\nt] 0 to be ano!r fir/ look at ,jupit] & its satellites1 ) a view ( ea* object t 0 q diff]5t f :at _h be5 se5 be=e4 ,*anges 9 ,jupit]'s cl\d =mations became noticeable long be=e ,july4 ,aft] a gap ( six weeks foll[+ ! fir/ flyby1 ,voyag] #b's obs]vatory phase began on ,april #bd1 #aigi1 sev5ty-six days be=e its ,july #i enc\nt] ) ,jupit]4 ,dur+ ?is "t1 ! spacecraft's ultraviolet & fields & p>ticles in/rum5ts /udi$ ! ,jovian sy/em & its int]action ) ! sol> w9d4 ,betwe5 ,april #bd & ,may #bg1 ,voyag] #b's imag+ sy/em conc5trat$ on ! motions 9 ,jupit]'s atmosph]e1 creat+ ano!r approa* "t-lapse 8movie40 ,f ,may #bg to #bi photographs 7 tak5 9 a m rapid sequ5ce1 %[+ ! planet dur+ five #aj-;h\r rotations4 ,f ^! /udies x 0 app>5t t ,g>ry ,hunt's pr$iction _h be5 "r--! wea!r _h *ang$ by ,july4 ,a mon? be=e ! enc\nt] ,,jpl's ,voyag] ,bullet9--,mission ,/atus ,report ann\nc$ t 8,jupit] is sport+ q a diff]5t face ?an x did j f\r mon?s ago4 ,! bright #8tongue' ext5d+ upw>d f ! ,r$ ,spot is int]act+ ) a ?91 bright cl\d above x t has travel$ twice ar\nd ,jupit] 9 f\r mon?s40 ,! turbul5t region we/ ( ! ,great ,r$ ,spot _h begun to break up & sep>ate f ! ,r$ ,spot4 ,! :ite ovals s\? ( ! ,r$ ,spot _h drift$ to ! ea/ 7ab\t #j4ce degrees a day71 :ile ! ,r$ ,spot itself _h drift$ we/ 7ab\t #j4bf degrees a day74 ,! :ite zone se5 j s\? ( ! ,r$ ,spot by ,voyag] #a _h become v n>r[--l a ?9 :ite l9e j b>ely outl9+ ! bottom ( ! spot4 ,! ,r$ ,spot _h also *ang$3 ,x _h become a m uni=m orange-r$1 p]haps rev]t+ to ! color se5 by ,pione]s #aj & #aa4 ,! br[n spots t _h be5 se5 9 ! nor? temp]ate region at ! same longitude z ! ,r$ ,spot 7 n[ on ! o!r side ( ! planet4 ,a d>k br[n spot n pres5t dur+ ! ,voyag] #a flyby _h develop$ along ! nor!rn edge ( ! br[n equatorial region on ! ,r$ ,spot side ( ! planet4 ,"s ( ! :ite m>k+s t seem$ to h protrud$ into ! equatorial region at ! "t ( ! fir/ flyby 7 miss+ 9 ! ,voyag] #b photographs4 ,z ,voyag] #b ent]$ ! f> enc\nt] p]iod on ,may #bi1 all in/rum5ts on ! spacecraft 7except = ! photopol>imet]7 seem$ to be 9 good %ape = enc\nt]4 ,z 0 ! case ) ,voyag] #a1 ! pol>ization :eel on ,voyag] #b's photopol>imet] 0 /uck1 s ! in/rum5t 0 able to obta9 only color photometry measurem5ts4 ,illu/ration3 ,9 e>ly ,june1 z ,voyag] #b c>ri$ out its obs]vatory phase1 additional *anges 9 ,jupit]'s face began to be app>5t4 ,^! two images1 tak5 f a di/ance ( #bd million kilomet]s1 h a resolution ( ab\t #ejj kilomet]s4 ,illu/ration3 ,! ,great ,r$ ,spot & ! :ite oval s\? ( x are se5 to be foll[$ on ! we/ by regions ( *aotic & turbul5t cl\ds4 ,?is is n ! same :ite oval t 0 ne> ! ,r$ ,spot 9 ,m>*2 ! diff]5tial rotation ( ! planet c>ri$ a diff]5t oval close to ! ,r$ ,spot dur+ ! int]v5+ ?ree mon?s4 ,p-#bagac;,c ,illu/ration3 ,io is visible to ! "r ( ! planet1 & ! %ad[ ( ,ganym$e falls on ! color$ cl\ds ( ,jupit]'s equatorial belt4 ,p-#bagad;,c ,illu/ration3 ,! ,voyag] #b trajectory 0 complem5t>y to t ( ,voyag] #a4 ,?is "t1 ! satellites 7 enc\nt]$ be=e ,jupit]1 reveal+ _! o!r hemisph]es4 ,z %[n 9 ?is draw+1 ! spacecraft flew by fir/ ,calli/o1 !n ,ganym$e1 !n ,europa4 ,! t5-h\r ,io volcano wat* took place imm$iately aft] close/ approa* to ,jupit]4 #bfj-ecc;,a ,voyag] #b trajectory ,view normal to ,jupit] equator ,sun occultation ,e>? occultation ,laun* date #h_/bj_/gg ,jupit] arrival date #g_/i_/gi ,p]iapsis ,satellite close/ approa* ,amal!a ,europa ,io ,ganym$e ,calli/o ,illu/ration3 ,^! two faces ( ,jupit] 7 photograph$ by ,voyag] #b on ,may #i at a di/ance ( #df million kilomet]s f ! planet4 ,voyag] sci5ti/s began to detect significant *anges 9 ! cl\d patt]ns s9ce ! ,voyag] #a enc\nt] two mon?s e>li]4 #bfj-ejg ,illu/ration3 ,jupit]4 ,illu/ration3 ,jupit]4 ,illu/ration3 ,! wea!r is *ang+ ov] "o ( ! nor!rn hemisph]e br[n ovals 9 ?is picture tak5 ,july #f4 ,! br[n ovals are regions 9 :i* breaks 9 ! upp] lay] ( ammonia cl\ds reveal d>k] cl\ds bel[4 ,a high1 :ite cl\d is se5 mov+ ov] ! d>k] cl\d1 provid+ an indication ( ! /ructure ( ! cl\d lay]s4 ,?9 :ite cl\ds are also se5 )9 ! d>k cl\d4 ,at "r1 blue areas1 free ( high cl\ds1 are se54 ,p-#bagec;,c ,al?\gh ,voyag] #b's radio receiv] /ill c\ld n track a ,doppl]-%ift$ radio signal f ,e>? 7! problem is t x 8he>s a monotone10 expla9$ ,deputy ,project ,manag] ,esk] ,k4 ,davis71 ! ,deep ,space ,network eng9e]s _h le>n$ to "w ) ! spacecraft1 det]m9+ :at frequ5cy ! spacecraft w\ld li/5 to at any p>ticul> "t4 ,!y _h discov]$ t "s ( ! 8h\sekeep+0 telemetry signals f ! receiv] 7 s5sitive to ! mat* betwe5 ! incom+ frequ5cy & ! receiv] frequ5cy4 ,by monitor+ ^! signals1 !y c\ld detect a frequ5cy drift 9 "t to correct ! transmission1 ?us keep+ ! sy/em 9 tune 9 spite ( sl[ *anges 9 ! receiv]4 ,! sy/em 0 sl[ & dem&+ b effective2 all ! necess>y comm& sequ5ces 7 successfully load$ into ! comput]1 & communications dur+ ! enc\nt] 7 entirely successful4 ,! tim+ (fset exp]i5c$ by ,voyag] #a z a result ( ,jupit]'s int5se radiation environm5t 0 n expect$ to be a problem on ,voyag] #b = two reasons3 ,ev5 at close/ approa*1 ,voyag] #b w\ld /ill be m ?an twice z f> f ,jupit] z ,voyag] #a _h be51 & ! ,voyag] #b comput] 0 programm$ to resyn*ronize ! spacecraft's tim+ sy/ems automatically e h\r4 ,9 ?is way1 ev5 if ! radiation environm5t prov$ to be mu* high] ?an anticipat$1 ! image sme> t might occur f a tim+ (fset w\ld be prev5t$4 ,illu/ration3 ,complex activity 9 ! s\!rn hemisph]e ( ,jupit] cont9u$ dur+ ! ,voyag] #b enc\nt]1 al?\gh *anges _h occurr$ 9 ! region ( ! ,great ,r$ ,spot4 ,a :ite oval1 diff]5t f ! "o obs]v$ 9 a simil> position at ! "t ( ! ,voyag] #a enc\nt]1 0 situat$ s\? ( ! ,r$ ,spot4 ,! region ( :ite cl\ds ext5d$ f ea/ ( ! ,r$ ,spot & ar\nd its nor!rn b\nd>y1 prev5t+ small cl\d vortices f circl+ ! feature4 ,! di/urb$ region we/ ( ! ,r$ ,spot _h also *ang$ s9ce ! equival5t ,voyag] #a image4 ,! picture 0 tak5 on ,july #c f a di/ance ( #f million kilomet]s4 ,p-#bagdb;,c ,z a result ( ! discov]ies made by ,voyag] #a1 ! project sci5ti/s decid$ to modify "s ( ,voyag] #b's preplann$ sequ5ces4 ,z e>ly z ,april #a1 ! pa9/ak+ job ( con/ruct+ new comput] comm&s began4 ,a t5-h\r ,io ,volcano ,wat* 0 add$ to ! spacecraft's program1 tak+ advantage ( ! fact t %ortly aft] close/ approa* to ,jupit]1 ! spacecraft w\ld rema9 )9 ab\t #a million kilomet]s ( ,io = a long p]iod1 keep+ ne>ly ! same face 9 view4 ,provisions 7 also made to take ext5sive ultraviolet measurem5ts ( ! emission f ! gl[+ torus surr\nd+ ,jupit] ne> ! orbit ( ,io4 ,fur!r /udies w\ld be made ( ! d>k side ( ,jupit] to se>* = lightn+ & auroral activity1 & !re 0 also ! hope t ! plasma wave in/rum5t w\ld be able to detect lightn+ :i/l]s 7radio signals creat$ by lightn+ bolts7 z ! ,voyag] #a in/rum5t _h done4 ,a high priority 0 giv5 to obs]vations ( ! newly discov]$ r+1 :i* _h n be5 9 ! orig9al ,voyag] #b sequ5ce at all4 ,! spacecraft w\ld cross ! r+ plane twice1 photograph+ ! r+ dur+ bo? ! inb\nd & ! outb\nd passages4 ,z 0 orig9ally plann$1 ,voyag] #b w\ld make its close/ approa*es to ,calli/o1 ,ganym$e1 ,europa1 & ,amal!a be=e enc\nt] ) ,jupit]4 ,because ( ! diff]5ce 9 ! trajectories ( ! two spacecraft1 ,voyag] #b w\ld see ! faces ( ,calli/o & ,ganym$e n se5 by ,voyag] #a4 ,! mo/ important diff]5ce1 h[ev]1 0 t ! second ,voyag] w\ld fly mu* clos] to ,europa ?an ,voyag] #a did1 giv+ sci5ti/s _! fir/ good look at ! my/]i\s /reaks scrat*$ on ! surface ( t bright gold5 _w4 ,voyag] #b w\ld also h a clos] flyby ( ,ganym$e1 giv+ u a second *ance to exam9e its /range 8sn[mobile tracks40 ,! major loss1 ( c\rse1 0 ,io1 :i* w\ld be se5 f ,voyag] #b only at di/ances ( a million kilomet]s or m4 ,illu/ration3 ,io appe>$ 9 front ( ,jupit] z se5 by ,voyag] on ,june #be1 at a range ( #ab million kilomet]s4 ,at a resolution ( ab\t #bjj kilomet]s1 ! bright & d>k spots on ! satellite are j beg9n+ to be resolv$1 b x 0 n possible to det]m9e if any eruptions 7 /ill 9 progress4 ,p-#bagai;,c ,! ,enc\nt] ,w$nesday1 ,july #d4 7,range to ,jupit]1 #e4c million kilomet]s2 range to ,e>?1 #iba million kilomet]s74 ,:ile mo/ ( ! nation celebrat$ ,indep5d5ce ,day ) picnics1 sports ev5ts1 & fireworks1 ! sci5ti/s & eng9e]s at ,,jpl 7 work+ ar\nd ! clock4 ,voyag] #b _h already ent]$ ,jupit]'s t]ritory1 cross+ ! b[ %ock = ! fir/ "t on ,july #b at a di/ance ( #ii ,r,j f ,jupit]1 indicat+ t ! magnetosph]e _h exp&$ 9 ! int]val betwe5 ! two enc\nt]s4 ,at ab\t noon on ,july #c1 ! spacecraft enc\nt]$ ! magnetopause1 b on ,july #d1 ! data f ! p>ticles & fields in/rum5ts 7 ambigu\s4 ,app>5tly ! magnetosph]e 0 pulsat+ 9 response to *ang+ pressures1 & ! spacecraft 0 play+ tag ) ! rapidly %ift+ b\nd>ies ( ! b[ %ock & ! magnetopause4 ,z ! l[ en]gy *>g$ p>ticle in/rum5t began to measure p>ticles com+ f inside ! ,jovian magnetosph]e1 x became app>5t t "s important *anges _h tak5 place s9ce ,voyag] #a's enc\nt]4 ,f ! composition ( ! p>ticles1 x appe>$ t !y 7 l>gely ( sol> orig91 unlike ! heavy conc5trations ( ions ( sulfur & oxyg5 se5 by ,voyag] #a4 ,sci5ti/s began to speculate t ! ,io volcanoes1 :i* presumably eject sulfur & oxyg5 into ! magnetosph]e1 might h decl9$ 9 activity4 ,9 ! ev5+1 ! fir/ images ( ,io at a resolution high en\gh to all[ ! volcanic plumes to be se5 w\ld be beam$ back to ,e>?4 ,,enc\nt] ,,di/ances ,,= ,,voyag] #b ,object ,range to ,c5t] at ,close/ ,be/ ,image ,resolution ,approa* 7kilomet]s7 7km p] l9e pair7 ,jupit] #gbb #jjj #ae ,amal!a #eeh #jjj #aj ,io #a #acj #jjj #bj ,europa #bjf #jjj #d ,ganym$e #fb #jjj #a ,calli/o #bae #jjj #d ,illu/ration3 ,voyag] sci5ti/s anxi\sly await$ ! fir/ views ( ,io t w\ld %[ :e!r ! volcanic eruptions se5 9 ,m>* 7 /ill active4 ,?is picture 0 tak5 on ,july #d1 at a range ( #d4g million kilomet]s1 ab\t ! same z t ( ! volcano discov]y picture on ,m>* #h4 ,"o l>ge plume is cle>ly visible1 ris+ ne>ly #bjj kilomet]s above ! surface4 ,at ! "t ( release ( ?is picture on ,july #f1 ! sci5ti/s wrote1 8,! volcano app>5tly has be5 erupt+ s9ce x 0 obs]v$ by ,voyag] #a 9 ,m>*4 ,?is sugge/s t ! volcanoes on ,io probably are 9 cont9u\s eruption40 ,p-#bagch;,b_/,w ,?ursday1 ,july #e4 7,range to ,jupit]1 #d4d million kilomet]s74 ,! press room at ,von ,k>man ,auditorium op5$ & ! memb]s ( ! press1 mo/ ( !m vet]ans ( ! fir/ enc\nt]1 arriv$ at ,,jpl4 ,mean:ile1 ! spacecraft cont9u$ to measure fluctuations 9 ! magnetosph]ic b\nd>y4 ,by noon1 ,,jpl _h report$ at lea/ elev5 cross+s ( ! b[ %ock z ! sol> w9d flirt$ ) ,jupit]'s magnetosph]e4 ,app>5tly ! sol> w9d 0 mu* m v>iable 9 ,july ?an x _h be5 9 ,m>*4 ,at times ! b[ %ock seem$ to be ?ick] ?an t exp]i5c$ by ,voyag] #a2 "o ,voyag] #b cross+ took t5 m9utes1 :]eas ! longe/ ,voyag] #a cross+ 0 only "o m9ute long4 ,ev5 ?\gh ! processes affect+ ! magnetosph]e seem$ m complex1 ! magnetosph]e 0 less compress$2 :5 ,voyag] #b actually ent]$ ! magnetosph]e at a di/ance ( #fb ,r,j1 x 0 mu* f>!r f ,jupit] ?an ,voyag] #a _h be5 at its f9al cross+ 7#dg ,r,j74 ,photos obta9$ ! day be=e f ov] #d million kilomet]s %[$ t at lea/ "o ( ,io's volcanoes 0 /ill active4 ,a total ( eight ongo+ eruptions _h be5 se5 by ,voyag] #a1 & sci5ti/s 7 anxi\s to see h[ _m ( ^! 7 /ill erupt+ f\r mon?s lat]4 ,,voyag] #b ,,b[ ,,%ock 7,s7 ,,& ,,magnetopause 7,m7 ,,cross+s ,b\nd>y ,day ,di/ance 7,r,j7 ,inb\nd ,s #g_/jb #ii 7multiple7 ,s #g_/jb #ig ,s #g_/jc #hg ,m #g_/jd #gb 7multiple7 ,m #g_/je #ga ,s #g_/je #fi ,s #g_/je #fg ,m #g_/je #fb ,outb\nd ,m #g_/bc #afi ,m #g_/bc #agc ,m #g_/bd #agd ,m #g_/bd #age ,m #g_/bd #agf ,m #g_/bd #agg ,m #g_/be #ahd ,m #g_/be #ahe ,m #g_/bg #bac ,m #g_/ca #bec ,m #h_/ja #beh ,m #h_/ja #bfb 7multiple7 ,m #h_/jc #bgi 7multiple7 ,s #h_/jc #bhc 7multiple7 ,illu/ration3 ,al?\gh ,voyag] #b did n come z close to ,io z _h ,voyag] #a1 "s *anges 9 ! surface dur+ ! f\r mon?s betwe5 enc\nt]s 7 s l>ge t !y c\ld /ill be easily se54 ,^! two pictures ( ! region ( ! volcano ,pele 7 tak5 9 e>ly ,m>* & e>ly ,july1 respectively4 ,! mo/ dramatic *ange 0 ! fill+ 9 ( ! ind5tation 9 ! ejecta r+1 turn+ ! ho(pr9t into a symmetric oval4 ,! oval is ab\t #ajjj by #gjj kilomet]s 9 out]mo/ dim5sion1 & ! area t *ang$ am\nts to m ?an #aj #jjj squ>e kilomet]s4 #bfj-fhg;,,ac ,illu/ration3 ,volcano ,pele on ,io4 ,illu/ration3 ,volcano ,pele on ,io4 ,:ile att5tion at ,,jpl focus$ on ! unfold+ drama ( ! ,jupit] enc\nt]1 _m memb]s ( ! _w's press seem$ m int]e/$ 9 ! fate ( ,skylab1 :i* 0 ne>+ its dea? plunge into ! ,e>?'s atmosph]e4 ,laun*$ 9 #aigc1 ,skylab _h be5 "o ( ,,nasa's m successful projects4 ,?ree crews ( a/ronauts _h visit$ x1 c>ry+ out int5sive /udies ( ! ,sun & break+ "o record aft] ano!r = ! duration ( mann$ space flight4 ,s9ce ! dep>ture ( ! f9al gr\p ( ?ree a/ronauts 9 #aigd1 ,skylab _h be5 s9k+ gradually l[] z a result ( friction ) ! extreme upp] atmosph]e ( ,e>?4 ,dur+ ! pa/ ye>1 high] temp]atures 9 ! atmosph]e _h increas$ ?is drag1 & n[ ! end 0 ne>4 ,) a /range fasc9ation1 ! _w wat*$ ! end ( ?is old spacecraft1 almo/ seem+ to =get ! spectacul> new results be+ transmitt$ f ,jupit]4 ,to ! fru/ration ( ! ,voyag] team & ! press 8camp$ out0 9 ,von ,k>man ,auditorium = ! second enc\nt]1 ! exagg]at$ /ories ( a possible ,skylab disa/] took prec$5ce ov] ,voyag] news4 ,ultimately1 ,skylab fell ov] ! ,indian ,ocean & ,au/ralia on ,w$nesday1 ,july #aa1 j z ! major f9d+s ( ,voyag] #b 7 be+ releas$4 ,friday1 ,july #f4 7,range to ,jupit]1 #c4e million kilomet]s74 ,) ! fir/ satellite enc\nt] /ill two days away1 ,voyag] #b cont9u$ to make a v>iety ( measurem5ts ( ,jupit] & all ! ,galilean satellites4 ,z ! di/ance to ,io decreas$1 x 0 possible to see detail$ surface features z well z to look = ! volcanic plumes at ! edge ( ! disk1 silh\ett$ aga9/ black space4 ,by ! end ( ! day1 ! ,great ,r$ ,spot loom$ s l>ge t six imag+ frames 7a #b #c mosaic7 7 requir$ to encompass x & its imm$iate surr\nd+s4 ,at ! fir/ =mal press conf]5ce ( ! ,voyag] #b enc\nt]1 ,project ,sci5ti/ ,ed ,/one review$ ! progress ( ! mission4 ,because ! ail+ spacecraft receiv] 0 work+ s well1 ,ray ,heacock1 ,voyag] ,project ,manag]1 ann\nc$ t ! major trajectory correction maneuv] at ,jupit] _h be5 res*$ul$ to take place only two h\rs aft] close/ approa*4 ,s9ce ! geometry 0 especially favorable at ?is "t1 ! #gf-m9ute rocket burn c\ld put ! spacecraft on its plann$ r\te to ,saturn ) a m9imum exp5diture ( fuel1 !reby pres]v+ ! option ( s5d+ ! spacecraft on to ,uranus4 ,! ,io torus 0 "u obs]vation1 bo? directly by ! ultraviolet spectromet]1 & indirectly by ! *>g$ p>ticle in/rum5ts4 ,! ,,lecp in/rum5t _h begun to pick up sulfur ions1 b at l[] en]gies & l[] conc5trations ?an ^? record$ dur+ ! fir/ enc\nt]4 ,9 ! ultraviolet1 gl[s c\ld be se5 bo? f ! torus & f aurorae 9 ! pol> regions ( ,jupit]4 ,photographs ( ,io %[$ t ! he>t-%ap$ feature surr\nd+ ,pele 7,p71 ,io's l>ge/ volcano1 _h *ang$ %ape4 ,! ind5tation ( ! he>t _h disappe>$1 mak+ ! he>t into an oval4 ,app>5tly a new deposit ( volcanic ejecta _h blanket$ ! surface1 alt]+ its color4 ,p]haps an e>li] ob/ruction 9 ! volcanic v5t1 or ! %ape ( ! v5t itself1 _h caus$ ! area surr\nd+ ,pele to look he>t-%ap$4 ,9 any case1 :atev] _h caus$ ! ind5tation 0 n[ gone4 ,at ! same "t1 new photos fail$ to %[ a plume above ,pele1 & !re 0 speculation t *anges 9 ?is eruption might be relat$ to ! alt]$ population ( *>g$ p>ticles 9 ! magnetosph]e4 ,illu/ration3 ,! ,voyag] #b pictures ( ,calli/o look$ rem>kably simil> to ^? obta9$ ( ! o!r side ( ! satellite by ,voyag] #a4 ,se5 f a di/ance ( #b4c million kilomet]s1 ! l>ge crat]s 7#ajj kilomet]s or m across7 appe> z light spots4 ,no new major impact features su* z ,valhalla1 discov]$ by ,voyag] #a1 are visible on ! hemisph]e se5 by ,voyag] #b4 ,p-#bagdj;,c ,saturday1 ,july #g4 7,range to ,jupit]1 #b4f million kilomet]s74 ,z ! spacecraft rapidly clos$ on ,calli/o1 bett] & bett] photographs 7 tak5 ( ! previ\sly unse5 hemisph]e4 ,z ) ! ,voyag] #a obs]vations1 h[ev]1 ! ma9 impression 0 "o ( heavy crat]+1 unreliev$ by o!r geologic /ructures4 ,mean:ile1 ! cov]age ( ,io _h improv$ z ! satellite rotat$ to ! po9t at :i* a c5sus ( ! volcanic eruptions se5 9 ! fir/ enc\nt] began to em]ge4 ,at ! #aa3jj a4m4 press conf]5ce1 ,l>ry ,sod]blom ann\nc$ t f\r ( ! volcanoes discov]$ by ,voyag] #a _h be5 look$ at aga9 by ,voyag] #b1 & ?ree ( !m--,prome!us 7,p71 ,loki 7,p71 & ,m>duk 7,p7--7 /ill active4 ,h[ev]1 !re 0 no trace ( volcanic activity com+ f ,pele1 ! s\rce ( ! l>ge/ plume se5 by ,voyag] #a4 ,p 0 ei!r greatly subdu$ or _h turn$ (f completely4 ,dr4 ,sod]blom also ann\nc$ t ,voyag] #b images _h detect$ ano!r giant r+ /ructure on ,calli/o1 br++ ! total to ?ree1 & !re 7 probably m4 ,?is p>ticul> r+ feature 0 e/imat$ to be ab\t #aejj kilomet]s across4 ,x 0 also not$ t al?\gh ,calli/o g5]ally seem$ to be saturat$ ) %\ld]-to-%\ld] crat]s1 ! crat] d5sity ne> ! r+ /ructures seem$ to be l[]4 ,saturday 0 a fairly quiet "t = ! sci5ti/s b n = ! spacecraft or ! spacecraft team4 8,we block$ out ab\t #g h\rs10 expla9$ ,mi*ael ,devirian1 ,gr\nd ,data ,sy/ems ,developm5t1 ,integration1 & ,te/ ,director1 89 :i* we c\ld s5d x a set ( comm&s & re-s5d x if necess>y to make sure all close-enc\nt] comm&s 7 receiv$ by ,voyag] #b until all ! comm&s got ?r\gh4 ,! :ole ?+ w5t p]fectly ! fir/ "t40 ,s ev]y?+ 0 8g0 = close enc\nt]4 ,! ne> enc\nt] phase began at #f3cf p4m4 ,,pdt4 ,illu/ration3 ,a new face ( ,ganym$e 0 reveal$ to ,voyag] #b4 ,?is image 0 tak5 ,july #g f a di/ance ( #a4b million kilomet]s & cle>ly %[s ! l>ge d>k area ,regio ,galileo1 z well z mu* ( ! light] groov$ t]ra9 discov]$ by ,voyag] #a4 ,! bright spots are impact crat]s4 ,?is image also %[s :at appe> to be pol> caps1 ext5d+ d[n to ab\t latitude #de 9 bo? ! nor!rn & s\!rn hemisph]es4 #bfj-fgj ,sunday1 ,july #h4 7,range to ,jupit]1 #a4e million kilomet]s74 ,at #b3cj a4m4 ! fir/ long-exposure sequ5ce ( r+ pictures 0 tak51 & at #c3jj a4m4 ! int5sive p]iod ( ! ,calli/o enc\nt] began4 ,eighty high-resolution images 7 obta9$ ( ! satellite1 c5t]$ ar\nd close/ approa* 7#bae #jjj kilomet]s7 at #f3ac a4m4 ,incom+ photos %[$ "s features t look$ l d\ble-wall$ crat]s1 b no m giant r+ /ructures 7 se54 ,x appe>$ t !re 0 an asymmetry 9 ! di/ribution ( l>ge impact features ov] ,calli/o's surface4 8,calli/o may turn out to be ! mo/ heavily crat]$ body 9 ! sol> sy/em10 ,torr5ce ,johnson rem>k$4 ,g>ry ,hunt 0 to add lat] on1 8,!re's j n room = ano!r crat] on t body--x's totally full40 ,at ! press conf]5ce1 ,brad ,smi? confirm$ ! e>li] f9d+ t ,io's volcano ,pele 0 q dead--at lea/ = n[4 ,al?\gh ,p _h n yet be5 look$ at1 all o!r volcanoes discov]$ by ,voyag] #a 7 /ill active1 b no new plumes _h be5 f\nd4 ,h[ev]1 new ultraviolet images ( ,p 7,loki7 sugge/$ t ! eruption _h increas$ 9 size4 7,9 a lat] report1 ! imag+ team ann\nc$ t ,p _h increas$ 9 height to #age kilomet]s & _h *ang$ to a two-column plume47 ,! new photographs ( ,jupit]'s r+ %[$ x to be q n>r[ & ribbonlike1 ,dr4 ,smi? ann\nc$4 ,! arti/'s draw+ 7releas$ dur+ ! ,voyag] #a enc\nt]71 int5d$ to %[ ! out] edge ( ! r+1 turn$ out to be a good repres5tation ( ! actual r+1 ,dr4 ,smi? said4 ,!re seem$ to be less high-spe$ sulfur & oxyg5 inside ,jupit]'s magnetosph]e ?an !re _h be5 dur+ ! ,voyag] #a enc\nt]1 ,george ,gloeckl] ann\nc$4 ,voyag] #b's l[ en]gy *>g$ p>ticle in/rum5t 0 f9d+ sub/antial am\nts ( c>bon1 silicon1 magnesium1 & o!r elem5ts ( sol> orig91 b ! ,io-associat$ elem5ts 7 almo/ deplet$4 ,! ultraviolet in/rum5t _h f\nd z mu* gl[+ sulfur 9 ,io's torus z be=e1 b less ( x seem$ to be rais$ to en]gies high en\gh to leave ! torus & be detect$ else:]e 9 ! magnetosph]e4 ,!re 7 o!r indications ( ,jupit]'s *ang+ wea!r4 ,9 a ,voyag] report ,sunday ev5+1 ,g>ry ,hunt rem>k$1 8,"o v excit+ obs]vation came ! o!r day :i* caus$ major excitem5t d[n 9 ! imag+ area4 ,we actually saw a :ite cl\d />t+ to intrude across a d>k b>ge l>ge br[ni% oval-%ap$ feature 9 ,jupit]'s nor!rn hemisph]e4 ,atmosph]ic sci5ti/s get v excit$ by t because ?is is %[+ u h[ ! colors lay] !mselves up--t :ite cl\d is cle>ly above ! d>k br[n4 ,we're desp]ately try+ to und]/& ! relation%ip ( colors on ,jupit]40 ,illu/ration3 ,! fir/ close-up views ( ,europa 7 bo? excit+ & p]plex+ to ,voyag] sci5ti/s4 ,! be/ ,voyag] #a resolution _h be5 only ab\t #cj kilomet]s1 b ! ,voyag] #b trajectory p]mitt$ a mu* clos] flyby4 ,^! pictures1 tak5 on ,july #i at a range ( #bdj #jjj kilomet]s1 h a resolution ( ab\t #e kilomet]s4 ,! bright icy cru/ ( ,europa is cov]$ ) a spectacul> s]ies ( d>k /reaks1 giv+ ! satellite a crack$ appe>ance4 ,9 a few cases1 n>r[] light l9es run d[n ! c5t]s ( ! d>k /reaks1 :i* are typically a few t5s ( kilomet]s 9 wid?4 ,v few1 if any1 impact crat]s are visible on ,europa4 ,p-#bagfj;,c & ,p-#bagfd;,c ,illu/ration3 ,europa ,monday1 ,july #i4 7,range to ,jupit] at enc\nt]1 #gbb #jjj kilomet]s74 ,enc\nt] day6 ,& n j "o enc\nt]1 b a :ole sequ5ce3 ,ganym$e1 ,europa1 ,amal!a1 ,jupit]1 & ,io4 ,by e>ly ,sunday ev5+1 a weal? ( new data on ,ganym$e 0 p\r+ 94 ,n only 0 ?is a side ( ! satellite n se5 be=e1 b ,voyag] #b w\ld pass clos] to ,ganym$e ?an _h ,voyag] #a4 ,enc\nt] took place at #a3jf a4m41 at a range ( #fb #jjj kilomet]s4 ,betwe5 #i3jj p4m4 ,sunday night & #a3cj a4m4 ,monday morn+ a total ( #bag photos1 plus infr>$ & ultraviolet spectra1 7 s*$ul$4 ,sixty-n9e photos 7 s5t back 9 real "t2 o!rs 7 record$ = playback lat]4 ,z ! ,ganym$e pictures appe>$ on ! ,,tv scre5s1 !y reveal$ a _w ( trem5d\s v>iety4 ,"s regions 7 heavily crat]$3 8,ganym$e looks l ,m]cury or ! highl&s ( ! moon10 "o ,voyag] sci5ti/ rem>k$4 ,o!r p>ts ( ! surface1 h[ev]1 %[$ v diff]5t features3 long1 p>allel m\nta9 ridges t look$ l grooves made ) a giant's rake2 n>r[1 segm5t$ l9es2 :ite ejecta blankets f impacts t look$ l a dazzl+1 sn[-cov]$ l&scape4 ,"s ( ! pictures sugge/$ crack+ & slipp+ ( ,ganym$e's cru/1 :ile o!rs %[$ :at appe>$ to be remnants ( anci5t t]ra9 unaffect$ by subsequ5t int5se geologic activity4 ,_m ( ! highe/ resolution frames 7 n se5 at ?is "t2 !y 7 record$ on ! spacecraft = playback lat]4 ,/>t+ at ab\t #h a4m41 ,e>? began receiv+ ! fir/ closeup views ( ,europa4 ,europa 8c\ld be ! mo/ excit+ satellite 9 ! :ole ,jovian sy/em10 said ,l>ry ,sod]blom1 8because x's sort ( ! transition body betwe5 ! solid silicate body1 ,io1 & ! ice balls1 ,ganym$e & ,calli/o40 ,! icy cru/ look$ z ?\gh x 8_h be5 ruptur$ all ov]--z ?\gh x 0 9 pieces--j z ?\gh x _h be5 brok5 9 place & left !re40 ,at #aa3dc a4m41 close/ approa* took place at a range ( #bjf #jjj kilomet]s4 ,by ?is "t ! sci5ti/s 7 dazzl$ by :at !y _h se52 "s 7 call+ ,europa ! mo/ biz>re ( all ! ,galilean satellites4 ,9 ! ,imag+ ,team view+ area1 ,david ,morrison comp>$ ,europa's surface to 8a crack$ egg10 & ,g5e ,%oemak] said1 8,x looks l sea ice to me40 ,:5 someone comm5t$ t ! canal-l /reaks 7 rem9isc5t ( ,m>s1 ,torr5ce ,johnson repli$1 8,x looks l "s pictures ( ,m>s ,i've se51 b only on ! walls ( ,l[ell ,obs]vatory40 ,ano!r quipp$1 8,:]e is ,p]cival ,l[ell1 n[ t we ne$ him60 ,!re 7 to be two press conf]5ces3 "o to pres5t spacecraft & sci5tific results & "o to celebrate ! second successful flyby & to talk ( new goals--,saturn1 & p]haps ,uranus4 ,at ! fir/ conf]5ce1 ,ed ,/one began by discuss+ ! radiation ,voyag] 0 exp]i5c+4 ,"o ( ,jupit]'s surprises 0 t ! radiation environm5t 0 great] ?an _h be5 anticipat$1 & ?is caus$ problems ) ! radio receiv]4 ,! receiv] frequ5cy 0 %ift+ 8m rapidly ?an we _h anticipat$10 said ,ray ,heacock1 8& we h n be5 able to keep an upl9k cont9u\sly ) ! spacecraft40 ,! solution 0 to keep s5d+ up comm&s at diff]5t frequ5cies until a frequ5cy ! spacecraft w\ld accept 0 f\nd4 ,j h[ bad 7 ! radiation levels8 ,ed ,/one comm5t$1 8,! p5etrat+ radiation at a giv5 di/ance is m int5se n[ at ?is di/ance ?an x 0 :5 ,voyag] #a flew by40 ,f a prelim9>y analysis x seem$ t1 ov]all1 ,voyag] #b w\ld /ill be subject$ to l[] radiation levels ?an ,voyag] #a _h be51 b to high] levels ?an _h be5 expect$4 ,9 addition1 ,voyag] #b's radio receiv] 0 mu* m s5sitive4 ,! high] ?an expect$ radiation int5sity also l$ ,voyag] sci5ti/s to h ! ultraviolet spectromet] %ut (f1 s9ce t in/rum5t 0 also q s5sitive to ! radiation4 ,! f\r? memb] ( ! ,galilean satellites _h f9ally be5 se51 & ,l>ry ,sod]blom happily introduc$ ,europa4 8,well1 "s few mon?s ago1 be=e ! ,voyag] #a enc\nt]1 we ?\ght we _h "s idea ( :at planets 7 l--at lea/ ! planets 9 ! inn] sol> sy/em3 ,m>s1 ,m]cury1 ! ,moon1 ! ,e>?4 ,& we've discov]$ _m times ov] 9 ! la/ c\ple ( mon?s h[ n>r[ our vision really 04 ,includ$ 9 ! ,jovian collection ( satellites are ! olde/ 7,calli/o71 ! y\nge/ 7,io71 ! d>ke/ 7,amal!a71 ! brighte/ 7,europa71 ! r$de/ 7,amal!a & ,io71 ! :ite/ 7,europa71 ! mo/ active 7,io71 & ! lea/ active 7,calli/o74 ,today we f\nd ! flatte/ 7,europa740 ,9 spite ( ! appe>ance ( a crack$ or brok5 surface1 ,europa %[$ no topography at all4 ,t[>d ! sunset l9e1 :]e ! l[ angle ( illum9ation %\ld reveal ev5 l[ relief1 8! surface disappe>s--z if x 7 ! surface ( a billi>d ball40 ,x seem$ cle> t ,europa has mu* less relief ?an ! o!r two icy satellites1 ,ganym$e & ,calli/o4 ,b :y c't ,europa's surface support relief8 ,p]haps ,europa has a ?ick ice mantle--on ! ord] ( #ajj kilomet]s4 ,if ,europa is affect$ by tidal heat+1 !n su* an ice mantle might be 8sort ( s(t & slu%y0 r ?an rigid z are ! cru/s ( ,ganym$e & ,calli/o4 8,! fact t ! surface ( ,europa _c support relief ( any sub/antial am\nt sugge/s t ! surface mu/ be s(t40 ,b1 ,dr4 ,sod]blom add$1 !re does n appe> to be mu* lat]al motion or rotation caus+ ! surface m>k+s--!y don't seem to be (fset--r1 8x's z if ,europa _h be5 crack$1 brok51 by "s process :i* cru%$ x l an egg%ell & j left ! pieces sitt+ !re4 ,expansion & contraction ( ice & wat] are a good way to crun* up ! surface40 ,illu/ration3 ,regio ,galileo is ! l>ge/ remnant ( ! anci5t1 heavily crat]$ cru/ ( ,ganym$e4 ,?is ,voyag] #b color recon/ruction 0 made f pictures tak5 at a range ( #caj #jjj kilomet]s2 ! sc5e is ab\t #acjj kilomet]s across4 ,num]\s crat]s1 _m ) c5tral peaks1 are visible4 ,! l>ge bright circul> features h little relief & are probably ! remnants ( old l>ge crat]s t h be5 anneal$ by ! fl[ ( icy ne>-surface mat]ial4 ,! closely spac$1 arcuate l9e> features are analog\s to features on ,calli/o1 su* z ! 8ripple0 m>ks surr\nd+ ! anci5t impact feature ,valhalla4 ,p-#bagfa;,c ,illu/ration3 ,at high resolution1 ! groov$ t]ra9 on ,ganym$e %[s a wond]ful complexity4 ,surface features z small z #a kilomet] across c be se5 9 ?is mosaic ( ,voyag] #b images tak5 ,july #i4 ,! grooves are basically long1 p>allel m\nta9 ridges1 #aj to #ae kilomet]s f cre/ to cre/--ab\t ! same scale z ! ,appala*ian m\nta9s 9 ! ,ea/]n ,unit$ ,/ates4 ,! num]\s impact crat]s sup]pos$ on ! m\nta9 ridges indicate t !y are old--probably =m$ sev]al billion ye>s ago4 #bfj-fcg ,! o!r side ( ,ganym$e pres5t$ q a diff]5t face f ! "o ,voyag] #a _h se54 ,"h 7 ! d>k anci5t crat]$ t]ra9s1 ! %\ld]-to-%\ld] crat]s rem9isc5t ( ,calli/o1 & !re 0 a huge circul> feature on ,ganym$e look+ l ! remnant ( a ,calli/o-/yle r+$ bas91 pres]v$ 9 ! anci5t1 d>k t]ra94 ,! v l>ge d>k feature reveal$ by ,voyag] 9 ! nor!rn hemisph]e :i* be>s ^! impact sc>s 0 lat] nam$ 8,regio ,galileo10 = ! discov]] ( ! ,galilean satellites4 ,x 0 se5 9 ! l[-resolution ,pione] #aj picture ( ,ganym$e tak5 9 #aigc1 b its nature 0 n und]/ood4 ,x is s l>ge x has ev5 be5 glimps$ on occasions ( exceptionally /able 8see+0 ) gr\nd-bas$ telescopes4 #c3bi p4m4 ,,pdt--,jupit] ,enc\nt]6 ,9 ! press room half a doz5 cam]as click$ 9 unison z ! univ]sal clock decl>$ ! ,voyag] #b _h made its close/ approa* to ,jupit]--#fej #jjj kilomet]s f ! cl\d tops1 zipp+ by at ab\t #gc #jjj kilomet]s p] h\r--nei!r z close nor z fa/ z ,voyag] #a4 ,by ! "t ( ! special press conf]5ce at #d3cj p4m41 ev]yone at ,,jpl 0 9 a p>ty mood4 ,?omas ,a4 ,mut*1 :o _h replac$ ,noel ,h9n]s z ,,nasa ,associate ,adm9i/rator = ,space ,sci5ce1 ,rob]t ,p>ks1 & ,rodney ,mills 7 ! speak]s4 ,! ,jovian sy/em is a place ( 8incr$ible beauty & my/]y4 ,jupit] has be5 a nice place to g by1 b we w\ldn't want to /op !re--we're go+ on to ,saturn10 ,rod ,mills expla9$1 & ,bob ,p>ks agre$4 ,tim ,mut* _h a diff]5t p]spective4 8,al?\gh we h j he>d ,jupit] some:at d[ngrad$ 9 favor ( ,saturn1 none!less :at we h be5 witness+1 fir/ 9 ,m>* & n[1 9 ,july1 is a truly revolution>y j\rney ( exploration4 ,we h gone beyond ! famili> "p ( ! sol> sy/em to objects t are s exotic t _! v exi/5ce1 at lea/ z f> z ,i'm conc]n$1 0 some?+ ,i'd accept$ intellectually1 b didn't really accept 9 an imm$iate s5se4 ,we're />t+ out 9 our own space program on a new /age ( space exploration--on our own long j\rneys beyond ! sol> sy/em to di/ant l&s4 ,we nev] l to ?9k1 or r1 x's /ati/ically unlikely1 t we're at a turn+ po9t 9 hi/ory4 ,b if y look back at hi/ory books1 su* ev5ts are cle>ly read into ! record4 ,& ,i submit to y t :5 ! hi/ory books are writt5 a hundr$ ye>s f n[1 two hundr$ ye>s f n[1 ! hi/orians are go+ to cite ?is p>ticul> p]iod ( exploration z a turn+ po9t 9 our cultural1 our sci5tific1 our intellectual developm5t40 ,al?\gh ev]yone 0 already celebrat+ ano!r successful mission1 ! enc\nt] 0 f> f ov]4 ,data cont9u$ to come 92 !re 0 /ill ! t5-h\r ,io ,volcano ,wat*1 :i* _h begun at #d3ca p4m42 !re 7 m obs]vations ( ,jupit]1 includ+ s*$ul$ r+ obs]vations & d>k side se>*es = aurorae & lightn+ bolts4 ,!re 0 a lot ( "w & excitem5t yet to come4 ,jupit] _h ano!r surprise 9 /ore = ,voyag] #b4 ,illu/ration3 ,dur+ ! #aj-;h\r ,io volcano wat* on ,july #i1 ! spacecraft kept ne>ly ! same face ( ,io 9 view4 ,mo/ ( ! surface 0 turn$ away f ! ,sun1 h[ev]1 & only a ?9 cresc5t c\ld be se51 %r9k+ z ! obs]vations cont9u$4 ,^! f\r frames 7 all photograph$ ) id5tical exposures f a range ( ab\t #a million kilomet]s4 ,^! images %[ ,amirani 7,p7 & ,maui 7,p7 on ! we/ edge1 bright5+ z ! ,sun illum9ates !m m ne>ly f beh9d4 #bfj-fgg ,illu/ration3 ,io volcanoes4 ,illu/ration3 ,masubi 7,p7 is fa9tly visible 9 ! cresc5t 7above & bel[74 ,illu/ration3 ,io volcanoes4 ,illu/ration3 ,loki 7,p7 rises #bej kilomet]s above ! surface1 cat*+ ! morn+ sunlight on ! ea/ edge ( ,io4 ,tuesday1 ,july #aj4 7,range to ,jupit]1 #a4d million kilomet]s74 ,! ,io wat* cont9u$ ?r\gh ! night4 ,z "t pass$1 ! satellite rotat$ 9 ! same direction z ! motion ( ! spacecraft1 keep+ ne>ly ! same side 9 view4 ,because ( ?is1 a few volcanoes c\ld be closely wat*$1 b mo/ w\ld be miss$ entirely4 ,dur+ ! sequ5ce1 ! illum9at$ cresc5t /eadily %rank1 until at ! end1 volcanic plumes c\ld be se5 on bo? edges1 "o illum9at$ by ! sett+ ,sun1 ! o!r %9+ 9 ! dawn light4 ,at ! #aa a4m4 press conf]5ce1 ,esk] ,davis ann\nc$ t eng9e]s _h lo/ contact ) ! spacecraft radio receiv] ,monday ev5+ 7probably due to ,jupit]'s radiation7 & _h to 8*ase x ar\nd mo/ ( ! night10 s5d+ comm&s at v>i\s frequ5cies until !y lock$ on to ! frequ5cy ! spacecraft w\ld accept4 ,! major trajectory correction maneuv]1 begun at ab\t ! same "t contact ) ! receiv] 0 lo/1 0 successful4 ,! #gf-m9ute ?ru/] fir+1 done at p]iapsis in/ead ( two weeks aft] enc\nt]1 enabl$ ! spacecraft to get a bigg] 8boo/0 f ,jupit] ?an 0 orig9ally plann$1 am\nt+ to a fuel sav+ ( ab\t #aj kilograms ( hydraz9e1 en\gh to pres]ve ! option ( go+ on f ,saturn to ,uranus4 ,&rew ,+]soll discuss$ "s results ( ! analysis ( ! ,jovian atmosph]e4 8,at fir/1 ,voyag] seem$ to d no?+ b emphasize ! *aos1 n ! ord]40 ,b1 ) ! help ( gr\nd-bas$ obs]vations1 ,reta ,beebe f\nd t !re is a 8regul> alt]nation ( ea/w>d & we/w>d jets0 und]ly+ ! seem+ly *aotic visible features4 8,! turbul5ce we see 9 ! visible cl\ds seems to be a m9or side %[1 or a process )\t mu* en]gy or mass comp>$ to ! v great en]gy & mass t might be mov+ ar\nd 9 ! deep atmosph]e40 8,we're cont9u+ to op]ate 9 our panic mode to try to get pictures to ! press10 ,brad ,smi? said z he introduc$ new photographs ( ! satellites4 ,9 e>li] photos1 ,ganym$e _h seem$ to h two diff]5t k9ds ( t]ra9--an anci5t1 crat]$1 ,calli/o-l surface1 & ! /rang]1 groov$ t]ra9--t]ra9s t might be repres5tative ( two v diff]5t types ( major episodes 9 ,ganym$e's hi/ory4 ,! mo/ rec5t images %[$ a mu* m confus$ picture1 ) sev]al additional types ( surface geology4 ,at ! daily project sci5ce brief+1 ano!r int]pretation 0 be+ discuss$4 ,lyle ,broadfoot report$ t new measurem5ts ( ! position ( ! ultraviolet aurora demon/rat$ t x 0 caus$ by *>g$ p>ticles f ! ,io torus1 n f ! out] p>ts ( ! magnetosph]e4 ,app>5tly ^! plasma p>ticles arise 9 ! volcanic eruptions1 are trapp$ = a "t 9 ! torus1 & !n fall into ! pol> regions ( ,jupit]1 :]e !y excite auroral emissions4 ,a t]re/rial aurora1 9 contra/1 is caus$ by p>ticles t orig9ate 9 ! sol> w9d4 ,jim ,sullivan ( ! plasma inve/igation e/imat$ t ab\t two tons ( mat]ial ea* second are f$ f ,io into ! plasma torus4 ,?is plasma1 driv5 by ! rotation ( ! ,jovian magnetic field1 appe>s to be able to supply ! million-million watts ( p[] radiat$ 9 ! ultraviolet4 ,by #e3jj p4m4 ! excitem5t _h di$ d[n2 _m ( ! sci5ti/s _h p>ties to att5d t ev5+1 & "s memb]s ( ! press 7 plann+ p>ties ( _! own4 ,! s*$ule ( spacecraft activities also seem$ to h sl[$4 ,!re 7 d>k-side obs]vations plann$ to se>* = lightn+ & aurorae4 ,!re w\ld be a few m r+ pictures--n too mu* to see on ! monitors t night 444 or s _m p ?\ght4 ,b a few p 7 wait+ ar\nd1 p]haps to cat* a glimpse ( lightn+ or auroral activity1 or to wait = ano!r look at ,jupit]'s fa9t r+4 ,betwe5 #e3eb & #f3af p4m41 six long-exposure1 wide-angle photographs ( ! d>k side ( ,jupit] _h be5 s*$ul$ to se>* = aurorae & lightn+4 ,! spacecraft 0 #a #dej #jjj kilomet]s f ,jupit] & ab\t two degrees bel[ ! equatorial plane4 ,%ortly aft] #f p4m41 ! fir/ ( ^! r+ photographs appe>$ on ! ,,tv monitors ) unexpect$ brilliance4 ,tak5 9 orange & violet light1 ! images %[$ ! outl9e ( ,jupit] &1 protrud+ f x1 two n>r[ l9es--"o rea*+ all ! way to ,jupit]'s limb1 ! o!r brok5 (f1 app>5tly hidd5 by ! %ad[ ( ! giant planet4 ,se5 f ! new p]spective ( ! %ad[ ( ,jupit]1 ! t5u\s r+s 7 rem>kably cle>4 ,a sudd5 r5ewal ( excitem5t surg$ ?r\gh ! devotees rema9+ 9 ! press room4 ,ab\t #f3ae1 ,brad ,smi? came d[n to jo9 ! press to wat* ! rema9d] ( ?is s]ies ( pictures come 94 8,hey ,brad1 are y go+ to burn out ! cam]a ) ! r+80 someone jok$4 8,well1 ! r+s d =w>d scatt] nicely1 don't !y80 ,dr4 ,smi? repli$4 ,z ! wide-angle pictures 7 foll[$ by n>r[-angle views1 m & m detail became app>5t4 ,= ! fir/ "t1 a def9ite wid? = ! r+ c\ld be se51 & !re 0 ev5 a h9t ( additional mat]ial inside ! ma9 r+4 ,all 9 all1 ,voyag] _h provid$ "o m spl5did s]ies ( pictures be=e x took (f = ,saturn4 ,illu/ration3 ,f a vantage po9t #b4e degrees above ! r+ plane1 ,voyag] #b 0 able = ! fir/ "t to det]m9e ! wid? ( ,jupit]'s r+4 ,?is picture %[s t ! r+ is ribbon-l & only a few ?\s& kilomet]s wide1 q unlike ! broad r+s ( ,saturn4 ,p-#bageg;,b_/,w ,w$nesday1 ,july #aa4 ,,jpl ,public ,in=mation ,(fic] ,frank ,bri/[ op5$ ! #aj a4m4 press conf]5ce ) an ann\ncem5t3 8,we'll h ! report f ! ,imag+ ,team includ+ ! trem5d\s pictures t we receiv$ "h la/ night ( ! ,jupit] r+ t excit$ ! entire team40 ,brad ,smi? %[$ ! r+ pictures4 8,z _m ( y :o 7 "h la/ night "k1 we got "s r nice pictures ( ! r+ ( ,jupit]4 ,x's z ?\gh ,voyag] #b 0 fe>ful t we might be becom+ j a little bit apa!tic aft] ?is s]ies ( m>vel\s discov]ies & felt t x _h to dazzle u "o m "t be=e x left = ,saturn4 ,! r+s appe> v mu* bright] ?an we _h expect$ !m to be40 ,! out] r+ is ab\t #fejj kilomet]s wide4 ,!re is mat]ial inside ! r+4 ,!re is a r %>p out] b\nd>y & a some:at diffuse inn] region4 8,& x is n[ our belief t ! mat]ial 9 ! r+ goes all ! way d[n to ! surface ( ,jupit]40 ,!re is a v n>r[ relatively bright out] r+ & an extremely fa9t inn] r+ t goes all ! way d[n to ,jupit]'s cl\d tops4 ,l>ry ,sod]blom summ>iz$ ! satellite data3 ,) respect to ! ,galilean satellites1 8,we're 9 a relatively high /ate ( ignorance40 ,! ,io ,volcano ,wat* images seem$ to indicate t plume ,p 0 n[ ! highe/ volcano on ,io1 s9ce ,p seem$ to h become quiet4 ,io may be ! easie/ ,galilean satellite to try to und]/&1 because we c actually see ! geological processes t are %ap+ ! planet4 ,io's 8tw910 ,europa1 seems to be :]e 8our highe/ /ate ( ignorance0 lies4 8,! fa9t bright /reaks :i* %[ "s relief are evid5tly diff]5t f ! diffuse d>k b&s :i* don't seem to %[ topography1 b ! simil>ity ( ^! =ms t bo? ! light & d>k m>k+s are ( planet>y scale sugge/s t !y mu/ be relat$40 ,ed ,/one speculat$ ab\t ! o!r two ,galilean satellites4 ,ganym$e & ,calli/o are ess5tially id5tical 9 size1 mass1 & probably composition4 ,by exam9+ !m1 we c p]haps le>n :at happ5s :5 bodies ) v simil> *emi/ry h diff]5t 8life hi/ories0 & diff]5t surface prop]ties 7!re are indications t ,ganym$e's cru/ may n h be5 z rigid z ,calli/o's74 ,go+ fur!r1 he add$ t ,calli/o & ,m]cury1 ! lea/ d5se & ! mo/ d5se1 respectively1 ( ! t]re/rial-/yle planets1 al?\gh totally diff]5t 9 composition & d5sity1 seem to h simil> surfaces & simil> hi/ories4 ,:at w\ld h happ5$ to ,m]cury if x _h be5 made ( ice1 wat]1 & rock z ,calli/o is8 ,w\ld x h evolv$ z ,calli/o did8 ,illu/ration3 ,"o ( ! mo/ spectacul> ( ! ,voyag] #b images 0 obta9$ f inside ! %ad[ ( ,jupit]4 ,look+ back t[>d ! planet & ! r+s ) its wide-angle cam]a1 ! spacecraft took ^! photos on ,july #aj f a di/ance ( #a4e million kilomet]s4 ,! ribbon-l nature ( ! r+s is cle>ly %[n4 ,! planet is outl9$ by sunlight scatt]$ f a haze lay] high 9 ! atmosph]e4 ,on ea* side1 ! arms ( ! r+ curv+ back t[>d ! spacecraft are cut (f by ! planet's %ad[ z !y approa* ! brightly outl9$ disk4 ,p-#baggd;,b_/,w ,illu/ration3 ,! r+s ( ,jupit] prov$ to be unexpect$ly bright :5 se5 ) ! ,sun ne>ly beh9d !m4 ,/rong =w>d scatt]+ ( sunlight is *>act]i/ic ( small p>ticles4 ,^! two views 7 obta9$ by ,voyag] #b on ,july #aj f a p]spective inside ! %ad[ ( ,jupit]4 ,! di/ance ( ! spacecraft f ! r+s 0 ab\t #a4e million kilomet]s4 ,al?\gh ! resolution has be5 degrad$ by cam]a motion dur+ ! "t exposures1 ^! images reveal t ! r+s h "s radial /ructure4 #bfj-faj;,b_/,w & #bfj-fgd ,illu/ration3 ,r+s ( ,jupit]4 ,,highlights ,,( ,,! ,,voyag] #b ,,sci5tific ,,f9d+s#c ,atmosph]e ,! ma9 atmosph]ic jet /reams 7 pres5t dur+ bo? ,voyag] enc\nt]s1 ) "s *anges 9 velocity4 ,! ,great ,r$ ,spot1 ! :ite ovals1 & ! small] :ite spots at #da,s1 appe> to be meteorologically simil>4 ,! =mation ( a /ructure ea/ ( ! ,great ,r$ ,spot creat$ a b>ri] to ! fl[ ( small spots :i* e>li] 7 circulat+ ab\t ! ,great ,r$ ,spot4 ,! e?ane to acetyl5e abundance ratio 9 ! upp] atmosph]e appe>s to be l>g] 9 ! pol> regions ?an at l[] latitudes & appe>s to be #a4g times high] on ,voyag] #b ?an on ,voyag] #a4 ,an ultraviolet map ( ,jupit] %[s ! di/ribution ( absorb+ haze4 ,! pol> regions are surpris+ly d>k1 sugge/+ t ! absorb+ mat]ial mu/ be at high altitudes4 ,equatorial ultraviolet emissions indicate planet-wide precipitation ( *>g$ p>ticles into ! atmosph]e f ! magnetosph]e4 ,! high-latitude ultraviolet auroral activity is due to *>g$ p>ticles t orig9ate 9 ! ,io torus4 ,satellites & ,r+ ,sy/em ,! r+ consi/s ( a bright1 n>r[ segm5t surr\nd$ by a broad]1 dimm] segm5t1 ) a total wid? ( ab\t #ehjj kilomet]s4 ,! int]ior ( ! r+ is fill$ ) mu* fa9t] mat]ial t may ext5d d[n to ! top ( ! atmosph]e4 ,images ( ,amal!a 9 silh\ette aga9/ ,jupit] indicate t ! satellite may be facet$ or diamond %ap$4 ,volcanic activity on ,io *ang$ some:at1 ) six ( ! plumes obs]v$ by ,voyag] #a /ill erupt+4 ,! l>ge/ ,voyag] #a plume 7,pele7 _h ceas$1 :ile ! dim5sions ( ano!r plume 7,loki7 _h increas$ by #ej p]c5t4 ,sev]al l>ge-scale *anges 9 ,io's appe>ance _h occurr$1 consi/5t ) surface deposition rates calculat$ = ! l>ge eruptions4 ,europa is rem>kably smoo? ) v few crat]s4 ,! surface consi/s prim>ily ( uni=mly bright t]ra9 cross$ by l9e> m>k+s & v l[ ridges4 ,!re are f\r basic t]ra9 types on ,ganym$e1 includ+ y\ng]1 smoo? t]ra9 & a rugg$ impact bas9 fir/ obs]v$ by ,voyag] #b4 ,calli/o's entire surface is d5sely crat]$ & is likely to be sev]al billion ye>s old4 ,equatorial surface temp]atures on ! ,galilean satellites range f #hj ,k 7night7 to #aee ,k 7! subsol> po9t on ,calli/o74 ,magnetosph]e ,! out] region ( ! magnetosph]e conta9s a hot plasma consi/+ prim>ily ( hydrog51 oxyg51 & sulfur ions4 ,! hot plasma g5]ally fl[s 9 ! corotation direction out to ! b\nd>y ( ! magnetosph]e4 ,beyond ab\t #afj ,r,j1 ! hot plasma /reams ne>ly antisunw>d4 ,outb\nd ! spacecraft exp]i5c$ multiple magnetopause cross+s betwe5 #bjd ,r,j & #bae ,r,j4 ,! abundance ( oxyg5 & sulfur relative to helium at high en]gy increases ) decreas+ di/ance f ,jupit]4 ,measurem5ts ( high en]gy oxyg5 sugge/ t ^! nuclei are diffus+ inw>d t[>d ,jupit]4 ,! ultraviolet emission f ! ,io plasma torus 0 twice z bright z f\r mon?s e>li] & ! temp]ature _h decreas$ by #cj p]c5t to #fj #jjj ,k4 ,! l[-frequ5cy 7kilometric7 radio emissions f ,jupit] h a /rong latitude dep5d5ce & (t5 conta9 n>r[b& emissions t drift to l[] or high] frequ5cies ) "t4 ,a complex magnetosph]ic int]action ) ,ganym$e 0 obs]v$ 9 ! magnetic field1 plasma1 & en]getic p>ticles up to ab\t #bjj #jjj kilomet]s f ! satellite4 #c;,adapt$ f a summ>y prep>$ by ,e4 ,c4 ,/one & ,a4 ,l4 ,lane = ! ,voyag] #b ,?irty-,day ,report4 ,illu/ration3 ,a new inn] satellite ( ,jupit]1 provisionally designat$ #aigi;,j#a1 0 discov]$ by ,david ,jewitt & ,ed ,danielson ( ,calte* 9 ^! ,voyag] #b r+ photographs4 ,illu/ration3 ,9 a #ae-second exposure ) ! wide-angle cam]a1 ! edge-on r+ %[s z a fa9t l9e1 & ! satellite is ! dot indicat$ by ! arr[4 #bfj-hjg ,illu/ration3 ,9 a n>r[ angle #if-second exposure1 ! motion ( ! satellite c be se54 ,aga91 ! fa9t b& is ! r+1 blurr$ by cam]a motion1 & ! arr[ indicates ! /reak due to ! satellite4 ,a /> /reak is locat$ above & to ! left ( ! satellite2 note t ! l5g? & angle ( ! two trails are diff]5t1 ow+ to satellite motion4 ,p-#bbagb ,a ,new ,satellite ,"o ( ! mo/ fasc9at+ discov]ies ( ,voyag] #b 0 n recogniz$ at fir/4 ,graduate /ud5t ,david ,jewitt ( ! ,cali=nia ,in/itute ( ,te*nology1 work+ ) ,imag+ ,team memb] ,ed ,danielson1 began a detail$ analysis ( all ! r+ photos 9 late summ]4 ,9 e>ly ,octob] he det]m9$ t a %ort /reak on a photo tak5 ,july #h1 previ\sly presum$ to be an image ( a /> trail$ by ! "t exposure1 did n correspond to any kn[n /> position4 ,p]haps ?is 0 a new satellite6 ,additional sleu?+ turn$ up a second image ( ! same "p ( ! r+ t also %[$ ! anomal\s object1 toge!r ) trails due to kn[n />s4 ,! diff]+ angles & l5g?s ( ! trails ( ! object & ! />s confirm$ t ?is 0 inde$ a #ad? satellite ( ,jupit]4 ,foll[+ ! guidel9es ( ! ,int]national ,a/ronomical ,union1 x 0 designat$ #aigi;,j#a1 p5d+ lat] assignm5t ( a my?ological "n4 ,! propos$ "n is ,adra/ea1 a nymph :o nurs$ ! infant ,zeus 9 ,greek leg5d4 ,! newly discov]$ satellite orbits ,jupit] at a di/ance ( #eh #jjj kilomet]s above ! equatorial cl\d tops1 plac+ x j at ! out] edge ( ! r+ & mu* clos] to ! planet ?an is ,amal!a1 previ\sly ?\ght to be ! inn]mo/ satellite4 ,x travels at #cj kilomet]s p] second 7ne>ly #gj #jjj miles p] h\r71 circl+ ,jupit] 9 j sev5 h\rs & eight m9utes4 ,f its brightness1 sci5ti/s guess$ t x might be #cj-dj kilomet]s 9 diamet]4 ,! proximity ( ,adra/ea to ! r+ sugge/s a relation%ip betwe5 ! two4 ,:5 ! discov]y 0 ann\nc$ to ! press 9 mid-,octob]1 x 0 speculat$ t ! r+ mat]ial might orig9ate on ! satellite1 p]haps erod$ away by ! en]getic *>g$ p>ticles 9 ! inn] ,jovian magnetosph]e4 ,once aga91 ,voyag] _h add$ to our p]spective on planet>y processes1 sugge/+ t undiscov]$ b simil> small satellites might also be associat$ ) ! r+s ( ,saturn & ,uranus4 ,voyag] #b _h c]ta9ly add$ a few ye>s' ( data ( its own to ,voyag] #a's 8t5 ye>s' wor? ( data40 ,x _h giv5 a diff]5t view ( ! ,jovian sy/em1 help+ to solve "s ( ! my/]y surr\nd+ ,jupit] & its satellites1 & creat+ new my/]ies4 ,z ,voyag] #b sp$ out away f ,jupit]1 rid+ along ! giant planet's huge magnetotail1 att5tion turn$ to ,saturn3 ,:at w\ld ,pione] #aa1 ! ,pa?f9d]1 discov] 9 ,septemb] #aigi8 ,:at w\ld ! ,voyag]s le>n 9 ,novemb] #aihj & ,augu/ #aiha8 ,w\ld all g well8 ,w\ld ,voyag] #b fly on to ,uranus8 ,!re 0 also a ye>n+ to exam9e m closely1 ) ! ,galileo ,project1 :at _h be5 unkn[n = s long1 yet _h become s famili> 9 only a few mon?s' "t--! little d>k1 r$ 8potato0 ,amal!a1 ! volcano-cov]$ _w ,io1 ! my/]i\s 8crack$ billi>d ball0 ,europa1 crat]$ & groovy ,ganym$e1 anci5t ,calli/o1 & ! k+ ( ! planets itself1 a colorful1 b&$ _w ( /able climate & ev]-*ang+ wea!r patt]ns4 ,illu/ration3 ,a fifte5? satellite ( ,jupit] 0 discov]$ 9 ! spr+ ( #aihj by ,/ev5 ,synnott ( ,,jpl4 ,x 0 fir/ se5 on ?is ,voyag] #a image tak5 ,m>* #e1 #aigi1 9 :i* ! #ge-kilomet]-diamet] satellite %[s z a d>k oval aga9/ ! planet4 ,also visible is ! %ad[ ( ! satellite1 designat$ #aigi;,j#b4 ,?is satellite orbits betwe5 ,io & ,amal!a ) a p]iod ( #af h\rs & #aa m9utes4 ,p-#bbehj;,b_/,w ,illu/ration3 ,! ,jupit] se5 by ! ,voyag] cam]as is a cl\d-belt$ _w ( rapid jet /reams & complex cl\d =ms4 ,prom95t 9 ?is ,voyag] #a image1 tak5 ,febru>y #e at a range ( #bh4d million kilomet]s1 is ! alt]nat+ /ructure ( light zones & d>k belts1 & ! ,great ,r$ ,spot & num]\s small] spots4 ,also easily visible are ! two inn] ,galilean satellites1 ,io & ,europa4 ,! resolution 9 ?is picture is #ejj kilomet]s1 ab\t five times bett] ?an c be obta9$ f ,e>?-bas$ telescopes4 ,calli/o c be fa9tly se5 at ! l[] left4 ,p-#bajhc;,c ,,*apt] #h ,,jupit]--,,k+ ,,( ,,! ,,planets ,a ,/> ,t ,fail$ ,m massive ?an all ! o!r planets comb9$1 ,jupit] dom9ates ! planet>y sy/em4 ,! giant reveal$ by ,voyag] is a gas planet ( great complexity2 its atmosph]e is 9 con/ant motion1 driv5 by heat escap+ f a gl[+ int]ior z well z by sunlight absorb$ f above4 ,en]getic atomic p>ticles /ream ar\nd x1 caught 9 a magnetic field t rea*es out ne>ly #aj million kilomet]s into ! surr\nd+ space1 embrac+ ! sev5 inn] satellites4 ,f its deep int]ior ?r\gh its see?+ cl\ds out to its pulsat+ magnetosph]e1 ,jupit] is a place :]e =ces ( incr$ible en]gy cont5d4 ,at its bir?1 ,jupit] %one l a />4 ,! en]gy releas$ by infall+ mat]ial f ! sol> nebula heat$ its int]ior1 & ! l>g] x grew ! hott] x became4 ,!ori/s calculate t :5 ! nebul> mat]ial 0 f9ally exhau/$1 ,jupit] _h a diamet] m ?an t5 times its pres5t "o1 a c5tral temp]ature ( ab\t #ej #jjj ,k1 & a lum9osity ab\t "o p]c5t z great z t ( ! ,sun today4 ,at ?is e>ly /age1 ,jupit] rival$ ! ,sun4 ,_h x be5 p]haps #gj times m massive ?an x 01 x w\ld h cont9u$ to contract & increase 9 temp]ature1 until self-su/a9+ nucle> reactions c\ld ignite 9 its int]ior4 ,if ?is _h happ5$1 ! ,sun w\ld h be5 a d\ble />1 & ! ,e>? & ! o!r planets might n h =m$4 ,h[ev]1 ,jupit] did n make x z a />2 aft] a brief fla% ( glory1 x began to cool4 ,at fir/ ,jupit] cont9u$ to collapse4 ,)9 ! fir/ t5 million ye>s ( its life1 ! planet 0 r$uc$ to ne>ly its pres5t size1 ) only a few p]c5t additional %r9kage dur+ ! pa/ #d4e billion ye>s4 ,! lum9osity also dropp$ z int]nal heat 0 c>ri$ to ! surface by convection & radiat$ away to space4 ,aft] a million ye>s ,jupit] emitt$ only "o-hundr$ ?\s&? z mu* radiation z ! ,sun1 & today its lum9osity is only "o-t5 billion? ( ! ,sun's4 ,jupit]'s int]nal en]gy1 al?\gh small by /ell> /&>ds1 has important effects on ! planet4 ,ab\t #aj watts ( p[]1 comp>able to t receiv$ by ,jupit] f ! ,sun1 rea* ! surface f ! /ill-lum9\s int]ior4 ,! c5tral temp]ature is /ill ?\ght to be ab\t #cj #jjj ,k1 suffici5t to ma9ta9 ! int]ior 9 a molt5 /ate4 ,sci5ti/s g5]ally agree t ,jupit] is an entirely fluid planet1 ) no solid core :atev]4 ,composition & ,atmosph]ic ,/ructure ,because ( its great mass1 ,jupit] has be5 undiscrim9at+ 9 its composition4 ,all gases & solids available 9 ! e>ly sol> nebula 7 attract$ & held by its p[]ful gravity4 ,?us x is expect$ t ,jupit] has ! same basic composition z ! ,sun1 ) bo? bodies pres]v+ a sample ( ! orig9al cosmic mat]ial f :i* ! sol> sy/em =m$4 ,illu/ration3 ,jupit] is a gas giant1 compos$ ( ! same elem5ts z ! ,sun & />s--prim>ily hydrog5 & helium4 ,its int]nal /ructure is dom9at$ by ! prop]ties ( hydrog51 its mo/ abundant con/itu5t & by ! high temp]atures 9 ! deep int]ior t rema9 f its lum9\s y\?4 ,mo/ ( ! int]ior is liquid3 metallic hydrog5 at great dep?s & high pressures1 & normal hydrog5 ne>] ! surface4 ,9 ! upp] few ?\s& kilomet]s1 ! hydrog5 is a gas4 ,! prim>y kn[n or suspect$ cl\d lay]s are1 f ! top d[n1 ?9 hydroc>bon 8smog02 ammonia2 ammonium hydrosulfide2 wat]-ice1 & liquid wat]4 #bfj-hbh ,cl\d top-a]osols ,ammonia cry/als ,ammonium hydrosulfide cl\ds ,ice cry/al cl\ds ,wat] droplets ,trace comp\nds ,fluid molecul> hydrog5 ,transition ,zone ,fluid metallic hydrog5 ,possible core ,! prim>y con/itu5ts ( ,jupit] h long be5 suspect$ to be hydrog5 & helium1 ! two simple/ & lighte/ atoms4 ,h[ev]1 x has prov$ impossible to d]ive accurate measurem5ts ( ! abundance ( ^! two elem5ts f a/ronomical obs]vations4 ,on ! basis ( a r simple infr>$ measurem5t1 ,pione] inve/igators f\nd ,he_/,h #j4ad #j4jh4 ,on ,voyag]1 ,,iris 0 able to obta9 mu* improv$ infr>$ spectra1 yield+ an initial value ( ,he_/,h #j4aa #j4c4 ,voyag] sci5ti/s expect t fur!r analysis w r$uce ! unc]ta9ty to ab\t #j4ja4 ,! ratio ( #j4aa is 9 excell5t agreem5t ) ! sol> value ( ab\t #j4ab1 support+ ! idea t ,jupit] & ! ,sun h simil> elem5tal compositions4 ,a/ronom]s h kn[n = a long "t t1 9 addition to hydrog5 & helium1 ! comp\nds me?ane 7,,*7 & ammonia 7,,nh7 are pres5t 9 ! visible atmosph]e ( ,jupit]4 ,9 ! #aigjs1 additional spectra 9 ! infr>$ result$ 9 ! discov]y ( wat] 7,h,o71 e?ane 7,c,h71 g]mane 7,ge,h71 acetyl5e 7,c,h71 phosph9e 7,,ph71 c>bon monoxide 7,,co71 hydrog5 cyanide 7,,hcn71 & c>bon dioxide 7,,co74 ,all ^! are trace con/itu5ts1 ) two ( !m1 e?ane & acetyl5e1 app>5tly =m$ at high altitudes by ! action ( sunlight on me?ane4 ,a total ( approximately #ajj #jjj infr>$ spectra1 _m ( small regions on ! disk1 7 obta9$ by ,,iris4 ,^! spectra g5]ally %[ hydrog51 helium1 me?ane1 ammonia1 phosph9e1 e?ane1 & acetyl5e4 ,9 addition1 excell5t spectra 7 obta9$ 9 8hot spots10 regions 9 :i* breaks 9 ! upp] cl\ds p]mit radiation f deep] lay]s to escape4 7,! hot spots g5]ally correspond to d>k br[n regions on photographs ( ! planet47 ,,iris measur$ temp]atures 9 ! hot spots up to -#ac ,c b no high]2 app>5tly ?is temp]ature corresponds to ! top ( a deep] cl\d deck4 ,spectral features indicative ( ! pres5ce ( wat] vapor & g]mane 7 cle>ly se5 9 ! hot spots4 ,fur!r analysis ( ! ,,iris spectra w be requir$ to d]ive ! abundances ( ! gases detect$4 ,h[ev]1 ev5 ! prelim9>y data %[$ h[ v>iable ,jupit] c be1 especially 9 its upp] atmosph]e4 ,! two hydroc>bons1 e?ane & acetyl5e1 v>y 9 relative abundance ) latitude2 !re is less acetyl5e ne> ! poles4 ,9 addition to ?is planetwide tr5d1 small] v>iations 7 se5 f place to place & betwe5 ! obs]vations 9 ,m>* & ,july4 ,all ! v>iations w ev5tually provide in=mation on ! processes ( =mation1 transportation1 & de/ruction ( hydroc>bons 9 ! upp] atmosph]e4 ,,elem5ts ,,detect$ ,,9 ,,! ,,jovian ,,magnetosph]e ,elem5t ,atomic ,in/rum5ts ,numb] ,hydrog5 7,h7 #a ,,uvs1 ,plasma1 ,,lecp1 ,,crs ,helium 7,he7 #b ,plasma1 ,,lecp ,c>bon 7,c7 #f ,,lecp ,nitrog5 7,n7 #g ,,crs ,oxyg5 7,o7 #h ,,uvs1 ,plasma1 ,,lecp1 ,,crs ,neon 7,ne7 #aj ,,crs ,sodium 7,na7 #aa ,,lecp1 ,,crs ,magnesium 7,mg7 #ab ,,crs ,silicon 7,si7 #ad ,,crs ,sulfur 7,s7 #af ,,uvs1 ,plasma1 ,,lecp1 ,,crs ,iron 7,fe7 #bf ,,crs ,voyag] did n make any direct measurem5ts ( ! *emical composition ( ! cl\ds1 b !ori/s g5]ally agree t ! upp]mo/ cl\ds are ammonia cirrus1 & t lay]s ( ammonium hydrosulfide 7,,nh,,%7 & wat] exi/ at deep] levels4 ,all ^! cl\ds are =m$ 9 ! troposph]e1 ! lay] ( ! atmosph]e 9 :i* convection takes place4 ,! top ( ! ammonia cl\d deck is ?\ght to h a pressure ( ab\t #a atmosph]e & a temp]ature ( ab\t -#aac ,c4 ,ammonia cirrus is :ite1 yet ,jupit]'s cl\ds display a spectacul> range ( colors4 ,voyag] did n det]m9e ! nature ( ! color+ ag5ts2 !y may be m9or con/itu5ts--trace impurities 9 a sea ( :ite cl\ds4 ,p]haps organic polym]s1 =m$ f atmosph]ic *emicals su* z me?ane & ammonia t h react$ ) lightn+1 are responsible = ! oranges & yell[s4 ,! color ( ! ,r$ ,spot c\ld be caus$ by r$ phosphorus 7,p74 ,accord+ to ?is !ory1 phosph9e 7,,ph7 f deep 9 ,jupit]'s atmosph]e is br\ght to high altitudes by ! upwell+ ( ! ,great ,r$ ,spot4 ,ultraviolet light1 p5etrat+ ! upp] rea*es ( ! ,r$ ,spot1 splits ! phosph9e molecules1 &1 ?r\gh a s]ies ( *emical reactions1 conv]ts ! phosph9e into pure phosphorus4 ,h[ev]1 ?is !ory fails to expla9 ! exi/5ce ( ! small] r$ spots on ,jupit]2 ^! spots are n at su* high altitudes z ! ,great ,r$ ,spot 7:i* is ! highe/ & colde/ ( ,jupit]'s visible cl\ds71 s x is unlikely t ultraviolet light c\ld react ) any phosph9e 9 ^! areas to produce r$ phosphorus4 ,illu/ration3 ,al?\gh ! ,voyag] spacecraft nev] flew ov] ! poles ( ,jupit]1 x is possible to recon/ruct f sev]al images ! ,view t w\ld be se5 f directly above or bel[ ! planet4 ,note ! abs5ce ( a /rong b&$ /ructure ne> bo? poles4 ,! regul> spac+ ( cl\d features is obvi\s4 ,9 ! ,s\!rn hemisph]e1 ! ?ree :ite ovals are #ij degrees ap>t 9 longitude1 b a f\r? oval at ! o!r quadrant is miss+4 ,! irregul> black areas at ea* pole are places = :i* no ,voyag] data exi/4 ,! resolution ( ! orig9al pictures f :i* ^! pol> projections 7 made 0 ab\t #fjj kilomet]s4 ,illu/ration3 ,nor? pole4 ,p-#bafch;,c ,illu/ration3 ,s\? pole4 ,p-#bafci;,c ,v>i\s =ms ( elem5tal sulfur might be responsible = ! riot ( color we see on ,jupit]4 ,sulfur =ms polym]s 7,s1 ,s1 ,s1 ,s17 t are yell[1 r$1 & br[n1 b no sulfur 9 any =m has be5 detect$ on ,jupit]4 8,we nev] promis$ y we 7 go+ to id5tify ! colors on ,jupit] ) ?is mission10 "o ( ! atmosph]ic sci5ti/s rem>k$1 8b we w h a probe t is go+ into ! atmosph]e 9 ! mid-#aihjs--,galileo40 ,p]haps ! my/]y ( ! ,jovian cl\ds w h to wait till !n4 ,temp]ature maps ( ,jupit] 7 obta9$ by ,,iris 9 radiation aris+ at diff]5t levels above ! cl\ds4 ,maps %[ temp]atures at pressures ( #j4h atmosph]e ne> ! cl\ds1 & #j4b atmosph]e ne> ! top ( ! troposph]e4 ,9 addition to ! l[ temp]atures ov] ! bright zones & ! high] temp]atures ov] d>k belts1 !re is a great deal ( small] scale /ructure4 ,x is int]e/+ t a cold area correspond+ to ! ,great ,r$ ,spot is cle>ly visible ev5 ne> ! top ( ! troposph]e1 indicat+ t ?is feature di/urbs ! atmosph]e to v high altitudes4 ,! /ructure ( ! atmosph]e ( ,jupit] above ! troposph]e 0 inve/igat$ ?r\gh ! radio occultation exp]im5t z well z by ,,iris4 ,! level 9 :i* ! m9imum temp]ature ( ab\t -#agc ,c occurs has a pressure ( #j4a atmosph]e4 ,above ?is po9t lies ! /ratosph]e1 9 :i* temp]atures increase ) altitude z a result ( sunlight absorb$ by ! gas or by a]osol p>ticles resembl+ smog4 ,at #gj kilomet]s above ! ammonia cl\ds1 ! temp]ature is ab\t -#aac ,c4 ,above ?is level1 ! temp]ature /ays approximately con/ant1 al?\gh at extreme altitudes ! temp]ature aga9 rises 9 ! ionosph]e4 ,illu/ration3 ,if "o c\ld 8unwrap0 ,jupit] l a map1 views su* z ^! w\ld be obta9$4 ,! comp>ison betwe5 ! pictures %[s ! relative motions ( features 9 ,jupit]'s atmosph]e4 ,x c be se51 = example1 t ! ,great ,r$ ,spot mov$ we/w>d & ! :ite ovals ea/w>d dur+ ! "t betwe5 ! acquisition ( ^! pictures4 ,regul> plume patt]ns are equidi/ant ar\nd ! nor!rn edge ( ! equator1 :ile a tra9 ( small spots mov$ ea/w>d at approximately latitude #hj ,s4 ,9 addition to ^! relative motions1 significant *anges are evid5t 9 ! recirculat+ fl[ ea/ ( ! ,great ,r$ ,spot1 9 ! di/urb$ region we/ ( ! ,great ,r$ ,spot1 & z se5 9 ! bright5+ ( mat]ial spread+ into ! equatorial region f ! m s\!rly latitudes4 ,p-#bagga;,c ,illu/ration3 ,! planet z x appe>$ ab\t ,m>* #a4 ,illu/ration3 ,z x 0 9 e>ly ,july4 ,wea!r on ,jupit] ,! ,voyag] pictures reveal a planet ( complex atmosph]ic motions4 ,spots *ase aft] ea* o!r1 meet1 :irl ar\nd1 m+le1 & !n split up aga92 filam5t>y /ructures curl into spirals t op5 outw>d2 fea!ry cl\d sy/ems rea* out t[>d neighbor+ regions2 cumulus cl\ds t look l o/ri* plumes may bright5 sudd5ly z !y float t[>d ! ea/2 spots /ream ar\nd ! ,r$ ,spot or get caught up 9 its vortical motion--all 9 an incr$ible int]play ( color1 texture1 & ea/w>d & we/w>d fl[s4 ,su* *anges c be notic$ 9 ! space ( only a few ,jovian days4 ,illu/ration3 ,diff]+ *>act]i/ics ( ,jupit]'s meteorology are app>5t 9 high-resolution images1 su* z ?is "o tak5 by ,voyag] #a on ,m>* #b at a range ( #d million kilomet]s4 ,! well-def9$ pale orange l9e runn+ f s\?we/ to nor!a/ 7nor? is at ! top7 m>ks ! high-spe$ nor? temp]ate curr5t ) w9d spe$s ( ab\t #abj met]s p] second4 ,t[>d ! top ( ! picture1 a weak] jet ( approximately #cj met]s p] second is *>act]iz$ by wave patt]ns & cl\d features :i* h be5 obs]v$ to rotate 9 a clockwise mann] at ^! latitudes ( ab\t #ce,n4 ,^! cl\ds h be5 obs]v$ to h lifetimes ( "o to two ye>s4 ,p-#baaic;,c ,on a broad] "t scale1 great] *anges on ! face ( ,jupit] c be se54 ,features drift ar\nd ! planet2 ev5 ! l>ge :ite ovals & ! ,great ,r$ ,spot slide along 9 _! respective latitudes4 ,belts or zones intrude ^u ea* o!r1 result+ 9 "o ( ! b&$ /ructures splitt+ up or seem+ to squeeze toge!r & ev5tually disappe>4 ,small /ructures =m1 !n die4 ,! l>ge/ spots may sl[ly %r9k 9 size1 & ! ,r$ ,spot itself *anges its size & color4 ,! ,jupit] ( ,pione]s #aj & #aa 0 q unlike ! planet se5 by ,voyag] #a4 ,at ! "t ( ! ,pione] exploration1 ! ,great ,r$ ,spot1 emb$d$ 9 a huge :ite zone1 0 m uni=mly color$1 & pale br[n b&s circl$ ! nor!rn hemisph]e4 ,9 ! int]v5+ ye>s1 ! s\? temp]ate latitudes h *ang$ completely1 develop+ ! complex turbul5t cl\ds se5 ar\nd ! ,r$ ,spot by ,voyag] #a4 ,yet1 ev5 betwe5 ! two ,voyag]s1 ,jupit] appe>$ to be und]go+ a dynamic 8facelift40 ,at a quick glance1 ,voyag] #b photographs %[$ ! visage t _h be5 famili> s9ce e>ly 9 #aigi1 b a clos] look %[$ t x is n q ! same4 ,! :ite b& bel[ ! ,great ,r$ ,spot1 fairly broad dur+ ! fir/ flyby1 _h become a ?9 :ite ribbon :]e x rims ! s\!rn edge ( ! ,spot4 ,! turbul5ce to ! we/ ( ! ,r$ ,spot _h /ret*$ out & become 8bl&]0 ?an x 0 be=e4 ,small rotat+ cl\ds seem$ to be =m+ out ( ! waves 9 ?is region4 ,! cl\d /ructure t _h be5 ea/ ( ! ,r$ ,spot dur+ ! ,voyag] #a flyby spread out1 cov]+ ! nor!rn b\nd>y & prev5t+ small cl\ds f circl+ ! huge r$ oval4 ,! ,r$ ,spot itself also *ang$4 ,its nor!rn b\nd>y seem$--at lea/ visually--to be m set (f f ! cl\ds t surr\nd x1 & ! feature appe>$ to be m uni=m 9 color1 p]haps rev]t+ back to ! p]sonality x _h 9 ,pione] days4 ,illu/ration3 ,jupit]'s cl\d patt]ns *ang$ significantly 9 ! few mon?s betwe5 ! two ,voyag] flybys4 ,mo/ ( ! *anges are ! result ( diff]5tial rotation1 9 :i* ! prevail+ w9ds at diff]5t latitudes %ift long-liv$ features ) respect to ^? nor? or s\?4 ,?us1 = example1 ! ?ree l>ge :ite ovals %ift$ ne>ly #ij degrees 9 longitude1 relative to ! ,great ,r$ ,spot1 betwe5 ,m>* & ,july4 ,p-#baeii ,illu/ration3 ,cl\d patt]ns f ,voyag] #b4 ,! mo/ obvi\s features 9 ! atmosph]e ( ,jupit]1 aft] ! b&$ belts & zones1 are ! ,great ,r$ ,spot & ! ?ree :ite ovals4 ,^! h (t5 be5 describ$ z 8/orms0 9 ,jupit]'s atmosph]e4 ,! ovals are ab\t ! size ( ! ,moon1 & ! ,r$ ,spot is l>g] ?an ! ,e>?4 ,voyag] has reveal$ t 9 _m respects ! :ite ovals1 :i* =m$ 9 #aici1 resemble _! anci5t r$ relative4 ,all f\r spots are s\!rn hemisph]ic anticyclonic features t exhibit c\nt]clockwise motion2 h5ce !y are meteorologically simil>4 ,o!r small] bright elliptical & circul> spots also exhibit anticyclonic motion1 rotat+ clockwise 9 ! nor!rn hemisph]e & c\nt]clockwise 9 ! s\!rn hemisph]e4 ,9 g5]al1 ^! features are circl$ by filam5t>y r+s t are d>k] ?an ! spots !y surr\nd4 ,h9ts ( int]ior spiral /ructure c be se5 9 "s ( ^! spots4 ,all ! elliptical features 9 ! s\!rn hemisph]e lie to ! s\? ( ! /rong we/w>d-bl[+ jet /reams4 ,! spots t5d to become r\nd] ! clos] !y are to ! poles4 ,along ! nor!rn edge ( ! equator are a numb] ( cl\d plumes1 :i* appe> to be regul>ly spac$ all ar\nd ! planet4 ,"s ( ! plumes h be5 obs]v$ to bright5 rapidly1 :i* may be an indication ( convective activity2 inde$1 "s ( ! plume /ructures seem to resemble ! convective /orms t =m 9 ! ,e>?'s tropics4 ,! plumes travel ea/w>d at spe$s rang+ f ab\t #ajj to #aej met]s p] second1 b !y d n move z a unit4 ,illu/ration3 ,! ,great ,r$ ,spot ( ,jupit] is a magnific5t sight1 :e!r view$ 9 normal or exagg]at$ color4 ,^! pictures 7 tak5 by ,voyag] #a at a range ( ab\t #a million kilomet]s2 ! area %[n is ab\t #be #jjj kilomet]s1 ) features visible on ! orig9als t are z small z #cj kilomet]s across4 ,! ,r$ ,spot is p>tly obscur$ on ! nor? by a ?9 lay] ( ov]ly+ ammonia cirrus cl\d4 ,s\? ( ! ,r$ ,spot is "o ( ! ?ree :ite ovals1 :i* are also anticyclonic vortices 9 ! atmosph]e4 ,illu/ration3 ,?is frame is 9 natural color4 ,p-#badcj;,c ,illu/ration3 ,! r$ & blue h be5 greatly exagg]at$ 9 ?is frame to br+ out f9e detail 9 ! cl\d /ructure4 ,p-#badca;,c ,! mo/ visible cl\d int]actions take place 9 ! region ( ! ,great ,r$ ,spot4 ,mat]ial )9 ! ,r$ ,spot rotates ab\t once e six days4 ,infr>$ measurem5ts %[ t ! ,r$ ,spot is a region ( atmosph]ic upwell+1 :i* ext5ds to v high altitudes2 h[ev]1 ! div]g5t fl[ sugge/$ by ?is upwell+ seems to be v small--"o bright feature 0 obs]v$ to circle ! ,r$ ,spot = sixty days )\t appreciably *ang+ its di/ance f ! spot's c5t]4 ,dur+ ! ,voyag] #a flyby1 spots 7 se5 to move t[>d ! ,r$ ,spot f ! ea/1 fl[ along its nor!rn bord]1 !n ei!r fl[ on to ! we/ pa/ ! ,r$ ,spot or into ! out] regions ( its vortex4 ,a spot caught on ! out] edge ( ! ,r$ ,spot fl[ might break 9 two z x rea*$ ! ea/]n edge ( ! spot1 ) "o piece rema9+ 9 ! vortex & ! o!r mov+ (f to ! ea/4 ,alt]natively1 a spot float+ t[>d ! ,r$ ,spot f ! ea/ might be pu%$ nor?w>d to jo9 ! ea/w>d curr5t fl[+ nor? ( ! giant r$ oval4 ,by ! "t ( ! second ,voyag] enc\nt]1 a ribbon ( :ite cl\ds curl$ ar\nd ! nor!rn bord] ( ! ,r$ ,spot1 block+ ! motion ( small spots t might o!rwise h be5 caught up 9 ! vortex4 ,spots approa*+ ! ,r$ ,spot f ! ea/ j turn$ ar\nd & head$ back 9 ! direction f :i* !y _h come4 ,illu/ration3 ,voyag] #b captur$ ! ,r$ ,spot region f\r mon?s aft] ,voyag] #a1 :5 "s *anges _h tak5 place 9 ! cl\d circulation patt]n ar\nd x4 ,?is is a mosaic ( ,voyag] #b frames1 tak5 on ,july #f4 ,! :ite oval to ! s\? is n ! same "o t 0 pres5t 9 a simil> location dur+ ! ,voyag] #a flyby1 because ( diff]5tial rotation at ! two latitudes4 #bfj-fjf ,9 ! nor!rn hemisph]e1 small br[n anticyclonic features spe$ ar\nd ! planet1 (t5 collid+ ) "o ano!r4 ,on collision1 ! spots may comb9e & roll ar\nd toge!r = a :ile4 ,ultimately1 "p ( ! mass ( ! comb9$ spots is eject$ z a /ream]1 & ! rema9+ mat]ial cont9ues on its ea/w>d pa?4 ,ord] out ( ,*aos ,despite all ! turbul5ce 9 ,jupit]'s atmosph]e--?is ev]-*ang+ *aotic mixture ( cyclonic & anticyclonic fl[s1 ( ovals & filam5ts1 ( r$s1 br[ns1 & :ites--a patt]n may be em]g+3 ,!re is an und]ly+ ord] to ! seem+ly r&om mix+ ( patt]ns we see 9 ! ,jovian atmosph]e4 ,fir/1 ! *ang+ wea!r patt]ns are 9 "s s5se cyclic4 ,! fact t ,jupit] may be rev]t+ to ! appe>ance x pres5t$ at ! "t ( ,pione]s #aj & #aa is n surpris+4 ,f ,e>?-bas$ /udies1 a/ronom]s h f\nd t ! face ( ,jupit] (t5 goes ?r\gh a major *ange e few ye>s4 ,! transition is v rapid1 b ! planet ma9ta9s its new 8look0 = "s "t--until ! next major transition4 ,at ! "t ( ! ,pione] flybys1 8,! ,r$ ,spot 0 prom95t1 b x 0 surr\nd$ by int5se cl\d4 ,!re 0 no visible /ructure at all 9 ! s\? tropical zone--x 0 totally bl&4 ,y c\ldn't see ! turbul5t area to ! we/10 expla9$ ,g>ry ,hunt4 8,&1 ,i believe t ! buildup ( cl\d t we're see+ to ! ea/ ( ! ,r$ ,spot is ! beg9n+ ( ! transition t w produce ! ,pione] look40 ,!re is ev5 m ord] und]ly+ ,jupit]'s *ang+ atmosph]e4 ,?is ord] is reveal$ 9 "p 9 ! alt]nat+ belts & zones4 ,x is believ$ t ! cl\d-cov]$ zones are regions ( ris+ air1 & ! belts are regions ( desc5d+ air4 ,! int]nal en]gy ( ,jupit] provides ! p[] to ma9ta9 ?is patt]n ( sl[ v]tical circulation4 ,9 addition1 !re are horizontal or zonal fl[s t are mu* m regul> ?an ! *ang+ cl\d patt]ns4 ,illu/ration3 ,! ?ree l>ge :ite ovals are ! longe/-liv$ features 9 ,jupit]'s atmosph]e1 aft] ! ,great ,r$ ,spot4 ,l ! ,r$ ,spot1 !y are anticyclonic1 or high-pressure1 regions4 ,dur+ ,voyag] #b enc\nt]1 "o ( ! ovals 0 j s\? ( ! ,r$ ,spot4 ,?is picture %[s ! o!r two ovals z !y look$ 9 e>ly ,july4 ,! cl\ds %[ v simil> int]nal /ructures4 ,to ! ea/ ( ea* ( !m1 recirculat+ curr5ts are cle>ly se54 ,p-#baged;,c ,illu/ration3 ,9 ?is frame1 a simil> /ructure is se5 to ! we/ ( ! cl\d4 ,illu/ration3 ,a sequ5ce ( pictures ( ,jupit]1 tak5 once p] rotation 7ab\t t5 h\rs71 c be us$ to con/ruct a "t-lapse movie ( ! circulation ( ! ,jovian atmosph]e4 ,^! frames are f ! ,voyag] #a 8,blue ,movie0 ( ! ,great ,r$ ,spot region4 ,e odd ,jovian rotation is %[n1 s ! #bd frames correspond to #dh ,jupit] days1 or ab\t #bj ,e>? days4 ,:ite spots c be se5 ent]+ ! ,r$ ,spot f ! upp] "r & be+ c>ri$ ar\nd by its six-day rotation until !y are eject$ t[>d ! l[] "r4 ,above ! ,r$ ,spot1 ! fl[ is t[>d ! "r2 bel[ x1 t[>d ! left4 ,! rotation ( ! ,spot is c\nt]clockwise1 or anticyclonic4 #bfj-ddi ,illu/ration3 ,at diff]5t latitudes1 ! /rong prevail+ zonal w9ds produce diff]5t app>5t rotation rates4 ,plott$ "h are ! horizontal velocities measur$ f a pair ( ,voyag] images tak5 "o rotation 7ab\t t5 h\rs7 ap>t4 ,also %[n = comp>ison are old] gr\nd-bas$ measurem5ts obta9$ f c>eful tim+s ( ! app>5t rotation rate at diff]5t latitudes4 ,! excell5t agreem5t ( ! two plots indicates ! /ability ( ! zonal w9ds4 ,also1 ! w9d patt]n %[s mu* great] symmetry betwe5 nor!rn & s\!rn hemisph]es ?an d ! m sup]ficial cl\d patt]ns4 8,at fir/1 ,voyag] seem$ to d no?+ b emphasize ! *aos1 n ! ord] 9 ,jupit]'s atmosph]e10 ,&y ,+]soll /at$4 8,!re are turbul5t regions 9 :i* individual little spots seem to *ange e ,jovian rotation4 ,& ! :ole texture 9 c]ta9 turbul5t regions is unrecognizable 9 "o e>? day40 ,) ! ,voyag] spacecraft1 m detail c\ld be se5 ?an ev] be=e2 9 addition1 *anges c\ld be obs]v$ on a small timescale1 z !y happ5$4 8,x became mu* m ( a my/]y h[ l>ge-scale ord] c\ld exi/ 9 ! face ( all ?is small-scale *aos4 ,b ,i ?9k we are beg9n+ to see ! ord] und]nea?4 ,:at we are look+ at :5 we obs]ve ,jupit] are m9ute cl\d p>ticles repres5t+ only a small fraction ( ! mass ( ! atmosph]e40 ,! l>ge-scale ord] ! sci5ti/s _h f\nd 0 a regul> alt]nation ( ea/w>d & we/w>d jets4 8,if we take all ! measurem5ts f ,e>?-bas$ obs]vations ov] ! la/ #ge ye>s1 we f9d t e curr5t t has ev] be5 se5 f ! ,e>? ov] #ge ye>s is visible 9 "o t5-h\r rotation4 ,!y're all !re--!y 7 j invisible40 ,! ev]-*ang+ appe>ance 0 danc+ above a regul>1 almo/ /ation>y patt]n ( alt]nat+ fl[s1 :i* may come f deep )9 ,jupit]'s atmosph]e4 ,:y ?is alt]nat+ patt]n p]si/s rema9s a my/]y4 ,ev5 if ! und]ly+ patt]n c be ?\ght ( z a sort ( ,jovian climate1 x /ill does n expla9 ! me*anics ( 8! m9or side%[0--! *ang+ wea!r patt]ns4 ,analysis ( ! ,voyag] pictures is sure to keep planet>y meteorologi/s busy = _m ye>s to come4 ,lights 9 ! ,night ,sky ,t[>d ! end ( ! fir/ enc\nt] p]iod1 ,voyag] #a flew beh9d ,jupit]1 & ! spacecraft's wide-angle cam]a scann$ ! nor!rn hemisph]e on ! nightside ( ! planet1 se>*+ = aurorae & lightn+ bolts4 ,! mo/ impressive d>kside feature f\nd 0 a trem5d\s aurora 9 ! nor? pol> region4 ,b ?is 0 n ! fir/ "t ,jovian aurorae _h be5 detect$4 ,v-high-en]gy auroral emissions result+ f ultraviolet gl[s ( atomic & molecul> hydrog5 _h be5 detect$ prior to enc\nt] on ! bright side ( ,jupit] by ! ultraviolet spectromet]4 ,! ultraviolet obs]vations indicate t atmosph]ic temp]atures 9 ! auroral regions are at lea/ #ajjj ,k4 ,9 bo? ! visible & ! ultraviolet spectra1 ! aurorae are conf9$ to ! pol> regions & result f *>g$ magnetosph]ic p>ticles /rik+ ! upp] atmosph]e4 ,! ultraviolet aurorae are creat$ :5 high-en]gy p>ticles f ! ,io plasma torus spiral 9 t[>d ,jupit] on magnetic field l9es4 ,sev]al meteor trails 7 also evid5t 9 ! d>kside pictures ( ,jupit]'s atmosph]e4 ,travel+ at r\ghly #fj kilomet]s p] second z !y ent]$1 ^! fireballs bright5$ quickly & seem$ to survive = ab\t #ajjj kilomet]s be=e !y di$4 ,clu/]s ( lightn+ bolts--indicative ( electrical /orms--7 also discov]$ on ,jupit]'s nightside4 ,?is p>ticul> ph5om5on does n seem to dep5d on latitude4 ,! ,voyag] #a photograph t captur$ ! huge ,jovian aurora also caught ! electrical dis*>ges ( #ai sup]bolts ( lightn+1 & ,voyag] #b photographs locat$ eight additional fla%es4 ,radio emission 7:i/l]s7 f lightn+ dis*>ges 7 also detect$ by ! ,voyag] radio a/ronomy receiv]s & ! plasma wave in/rum5t4 ,illu/ration3 ,! night side ( ,jupit] is n dull4 ,a l>ge aurora 7nor!rn light7 arcs across ! nor!rn horizon1 :ile f>!r s\? ab\t tw5ty l>ge bolts ( lightn+ illum9ate electrical /orms 9 ! cl\ds4 ,simil> pictures also reveal$ fireballs1 or l>ge meteors1 burn+ up 9 ! atmosph]e ( ,jupit]4 ,p-#babhc;,b_/,w ,magnetic ,field ,deep 9 ! int]ior ( ,jupit]1 ! pressures are s great t hydrog5 becomes an electrical conductor1 l a metal4 ,curr5ts driv5 by ! rapid rotation ( ! planet are ?\ght to fl[ 9 ?is metallic core4 ,! result is a magnetic field t p5etrates ! space ar\nd ,jupit]4 ,direct measurem5ts ( ! ,jovian magnetic field 7 fir/ made by ! ,pione]s1 & ,voyag] results g5]ally confirm ! initial f9d+s4 ,! /r5g? ( ! ,jovian field is ab\t #djjj times great] ?an t ( ! ,e>?4 ,! dipol> axis is n at ! c5t] ( ,jupit]1 b (fset by ab\t #aj #jjj kilomet]s & tipp$ by #aa degrees f ! axis ( rotation4 ,ea* "t ! planet sp9s1 ! field wobbles up & d[n1 c>ry+ ) x ! trapp$ plasma ( ! radiation belts4 ,! ,voyag] p>ticles & fields in/rum5ts conc5trat$ n on ! planet>y magnetic field b on ! processes tak+ place 9 ! magnetosph]e4 ,illu/ration3 ,a probe ( ! ,jovian atmosph]e is obta9$ ea* "t a spacecraft passes beh9d ! planet z se5 f ! ,e>?4 ,passage ?r\gh ! ionosph]e & atmosph]e alt]s ! phase ( ! radio telemetry signal1 & subsequ5t comput] analysis all[s memb]s ( ! ,radio ,sci5ce ,team to recon/ruct ! pr(ile ( ! atmosph]e4 ,%[n "h is ! atmosph]ic temp]ature z a function ( pressure z d]iv$ f ! ,voyag] #a ,x-b& occultation data1 correspond+ to a po9t at latitude #ab,s1 longitude #fc4 ,! two curves repres5t extreme int]pretations ( ! same data2 ! be/ fit lies some:]e betwe54 ,accuracy is high at great] dep?s b poor at levels above a pressure ( ab\t #j4jc b>4 ,cle>ly %[n is ! temp]ature m9imum ne> #j4a b> & ! /eady increase ( temp]ature ) dep? z ! radio beam prob$ t[>d ! cl\d level ne> #a4j b>4 ,illu/ration3 ,at a wavel5g? ne> #e micromet]s1 ! prim>y gases 9 ! atmosph]e ( ,jupit] are p>ticul>ly transp>5t1 & ! infr>$ radiation f ! planet comes f relatively great dep?s4 ,at ^! dep?s1 x is possible to see evid5ce ( gases su* z wat] vapor t cond5se at high] altitudes :]e ! temp]atures are l[]4 ,?is ,,iris spectrum 9 ! #e-micromet] spectral region %[s features id5tifi$ ) wat] 7,h,o71 g]mane 7,ge,h71 & deut]at$ me?ane 7,,*,d71 z well z ! m easily detect$ ammonia 7,,nh74 ,wavel5g? 7m7 ,h,o ,,*,d ,ge,h ,,nh ,voyag] #a ,voyag] #b ,wave numb] 7cm7 ,voyag] #a brightness temp]ature 7,k7 ,voyag] #b brightness temp]ature 7,k7 ,illu/ration3 ,! /ructure ( ! ,jovian atmosph]e c be d]iv$ f infr>$ spectra z well z f ! radio occultation data4 ,?is pr(ile ( temp]ature z a function ( pressure cov]s ! same range ( altitudes z does ! prec$+ figure & is 9 good agreem5t4 ,bo? pr(iles locate a temp]ature m9imum ( ab\t #aaj ,k ne> a pressure ( #j4a b> 7#ajjj mb #a b> #a atm74 ,! ,,iris data also %[ v>iation ( /ructure ) position1 includ+ a cool] m9imum temp]ature 7ab\t #ajj ,k7 ov] ! ,great ,r$ ,spot4 ,illu/ration3 ,! /ructure ( ! atmosph]e c be inf]r$ f ,,iris spectra at _m locations ov] ! disk ( ,jupit]4 ,sci5ti/s are beg9n+ to assemble ?is va/ am\nt ( in=mation into maps t %[ ! temp]atures at a giv5 pressure4 ,! temp]ature cont\rs are label$ 9 degrees ,kelv94 ,! b&$ /ructure1 ) high] temp]atures ne> ! d>k equatorial belt1 is mo/ cle>ly evid5t at ! l[] altitude4 ,surpris+ly1 ! cool region associat$ ) ! ,great ,r$ ,spot 7latitude #bc,s7 is m app>5t at high altitude4 ,illu/ration3 ,! obs]v$ temp]ature at a dep? ne> ! cl\d tops 7#j4h b>74 ,illu/ration3 ,! obs]v$ temp]ature at an altitude ab\t #cj kilomet]s high] 7#j4ae b>74 ,! ,magnetosph]e ,giant ,jupit] has an enorm\s realm--f ! size ( its satellite sy/em to its trem5d\s aurorae & sup]bolts ( lightn+1 to ! huge planet-siz$ cl\d features t surr\nd its atmosph]e4 ,! mo/ g>gantuan ,jovian feature is its magnetosph]e1 :i* envelopes ! satellites & con/antly *anges 9 size1 pump+ 9 & out at ! :im ( ! sol> w9d4 ,! ,pione] & ,voyag] spacecraft provid$ f\r cuts ?r\gh ?is dynamic region1 %[+ t its bord]s 9 ! upw9d sol> direction lie betwe5 #ej ,r,j & #ajj ,r,j f ,jupit]4 ,d[nw9d1 away f ! ,sun1 ! magnetosph]e ext5ds mu* f>!r2 "s sci5ti/s po/ulate t a magnetotail may rea* z f> z ! orbit ( ,saturn4 ,*>g$ p>ticles 9 ! magnetosph]e are subject to p[]ful =ces4 ,tightly emb$d$ 9 ,jupit]1 ! magnetic field sp9s ) a t5-h\r p]iod z ! planet rotates4 ,! p>ticles are caught 9 ! sp9n+ field & accel]at$ to high spe$s4 ,! result is a co-rotat+ plasma 9 ! magnetic equator ( ,jupit]1 ext5d+ outw>d to at lea/ #bj ,r,j4 ,beyond ?is di/ance1 ! fl[ breaks up & ! magnetosph]e is m un/able4 ,)9 ! co-rotation region1 ! sp9n+ plasma sets up a p[]ful electric curr5t girdl+ ! planet4 ,*>g$ p>ticles c be accel]at$ 9 ! magnetosph]e to high en]gies1 correspond+ to spe$s t5s ( ?\s&s ( kilomet]s p] second4 ,"s ( ^! p>ticle /reams escape f ! inn] p>ts ( ! magnetosph]e & c p5etrate ! magnetopause & be eject$ f ! ,jovian sy/em4 ,on ,voyag] #a1 ! l[ en]gy *>g$ p>ticle in/rum5t began detect+ ^! /reams ( 8hot0 plasma on #bb ,janu>y1 :5 ,voyag] #a 0 /ill #fjj ,r,j 7almo/ #ej million kilomet]s7 f ! planet4 ,voyag] #b fir/ detect$ ,jovian p>ticles at an ev5 great] di/ance1 #hjj ,r,j4 ,hydrog5 & helium ions 7protons & alpha p>ticles7 dom9ate ! magnetosph]e at great di/ances f ,jupit]1 b increas+ am\nts ( sulfur & oxyg5 appe>$ z ! spacecraft cross$ ! magnetopause4 ,! heavi] ions presumably orig9ate f ,io4 ,9 ! inn] magnetosph]e1 ! ,galilean satellites h a p[]ful influ5ce on ! populations ( fa/-mov+ p>ticles4 ,dur+ ! ,voyag] #a enc\nt]1 ! prim>y effect 0 obs]v$ at ,io1 :]e ! satellite app>5tly sweeps up en]getic electrons4 ,9 ! million-volt en]gy range1 ^! p>ticles are deplet$ ne> ,io1 ) peaks obs]v$ bo? inside & outside ! satellite's orbit4 ,voyag] #b pass$ close to ,ganym$e1 & "h also major effects 7 se51 ) ! satellite app>5tly absorb+ electrons4 ,9 ! wake creat$ by ! motion ( ! co-rotat+ plasma pa/ ,ganym$e1 ! p>ticle populations %[$ l>ge & complex v>iations4 ,illu/ration3 ,! magnetosph]e ( ,jupit] c be 8se50 f ,e>? by its emissions at radio wavel5g?s4 ,! rec5t developm5t ( imag+ radio telescopes 9 ,great ,brita91 ,! ,ne!rl&s1 & ! ,unit$ ,/ates all[s frequ5t mapp+ ( ! l>ge-scale features ( ! inn]mo/ magnetosph]e1 inside ! orbit ( ,io4 ,^! six images %[+ "o rotation ( ,jupit] 7 obta9$ ne> ! "t ( ! ,voyag] #a flyby by ,imke de ,pat] at ! ,we/]bork ,radio ,obs]vatory ne> ,leid54 ,! brighte/ emission is %[n by d>k r$ or black4 ,! size ( ! planet is indicat$ by a dott$ :ite circle4 ,! tilt ( ! magnetosph]e relative to ! rotation axis ( ! planet c be se5 by ! wobble ( ! magnetosph]e z ,jupit] rotates4 ,j inside ! ,jovian magnetosph]e is ! 8hot spot0 ( ! sol> sy/em3 a #cjj-djj million degree plasma detect$ by ,voyag] #a :ile x 0 /ill ab\t #e million kilomet]s f ,jupit]4 ,t4 ,p4 ,arm/rong comm5t$1 8,ev5 ! int]ior ( ! ,sun is e/imat$ to be less ?an #bj million degrees40 ,s4 ,m4 ,krimigis add$ t ! temp]ature ( ?is plasma is 8! highe/ yet measur$ any:]e 9 ! sol> sy/em40 ,=tunately = ,voyag]1 ?is region ( incr$ibly hot plasma is also "o ( ! sol> sy/em's be/ vacuums4 ,! spacecraft 0 9 little dang] because ! b[ %ock protects ?is region f ! sol> w9d1 & mo/ ( ! p>ticles 9 ,jupit]'s magnetosph]e are held 9 mu* clos] to ! planet4 ,illu/ration3 ,ea* ,voyag] pass$ ?r\gh ! b\nd>ies ( ! magnetosph]e--! b[ %ock 7,,bs7 & ! magnetopause 7,,mp7--on bo? ! inb\nd & ! outb\nd legs ( its passage ?r\gh ! ,jovian sy/em4 ,9 ?is diagram1 ! heavy solid l9e repres5ts ! spacecraft trajectory1 z se5 look+ d[n f ! nor?4 ,also %[n are ! positions ( ! b[ %ock 9 ,m>* & ( ! magnetosph]e 9 bo? ,m>* & ,july4 ,illu/ration3 ,sev]al regions ( plasma 7*>g$ p>ticles7 make up ! ,jovian magnetosph]e4 ,^! sket*es1 bas$ on ,voyag] data1 %[ ! magnetosph]e z view$ f above 7a7 & z se5 f ! ,jovian equatorial plane 7b74 ,mo/ ( ! plasma co-rotates ) ! planet & is conf9$ ne> ! magnetic equator1 :]e x =ms a broad plasma %eet ab\t #ajj ,r,j across4 ,! v hot plasma 9 ! out] magnetosph]e discov]$ by ,voyag] is ?\ght to play an important role 9 e/abli%+ ! size ( ! ,jovian magnetosph]e4 ,al?\gh ! d5sity is l[1 only ab\t "o *>g$ p>ticle p] hundr$ cubic c5timet]s1 ?is plasma actually c>ries a great deal ( en]gy because ( ! high spe$ ( ! p>ticles4 ,x is ?is plasma pressure1 r ?an ! magnetic field pressure1 t appe>s to hold (f ! pressure ( ! sol> w9d4 ,h[ev]1 ! balance betwe5 hot plasma inside ! magnetopause & ! sol> w9d outside is n v /able4 ,! ,voyag] exp]im5t]s sugge/ t a small *ange 9 sol> w9d pressure c cause ! b\nd>y to become sudd5ly un/able4 ,a l>ge quantity ( ! hot plasma c !n be lo/1 produc+ ! bur/s se5 at l>ge di/ances & p]mitt+ a sudd5 collapse ( ! out] magnetosph]e4 ,cont9u$ injection ( hot plasma f )9 w\ld !n re9flate ! magnetosph]e1 :i* w\ld exp& l a balloon until ano!r in/ability develop$4 ,processes ( ?is sort may be ! cause ( ! rapidly v>y+ magnetosph]ic b\nd>ies obs]v$ by bo? ,voyag] spacecraft4 ,illu/ration3 ,! r+s ( ,jupit] are be/ se5 :5 look+ ne>ly 9 ! direction ( ! ,sun1 s9ce ! small p>ticles t comprise !m are good =w>d scatt]]s ( sunlight4 ,?is mosaic is ( ,voyag] #b images 7two wide angle & f\r n>r[ angle7 obta9$ f a p]spective beh9d ! planet & inside ! %ad[ ( ,jupit]4 ,! spacecraft 0 #b degrees bel[ ! equator ( ,jupit] & #a4e million kilomet]s f ! r+s4 ,! %ad[ ( ! planet c be se5 to obscure ! ne> segm5t ( ! r+ ne> ! edge ( ! planet4 ,! brighte/ region ( ! r+ is ab\t #a4h ,r,j f ! c5t] ( ,jupit]4 #bfj-fgh;,b ,r+s ( ,jupit] ,"o ( ! spectacul> discov]ies ( ,voyag] 0 ! exi/5ce ( a r+ sy/em ( small p>ticles circl+ ,jupit]4 ,saturn & ,uranus 7 kn[n to h r+s1 b none _h be5 se5 be=e at ,jupit]4 ,z reveal$ by ! ,voyag] cam]as1 ! r+s ext5d outw>d f ! upp] atmosph]e to a di/ance ( #ec #jjj kilomet]s above ! cl\d tops1 #a4h ,r,j f ! c5t] ( ! planet4 ,! ma9 r+s1 h[ev]1 are mu* n>r[]1 spann+ f #dg #jjj to #ec #jjj kilomet]s above ,jupit]4 ,!re are two ma9 r+s1 a #ejjj-kilomet]-wide segm5t1 & a bright]1 out] #hjj-kilomet] segm5t4 ,! ?ickness ( ! r+s is unkn[n1 except t x is c]ta9ly less ?an #cj kilomet]s1 & probably "u #a kilomet]4 ,illu/ration3 ,/ructure )9 ! r+ c be se5 9 ! be/ ,voyag] #b images1 tak5 ab\t #bg h\rs aft] close/ approa* to ,jupit]4 ,?is enl>g$ portion ( a wide-angle picture tak5 ) a cle> filt] %[s a bright core ab\t #hjj kilomet]s across ) a dimm] region a few ?\s& kilomet]s across on ! inside1 & a n>r[ dim region on ! outside4 #bfj-fgd ,! r+s ( ,jupit] are q t5u\s1 :i* expla9s :y !y are invisible f ,e>? al?\gh !y h be5 detect$ f ,e>? s9ce ,voyag]4 ,se5 face on1 ! brighte/ "p ( ! r+ blocks less ?an "o "p 9 t5 ?\s& ( ! light pass+ ?r\gh1 mak+ x ess5tially transp>5t4 ,9 fact1 ! r+ does n ev5 (f] mu* resi/ance to a spacecraft2 ,pione] #aa trav]s$ ! r+ 9 #aigd ) no obvi\s ill consequ5ces4 ,app>5tly ! individual p>ticles t make up ! r+ are widely disp]s$4 ,!y c be se5 only :5 ! r+s are view$ ne>ly edge-on1 or t[>d ! ,sun1 :]e !y %[ up well 9 =w>d scatt]$ light4 ,x is ?is extra brilliance :5 backlit t creat$ ! excell5t photos tak5 by ,voyag] #b f inside ! %ad[ ( ,jupit]4 ,! individual r+ p>ticles are probably d>k1 rocky fragm5ts t are v small--ess5tially du/ gra9s4 ,!y move ar\nd ,jupit] 9 individual orbits1 circl+ ! planet 9 #e - #g h\rs4 ,sci5ti/s po/ulate t su* orbits are n /able & t ! p>ticles fall sl[ly 9 t[>d ,jupit]4 ,app>5tly ! r+s are con/antly r5ew$ f "s s\rce1 :i* may be ! satellite ,adra/ea 7,j#ad71 discov]$ by ,voyag] #b4 ,!re has also be5 speculation t ,adra/ea may influ5ce ! r+ /ructure by sweep+ p>ticles out ( ! r+4 ,at pres5t ! r+s ( ,jupit] rema9 my/]i\s4 ,!y are cle>ly v diff]5t f ! r+s ( ,saturn & ,uranus1 & rea*+ an und]/&+ ( _! orig9s & dynamics pres5ts _m *all5ges to planet>y sci5ti/s4 ,illu/ration3 ,! f\r ,galilean satellites ( ,jupit] are planet-l worlds1 reveal$ by ,voyag] to be z div]se & fasc9at+ z ! t]re/rial planets ,m]cury1 ,v5us1 ,e>?1 & ,m>s4 ,9 ?is ,voyag] #a composite1 all f\r are %[n 9 _! correct relative size1 z !y w\ld appe> f a di/ance ( ab\t #a million kilomet]s4 ,relative color & reflectivity are also approximately pres]v$1 al?\gh x is n possible to %[ on a s+le pr9t ! full range ( brightness f ! d>k rocky surface ( ,calli/o to ! brilliant :ite ( ,europa or orange ( ,io4 #bfj-dii;,c ,illu/ration3 ,io 7longitude #adj74 ,illu/ration3 ,europa 7longitude #cjj74 ,illu/ration3 ,calli/o 7longitude #cej74 ,illu/ration3 ,ganym$e 7longitude #cbj74 ,,*apt] #i ,,f\r ,,new ,,worlds ,jupit]'s ,satellite ,sy/em ,9 a s5se1 ! ,voyag] ,mission reveal$ a new planet>y sy/em4 ,a/ronom]s _h long be5 fasc9at$ by ! l>ge ,galilean satellites ( ,jupit]1 b !y _h only look$ f af>1 wat*+ ! danc+ po9ts ( light 9 _! telescopes1 &1 occasionally1 z ! atmosph]e /eadi$1 see+ ^! po9ts resolve !mselves into t9y disks be=e dissolv+ aga9 9 ! turbul5ce ( ! t]re/rial atmosph]e4 ,mu* _h be5 le>n$ f telescopic /udies1 b n until ! ,voyag] flights _h we truly se5 ! ,galilean satellites4 ,! hi/oric h\rs z ,voyag] #a cruis$ pa/ ea* satellite on ,m>* #e & #f1 #aigi1 fundam5tally alt]$ our p]spective4 ,f\r new worlds 7 reveal$1 z div]se & fasc9at+ z ! m famili> t]re/rial planets4 ,al?\gh n yet h\sehold words1 ! names ,io1 ,europa1 ,ganym$e & ,calli/o h n[ be5 add$ to ,m]cury1 ,v5us1 ,moon1 & ,m>s 9 ! lexicon ( important 8,e>?-siz$0 bodies 9 ! sol> sy/em4 ,jupit] has fifte5 kn[n satellites1 c\nt+ ! two new satellites discov]$ by ,voyag]4 ,^! moons v>y greatly 9 size1 composition1 & orbit4 ,! f\r out]mo/ satellites1 ,s9ope1 ,pasiphae1 ,c>me1 & ,ananke1 circle ! planet 9 retrograde orbits ( high incl9ation2 _! di/ances f ,jupit] v>y betwe5 #bj & #bd million kilomet]s 7#bij ,r,j to #ccc ,r,j74 ,^! small bodies1 none m ?an #ej kilomet]s 9 diamet]1 require ne>ly two ye>s = ea* orbit ( ,jupit]4 ,x is possible t !y are captur$ a/]oids1 b s little is kn[n ab\t !m t a/ronom]s _c tell if _! surface prop]ties resemble ^? ( a/]oids1 or if ^! f\r satellites are ev5 simil> to ea* o!r4 ,! next gr\p ( ,jovian satellites consi/s ( f\r small difficult-to-obs]ve objects4 ,^! are ,lysi!a1 ,el>a1 ,himalia1 & ,l$a1 ! latt] discov]$ by ,*>les ,k[al ( ,hale ,obs]vatories 9 #aigd4 ,!y h simil> orbits1 v>y+ 9 di/ance f ,jupit] betwe5 #aa & #ab million kilomet]s 7ab\t #afj ,r,j74 ,l ! out] gr\p1 ^! satellites h orbits ( high incl9ation2 unlike ! out] gr\p1 !y move 9 ! prop]1 prograde direction ar\nd ,jupit]4 ,! l>ge/1 ,himalia 7#agj kilomet]s 9 diamet]7 & ,el>a 7#hj kilomet]s diamet]71 are kn[n to be v d>k1 rocky objects1 & x seems probable t ! o!rs are simil>4 ,x is unlikely t ! c5sus ( ! out] gr\ps ( irregul> satellites is complete1 & new satellites less ?an #aj kilomet]s 9 diamet] w probably be discov]$4 ,! ,jovian sy/em is dom9at$1 ( c\rse1 by ! l>ge ,galilean satellites1 :i* v>y 9 size f j small] ?an ! ,moon 7,europa7 to ne>ly z l>ge z ,m>s 7,ganym$e74 ,^! satellites are 9 regul>1 ne>ly circul> orbits 9 ! same plane z ! equator ( ,jupit]1 & all f\r lie )9 ! inn] magnetosph]e ( ,jupit]1 :]e !y int]act /rongly ) en]getic *>g$ p>ticles & plasma4 ,mo/ ( ?is *apt] w be devot$ to a discussion ( ^! fasc9at+ worlds4 ,we n[ "k ( ?ree additional small satellites inside ! orbit ( ,io1 orbit+ close to ,jupit]4 ,! fir/1 ,amal!a1 0 discov]$ 9 #ahib2 x orbits ,jupit] 9 j twelve h\rs at a di/ance ( #aha #jjj kilomet]s 7#b4ee ,r,j74 ,a small] object1 ,adra/ea 7(ficially #aigi;,j#a = ! fir/ new satellite ( ,jupit] discov]$ 9 #aigi71 is mu* clos]1 at #acd #jjj kilomet]s 7#a4gf ,r,j74 ,z describ$ 9 ,*apt] #g1 x skirts ! out] edge ( ! r+1 circl+ ,jupit] 9 j ov] sev5 h\rs4 ,! inn] satellite moves fa/] ?an ,jupit]'s rotation2 se5 f ! planet1 x w\ld rise 9 ! we/ & set 9 ! ea/4 ,bo? ,amal!a & ,adra/ea are buri$ deep )9 ! inn] magnetosph]e :]e !y are cont9ually bomb>d$ by en]getic electrons1 protons1 & ions4 ,depletion ( ! ,jovian radiation belt p>ticles 0 obs]v$ at ! orbits ( bo? satellites by ,pione] #aa1 :i* w5t mu* clos] to ,jupit] ?an ! ,voyag]s1 te/ify+ to ! int5sity ( ! int]action betwe5 ^! objects & _! surr\nd+s4 ,illu/ration3 ,calli/o 0 reveal$ by ! ,voyag] cam]as to be a heavily crat]$ & h5ce geologically inactive _w4 ,?is mosaic ( ,voyag] #a images1 obta9$ on ,m>* #f f a di/ance ( ab\t #djj #jjj kilomet]s1 %[s surface detail z small z #aj kilomet]s across4 ,! prom95t old impact feature ,valhalla has a c5tral bright spot ab\t #fjj kilomet]s across1 probably repres5t+ ! orig9al impact bas94 ,! conc5tric bright r+s ext5d outw>d ab\t #aejj kilomet]s f ! impact c5t]4 #bfj-dej ,,satellites ,,( ,,jupit] ,di/ance ,f ,jupit] ,"n #aj ,jupit] ,p]iod ,ye> ( kilomet]s ,radii 7days7 ,discov]y ,adra/ea ,j#ad #acd #a4gf #j4cj #aigi ,amal!a ,j#e #aha #b4ee #j4di #ahib #aigi;,j#b ,j#ae #bbb #c4aa #j4fg #aihj ,io ,j#a #dbb #e4ie #a4gg #afaj ,europa ,j#b #fga #i4dg #c4ee #afaj ,ganym$e ,j#c #ajgj #ae4aj #g4ae #afaj ,calli/o ,j#d #ahhj #bf4fj #af4gj #afaj ,l$a ,j#ac #aa #aaj #aef #bdj #aigd ,himalia ,j#f #aa #dgj #afa #bea #aijd ,lysi!a ,j#aj #aa #gaj #afd #bfj #aich ,el>a ,j#g #aa #gdj #afe #bfj #aijd ,ananke ,j#ab #bj #gjj #bia #fag #aiea ,c>me ,j#aa #bb #cej #cad #fib #aich ,pasiphae ,j#h #bc #cjj #cbg #gce #aijh ,s9ope ,j#i #bc #gjj #ccc #geh #aiad ,illu/ration3 ,! /ate ( ! int]iors ( ! ,galilean satellites c be judg$ f _! sizes & d5sities4 ,^! cross-sectional views repres5t ! be/ guess foll[+ ! ,voyag] flybys z to ! composition & /ructure ( ! objects4 ,io1 ) a d5sity equal to t ( ! ,moon & a long hi/ory ( volcanic activity1 is a dry1 rocky object4 ,europa is less d5se1 & x probably has a global ocean ( ice z mu* z #ajj kilomet]s ?ick ov] a rocky int]ior4 ,ganym$e & ,calli/o bo? h d5sities ne> #b grams p] cubic c5timet]1 sugge/+ a composition ab\t half wat] & half rock4 ,!re is probably a rocky core surr\nd$ by an icy mantle4 ,io ,active volcanoes ,sulfur & froz5 ,,s ,molt5 silicate int]ior ,europa ,global fracture patt]ns ,ice cru/ ,rocky int]ior ,ganym$e ,fre% crat]s expose ice ,"y groov$ t]ra9 ) intricate fracture ,old1 d>k crat]$ areas ,ice cru/ ,wat] or ice mantle ,calli/o ,l>ge bas9s r$uc$ by ice fl[ ,fre% crat]s expose ice ,ice_/rock cru/ ,wat] or ice mantle ,moon ,m]cury ,long aft] ! flybys ( ,jupit]1 cont9u$ analysis ( ,voyag] images reveal$ ano!r new satellite1 ,jupit]'s fifte5?4 ,initially designat$ #aigi;,j#b1 ! unexpect$ new satellite orbits ! planet at #c4ag ,r,j1 betwe5 ,io & ,amal!a4 ,/eph5 ,synnott ( ! ,,jpl ,optical ,navigation ,team discov]$ ! satellite on pictures tak5 dur+ ! ,voyag] #a ev5ts on ,m>* #e1 #aigi1 :ile se>*+ = additional images ( satellite #aigi;,j#a4 ,x is ab\t #ge kilomet]s 9 diamet]1 b no?+ else is kn[n ab\t its physical prop]ties4 ,toge!r1 ! #ae satellites circl+ giant ,jupit] =m a m9i-sol> sy/em4 ,p]haps ! out]1 irregul> satellites 7 captur$ or result$ f ! cata/rophic collisions ( "o or m l>g] satellites ) pass+ a/]oids4 ,! inn] sev5 satellites con/itute a coh]5t sy/em1 almo/ c]ta9ly =m$ toge!r ) ,jupit] & %>+ a common #d4e-;billion-ye> hi/ory4 ,!y are fasc9at+ z individual worlds1 & also z bro!rs & si/]s1 & ! /udy ( _! int]relation%ips und\bt$ly w provide insights into ! g5]al problems ( planet>y =mation & evolution4 ,,sizes ,,& ,,d5sities ,,( ,,! ,,galilean ,,satellites ,"n ,diamet] ,d5sity 7grams p] 7kilomet]s7 cubic c5timet]7 ,io #cfdj #c4e ,europa #cacj #c4j ,ganym$e #ebgj #a4i ,calli/o #dhdj #a4h ,calli/o ,calli/o is ! lea/ active geologically ( ! ,galilean satellites4 ,basically a dead _w1 x be>s ! sc>s ( innum]able meteoric impacts1 ) virtually no sign ( major int]nal activity4 ,calli/o is a _w ( crat]s1 & to und]/& x we mu/ explore ! role t crat]+ plays 9 mold+ planet>y surfaces4 ,! space betwe5 ! planets is fill$ ) debris1 rang+ f ! l>g] a/]oids1 hundr$s ( kilomet]s 9 size1 d[n to microscopic gra9s ( du/4 ,inevitably1 ea* planet collides ) "s ( ^! fragm5ts4 ,! small] p>ticles d little damage2 9 ! case ( a planet ) an atmosph]e1 l ,e>?1 !y burn up z meteors be=e rea*+ ! surface1 :]eas on an airless planet1 !y erode ! surface by s&bla/+ ! expos$ rock4 ,! l>g] impacts are ano!r matt]1 & ! crat]s !y produce c be ! dom9ant features on ! surface ( a planet4 ,illu/ration3 ,voyag]s #a & #b photograph$ mo/ ( ! surface ( ,calli/o at resolutions ( a few kilomet]s or bett]4 ,%[n "h is a prelim9>y %ad$ relief map4 ,additional measurem5ts w improve ! accuracy ( ! coord9ate sy/em4 #bfj-fgb ,illu/ration3 ,calli/o is a _w ( crat]s1 z is well %[n 9 ?is ,voyag] #b photomosaic tak5 f a di/ance ( #djj #jjj kilomet]s4 ,crat]s ab\t #ajj kilomet]s 9 diamet] cov] ! surface uni=mly4 ,_m h bright rims1 p]haps compos$ ( expos$ wat]-ice4 ,!re are v few crat]s l>g] ?an #aej kilomet]s 9 diamet]1 h[ev]1 indicat+ t ! sc>s ( v l>ge impacts d n survive on ! surface ( ,calli/o4 ,p-#bagdf;,b_/,w ,illu/ration3 ,! conc5tric r+s surr\nd+ ,valhalla are p]haps ! mo/ di/9ctive geological feature on ,calli/o4 ,?is ,voyag] #a close-up %[s a segm5t ( ! ridg$ t]ra94 ,! pres5ce ( sup]pos$ impact crat]s %[s t ! r+s =m$ e>ly 9 ,calli/o's hi/ory2 h[ev]1 ! d5sity ( crat]s is less "h ?an on o!r p>ts ( ! satellite1 :]e ! surface is old]4 ,p-#bbaid ,we :o live on ,e>? t5d n to realize ! importance ( crat]+1 = ! simple reason t our planet has v few crat]s1 & ^! are frequ5tly ( volcanic r ?an meteoric orig94 ,:y are we s favor$8 ,is !re an invisible %ield to protect u f ! cosmic %oot+ gall]y8 ,cle>ly n2 ! ,e>? has exp]i5c$ j z _m crat]+ impacts z has ! ,moon or o!r planets4 ,! diff]5ce is n t crat]s are =m$ less (t51 b t ! great geological activity ( ,e>?--erosion1 volcanism1 m\nta9 build+1 cont95tal drift1 etc4--erases crat]s z fa/ z !y are =m$4 ,on ! av]age1 a #aj-kilomet]-wide crat] is =m$ on ,e>? ab\t once e million ye>s1 b all ^? old] ?an a few million ye>s h be5 erod$ away1 fill$ 91 or cru%$ beyond recognition by cru/al motion4 ,if a planet lacks great int]nal geologic =ces1 l>ge crat]s c survive almo/ indef9itely4 ,su* is ! case = ! ,moon4 ,mo/ ( ! volcanism & o!r activity on ! ,moon ceas$ #c billion ye>s ago1 z ! dat+ ( lun> samples obta9$ by ! ,apollo a/ronauts %[$4 ,s9ce t "t1 ! lun> surface has be5 passively accumulat+ impact sc>s4 ,! long] any p>ticul> surface area has be5 expos$1 ! m d5sely pack$ are ! crat]s4 ,?us crat] d5sity is ! fir/ ?+ a planet>y geologi/ looks = 9 photos ( a new _w4 ,crat]s are ! t\*/one ( ?is field1 reveal+ ! degree ( int]nal activity & all[+ ! det]m9ation ( ! relative ages ( diff]5t surface units4 ,on ,calli/o ! d5sity ( crat]s is v high4 ,9 "s places !y are pack$ z closely z "o c imag9e1 p>ticul>ly = crat]s sev]al t5s ( kilomet]s 9 diamet]4 ,al?\gh no "o kn[s ! exact rate ( =mation ( impact crat]s on ! ,jovian satellites1 geologi/s on ! ,voyag] ,imag+ ,team e/imate t x w\ld require sev]al billion ye>s to accumulate ! numb] ( crat]s f\nd on ,calli/o4 ,!y !re=e conclude t ,calli/o has be5 geologically inactive almo/ s9ce ! "t ( its =mation4 ,al?\gh sup]ficially simil> to ! heavily crat]$ surfaces ( ! ,moon & ,m]cury1 ,calli/o is f> f id5tical to ^! rocky worlds4 ,"o ( ! mo/ obvi\s diff]5ces is a lack ( crat]s l>g] ?an ab\t #aej kilomet]s on ,calli/o1 toge!r ) a t5d5cy = l>ge crat]s to h mu* %all[] dep?s4 ,app>5tly ! ice-rock composition ( ,calli/o alt]s ! ability ( ! cru/ to reta9 l>ge crat]s4 ,geologi/s speculate t ! ice fl[s ov] _m millions ( ye>s1 fill+ 9 crat] floors & gradually oblit]at+ ! l>ge/ crat]s4 ,!re is also a conspicu\s abs5ce ( m\nta9s on ,calli/o1 aga9 sugge/ive ( a weak1 icy cru/4 ,illu/ration3 ,! ,,iris in/rum5t measur$ ! temp]ature ( spots on ! surface ( ,calli/o z ea* ,voyag] sp$ pa/4 ,! measurem5ts %[n "h 7 all made at equatorial latitudes 7betwe5 -#aj & #be74 ,%[n are v l[ pr$awn temp]atures 7-#aij ,c7 foll[$ by an increase to a noon-"t maximum ( ab\t -#abj ,c1 & !n a drop aga9 z ! ,sun sets4 #bfj-gce ,! mo/ prom95t features 9 ! ,voyag] pictures are ! gho/ remnants ( :at mu/ h be5 imm5se impact bas9s4 ,! l>ge/ ( ^!1 ! 8bullseye0 ( ! ,voyag] #a images1 has be5 nam$ ,valhalla1 = ! home ( ! ,norse gods4 ,^! gho/ bas9s h lo/ ne>ly all _! v]tical relief4 ,:at rema9s is a c5tral1 light-color$ zone 7probably ! location ( ! orig9al crat]71 surr\nd$ by num]\s conc5tric r+s ( subdu$1 bright ridges4 ,su* features _h nev] be5 se5 be=e on any planet1 & !y appe> to be ! *>act]i/ic geologic feature ( an ice-rock planet4 ,little is kn[n ab\t ! composition ( ,calli/o's surface1 ! mat]ial f :i* sunlight is reflect$4 ,x appe>s to be prim>ily d>k rock or soil1 b x lacks diagno/ic spectral features1 except = "o infr>$ b& due to wat] molecules b\nd 9 ! soil4 ,! _m light] spots & arcs t outl9e crat]s 9 ! high-resolution pictures may be regions 9 :i* ! ice is %[+ ?r\gh1 b ^! cov] only a v small fraction ( ! expos$ surface4 7,x %\ld be not$ t1 al?\gh ,calli/o is ! d>ke/ ( ! ,galilean satellites1 ! t]m 8d>k0 is relative1 = ev5 ,calli/o is bright] ?an ,e>?'s moon47 ,! daytime surface temp]ature ( ,calli/o1 obs]v$ bo? f ! gr\nd & by ,voyag]1 is ab\t -#aah ,c4 ,! ,voyag] infr>$ int]f]omet] spectromet] also det]m9$ ! m9imum temp]ature1 rea*$ j be=e dawn1 ( -#aic ,c4 ,no atmosph]e is expect$ at ^! cold temp]atures1 & none 0 se54 ,analysis ( ,voyag] images provid$ an improv$ diamet] = ,calli/o ( #dhdj kilomet]s1 yield+ an av]age d5sity ( #a4h grams p] cubic c5timet]4 ,z not$ previ\sly1 x is ?is l[ d5sity t leads to ! conclusion t ice or wat] is an important compon5t ( ! int]ior ( ,calli/o4 ,! ice has nev] be5 detect$ directly1 b ! peculi> nature ( ! crat]s se5 by ,voyag] adds /rong circum/antial support to ?is conclusion4 ,calli/o1 ) its heavy crat]+1 is ! mo/ famili>-look+ ( ! ,galilean satellites2 if all ( !m _h turn$ out to be z geologically dead z ,calli/o1 planet>y geologi/s w\ld c]ta9ly h be5 disappo9t$4 ,h[ev]1 ea* satellite1 progress+ 9 t[>d ,jupit]1 pres5ts increas+ evid5ce ( int]nal activity4 ,ganym$e ,! l>ge/ ( ! ,galilean satellites 7#ebgj kilomet]s 9 diamet]71 ,ganym$e 0 expect$ to be simil> to ,calli/o 9 _m ways4 ,bo? h l[ d5sities 7= ,ganym$e1 #a4i grams p] cubic c5timet]71 indicat+ a bulk composition ( ab\t half rocky mat]ials & half wat]4 ,9 addition1 _! diamet]s diff] by only eight p]c5t1 & bo? are f> en\gh f ,jupit] to escape ! sev]e p\nd+ ,io receives f magnetosph]ic *>g$ p>ticles4 ,?us x 0 ) great int]e/ t ,voyag] sci5ti/s look$ at ! diff]5ces t em]g$ betwe5 ^! two satellites4 ,illu/ration3 ,%ad$ relief map ( ,ganym$e4 #bfj-fgc ,! surface ( ,ganym$e z reveal$ by ! ,voyag] cam]as is "o ( great div]sity1 indicat+ diff]+ p]iods ( geologic activity4 ,at "o extreme !re are num]\s d>k areas t resemble ! surface ( ,calli/o 9 bo? alb$o 7reflectivity7 & crat] d5sity4 ,! l>ge/ ( ^!1 ,regio ,galileo1 /ret*es f ! equator to latitude #de & is #djjj kilomet]s across1 ne>ly z l>ge z ! cont95tal ,unit$ ,/ates4 ,?is anci5t t]ra9 ev5 pres]ves ! remnants ( a ,calli/o-type impact bas9 9 ! =m ( a sy/em ( p>allel1 curv+1 subdu$ ridges ab\t #aj kilomet]s wide1 #ajj met]s high1 & spac$ ab\t #ej kilomet]s ap>t4 ,! c5tral "p ( ?is gho/ bas9 is miss+1 h[ev]2 x 0 presumably de/roy$ by subsequ5t geologic activity4 ,o!r regions ( ! surface ( ,ganym$e are cle>ly ! product ( int5se int]nal geologic activity4 ,g5]ally1 ^! regions are ( high] alb$o & consi/ ( _m /raight p>allel l9es ( m\nta9s & valleys4 ,! ,voyag] geologi/s call ^! ! groov$ t]ra9 because ( _! appe>ance f a great di/ance4 ,typically1 ^! m\nta9 ridges are #aj-ae kilomet]s across & ab\t #ajjj met]s high1 simil> 9 scale to "s sections ( ! ,appala*ian ,m\nta9s 9 ! ,ea/]n ,unit$ ,/ates4 ,no high] relief exi/s1 presumably = ! same reason x is abs5t on ,calli/o4 ,9 _m places ! groov$ t]ra9 =ms betwe5 areas ( ! old]1 d>k] surface1 giv+ ! appe>ance ( m\nta9s extrud$ betwe5 sep>at+ plates ( anci5t cru/4 ,9 o!r areas ! relation%ips are mu* m complex1 ) curv$ sy/ems ( grooves & ridges ov]ly+ ea* o!r1 display+ intricate crosscutt+ relation%ips4 ,app>5tly ,ganym$e has exp]i5c$ a s]ies ( m\nta9-build+ ev5ts4 ,! groov$ t]ra9s %[ a sub/antial range 9 age1 z indicat$ by ! crat] d5sities4 ,! olde/ h ne>ly ! same d5sity z ! anci5t1 d>k pla9s1 sugge/+ t =mation ( ! groov$ t]ra9 began e>ly1 p]haps #d billion ye>s ago4 ,! y\nge/ groov$ t]ra9 has only ab\t "o-t5? z _m crat]s1 b ?is is /ill z _m z are se5 9 ! #c4e-;billion-ye>-old lun> pla9s4 ,! ,voyag] geologi/s believe t ev5 9 ^! areas geologic activity ceas$ billions ( ye>s ago4 ,illu/ration3 ,! hemisph]e ( ,ganym$e t faces away f ! ,sun displays a great v>iety ( t]ra94 ,9 ?is ,voyag] #b mosaic1 photograph$ at a range ( #cjj #jjj kilomet]s1 ! anci5t d>k area ( ,regio ,galileo lies at ! upp] left4 ,bel[ x1 ! light] groov$ t]ra9 =ms b&s ( v>y+ wid?1 sep>at+ old] surface units4 ,on ! "r edge1 a prom95t crat] ray sy/em is probably caus$ by wat]-ice spla%$ out 9 a relatively rec5t impact4 #bfj-fga ,illu/ration3 ,! s9u\s nature ( "s ( ! n>r[] ,ganym$e groove sy/ems c be se5 9 ?is oblique view1 obta9$ on ,m>* #e by ,voyag] #a4 ,! area %[n is ab\t ! size ( ,cali=nia1 ) features visible z small z #e kilomet]s across4 ,! ridges appe> to be ! result ( de=mation ( ! cru/ ( ,ganym$e4 ,p-#babce ,o!r types ( surfaces are se5 on ,ganym$e4 ,"s regions are lightly crat]$ & smoo?1 ) no indication ( m\nta9 build+4 ,9 "o place1 !re is a r\gh m\nta9\s area t looks m l ! jumbl$ lun> m\nta9s ?an ! long ridges & valleys ( ! re/ ( ,ganym$e4 ,_m ( ! l>g] crat]s are di/+ui%$ by brilliant :ite halos & rays t sugge/ t impacts may h spla%$ l>ge quantities ( wat] or ice ov] ! surface4 ,_m ( ! geologic features se5 on ,ganym$e appe> to h be5 caus$ by break+1 fault+1 or spread+ ( ! cru/4 ,9 a few cases1 !re ev5 seem to be indications ( transv]se1 or sideways1 motion along faults4 ,?is evid5ce is extremely excit+ to geologi/s1 s9ce simil> cru/al motion on ,e>? is associat$ ) ! drift ( cont95tal plates1 drawn by convection curr5ts deep 9 ! mantle4 ,su* activity has nev] be5 se5 be=e on ano!r planet4 ,a/ronom]s on ,e>? _h kn[n s9ce #aiga t ab\t half ! surface ( ,ganym$e 0 cov]$ ) expos$ wat] ice & ab\t half ) d>k] rock4 ,an exam9ation ( ! alb$o v>iations 9 ! ,voyag] pictures sugge/s t ! ice is expos$ ne> l>ge crat]s &1 to a less] ext5t1 9 ! groov$ t]ra91 b no direct measurem5ts 7 made by ,voyag] ( ! composition ( diff]5t p>ts ( ! surface4 ,! pres5ce ( ice on ! surface sugge/$ to _m a/ronom]s t ,ganym$e might h a v t5u\s atmosph]e ( wat] vapor or oxyg51 :i* might be releas$ by ! breakd[n ( wat] vapor by sunlight4 ,dur+ ! ,voyag] #a flyby1 a s5sitive te/ = an atmosph]e 0 made by ! ultraviolet in/rum5t f obs]vations ( ! /> ,kappa ,c5tauri z x 0 occult$ by ,ganym$e4 ,no dimm+ ( ! />light 0 se51 yield+ an upp] limit = ! surface pressure ( ! gases oxyg51 wat] vapor1 or c>bon dioxide ( #aj b>1 or "o hundr$-billion? ! atmosph]ic pressure at ,e>?4 ,! diff]5ces betwe5 ! geologic hi/ories ( ,ganym$e & ,calli/o are surpris+ly l>ge4 ,no "o kn[s ! reason4 ,p]haps only a small increase 9 int]nal temp]ature is necess>y to initiate geologic activity 9 an icy planet1 & = "s reason ,ganym$e cross$ ?is ?re%old = a "p ( its hi/ory1 :]eas ,calli/o did n4 ,illu/ration3 ,! complex patt]ns ( ! groov$ t]ra9 on ,ganym$e are app>5t 9 high-resolution images4 ,?is picture1 tak5 by ,voyag] #a on ,m>* #e1 has a resolution ( ab\t #c kilomet]s & %[s a region ab\t ! size ( ! /ate ( ,p5nsylvania4 ,! m\nta9 ridges are spac$ ab\t #aj to #ae kilomet]s ap>t & rise ab\t #ajjj met]s1 simil> to _m ( ! m\nta9s ( ,p5nsylvania4 ,! transections ( diff]5t m\nta9 sy/ems indicate t !y =m$ at diff]5t times4 ,a degrad$ crat] ne> ! left c5t] ( ! picture is cross$ by ridges1 indicat+ t x pr$at$ ! p]iod ( cru/al de=mation & m\nta9 build+4 ,p-#babgi ,illu/ration3 ,ray sy/ems ( expos$ wat]-ice are visible 9 ?is high-resolution mosaic ( ,ganym$e1 obta9$ by ,voyag] #b on ,july #i at a range ( ab\t #ajj #jjj kilomet]s4 ,! r\gh m\nta9\s t]ra9 at l[] "r is ! out] portion ( a l>ge fre% impact bas9 t po/dates mo/ ( ! o!r t]ra94 ,at ! bottom1 portions ( groov$ t]ra9 transect o!r portions1 indicat+ an age sequ5ce4 ,! d>k pat*es ( heavily crat]$ t]ra9 7"r c5t]7 are probably anci5t icy mat]ial =m$ prior to ! groov$ t]ra94 ,! l>ge ray$ crat] at upp] c5t] is ab\t #aej kilomet]s 9 diamet]4 ,p-#baggj;,b_/,w ,illu/ration3 ,! _m v>iants ( smoo? & groov$ t]ra9 on ,ganym$e sugge/ a complex geologic hi/ory = ?is satellite4 ,f\r high-resolution views by ,voyag] #b are gr\p$ toge!r4 #bfj-fgh;,a ,illu/ration3 ,a b& ( l[ m\nta9 ridges has app>5tly be5 cut & (fset by a fault4 ,illu/ration3 ,multiple sets ( m\nta9 ridges transect at ne>ly "r angles4 ,"s impact crat]s 7 =m$ be=e1 & "s aft]1 ! groov$ t]ra94 ,illu/ration3 ,_m %ort p>allel ridges butt into ea* o!r1 mak+ a crazy-quilt patt]n4 ,illu/ration3 ,9 ! c5t] ( ?is frame is an unusual smoo? area1 p]haps ! result ( flood+ ( ! surface by mat]ial t fill$ 9 ! grooves4 ,europa ,z "o proce$s inw>d ?r\gh ! ,galilean satellites1 ^! worlds become less & less famili> to ! planet>y geologi/4 ,?is 0 an unexpect$ effect4 ,calli/o & ,ganym$e 7 expect$ to h unusual prop]ties z a result ( _! l>ge p]c5tage ( ice4 ,! d5sities ( ,europa & ,io are m normal = ! small]1 t]re/rial-type planets1 & be=e ,voyag] _m sci5ti/s expect$ ^! two satellites might look mu* l ! ,moon1 :i* !y resemble 9 size4 ,europa1 ) a diamet] ( #cacj kilomet]s1 is ab\t #ae p]c5t small] ?an ! ,moon4 ,its d5sity is #c4j grams p] cubic c5timet]1 indicat+ a basically rocky composition4 ,h[ev]1 cosmic mixtures ( rocky & metallic mat]ials are (t5 a bit d5s] ?an ?is1 leav+ room = a sub/antial compon5t ( ice or wat]4 ,calculations indicate t if all ! ice 7 at ! surface1 x might =m a cru/ up to #ajj kilomet]s ?ick4 ,illu/ration3 ,%ad$ relief map ( ,europa4 #bfj-fei ,telescopic obs]vations ( ,europa demon/rat$ long be=e ,voyag] t ?is satellite is almo/ completely cov]$ ) ice4 ,x is a :ite1 highly reflect+ body1 look+1 f a great di/ance1 l a giant sn[ball4 ,9 ! e>ly ,voyag] pictures1 ,europa always %[$ a bl&1 :ite disk1 9 /rik+ contra/ to ! spott9ess ( ,ganym$e or ! brilliant colors ( ,io4 ,voyag] #a nev] got clos] to ,europa ?an #gcd #jjj kilomet]s1 & at t di/ance x rema9$ a ne>ly featureless planet1 ) no obvi\s impact crat]s or o!r famili> geologic /ructures4 ,:at did %[ 9 ! ,voyag] #a pictures1 h[ev]1 7 num]\s ?91 /raight d>k l9es crisscross+ ! surface1 "s ext5d+ up to #cjjj kilomet]s 9 l5g?4 ,to ! memb]s ( ! ,imag+ ,team1 ^! features 7 8/rongly sugge/ive ( global-scale tectonic processes1 induc$ ei!r ext]nally 7z by tidal desp9n+7 or int]nally 7z by convection740 ,x 0 ) ! greate/ int]e/ t ! ,voyag] #b images1 tak5 f ab\t f\r times clos]1 7 anticipat$4 ,! spectacul> pictures obta9$ ( ! satellite 9 ,july 7 p]haps m confus+ ?an cl>ify+4 ,europa is entirely cov]$ ) d>k /reaks t v>y 9 wid? f sev]al kilomet]s to approximately #gj kilomet]s & 9 l5g? f sev]al hundr$ to sev]al ?\s& kilomet]s4 ,mo/ /reaks are /raight1 b o!rs are curv$ or irregul>4 ,! /reaks lie on o!rwise smoo?1 bright t]ra91 featureless except = num]\s r&om d>k spots1 mo/ less ?an #aj kilomet]s 9 diamet]4 ,voyag] #b photos %[$1 9 addition to ! smoo? t]ra9 ) its d>k /reaks1 regions ( d>k]1 mottl$ t]ra94 ,?is mottl$ t]ra9 appe>s r\gh on a small scale1 & x may conta9 small crat]s j on ! limit ( resolution 7ab\t #d kilomet]s74 ,only ?ree def9ite impact crat]s h be5 id5tifi$1 ea* ab\t #bj kilomet]s across4 ,?is small numb] ( crat]s sugge/s ei!r t ! surface is relatively "y or t crat]s are n pres]v$ = long 9 ! icy cru/4 ,al?\gh ! d>k /reaks give ,europa a crack$ appe>ance1 ! /reaks !mselves are n obvi\sly cracks4 ,!y are n depress$ bel[ _! surr\nd+s2 9 fact1 !y h no topographic /ructure :atev]4 ,europa is extraord9>ily smoo?1 & ! d>k /reaks look r l m>ks made ) a felt-tipp$ p5 on a :ite billi>d ball4 ,! /reaks are n ev5 v d>k2 ! contra/ ) adjac5t smoo? t]ra9 is only ab\t #aj p]c5t4 ,"o ( ! mo/ rem>kable geologic ph5om5a discov]$ by ,voyag] is ! light /reaks t appe> on ,europa4 ,^! are small] ?an ! d>k /reaks1 only ab\t #aj kilomet]s 9 wid?1 b mu* m uni=m4 ,se5 at l[ ,sun angle1 !y also %[ v]tical relief ( less ?an a few hundr$ met]s4 ,^! light ridges are se5 be/ at l[ ,sun & t5d to be invisible at high] illum9ation angles4 ,! mo/ amaz+ ?+ ab\t ! light ridges is _! =m4 ,in/ead ( be+ /raight1 !y =m scallops or cusps1 ) smoo? curves t repeat regul>ly on a scale ( #ajj to a few hundr$ kilomet]s4 ,9 "s ( ! l[-,sun-angle pictures1 ! surface ( ,europa seems to be cov]$ ) a beautiful network ( ^! regul> curv+ l9es4 ,! impression is s biz>re t "o t5ds n to believe ! reality ( :at is se54 ,no?+ remotely l x has ev] be5 se5 on any o!r planet4 ,at pres5t ! geology ( ,europa rema9s beyond our und]/&+4 ,presumably !re is a ?ick ice cru/1 p]haps float+ on a liquid wat] ocean4 ,presumably !re is suffici5t heat com+ f ! int]ior to h produc$ crack+ or motion 9 ! ice cru/1 & ! light & d>k /reaks pres]ve a patt]n 9 "s way relat$ to ?is int]nal activity4 ,h[ev]1 ! actual me*anisms = produc+ ! obs]v$ features s lightly trac$ on ?is smoo? :ite _w rema9 = sci5ti/s to deciph]4 ,illu/ration3 ,europa looks l a crack$ egg 9 ?is comput] mosaic ( ! be/ ,voyag] #b images4 ,9 ?is pres5tation1 ! v>iation ( surface brightness due to ! angle ( ! ,sun has be5 remov$ by comput] process+1 s t surface features c be se5 equally well at all places4 ,! _m broad d>k /reaks %[ up well1 b ?is pres5tation does n br+ out ! mu* fa9t] & m enigmatic light /reaks4 ,^! pictures 7 tak5 f a di/ance ( ab\t #bej #jjj kilomet]s & %[ features z small z #e kilomet]s across4 #bfj-fhf ,io ,! mo/ spectacul> ( ! ,galilean satellites is ,io4 ,ev5 9 l[-resolution images1 its brilliant colors ( r$1 orange1 yell[1 & :ite set x ap>t f any o!r planet4 ,! dramatic scale ( its volcanic activity confirms t ,io is 9 a class by itself z ! mo/ geologically active planet>y body 9 ! sol> sy/em4 ,! diamet] ( ,io is #cfdj kilomet]s1 & its d5sity is #c4e grams p] cubic c5timet]4 ,bo? values are ne>ly id5tical to ^? ( our ,moon4 ,7 x n = ,io's proximity to ,jupit]1 x w\ld probably be a dead1 rocky _w mu* l ,e>?'s satellite4 ,c>eful exam9ation ( all ! ,voyag] images ( ,io1 "s ( :i* h resolutions z good z #a kilomet]1 has fail$ to reveal a s+le impact crat]4 ,yet ! flux ( crat]-produc+ impacts at ,io mu/ be ev5 great] ?an = ! o!r ,galilean satellites1 because ( ! focus+ effect ( ,jupit]'s gravity4 ,! abs5ce ( crat]s alone w\ld indicate t ,io has an extremely "y & dynamic planet>y surface1 ev5 )\t ! obs]vation ( active volcanoes4 ,calculations indicate t crat]s on ,io mu/ be fill$ 9 or o!rwise oblit]at$ at a rate correspond+ to ! deposition ( at lea/ #ajj met]s p] million ye>s1 & q probably a factor ( t5 great]1 or #a met] e ?\s& ye>s4 ,illu/ration3 ,"o ( ! mo/ rem>kable ( all ! ,voyag] discov]ies 0 ! arcuate :ite ridges on ,europa4 ,visible only at v l[ ,sun angle1 ^! curv$ bright /reaks are #e to #aj kilomet]s wide & rise at mo/ a few hundr$ met]s above ! surface4 ,_! graceful scallop$ patt]n is unique to ?is planet & has defi$ explanation4 ,also visible 9 ?is view1 tak5 by ,voyag] #b on ,july #i at a range ( #bbe #jjj kilomet]s1 are d>k b&s1 m diffuse ?an ! light ridges1 typically #bj to #dj kilomet]s wide & hundr$s to ?\s&s ( kilomet]s long4 ,p-#bagff ,illu/ration3 ,%ad$ relief map ( ,io z x appe>$ 9 e>ly ,m>* #aigi4 #bfj-fcd;,,bc ,illu/ration3 ,! great erupt+ volcanoes on ,io produce di/9ctive surface m>k+s4 ,^! are ?ree views ( ,prome!us 7,p74 ,! bright r+ on ! surface rims ! areas ( fall\t f ! plume1 & x is probably an area 9 :i* sulfur dioxide fro/ is be+ deposit$ on ! surface4 #bfj-dea ,illu/ration3 ,prome!us4 ,illu/ration3 ,prome!us4 ,illu/ration3 ,prome!us4 ,illu/ration3 ,^! views are ( ,loki 7,p7 z se5 by ,voyag] #a4 #bfj-dea ,illu/ration3 ,! asymmetric /ructure ( ! plume c be se54 ,illu/ration3 ,loki4 ,illu/ration3 ,an ultraviolet image has be5 us$ to produce a false-color composite2 ! l>ge ultraviolet halo above ! visible-light plume may be due to scatt]+ f sulfur dioxide gas r ?an solid p>ticles4 ,illu/ration3 ,p]haps ! mo/ spectacul> ( all ! ,voyag] photos ( ,io is ?is mosaic obta9$ by ,voyag] #a on ,m>* #e at a range ( #djj #jjj kilomet]s4 ,a great v>iety ( color & alb$o is se5 on ! surface1 n[ ?\ght to be ! result ( surface deposits ( v>i\s =ms ( sulfur & sulfur dioxide4 ,! two great volcanoes ,pele & ,loki 7upp] left7 are prom95t4 #bfj-dfd ,9 place ( impact crat]s1 ! surface ( ,io has a great _m volcanic c5t]s1 :i* g5]ally take ! =m ( black spots a few t5s ( kilomet]s across4 ,9 a few cases1 high-resolution pictures %[ ! *>act]i/ic %apes associat$ ) volcanic cald]as on ,e>? & ,m>s1 &1 if ! o!r volcanic c5t]s are simil>1 ab\t #e p]c5t ( ! entire surface ( ,io is occupi$ by cald]as4 ,^! are extremely black1 reflect+ less ?an #e p]c5t ( ! sunlight2 (t5 !y are surr\nd$ by irregul>1 diffuse halos ne>ly z black z ! c5tral spot4 ,! cald]as seem m l ! ,valles cald]a 9 ,new ,mexico1 :i* is associat$ ) v5ts t produc$ l>ge quantities ( a%1 ?an ) ^? ( ,hawaiian-type %ield volcanic m\nta9s4 ,!re is evid5ce 9 _m ( ! ,voyag] photos ( ext5sive surface fl[s on ,io4 ,^! orig9ate 9 d>k volcanic c5t]s & ei!r spread to fan %apes1 typically #ajj kilomet]s across1 or else snake out 9 long1 twi/+ t5tacles4 ,"s ( ! fl[s are light] ?an ! backgr\nd & "s are d>k]4 ,mo/ are r$ or orange 9 color1 (t5 outl9$ by fr+es ( contra/+ alb$o4 ,! equatorial regions ( ,io are q flat1 ) no v]tical relief great] ?an ab\t #a kilomet] high2 inde$1 _m ( ! volcanic c5t]s d n appe> to correspond to m\nta9s or domes at all4 ,!re are1 h[ev]1 a numb] ( long1 curvil9e> cliffs or sc>ps & n>r[1 /raight-wall$ valleys a few hundr$ met]s deep4 ,^! appe> to be places 9 :i* ! cru/ has brok5 "u t5sion1 some:at simil> to t]re/rial faults & ! valleys call$ grab54 ,a few rugg$ m\nta9s ( unc]ta9 orig9 are visible 9 l[ ,sun elevation pictures4 ,ne> ! poles ( ,io ! t]ra9 is m irregul>4 ,!re are few volcanic c5t]s1 b m m\nta9s1 "s ) heights ( sev]al kilomet]s4 ,9 addition1 !re are regions t appe> to be made ( /ack$ lay]s ( mat]ial4 ,^! s-call$ lay]$ t]ra9s are reveal$ :5 erosion cuts into !m1 expos+ ! lay]s along ! cliff or sc>p4 ,! l>ge/ su* plateau or mesa has an area ( ab\t #ajj #jjj squ>e kilomet]s4 ,! sc>ps sometimes int]sect ea* o!r1 sugge/+ a complex hi/ory ( deposition1 fault+1 & erosion4 ,voyag] geologi/s believe t ^! sc>ps may be areas 9 :i* ! release ( liquid sulfur or sulfur dioxide has und]cut cliffs1 analog\s to int]nal sapp+ by gr\ndwat] at simil> sc>ps on ,e>?4 ,p]haps ! mo/ di/9ctive surface features on ,io are ! circul> or oval alb$o m>k+s t surr\nd ! great volcanoes4 ,! fir/ ( ^! to be se5 0 ! #cjj-kilomet]-wide :ite donut ( ,prome!us1 on ! equator at longitude #aej4 ,mu* m spectacul> is ! ho(pr9t ( ,pele1 ab\t #gjj by #ajjj kilomet]s4 ,^! symmetric r+s m>k ! locations ( ! k9ds ( eruptions t g5]ate l>ge f\nta9s or plumes1 & may be produc$ by cond5sible sulfur or sulfur dioxide ra9+ d[n f ! volcanic f\nta94 ,at lea/ "o new r+ appe>$ dur+ ! f\r mon?s betwe5 ! ,voyag] enc\nt]s1 c5t]$ at longitude #ccj1 latitude #bj1 b by ! "t ,voyag] #b photograph$ ?is area1 no plume rema9$ active4 ,dur+ ! ,voyag] #a flyby1 temp]ature scans ( ! surface ( ,io 7 made ) ! infr>$ int]f]omet] spectromet] 7,,iris74 ,a numb] ( localiz$ w>m regions 7 f\nd1 ! mo/ dramatic be+ j s\? ( ! volcano ,loki4 ,"h ! images %[$ a /range1 ,u-%ap$ black feature ab\t #bjj kilomet]s across4 ,! ,,iris team int]pret$ its data to indicate a temp]ature = ! black feature ( #ag ,c 7or room temp]ature71 9 contra/ to ! surr\nd+ surface at -#adf ,c4 ,p]haps ! d>k feature 0 "s sort ( lava lake1 ei!r ( molt5 rock or molt5 sulfur4 ,! melt+ po9t ( sulfur is #aab ,c4 ,if !re 7 a scum ( solidify+ sulfur on top ( ! 8lake10 ?is int]pretation might well be ! correct "o4 ,! brilliant r$s & yell[s ( ! surface ( ,io imm$iately sugge/ ! pres5ce ( sulfur4 ,:5 heat$ to diff]5t temp]atures & sudd5ly cool$1 sulfur c assume _m colors1 rang+ f black ?r\gh v>i\s %ades ( r$ to its normal light-yell[ appe>ance4 ,ev5 be=e ,voyag]1 laboratory /udies _h %[n t sulfur mat*es ! ov]all prop]ties ( ! spectrum ( ,io1 includ+ ! l[ alb$o 9 ! ultraviolet & ! high reflectivity ?r\gh\t ! infr>$4 ,contempor>y ) ! ,voyag] flybys1 additional telescopic obs]vations & laboratory /udies by ,fras] ,fanale at ,,jpl & ,dale ,cruik%ank at ! ,univ]sity ( ,hawaii id5tifi$ ano!r compon5t on ,io1 sulfur dioxide4 ,sulfur dioxide is an acrid gas releas$ f t]re/rial volcanoes1 :]e x comb9es ) wat] 9 ! ,e>?'s atmosph]e to produce sulfuric acid4 ,at ! temp]ature ( ! surface ( ,io1 sulfur dioxide is a :ite solid4 ,rese>*]s guess$ t ! ext5sive bright :ite areas 9 ! ,voyag] pictures ( ,io might be cov]$ ) sulfur dioxide fro/ or sn[4 ,! pres5ce ( ?is mat]ial on ,io 0 confirm$ :5 ! infr>$ ,,iris in/rum5t obta9$ a spectrum ( sulfur dioxide gas ov] ! erupt+ volcano ,loki dur+ ! ,voyag] #a enc\nt]4 ,illu/ration3 ,close-ups ( ,io reveal a wide v>iety ( volcanic ph5om5a4 ,?is ,voyag] #a view ( an equatorial region ne> longitude #cjj %[s sev]al l>ge surface fl[s t orig9ate 9 volcanic crat]s or cald]as4 ,at ! "r edge is a light fl[ ab\t #bej kilomet]s long4 ,ano!r d>k1 lobate fl[ ) bright edges is j left ( c5t]1 ) an exce$+ly d>k cald]a to its left4 #bfj-dfh;,a ,! discov]y ( ! ongo+ eruptions on ,io1 made %ortly aft] ! ,voyag] #a flyby1 did mu* to cl>ify ! confus$ evid5ce p\r+ 9 conc]n+ ! app>5t y\? ( ,io's surface4 ,"h1 "u ! v eyes ( ,voyag]1 eruptions 7 tak+ place on a scale t dw>f$ any?+ ev] se5 be=e4 ,! discov]y picture alone1 tak5 f a di/ance ( #d million kilomet]s1 %[$ two eruptions 7,pele & ,loki71 ea* ( :i* 0 mu* l>g] ?an ! mo/ viol5t volcanic eruption ev] record$ on ,e>?4 ,voyag] #a f\nd eight giant eruptions1 ) f\nta9s or plumes ris+ to heights ( betwe5 #gj & #bhj kilomet]s4 ,to rea* ^! altitudes1 ! mat]ial mu/ h be5 eject$ f ! v5ts at spe$s ( betwe5 #cjj & #ajjj met]s p] second1 sev]al times great] ?an ! highe/ ejection velocities f t]re/rial volcanoes4 ,al?\gh widely spac$ 9 longitude1 ^! volcanoes 7 conc5trat$ t[>d ! equator2 sev5 ( ! eight 7 at latitudes betwe5 #cj & -#cj1 & ! eigh? at -#dd4 ,:5 ,voyag] #b arriv$ f\r mon?s lat]1 x 0 able to reobs]ve sev5 ( ! eight volcanoes4 7,to be id5tifi$ reliably1 ! volcanic plumes mu/ be silh\ett$ aga9/ d>k space at ! edge ( ! disk47 ,six ( ^! 7 /ill erupt+2 "o1 ,pele1 ! l>ge/ plume se5 by ,voyag] #a1 _h ceas$ activity4 ,! plume associat$ ) ,loki _h also *ang$ m>k$ly1 increas+ 9 height f #ajj to #baj kilomet]s 9 visible light4 7,all ! plumes appe> l>g] :5 view$ 9 ! ultraviolet47 ,loki _h develop$ a m complex /ructure2 9 ,m>* x appe>$ to orig9ate ne> ! s\? end ( a #bej-kilomet]-long d>k feature1 b 9 ,july !re 0 a d\ble plume1 ) activity at bo? ends ( ! d>k feature4 ,illu/ration3 ,diff]5ces 9 surface elevation c cle>ly be se5 9 a few ( ! ,io close-ups f ,voyag] #a4 ,?is rem>kable picture is ( ! c5t] ( ! great volcano ,pele1 at latitude #ae,s & longitude #bbd4 ,a l[ m\nta9 ) fl[ features c be se54 ,9 ! backgr\nd1 !re are sev]al l>ge irregul> depressions ) flat floors t appe> to be ! result ( collapse4 ,! diffuse d>k features 9 ! c5t] are probably ! ejecta plumes be+ erupt$ f ! ,pele v5t4 ,p-#babbj;,b_/,w ,illu/ration3 ,at ! highe/ resolution obta9$ by ! ,voyag] cam]as1 ,io reveal$ "s l&scapes t look$ famili> to t]re/rial geologi/s4 ,?is picture1 tak5 by ,voyag] #a at a range ( only #ca #jjj kilomet]s1 %[s a region ab\t ! size ( ! /ate ( ,m>yl& at a resolution ( #cjj met]s4 ,cle>ly se5 is a volcano n too diff]5t f "s ( ^? on ! ,e>? or ,m>s4 ,at ! c5t] is an irregul> composite crat] or cald]a ab\t #ej kilomet]s 9 diamet] ) d>k fl[s radiat+ f its rim4 ,! /yle ( volcanism illu/rat$ "h is q diff]5t f ! explosive plumes or f\nta9s ) _! associat$ r+s ( bright mat]ial deposit$ on ! surface4 ,?is volcano is locat$ at ab\t longitude #ccj1 latitude #gj,s4 #bfj-ejb ,illu/ration3 ,9 addition to its giant volcanic plumes or f\nta9s1 ,io possesses o!r indications ( curr5t volcanic activity4 ,"o ( ^! takes ! =m ( int]mitt5t blue-:ite pat*es t may be caus$ by gas v5t+ f ! int]ior4 ,9 ?is pair ( photographs1 ! same region ( ! surface is %[n ab\t six h\rs ap>t4 ,on ! "r1 !re is an arcuate bright gas cl\d2 on ! left ! same region is black4 ,x is believ$ t ! v5t+ gas is sulfur dioxide1 & t ! cond5sation ( ?is gas produces f9e p>ticles ( 8sn[0 t look blue4 #bfj-ejh ,illu/ration3 ,"s ( ! mo/ dramatic *anges 9 ! surface ( ,io betwe5 ,m>* & ,july took place 9 ! vic9ity ( ! volcano ,loki1 at longitude #caj & latitude #ae,n4 ,on ! left is a ,voyag] #a view2 on ! "r1 "o f ,voyag] #b4 ,! 8lava lake0 associat$ ) ,loki has become less di/9ct1 app>5tly z a result ( deposits t fell on ! nor!rn "p ( ! d>k ,u-%ap$ feature4 ,p]haps ! surface _h also cool$ betwe5 ^! photos4 ,9 ! upp] left c5t]1 a new d>k volcanic cald]a ) bright spots ne> x & a l>ge1 fa9t bright r+ _h appe>$ by ,july1 al?\gh x 0 n active at ! "t ,voyag] #b flew by4 #bfj-fhg;,,ac ,no new eruptions 7 se5 by ,voyag] #b2 betwe5 !m1 ! two spacecraft effectively survey$ ! :ole surface ( ,io = plumes d[n to #dj kilomet]s height4 ,int]e/+ly1 ! smalle/ plume se5 0 #gj kilomet]s high2 !re appe>$ to be a real abs5ce ( small] eruptions4 ,f ! numb] & size ( ! obs]v$ eruptions1 x is possible to calculate ! resurfac+ rate = ,io due to ^! plumes4 ,! result is t ea* plume is erupt+ ab\t #aj #jjj tons ( mat]ial p] second1 or m ?an #ajj billion tons p] ye>4 ,?is quantity corresponds to ab\t #aj met]s ( deposition ov] ! :ole surface 9 a million ye>s4 ,:5 additional note is tak5 ( surface fl[s1 ! deposition rate c\ld easily be t5 times high]1 or #ajj met]s p] million ye>s1 9 agreem5t ) ! rate e/imat$ f ! abs5ce ( impact crat]s4 ,en]gy = ! ,io ,volcanoes ,cle>ly1 some?+ extraord9>y is happ5+ to ,io to g5]ate ! obs]v$ level ( volcanism4 ,! prim>y heat s\rce = ! int]iors ( ! t]re/rial planets is ! decay ( ! long-liv$ radioactive elem5ts ?orium & uranium4 ,b ,io w\ld h to be suppli$ ) a hundr$ times its quota ( ^! elem5ts to expla9 ! obs]v$ activity4 ,a way out ( ?is difficulty 0 provid$ by a !oretical inve/igation c>ri$ out by ,/anton ,peale ( ! ,univ]sity ( ,cali=nia at ,santa ,b>b>a & ,pat ,cass5 & ,ray ,reynolds at ! ,,nasa ,ames ,rese>* ,laboratory4 ,work+ 9 ! mon?s be=e ! fir/ ,voyag] flyby1 !y calculat$ t ! tidal effects ( ,jupit] on ,io c\ld g5]ate l>ge-scale heat+ ( ! satellite4 ,io is ab\t ! same di/ance f ,jupit] z ! ,moon f ,e>?1 b ! mu* great] mass ( ,jupit] raises enorm\s tides 9 its satellite4 ,^! tides di/ort its %ape1 b no o!r effect w\ld be pres5t if ,io rema9$ at a con/ant di/ance f ,jupit]4 ,:at ,peale1 ,cass51 & ,reynolds realiz$ 0 t ! di/ance ( ,io f ,jupit] v>ies z ! result ( small gravitational p]turbations f ! o!r ,galilean satellites4 ,!re=e ! tidal di/ortions also v>y1 9 effect squeez+ & unsqueez+ ,io ea* orbit4 ,su* flex+ pumps en]gy into ! int]ior ( ,io 9 ! =m ( heat2 !ori/s calculat$ t ! heat suppli$ c\ld be z high z #aj watts4 ,!y pr$ict$1 9 a pap] publi%$ j ?ree days be=e ! ,voyag] flyby ( ,io1 t 8widespread & recurr5t surface volcanism might occur10 & t 8consequ5ces ( a l>gely molt5 int]ior may be evid5t 9 pictures ( ,io's surface return$ by ,voyag]40 ,illu/ration3 ,voyag] #b obta9$ beautiful views ( ! volcanic eruptions dur+ its t5-h\r ,io volcano wat* on ,july #i4 ,on ! edge ( ! cresc5t image are ! volcanoes ,amirani 7,p7 & bel[ x ,maui 7,p71 ea* s5d+ up f\nta9s ab\t #ajj kilomet]s above ! surface4 ,! blue color is probably ! result ( sunlight scatt]$ by t9y p>ticles ( sulfur dioxide sn[ cond5s+ 9 ! erupt+ plume4 ,p-#baghj ,,volcanic ,,eruptions ,,on ,,io ,plume ,"n ,location ,height ,dur+ ,activity ,dur+ ,numb] 7latitude_/longitude7 ,voyag] #a ,voyag] #b ,flyby ,flyby 7kilomet]s7 #a ,pele -#bj_/bee #bhj ceas$ #b ,loki #bj_/cjj #ajj increas$ #c ,prome!us -#e_/aee #gj increas$ #d ,volund #bj_/age #ie no data #e ,amirani #be_/abj #hj simil> #f ,maui #bj_/abj #hj simil> #g ,m>duk -#be_/baj #abj simil> #h ,masubi -#dj_/ #ej #gj simil> ,illu/ration3 ,betwe5 ! two enc\nt]s1 ! volcanic eruption at ,loki 7,p7 *ang$ "*4 ,! s+le plume emanat+ f ! we/]n end ( an app>5t d>k fissure se5 9 ,m>* 0 jo9$ by a second f\nta9 ( simil> size ab\t #ajj kilomet]s to ! ea/4 ,! plume also increas$ 9 height1 f ab\t #abj kilomet]s 9 ! ,voyag] #a image 7left7 to #age kilomet]s 9 ! ,voyag] #b image 7"r74 #bfj-ffb;,a & ,b ,illu/ration3 ,! detail$ /ructure ne> ! volcano ,loki is l no?+ se5 else:]e on ,io4 #bfj-fdb;,b ,illu/ration3 ,:5 ?is ,voyag] #a picture 0 tak51 ! ma9 eruptive activity 7,p7 came f ! l[] left ( ! d>k l9e> feature 7p]haps a rift7 9 ! c5t]4 ,bel[ x is ! 8lava lake10 a ,u-%ap$ d>k area ab\t #bjj kilomet]s across4 ,9 ?is specially process$ image1 detail c be se5 9 ! d>k surface ( ?is feature1 possibly due to 8iceb]gs0 ( solid sulfur 9 a liquid sulfur lake4 ,illu/ration3 7,bottom7 ,! ,,iris on ,voyag] #a f\nd ?is 8lava lake0 to be ! hotte/ region on ,io1 ) a temp]ature ab\t #aej ,c high] ?an t ( ! surr\nd+ area4 ,illu/ration3 ,"o model = ! /ructure ( ,io indicates t an ocean ( liquid sulfur ) a solid sulfur cru/ cov]s mo/ ( ! satellite4 ,heat escapes f ! int]ior 9 ! =m ( lava1 :i* erupts b5ea? ! sulfur ocean4 ,second>y eruptions 9 ! sulfur ocean heat liquid sulfur dioxide1 :i* is mix$ ) solid sulfur 9 ! cru/4 ,! rapid expansion ( sulfur dioxide gas !n produces ! great eruptive plumes1 :i* consi/ ( a mixture ( solid sulfur1 sulfur dioxide gas1 & sulfur dioxide sn[4 ,solid sulfur solid ,,s ,solid sulfur liquid ,,s ,molt5 sulfur ,solid silicate ,! ,voyag] obs]vations appe> to confirm ! !oretical calculations4 ,! tidal heat s\rce has presumably be5 act+ s9ce ,io 0 =m$ m ?an #d billion ye>s ago4 ,) a totally molt5 int]ior & cont9u+ l>ge-scale volcanism1 ,io has _h an opportunity to ?or\ghly sort out its composition4 ,9 ! process x w\ld h lo/ all ! volatile gases su* z wat] & c>bon dioxide1 expla9+ :y ,io n[ has no appreciable atmosph]e 9 spite ( ! outp\r+ ( mat]ial f ! int]ior4 ,9 addition1 mo/ ( ! sulfur f ! int]ior c\ld h ris5 to ! surface1 :]e x w\ld be con/antly recycl$ ?r\gh volcanic activity4 ,! pres5ce ( l>ge am\nts ( sulfur on ! surface may help expla9 ! extraord9>y nature ( ! ,io volcanoes4 ,"o model consid]$ = ! satellite po/ulates t x is cov]$ by a sea ( liquid sulfur sev]al kilomet]s deep1 ) a cru/ ( solid sulfur &1 bel[ ! surface1 liquid sulfur dioxide4 ,calculations by ,sue ,kieff] ( ! ,u4,s4 ,geological ,survey & o!rs indicate t ! expansion ( ! sulfur dioxide 9 su* a model c expla9 ! obs]v$ eruption velocities ( up to a kilomet] p] second4 ,! volcanic plumes on ,io appe> to be made prim>ily ( sulfur & sulfur dioxide4 ,bo? are molt5 z !y em]ge f ! v5t1 b !y quickly cool z ! plume rises #ajj or m kilomet]s into ! ne> vacuum ( space4 ,unlike t]re/rial volcanoes1 !re is almo/ no gas 9 ! plumes4 ,x requires ab\t half an h\r = ! f9e p>ticles ( solidifi$ sulfur & sulfur dioxide sn[ to fall back to ! surface1 :]e !y =m ! colorful r+s t m>k ! major eruptive sites4 ,almo/ all ! r\ghly #ajj #jjj tons ( mat]ial erupt$ ea* second by ! ,io volcanoes sn[s back to ! surface4 ,b app>5tly a "p--p]haps #aj tons p] second--escapes f ,io & is captur$ by ! ,jovian magnetosph]e4 ,ano!r "p contributes to an ionosph]e--a t5u\s atmosph]e ( electrons & ions--t surr\nds ,io4 ,! injection ( sev]al tons ( p>ticles ea* second into ! magnetosph]e has dramatic consequ5ces t c be se5 ev5 f ,e>?4 ,illu/ration3 ,direct evid5ce ( an atmosph]e on ,io 0 obta9$ dur+ ! ,voyag] #a flyby by ! ,,iris4 ,9 ! region ne> ! volcano ,loki & its associat$ 8lava lake10 infr>$ spectra cle>ly %[$ ! signature ( sulfur dioxide gas4 ,x is n kn[n :e!r ?is gas 0 a tempor>y feature associat$ ) ! eruption ( ,loki or if x might be pres5t on ,io m g5]ally4 ,o!r evid5ce1 h[ev]1 po9ts to ! sulfur dioxide atmosph]e z a transi5t feature4 ,a small am\nt ( ! sulfur dioxide escapes & is brok5 ap>t by sunlight to provide ! oxyg5 & sulfur ions obs]v$ 9 ! ,io torus4 ,sulfur dioxide gas cl\d ,plume -#bce ,f ,hot surface areas 7#de ,f7 ,! ,io ,torus ,surr\nd+ ,jupit] at ! di/ance ( ,io is a donut-%ap$ volume1 or torus1 ( plasma t orig9ates at ! satellite4 ,at fir/1 ! atoms escap+ f ,io exp& outw>d z a gas1 b soon !y are /ripp$ ( electrons & become electrically *>g$4 ,"s ( ^! gases1 su* z sulfur dioxide1 app>5tly orig9ate 9 ! l>ge volcanic eruptions2 o!r1 su* z ! sodium cl\d be+ /udi$ ) ,e>?-bas$ telescopes1 result f sputt]+ ( surface mat]ials by en]getic p>ticles 9 ! magnetosph]e4 ,aft] !y are ioniz$ by ! loss ( "o or m electrons1 ! atoms are caught by ! sp9n+ magnetic field ( ,jupit] & become a "p ( :at is call$ a co-rotat+ plasma1 sp9n+ at #gd kilomet]s p] second ) ! same t5-h\r p]iod z ,jupit] itself4 ,! ,io torus 0 easily detect$ on ,voyag] by ! ultraviolet spectromet]1 ev5 f a di/ance ( #aej million kilomet]s4 ,! /ronge/ ultraviolet radiation comes f twice-ioniz$ sulfur 7atoms t h lo/ two electrons7 7,s ,,iii71 emitt+ a wavel5g? ( #fi nanomet]s or ab\t "o-eigh? ! wavel5g? ( visible light4 ,! spectromet] also detect$ gl[s f atoms ( triply ioniz$ sulfur 7,s ,,iv7 & twice-ioniz$ oxyg5 7,o ,,iii74 ,illu/ration3 ,at ! "t ( ! ,voyag] #a enc\nt]1 ! mo/ abundant heavy ions 9 ! ,jovian magnetosph]e 7 sulfur & oxyg54 ,multiply ioniz$ sulfur & oxyg5 bo? emit /rongly 9 ! ultraviolet1 :]e !y c\ld be obs]v$ by ! ultraviolet spectromet]4 ,?is spectrum ( ! ,io torus regi/]s ! trem5d\s am\nt ( ultraviolet en]gy 7ab\t a million million watts7 be+ radiat$4 ,to emit s /rongly1 ! temp]atures 9 ! torus mu/ be ne> #ajj #jjj ,k4 ,illu/ration3 ,direct measurem5t ( ! heavy ions associat$ ) ! ,io torus 7 made by ! ,voyag] #a ,,lecp in/rum5t4 ,"h ! am\nts ( v>i\s elem5ts are %[n = two cases3 ! ,jovian inn] magnetosph]e 7solid l9e7 & a typical sol> ev5t4 ,bo? ! ,jovian & ! sol> p>ticles h be5 scal$ to %[ simil> am\nts ( oxyg51 b ! sol> p>ticles are also ri* 9 c>bon & iron1 :]eas ,jupit] has a great deal ( sulfur4 ,evid5ce su* z ?is demon/rates t ! sulfur does n come f ! ,sun2 r1 ! sulfur & mo/ ( ! oxyg5 appe> to be ! product ( ! ,io sulfur dioxide volcanic eruptions4 ,scans across ! torus %[$ t x _h a ?ickness ( #a4j ,r,j & 0 c5t]$ at a di/ance ( #e4i ,r,j f ,jupit]4 ,! torus is c5t]$ on ! magnetic1 r ?an ! rotational1 equator ( ! planet4 ,to produce ! int5se gl[ obs]v$1 ! electron temp]atures 9 ! torus mu/ be #ajj #jjj ,k1 ) an electron d5sity ( ab\t #ajjj p] cubic c5timet]4 ,! brightness 9 ! ultraviolet corresponds to a radiat$ p[] ( m ?an a million million 7#aj7 watts4 ,?is enorm\s am\nt ( en]gy mu/ be cont9u\sly suppli$ by ! magnetosph]e4 ,! ultraviolet emissions f ! ,io torus se5 by ,voyag] 7 dramatically diff]5t f ^? se5 9 #aigc & #aigd ) ! simpl] ultraviolet in/rum5t on bo>d ,pione]s #aj & #aa4 ,^! *anges correspond to m ?an a factor ( #aj 9 brightness4 ,z not$ by ! ,voyag] ,team1 8,because ( ! rem>kable diff]5ces we conclude t ! ,jupit]-,io environm5t has *ang$ significantly s9ce ,decemb] #aigc4 ,! obs]v$ diff]5ces are s spectacul>ly l>ge t ?is conclusion does n dep5d on a detail$ comp>ison ( ! two in/rum5ts1 _! calibrations1 or ! obs]v+ geometry40 ,! reason = ?is *ange1 or ! degree to :i* x reflects a l>ge-scale v>iation 9 ! volcanic activity ( ,io1 is "o ( ! major que/ions aris+ f ! ,voyag] mission4 ,! ,io torus c also be obs]v$ f ! gr\nd4 ,9 #aigf1 spectra %[$ ! gl[ ( s+ly ioniz$ sulfur 7,s ,,ii71 & 9 #aigi s+ly ioniz$ oxyg5 7,o ,,ii7 0 detect$4 ,! obs]vations ( ,s ,,ii & ,o ,,ii are p>ticul>ly int]e/+ because !y provide a measure ( ! d5sity & temp]ature ( ! plasma4 ,9 ,april #aigi1 betwe5 ! two ,voyag] flybys1 ,c>l ,pil*] ( ! ,univ]sity ( ,hawaii succe$$ 9 obta9+ a telescopic image ( ! torus 9 ! light ( ,s ,,ii4 ,he measur$ ne>ly ! same r+ diamet] 7#e4c-e4g ,r,j7 z _h ,voyag]2 int]e/+ly1 bo? agree t ! sulfur torus is c5t]$ slightly inside ! orbit ( ,io 7#f4j ,r,j74 ,illu/ration3 ,! emission ( light f sulfur ions 9 ! ,io torus is s /rong x c be measur$ f ! ,e>?4 ,9 ^! pictures1 ,univ]sity ( ,hawaii a/ronom] ,c>l ,pil*] photograph$ ! torus 9 ! light ( ioniz$ sulfur on ! night ( ,april #i1 #aigi4 ,z ! planet rotates1 ! torus is se5 fir/ p>tly op5$1 !n edge-on1 & aga9 op5$ 9 ! opposite direction4 ,! d>k b& on ! "r ( ea* image is due to light f ,jupit] scatt]$ 9 ! telescope1 z %[n 9 ! bottom picture1 :i* conta9s ! scatt]$ light only4 ,direct measurem5ts ( ! torus 7 made f ,voyag] #a z ! spacecraft pass$ twice ?r\gh ?is region1 once inb\nd & once outb\nd4 ,! l[ en]gy *>g$ p>ticle in/rum5t & ! cosmic ray in/rum5t bo? det]m9$ t ! composition ( ! ions 9 ! ,io torus 0 prim>ily sulfur & oxyg54 ,ioniz$ sodium 0 also obs]v$4 ,= sev]al ye>s1 gr\nd-bas$ telescope obs]vations _h reveal$ a cl\d ( neutral sodium ar\nd ,io2 ! ,voyag] in/rum5ts pick$ up ^! atoms aft] !y _h ea* lo/ an electron & become trapp$ 9 ! magnetosph]e4 ,^! in/rum5ts also d]iv$ ! electron & ion d5sity 7ab\t #ajjj p] cubic c5timet]7 & confirm$ t ! ions 7 co-rotat+ ) ! inn] magnetosph]e4 ,ano!r ,io-associat$ ph5om5on se>*$ = by ,voyag] 0 ! ,io flux tube4 ,z a conductor mov+ ?r\gh ! ,jovian magnetic field1 ,io g5]ates an electric curr5t1 e/imat$ to h a /r5g? ( ab\t #aj million 7#aj7 amp]es & a p[] ( ! ord] ( a million million 7#aj7 watts4 ,! region ( space ?r\gh :i* ?is curr5t fl[s f ! satellite to ,jupit] is call$ ! flux tube4 ,voyag] #a 0 t>get$ to fly ?r\gh ! ,io flux tube4 ,?is 0 an important decision1 s9ce ?is option preclud$ ! possibility ( obta9+ occultations by ei!r ,io or ,ganym$e4 ,! ev5t 0 to take place on ,m>* #e1 j aft] close/ approa* to ,io4 ,! effects ( ! flux tube 7 cle>ly obs]v$ by ! magnetomet]1 ! ,,lecp in/rum5t1 & o!r p>ticle & field in/rum5ts2 h[ev]1 subsequ5t analysis indicat$ t ! spacecraft _h n p5etrat$ ! region ( maximum curr5t fl[2 x probably miss$ ! c5t] ( ! flux tube betwe5 #ejjj & #aj #jjj kilomet]s4 ,! flux tube is n ! only connection betwe5 ,io & ,jupit]4 ,radio emissions f ! atmosph]e are trigg]$ by ,io's orbital position1 & ! aurorae t illum9ate ,jupit]'s pol> regions are ! result ( *>g$ p>ticles fall+ into ! planet f ! ,io torus4 ,o!r *>g$ p>ticles c occasionally escape outw>d & be detect$ z f> away z ,e>?4 ,io is unque/ionably a rem>kable _w4 ,! only planet>y body kn[n to be geologically m active ?an ! ,e>?1 x provides _m extreme examples to te/ ! !ories ( geosci5ti/s4 ,its intimate int]connections ) ! ,jovian magnetosph]e & ! planet itself provide a unify+ !me to ! complex processes tak+ place 9 ! inn] p>ts ( ! ,jovian sy/em4 ,illu/ration3 ,! ,galileo ,probe w make a fi]y entry into ! ,jovian atmosph]e1 c>ry+ a payload ( sci5tific in/rum5ts = ! fir/ direct sampl+ ( ! atmosph]e ( a giant planet4 ,%[n "h is ! mom5t1 at a pressure level ( ab\t #j4a b>1 :5 ! p>a*ute is deploy$ & ! /ill-gl[+ heat%ield drops free f ! ,probe4 ,,*apt] #aj ,,return ,,to ,,jupit] ,a ,successor to ,voyag] ,! spectacul> discov]ies ( ! ,voyag]s did n exhau/ our int]e/ 9 ! ,jovian sy/em4 ,bo? ! giant planet & its sy/em ( satellites w almo/ c]ta9ly play a c5tral role 9 any future program ( sol> sy/em exploration & rese>*4 ,?us1 ev5 z ! two ,voyag] spacecraft direct$ _! att5tion fur!r outw>d t[>d ,saturn1 ,,nasa _h begun developm5t ( ! next ,jupit] mission1 nam$ ,galileo4 ,galileo is an ambiti\s1 multiple-vehicle planet>y mission4 ,x has two major int]lock+ elem5ts3 a probe to be plac$ 9 ! atmosph]e ( ,jupit] & an orbit] to explore ,jupit]1 its satellites1 & its magnetosph]e4 ,by us+ individual satellite flybys to alt] its orbit1 ! ,galileo spacecraft c c>ry out a satellite 8t\r0 consi/+ ( flybys ( ! ,galilean satellites at diff]5t geometries & a deep p5etration into ! magnetosph]e 9 ! unexplor$ region ( space beh9d ,jupit]4 ,bo? an atmosph]ic probe = ! planet & a long-liv$ orbit] to /udy ! satellites & magnetosph]e are logical successors to ,voyag]4 ,9 #aigd1 ?ree ye>s be=e ,voyag] laun*1 ! ,space ,sci5ce ,bo>d ( ! ,national ,academy ( ,sci5ces 0 already emphasiz+ ! sci5tific advantages ( bo? ( ^! approa*es4 ,9 sugge/+ goals = #aige-aihe1 ! ,bo>d wrote1 8,we recomm5d t a significant ef=t 9 ! ,,nasa planet>y program ov] ! next decade be devot$ t[>d ! out] sol> sy/em4 ,jupit] is ! prim>y object ( out] sol> sy/em exploration40 ,look+ at specific mission goals1 ! ,bo>d recomm5d$ t 8! prim>y objectives 9 ! exploration ( ,jupit] & its satellites = ! p]iod #aige-aihe 9 ord] ( importance are 7#a7 det]m9ation ( ! *emical composition & physical /ate ( its atmosph]e1 7#b7 ! *emical composition & physical /ate ( ! satellites1 & 7#c7 ! topology & behavior ( ! magnetic field & ! en]getic p>ticle fluxes4 ,9 ord] to c>ry out ?is program1 x w be necess>y to utilize orbit+ spacecraft & probe-deliv]+ spacecraft40 ,9 ! same p]iod ,,nasa c>ri$ out /udies ( two possible orbit] & probe missions4 ,work+ ?r\gh ! ,ames ,rese>* ,c5t]1 a sci5tific panel *air$ by ,james ,van ,all5 explor$ ! adaptation ( ! ,pione] #aj & #aa sp9n+ spacecraft to c>ry a probe to ,jupit] & to c>ry out an orbit] mission emphasiz+ magnetosph]ic /udies4 ,william ,b4 ,hubb>d ( ! ,univ]sity ( ,arizona *air$ a ,,jpl-bas$ panel inve/igat+ ! use ( a ,m>9]-class fully /abiliz$ spacecraft simil> to ,voyag] to c>ry out a satellite-ori5t$ orbit] mission4 ,9 #aigf ^! concepts 7 comb9$ 9 a /udy1 aga9 *air$ by ,dr4 ,van ,all51 ( a ,voyag]-type orbit] ) probe-c>ry+ capability4 ,?is mission concept 0 giv5 ! "n ,,jop1 = ,jupit] ,orbit] ,probe1 & lead responsibility 0 assign$ by ,,nasa to ,,jpl1 ) ,ames c>ry+ out ! design ( ! probe4 ,9 #aigg1 z ,voyag] activity 0 build+ t[>d autumn laun*1 a /ruggle 0 und]way 9 ,wa%+ton to obta9 approval = ! new ,jupit] orbit] & probe mission4 ,budget+ au?ority 0 reque/$ 9 ! ,presid5t's ,fiscal ,ye> #aigh budget1 b only aft] ext5sive te/imony & sev]al ,congressional votes 0 ! mission approv$4 ,! (ficial new />t = ,,jop1 soon to be r5am$ ,galileo1 0 set = ,july #a1 #aigg1 & ! sci5tific inve/igators & _! in/rum5ts 7 select$ 9 ,augu/4 ,at ,,jpl1 _m memb]s ( ! ,voyag] ,team made a smoo? transition to ! ,galileo ,project4 ,mu* ( ! k t _h gone into ! design ( ! ,voyag] spacecraft & its subsy/ems 0 n[ incorporat$ into ,galileo4 ,simil>ly1 at ,ames ! k ga9$ f ! design ( ! ,pione] ,v5us probes1 :i* 7 laun*$ to ,v5us 9 #aigh1 a ye> aft] ,voyag] laun*1 0 appli$ to design ( a ,jupit] probe4 ,among ! individuals :o br\ght _! ,voyag] exp]i5ce to ,galileo 7 ,john ,casani1 :o left ! position ( ,voyag] ,project ,manag] to become ,galileo ,project ,manag]1 & ,torr5ce ,johnson ( ! ,voyag] ,imag+ ,team1 :o became ,galileo ,project ,sci5ti/4 ,! ,sci5tific ,capability ( ,galileo ,! inve/igations ( ,jupit] & its sy/em plann$ = ! ,galileo ,project repres5t$ sub/antial advances ov] ^? c>ri$ out by ,voyag]4 ,9 "p1 ?is 0 ! result ( new spacecraft capabilities1 p>ticul>ly ! atmosph]ic entry probe4 ,x also repres5t$ increas+ sophi/ication 9 sci5tific in/rum5tation ov] ! sev5-ye> int]val betwe5 ! selection ( ! payloads = ! two missions4 ,! ma9 emphasis 9 ! /udy ( ,jupit] itself is on direct measurem5ts ) ! ,probe4 ,= ! fir/ "t x w be possible to exam9e directly ! atmosph]e ( a giant planet4 ,by measur+ ! temp]ature & pressure z x desc5ds ?r\gh ! cl\ds1 ! ,probe c det]m9e ! /ructure ( ! atmosph]e ) mu* high] precision ?an c\ld ev] be obta9$ f remote obs]vations4 ,! /ructure1 9 turn1 provides in=mation on dynamics--! circulation & heat balance ( ! ,jovian atmosph]e4 ,9 addition1 ! ,probe c make direct measurem5ts ( ! composition ( ! gases1 ) s5sitivity 9 "s cases to quantities z l[ z a few p>ts p] billion4 ,9 addition to ! elem5tal abundance1 ! am\nt ( diff]5t isotopes c also be measur$4 ,direct /udies ( ! cl\ds ( ,jupit] c be made f ! ,galileo ,probe4 ,) a device call$ a nephelomet] 7lit]ally1 cl\d-met]71 ! sizes & compositions ( individual a]osol p>ticles w be det]m9$4 ,an infr>$ in/rum5t w det]m9e ! temp]atures ( ! cl\d lay]s & measure ! am\nts ( sunlight deposit$ 9 diff]5t regions ( ! atmosph]e4 ,ano!r in/rum5t w se>* = lightn+2 x has ! ability to detect bo? ! fla% ( light & ! radio /atic g5]at$ by ea* bolt4 ,additional /udies ( ! atmosph]e1 simil> to ^? ( ,voyag]1 c be c>ri$ out f ! ,galileo ,orbit]4 ,television pictures1 ultraviolet & infr>$ spectra1 & measurem5ts ( ! pol>ization ( reflect$ light w all be obta9$ ) ! same scan plat=m in/rum5ts t are us$ to /udy ! surfaces ( ! satellites4 ,a full batt]y ( fields & p>ticles in/rum5ts is plann$ = ! ,galileo ,orbit]4 ,_m ( ^! are direct desc5dants ( ,voyag] in/rum5ts4 ,9 g5]al1 _! capabilities h be5 improv$1 p>ticul>ly _! ability to det]m9e ! composition ( *>g$ p>ticles4 ,!re is a /eady progression f ,pione] to ,voyag] to ,galileo3 ,! e>ly measurem5ts 7 conc5trat$ on p>ticle en]gies1 b m sophi/icat$ in/rum5ts yield ! composition ( ! ions & ! details ( _! motion4 ,_m ( ! advances expect$ f ,galileo 9 magnetosph]ic /udies result f ! ,orbit]'s ability to explore _m p>ts ( ! environm5t ( ,jupit]4 ,! ,pione] & ,voyag] spacecraft made s+le cuts ?r\gh ! magnetosph]e1 & (t5 x 0 difficult to di/+ui% temporal f spatial effects4 ,galileo w repeat$ly sw+ ar\nd ,jupit]1 sampl+ conditions at _m di/ances f ! planet ov] a "t span ( two ye>s or m4 ,9 addition1 x is plann$ to adju/ ! orbit ( ,galileo to sw+ out into ! magnetotail1 ! turbul5t region ( ! magnetosph]e t /ret*es 8d[nw9d0 f ,jupit] = hundr$s ( ,jupit] radii4 ,no flybys c rea* ! magnetotail2 an orbit+ spacecraft is requir$4 ,! ,galilean satellites naturally w be a prim>y focus ( ,galileo sci5ce1 p>ticul>ly aft] ,voyag]4 ,x is plann$ to h z _m z a doz5 individual enc\nt]s1 mo/ ( !m at mu* clos] range ?an ! ,voyag] flybys4 ,to take advantage ( ^! opportunities1 ! ,galileo scan plat=m w c>ry two new remote s5s+ sy/ems4 ,illu/ration3 ,! ,orbit] section ( ! ,galileo spacecraft w c>ry bo? remote s5s+ & direct measur+ in/rum5ts = ! /udy ( ,jupit]1 its satellites1 & its magnetosph]e4 ,sev]al remote s5s+ in/rum5ts--an imag]y sy/em1 a ne> infr>$ mapp+ spectromet]1 an ultraviolet spectromet]1 & a photopol>imet]_/radiomet]--w be m\nt$ on a scan plat=m4 ,! p>ticles & fields in/rum5ts w be on a sp9n+ section ( ! spacecraft4 ,! ,orbit] is expect$ to op]ate = at lea/ two ye>s ar\nd ,jupit]1 provid+ "o close flyby ( ,io & sev]al ea* ( ,europa1 ,ganym$e1 & ,calli/o4 ,p-#bjggb ,in/ead ( ! vidicon television cam]a on ,voyag]1 ,galileo imag+ w be done ) a new solid-/ate detector call$ a *>g$ c\pl$ device 7,,ccd74 ,! ,,ccd has a wid] spectral response & great] photometric accuracy4 ,9 addition1 its increas$ s5sitivity p]mits %ort] exposures1 s t ev5 on v close flybys ! pictures w n be blurr$ by spacecraft motion4 ,sub/antial cov]age at a resolution ( #ajj met]s %\ld be possible1 comp>$ to ,voyag]'s be/ resolution ( #a kilomet] = ,io & #d kilomet]s = ,europa4 ,illu/ration3 ,galileo w be laun*$ by ! ,space ,%uttle1 ! c5tral elem5t ( ! new ,,nasa ,space ,transportation ,sy/em4 ,toge!r ) its upp] /age laun* rocket1 ,galileo w be plac$ into ,e>?'s orbit 9 ! l>ge ,%uttle bay1 ab\t #bj met]s long & #e met]s 9 diamet]4 ,aft] releas+ ,galileo1 ! ,%uttle w be pilot$ back to a l&+ at ,cape ,canav]al1 to be us$ aga9 = _m future flights4 #e-gh-bceii ,illu/ration3 ,! ,space ,%uttle & ! ,in]tial ,upp] ,/age ( ,galileo z !y w appe> 9 ,e>? orbit4 ,! upp] /age has be5 releas$ f ! ,%uttle bay & is be+ prep>$ = laun* to ,jupit]4 ,to det]m9e ! composition ( satellite surface mat]ials1 ,galileo w also c>ry a ne>-infr>$ mapp+ spectromet] 7,,nims74 ,?is in/rum5t w obta9 measurem5ts ov] ! visible & infr>$ spectra ( areas z small z #aj kilomet]s across4 ,) ,,nims1 x %\ld be possible to inve/igate ! composition ( individual features z small z ! volcanic cald]as on ,io or ! ejecta blankets ( ,ganym$e's crat]s4 ,galileo ,mission ,design ,! ,galileo ,orbit] & ,probe are to be laun*$ ) ,,nasa's new ,space ,%uttle & ,in]tial ,upp] ,/age4 ,to c>ry ! maximum possible payload to ,jupit]1 a close flyby ( ,m>s is plann$ en r\te4 ,! gravitational field ( ,m>s w give a boo/ to ,galileo1 j z t ( ,jupit] 0 us$ by ,voyag] to sw+ on to ,saturn4 ,! exact laun* date & trajectory = ,galileo h n yet be5 specifi$1 b if all goes well1 ! ,orbit] spacecraft w approa* ,jupit] f ! dawn side ( ! planet sometime 9 ! mid-#aihjs4 ,x w n be mov+ z fa/ z ,voyag]1 s9ce x mu/ be plac$ into orbit ar\nd ,jupit] r ?an fla%+ pa/ on its way to ! out] sol> sy/em4 ,on its initial trajectory1 ,galileo w probably come )9 #e ,r,j ( ,jupit]1 slightly clos] ?an ,voyag] #a4 ,at ?is "t x w fire its rocket eng9es 7suppli$ by ! ,f$]al ,republic ( ,g]many 9 a coop]ative program ) ,,nasa7 to %$ excess spe$ & let itself be captur$ by ,jupit]'s gravity4 ,! fir/ pass w also be ! "t = a close flyby ( ,io4 ,illu/ration3 ,! mo/ critical p]iod ( ! ,galileo flight w be ! ,probe entry at ,jupit]4 ,! ,probe mu/ /rike ! atmosph]e at precisely ! correct angle & spe$ to be sl[$ d[n )\t be+ de/roy$4 ,at a pressure level ( ab\t #j4a b> ! rapid decel]ation p]iod ends & ! heat %ield is releas$4 ,a p>a*ute is deploy$ to sl[ ! desc5t fur!r1 & ! ,probe !n has a p]iod ( ne>ly an h\r to /udy ! atmosph]e & cl\ds ( ,jupit]4 ,! ,probe mission ends :5 its batt]ies run d[n or :5 x is cru%$ by ! pressure ( ! ,jovian atmosph]e ne> ! #bj-;b> level1 :i*ev] comes fir/4 ,,sl#gh-ede7c7 ,,galileo ,,probe ,,sci5ce ,,inve/igations ,probe ,sci5ti/3 ,l4 ,coll91 ,,nasa ,ames ,inve/igation ,pr9cipal ,inve/igator ,prim>y ,objectives ,atmosph]ic /ructure ,a4 ,seiff1 ,,nasa ,ames ,measure temp]ature1 d5sity1 pressure1 & molecul> weight to det]m9e ! /ructure ( ,jupit]'s atmosph]e4 ,neutral mass ,h4 ,b4 ,neimann1 ,,nasa ,measure ! spectromet] ,godd>d composition ( ! gases 9 ,jupit]'s atmosph]e & ! v>iations at diff]5t levels 9 ! atmosph]e4 ,helium abundance ,u4 von ,zahn1 ,bonn ,u4 ,measure ) high int]f]omet] 7,g]many7 accuracy ! ratio ( hydrog5 to helium 9 ,jupit]'s atmosph]e4 ,nephelomet] ,b4 ,rag5t1 ,,nasa ,ames ,det]m9e ! sizes ( cl\d p>ticles & ! location ( cl\d lay]s 9 ,jupit]'s atmosph]e4 ,net flux radiomet] ,r4 ,w4 ,boese1 ,,nasa ,ames ,measure en]gy be+ radiat$ f ,jupit] & ! ,sun1 at diff]5t levels 9 ,jupit]'s atmosph]e4 ,lightn+ & radio ,l4 ,j4 ,lanz]otti1 ,measure lightn+ emission ,bell ,labs fla%es 9 ,jupit]'s atmosph]e1 f ! light & radio transmissions f ^? fla%es4 ,en]getic p>ticles ,h4 ,m4 ,fis*]1 ,u4 ,measure en]getic ,kiel 7,g]many7 electrons & protons 9 ! inn] regions ( ! ,jovian radiation belts & det]m9e _! spatial di/ributions4 ,because ( ! int5se radiation environm5t1 ! ,galileo ,orbit] w n be able to sp5d mu* "t 9 ! inn] magnetosph]e1 ne> ! orbit ( ,io4 ,to d s w\ld risk damage to ! spacecraft electronics & a premature end to ! mission4 ,additional ?ru/] fir+ dur+ ! fir/ orbit c be us$ to raise ! p]iapse to #aj ,r,j or great]4 ,no m close passes by ,io w be possible1 b /udies ( ?is satellite c be made on ea* subsequ5t orbit ) imag+ resolutions ( ab\t #aj kilomet]s1 suffici5t to see details ( ! volcanic eruptions & monitor volcano-associat$ *anges 9 ! surface4 ,at ea* subsequ5t orbit1 ,galileo w be programm$ = a close flyby ( "o ( ! o!r satellites4 ,sev]al passes ea* ( ,calli/o1 ,ganym$e1 & ,europa %\ld be possible4 ,! satellite t\r does n ne$ to be fully plann$ 9 advance2 by adju/+ ! spacecraft trajectory ) small bur/s ( ! ?ru/] motors1 navigation eng9e]s c modify ! orbit to p]mit adaptation to sci5tific ne$s4 ,z ! ,orbit] mission progresses1 ! spacecraft w also sample _m p>ts ( ! magnetosph]e1 includ+ "o long excursion1 at lea/ #aej ,r,j1 into ! magnetotail4 ,! total duration ( ! ,orbit] mission is plann$ to be at lea/ #bj mon?s4 ,additions to ! basic mission are possible if ! spacecraft rema9s heal?y & fuel res]ves are adequate4 ,9 contra/1 ! ,galileo ,probe mission la/s only a few h\rs4 ,z ! ,probe approa*es ! atmosph]e ( ,jupit] at ! awesome spe$ ( #bf kilomet]s p] second1 x w be trav]s+ a region ( space nev] be=e explor$4 ,an en]getic p>ticle detector w inve/igate ! inn]mo/ magnetosph]e be=e ! entry beg9s4 ,!n1 )9 a p]iod ( j a few m9utes1 friction ) ! upp] atmosph]e mu/ dissipate ! ,probe en]gy until x is fall+ g5tly 9 ! ,jovian air4 ,jupit]1 be+ ! l>ge/ planet1 pres5ts ! mo/ *all5g+ atmosph]ic entry mission ev] und]tak5 by ,,nasa4 ,! design ( ! ,galileo ,probe calls = a massive heat %ield to protect ! in/rum5ts dur+ ! high-spe$ entry phase4 ,aft] ! ,probe has sl[$ to subsonic velocities1 a p>a*ute w be deploy$1 & ! heat %ield1 hav+ done its job1 w be dropp$ free4 ,,galileo ,,orbit] ,,sci5ce ,,inve/igations ,project ,sci5ti/3 ,t4 ,v4 ,johnson1 ,,jpl ,inve/igation ,pr9cipal ,inve/igator ,prim>y ,objectives ,solid /ate imag+ ,m4 ,j4 ,s4 ,belton1 ,kitt ,provide images ( ,peak ,obs]vatory ,jupit]'s 7,team ,lead]7 atmosph]e & its satellites2 /udy atmosph]ic /ructure & dynamics on ,jupit]2 inve/igate ! composition & geology ( ! satellite surfaces2 /udy ! active volcanic processes on ,io4 ,ultraviolet spectromet] ,c4 ,w4 ,hord1 ,u4 ,/udy composition & ,colorado /ructure ( ! upp] atmosph]es ( ,jupit] & its satellites4 ,ne>-infr>$ mapp+ ,r4 ,w4 ,c>lson1 ,,jpl ,provide spectral spectromet] 7,,nims7 images & reflect$ sunlight spectra ( ,jupit]'s satellites1 indicat+ ! composition ( _! surfaces2 measure reflect$ sunlight & !rmal emission f ,jupit]'s atmosph]e to /udy composition1 cl\d /ructure1 & temp]ature pr(iles2 monitor hot spots on ,io4 ,photopol>imet]_/radiomet] ,j4 ,e4 ,hans51 ,,nasa ,measure temp]ature ,godd>d pr(iles & en]gy balance ( ,jupit]'s atmosph]e2 measure ,jupit]'s cl\d *>act]i/ics & composition4 ,magnetomet] ,m4 ,g4 ,kivelson1 ,,uc ,measure magnetic ,los ,angeles fields & ! ways !y *ange ne> ,jupit] & its satellites2 measure v>iations caus$ by ! satellites int]act+ ) ,jupit]'s field4 ,plasma p>ticles ,l4 ,a4 ,frank1 ,u4 ,i[a ,provide in=mation on l[-en]gy p>ticles & cl\ds ( ioniz$ gas 9 ! magnetosph]e4 ,en]getic p>ticles ,d4 ,j4 ,williams1 ,,noaa ,measure composition1 ,space ,environm5t di/ribution1 & ,lab en]gy spectra ( high-en]gy p>ticles trapp$ 9 ,jupit]'s magnetosph]e4 ,plasma waves ,d4 ,a4 ,gurnett1 ,u4 ,i[a ,inve/igate waves g5]at$ inside ,jupit]'s magnetosph]e & waves radiat$ by possible lightn+ dis*>ges 9 ! atmosph]e4 ,du/ detection ,e4 ,grn1 ,det]m9e size1 ,max-,planck-,in/itut spe$1 & *>ge 7,g]many7 ( small p>ticles su* z micrometeorites ne> ,jupit] & its satellites4 ,cele/ial me*anics ,j4 ,d4 ,&]son1 ,,jpl ,use ! track+ data 7,team ,lead]7 to measure ! gravity fields ( ,jupit] & its satellites2 se>* = gravity waves propagat+ ?r\gh int]/ell> space4 ,radio propagation ,h4 ,t4 ,h[>d1 ,use radio signals ,/an=d ,u4 7,team f ! ,orbit] ,lead]7 & ,probe to /udy ! /ructure ( ! atmosph]es & ionosph]es ( ,jupit] & its satellites4 ,int]discipl9>y ,f4 ,p4 ,fanale 7,,jpl71 ,p4 ,j4 ,gi]as* 7,cornell ,sci5ti/s3 ,u471 ,d4 ,m4 ,hunt5 7,u4 ,arizona71 ,h4 ,masursky 7,u4,s4 ,geological ,survey71 ,m4 ,b4 ,mc,elroy 7,h>v>d ,u471 ,d4 ,morrison 7,u4 ,hawaii71 ,g4 ,s4 ,orton 7,,jpl71 ,t4 ,ow5 7,,su ,new ,york71 ,j4 ,b4 ,pollack 7,,nasa ,ames71 ,c4 ,t4 ,russell 7,,uc ,los ,angeles71 ,c4 ,sagan 7,cornell ,u471 ,f4 ,l4 ,sc>f 7,,trw71 ,g4 ,s*ub]t 7,,uc ,los ,angeles71 ,c4 ,p4 ,sonett 7,u4 ,arizona71 ,j4 ,a4 ,van ,all5 7,u4 ,i[a74 ,! ,probe w sp5d ne>ly an h\r desc5d+ f a pressure level ( ab\t #j4a b>1 :]e ! heat %ield is jettison$1 to a dep? ( #aj-bj b>s4 ,dur+ ?is "t x w make mo/ ( its sci5tific measurem5ts1 relay+ !m back to ,e>? via ! ,probe c>ri]4 ,design]s expect ! ,probe to s9k ?r\gh regions ( ammonia cl\ds1 ammonium hydrosulfide cl\ds1 & ice & wat] cl\ds dur+ ?is h\r4 ,by ! "t x has desc5d$ bel[ ! wat] cl\ds1 ! increas+ pressure w exce$ ! /r5g? ( "s ,probe compon5ts4 ,eng9e]s expect ! ,probe to h complet$ its mission1 exhau/$ its batt]y p[]1 & be5 cru%$ by ! atmosph]ic pressure be=e ! #bj-;b> level is rea*$4 ,lifeless1 x w !n s9k on into ! ?ick1 hot l[] atmosph]e ( ,jupit]4 ,illu/ration3 ,dur+ its two ye>s 9 orbit1 ! ,galileo ,orbit] w c>ry out _m inve/igations ( ! planet1 ! ,galilean satellites1 & ! ,jovian magnetosph]e4 ,repeat$ close flybys ( ! satellites are us$ to modify & %ape ! orbit to provide additional flybys at an optimum view+ geometry4 ,initially1 ! orbit is a long loop t ext5ds 9 ! g5]al direction ( ! sunset side ( ,jupit]4 ,! orbit is !n contract$1 & ! enc\nt]s ) ! satellites rotate x beh9d ! planet = a long excursion into ! magnetotail late 9 ! t\r4 ,beyond ,galileo ,aft] ,galileo1 ! future _c be pr$ict$4 ,p]haps !re w no long] be a program ( planet>y exploration4 ,b if humanity /ill has ! vision to seek a future 9 ! />s1 !re w surely be o!r ,jupit] missions4 ,p]haps ! next mission w conc5trate on ,jupit] itself4 ,probes c\ld be built to )/& pressures z high z sev]al hundr$ b>s1 feel+ _! way deep into ! murky dep?s ( ! planet4 ,or a hot-air balloon c\ld be deploy$ f a probe to c>ry in/rum5ts = long-t]m /udies ( ! atmosph]e4 ,a numb] ( proposals h also be5 made = additional satellite missions1 includ+ orbit]s or l&]s = ,ganym$e & ,calli/o4 ,or p]haps x w be desirable to l& a vehicle on "o ( ! satellites & collect a sample & return x to ,e>? = laboratory analysis4 ,:atev] ! future holds1 x is cle> t ! ,pione] & ,voyag] missions blaz$ ! pa? to ,jupit] & beyond4 ,! little ,pione]s prov$ t x c\ld be done1 & ! ,voyag]s exp&$ _! vision1 explor+ & discov]+ new worlds m rem>kable & excit+ ?an anyone c\ld h imag9$4 ,,app5dix ,a ,,pictorial ,,maps ,,( ,,! ,,galilean ,,satellites ,^! maps 7 prep>$ = ! ,voyag] ,imag+ ,team by ! ,u4,s4 ,geological ,survey 9 coop]ation ) ! ,jet ,propulsion ,laboratory1 ,cali=nia ,in/itute ( ,te*nology & ! ,national ,a]onautics & ,space ,adm9i/ration4 ,copies are available f ,bran* ( ,di/ribution1 ,u4,s4 ,geological ,survey1 #abjj ,s\? ,eads ,/reet1 ,arl+ton1 ,,va #bbbjb1 & ,bran* ( ,di/ribution1 ,u4,s4 ,geological ,survey1 ,box #bebhf1 ,f$]al ,c5t]1 ,d5v]1 ,,co #hjbbe4 ,prelim9>y ,pictorial ,map ( ,calli/o ,atlas ( ,calli/o #a3be1jjj1jjj ,topographic ,s]ies ,jc #be,m #b,,rmn1 #aigi ,i-#abci ,?is map 0 compil$ f ,voyag] #a & #b pictures ( ,calli/o4 ,placem5t ( features is bas$ on pr$ict$ spacecraft trajectory data & is highly approximate4 ,! l9kage betwe5 ,voyag] #a & ,voyag] #b pictures is p>ticul>ly t5u\s4 ,placem5t errors z l>ge z #aj are probably common ?r\gh\t ! map1 & a few may be ev5 l>g]4 ,feature names 7 approv$ by ! ,int]national ,a/ronomical ,union 9 #aigi4 ,airbru% repres5tation is by ,p4 ,m4 ,bridges4 ,jc #be,m #b,,rmn3 ,abbreviation = 7,jupit]7 ,calli/o1 #a3be1jjj1jjj s]ies1 second edition1 %ad$ relief map1 ,r1 ) surface m>k+s1 ,m1 & feature names1 ,n4 ,illu/ration3 ,nor? pol> region2 ,s\? pol> region ,scale #a3ac #ihj #jjj at #ef latitude ,pol> /]eographic projection ,illu/ration3 ,calli/o ,scale #a3be #jjj #jjj at #j latitude ,m]cator projection ,prelim9>y ,pictorial ,map ( ,ganym$e ,atlas ( ,ganym$e #a3be1jjj1jjj ,topographic ,s]ies ,jg #be,m #b,,rmn1 #aigi ,i-#abdb ,?is map 0 compil$ f ,voyag] #a & #b pictures ( ,ganym$e4 ,placem5t ( features is bas$ on pr$ict$ spacecraft trajectory data & is highly approximate4 ,! l9kage betwe5 ,voyag] #a & ,voyag] #b pictures is p>ticul>ly t5u\s4 ,placem5t errors z l>ge z #aj are probably common ?r\gh\t ! map1 & a few may be ev5 l>g]4 ,a l>ge unresolv$ discrepancy exi/s 9 ! area b\nd$ by ! -#de & -#ee p>allels betwe5 #abj & #ahj longitude4 ,relative placem5t ( features is di/ort$ 9 t area4 ,feature names 7 approv$ by ! ,int]national ,a/ronomical ,union 9 #aigi4 ,airbru% repres5tation is by ,j4 ,l4 ,+e4 ,jg #be,m #b,,rmn3 ,abbreviation = 7,jupit]7 ,ganym$e1 #a3be1jjj1jjj s]ies1 second edition1 %ad$ relief map1 ,r1 ) surface m>k+s1 ,m1 & feature names1 ,n4 ,illu/ration3 ,nor? pol> region2 ,s\? pol> region ,scale #a3ac #ihj #jjj at #ef latitude ,pol> /]eographic projection ,illu/ration3 ,ganym$e ,scale #a3be #jjj #jjj at #j latitude ,m]cator projection ,prelim9>y ,pictorial ,map ( ,europa ,atlas ( ,europa #a3be1jjj1jjj ,topographic ,s]ies ,je #be,m #b,,rmn1 #aigi ,i-#abda ,?is map 0 compil$ f ,voyag] #a & #b pictures ( ,europa4 ,placem5t ( features is bas$ on pr$ict$ spacecraft trajectory data & is highly approximate4 ,feature names 7 approv$ by ! ,int]national ,a/ronomical ,union 9 #aigi4 ,airbru% repres5tation is by ,j4 ,l4 ,+e4 ,je #be,m #b,,rmn3 ,abbreviation = 7,jupit]7 ,europa1 #a3be1jjj1jjj s]ies1 second edition1 %ad$ relief map1 ,r1 ) surface m>k+s1 ,m1 & feature names1 ,n4 ,illu/ration3 ,nor? pol> region2 ,s\? pol> region ,scale #a3ac #ihj #jjj at #ef latitude ,pol> /]eographic projection ,illu/ration3 ,europa ,scale #a3be #jjj #jjj at #j latitude ,m]cator projection ,prelim9>y ,pictorial ,map ( ,io ,atlas ( ,io #a3be1jjj1jjj ,topographic ,s]ies ,ji #be,m #b,,rmn1 #aigi ,i-#abdj ,?is map 0 compil$ f ,voyag] #a & #b pictures ( ,io4 ,placem5t ( features is bas$ on prelim9>y control in=mation provid$ by ,m4 ,e4 ,davies ( ! ,r& ,corporation1 ,santa ,monica1 ,cali=nia1 & is probably accurate )9 #ej to #ajj km4 ,feature names 7 approv$ by ! ,int]national ,a/ronomical ,union 9 #aigi4 ,airbru% repres5tation is by ,p4 ,m4 ,bridges4 ,ji #be,m #b,,rmn3 ,abbreviation = 7,jupit]7 ,io1 #a3be1jjj1jjj s]ies1 second edition1 %ad$ relief map1 ,r1 ) surface m>k+s1 ,m1 & feature names1 ,n4 ,illu/ration3 ,nor? pol> region2 ,s\? pol> region ,scale #a3ac #ihj #jjj at #ef latitude ,pol> /]eographic projection ,illu/ration3 ,io ,scale #a3be #jjj #jjj at #j latitude ,m]cator projection ,,app5dix ,b ,,voyag] ,,sci5ce ,,teams ,imag+ ,sci5ce ,brad=d ,a4 ,smi?1 ,univ]sity ( ,arizona1 ,team ,lead] ,ge(frey ,a4 ,briggs1 ,,nasa ,headqu>t]s ,a4 ,f4 ,cook1 ,smi?sonian ,in/itution ,g4 ,e4 ,danielson1 ,jr41 ,cali=nia ,in/itute ( ,te*nology ,m]ton ,davies1 ,r& ,corp4 ,g4 ,e4 ,hunt1 ,univ]sity ,college1 ,london ,tobias ,ow51 ,/ate ,univ]sity ( ,new ,york ,c>l ,sagan1 ,cornell ,univ]sity ,lawr5ce ,sod]blom1 ,u4,s4 ,geological ,survey ,v4 ,e4 ,suomi1 ,univ]sity ( ,wiscons9 ,h>old ,masursky1 ,u4,s4 ,geological ,survey ,radio ,sci5ce ,von ,r4 ,e%leman1 ,/an=d ,univ]sity1 ,team ,lead] ,j4 ,d4 ,&]son1 ,jet ,propulsion ,laboratory ,t4 ,a4 ,cr(t1 ,/an=d ,rese>* ,in/itute ,gunn> ,l9dal1 ,jet ,propulsion ,laboratory ,g4 ,s4 ,levy1 ,jet ,propulsion ,laboratory ,g4 ,l4 ,tyl]1 ,/an=d ,univ]sity ,g4 ,e4 ,wood1 ,jet ,propulsion ,laboratory ,plasma ,wave ,fr$]ick ,l4 ,sc>f1 ,,trw ,sy/ems1 ,pr9cipal ,inve/igator ,d4 ,a4 ,gurnett1 ,univ]sity ( ,i[a ,infr>$ ,spectroscopy & ,radiometry ,rudolph ,a4 ,hanel1 ,godd>d ,space ,flight ,c5t]1 ,pr9cipal ,inve/igator ,b4 ,j4 ,conra?1 ,godd>d ,space ,flight ,c5t] ,p4 ,gi]as*1 ,cornell ,univ]sity ,v4 ,kunde1 ,godd>d ,space ,flight ,c5t] ,p4 ,d4 ,l[man1 ,godd>d ,space ,flight ,c5t] ,w4 ,maguire1 ,godd>d ,space ,flight ,c5t] ,j4 ,pe>l1 ,godd>d ,space ,flight ,c5t] ,j4 ,pirraglia1 ,godd>d ,space ,flight ,c5t] ,r4 ,samuelson1 ,godd>d ,space ,flight ,c5t] ,cyril ,ponnamp]uma1 ,univ]sity ( ,m>yl& ,d4 ,gauti]1 ,meudon1 ,france ,s4 ,kuman1 ,univ]sity ( ,s\!rn ,cali=nia ,ultraviolet ,spectroscopy ,a4 ,lyle ,broadfoot1 ,kitt ,peak ,national ,obs]vatory1 ,pr9cipal ,inve/igator ,j4 ,l4 ,b]taux1 ,s]vice d',a]onomie du ,,cnrs1 ,france ,j4 ,blamont1 ,s]vice d',a]onomie du ,,cnrs1 ,france ,t4 ,m4 ,donahue1 ,univ]sity ( ,mi*igan ,r4 ,m4 ,goody1 ,h>v>d ,univ]sity ,a4 ,dalg>no1 ,h>v>d ,college ,obs]vatory ,mi*ael ,b4 ,mc,elroy1 ,h>v>d ,univ]sity ,j4 ,c4 ,mc,connell1 ,york ,univ]sity1 ,canada ,h4 ,w4 ,moos1 ,johns ,hopk9s ,univ]sity ,m4 ,j4 ,s4 ,belton1 ,kitt ,peak ,national ,obs]vatory ,d4 ,f4 ,/robel1 ,naval ,rese>* ,laboratory ,su%il ,atreya1 ,univ]sity ( ,mi*igan ,william ,r4 ,s&el1 ,univ]sity ( ,s\!rn ,cali=nia ,donald ,%emanski1 ,univ]sity ( ,s\!rn ,cali=nia ,photopol>imetry ,*>les ,w4 ,hord1 ,univ]sity ( ,colorado1 ,act+ ,pr9cipal ,inve/igator ,d4 ,l4 ,c(fe51 ,godd>d ,in/itute = ,space ,/udies ,j4 ,e4 ,hans51 ,godd>d ,in/itute = ,space ,/udies ,k4 ,pang1 ,sci5ce ,applications ,inc4 ,planet>y ,radio ,a/ronomy ,james ,w4 ,w>wick1 ,univ]sity ( ,colorado1 ,pr9cipal ,inve/igator ,an?ony ,riddle1 ,radiophysics1 ,inc4 ,jeffrey ,pe>ce1 ,radiophysics1 ,inc4 ,j4 ,k4 ,alex&]1 ,godd>d ,space ,flight ,c5t] ,a4 ,bois*ot1 ,obs]vatoire de ,p>is1 ,france ,w4 ,e4 ,br[n1 ,jet ,propulsion ,laboratory ,t4 ,d4 ,c>r1 ,univ]sity ( ,florida ,samuel ,gulkis1 ,jet ,propulsion ,laboratory ,f4 ,t4 ,haddock1 ,univ]sity ( ,mi*igan ,c4 ,c4 ,h>vey1 ,obs]vatoire de ,p>is1 ,france ,y4 ,le,blanc1 ,obs]vatoire de ,p>is1 ,france ,r4 ,g4 ,peltz]1 ,univ]sity ( ,colorado ,r4 ,j4 ,phillips1 ,jet ,propulsion ,laboratory ,d4 ,h4 ,/ael91 ,massa*usetts ,in/itute ( ,te*nology ,magnetic ,fields ,norman ,f4 ,ness1 ,godd>d ,space ,flight ,c5t]1 ,pr9cipal ,inve/igator ,m>io ,h4 ,acuna1 ,godd>d ,space ,flight ,c5t] ,k4 ,w4 ,behannon1 ,godd>d ,space ,flight ,c5t] ,l4 ,f4 ,burlaga1 ,godd>d ,space ,flight ,c5t] ,r4 ,p4 ,lepp+1 ,godd>d ,space ,flight ,c5t] ,f4 ,m4 ,neubau]1 ,te*nis*e ,univ]sitat1 ,f4,r4,g4 ,plasma ,sci5ce ,h]b]t ,s4 ,bridge1 ,massa*usetts ,in/itute ( ,te*nology1 ,pr9cipal ,inve/igator ,j4 ,w4 ,bel*]1 ,massa*usetts ,in/itute ( ,te*nology ,j4 ,h4 ,b9sack1 ,massa*usetts ,in/itute ( ,te*nology ,a4 ,j4 ,laz>us1 ,massa*usetts ,in/itute ( ,te*nology ,s4 ,olb]t1 ,massa*usetts ,in/itute ( ,te*nology ,v4 ,m4 ,vasyliunas1 ,max ,planck ,in/itute1 ,f4,r4,g4 ,l4 ,f4 ,burlaga1 ,godd>d ,space ,flight ,c5t] ,r4 ,e4 ,h>tle1 ,godd>d ,space ,flight ,c5t] ,k4 ,w4 ,ogilvie1 ,godd>d ,space ,flight ,c5t] ,g4 ,l4 ,siscoe1 ,univ]sity ( ,cali=nia1 ,los ,angeles ,a4 ,j4 ,hundhaus51 ,high ,altitude ,obs]vatory ,l[-,en]gy ,*>g$ ,p>ticles ,s4 ,m4 ,krimigis1 ,johns ,hopk9s ,univ]sity1 ,pr9cipal ,inve/igator ,t4 ,p4 ,arm/rong1 ,univ]sity ( ,kansas ,w4 ,i4 ,ax=d1 ,max ,planck ,in/itute1 ,f4,r4,g4 ,c4 ,o4 ,bo/rom1 ,johns ,hopk9s ,univ]sity ,c4 ,y4 ,fan1 ,univ]sity ( ,arizona ,g4 ,gloeckl]1 ,univ]sity ( ,m>yl& ,l4 ,j4 ,lanz]otti1 ,bell ,telephone ,laboratories ,cosmic ,ray ,r4 ,e4 ,vogt1 ,cali=nia ,in/itute ( ,te*nology1 ,pr9cipal ,inve/igator ,j4 ,r4 ,jokipii1 ,univ]sity ( ,arizona ,e4 ,c4 ,/one1 ,cali=nia ,in/itute ( ,te*nology ,f4 ,b4 ,mc,donald1 ,godd>d ,space ,flight ,c5t] ,b4 ,j4 ,teeg>d51 ,godd>d ,space ,flight ,c5t] ,james ,h4 ,tra9or1 ,godd>d ,space ,flight ,c5t] ,w4 ,r4 ,webb]1 ,univ]sity ( ,new ,hamp%ire ,,app5dix ,c ,,voyag] ,,managem5t ,,team ,,nasa ,(fice ( ,space ,sci5ce ,?omas ,a4 ,mut*1 ,associate ,adm9i/rator = ,space ,sci5ce ,&rew ,j4 ,/(an1 ,deputy ,associate ,adm9i/rator ,adri5ne ,f4 ,timo?y1 ,assi/ant ,associate ,adm9i/rator ,angelo ,gua/af]ro1 ,director1 ,planet>y ,division ,rodney ,a4 ,mills1 ,program ,manag] ,milton ,a4 ,mitz1 ,program ,sci5ti/ ,walt] ,jakob[ski1 ,vik+ & ,flight ,support ,manag] ,,nasa ,(fice ( ,space ,track+ & ,data ,sy/ems ,william ,s*neid]1 ,associate ,adm9i/rator ( ,space ,track+ & ,data ,sy/ems ,acquisition ,*>les ,a4 ,taylor1 ,director1 ,network ,op]ations & ,communication ,programs ,fr$]ick ,b4 ,bryant1 ,director1 ,network ,sy/em ,developm5t ,programs ,maurice ,e4 ,b9kley1 ,director1 ,,dsn ,sy/ems ,,nasa ,(fice ( ,space ,transportation ,sy/ems ,john ,f4 ,y>dley1 ,associate ,adm9i/rator = ,space ,transportation ,sy/ems ,joseph ,b4 ,mahon1 ,director1 ,exp5dable ,laun* ,vehicles ,joseph ,e4 ,mc,golrick1 ,*ief1 ,small & ,m$ium ,laun* ,vehicles ,b4 ,c4 ,lam1 ,titan ,,iii ,manag] ,jet ,propulsion ,laboratory1 ,pasad5a1 ,cali=nia ,bruce ,c4 ,murray1 ,laboratory ,director ,g54 ,*>les ,h4 ,t]hune1 ,jr41 ,deputy ,laboratory ,director ,rob]t ,j4 ,p>ks1 ,assi/ant ,laboratory ,director = ,flight ,projects ,raymond ,l4 ,heacock1 ,project ,manag] ,esk] ,k4 ,davis1 ,deputy ,project ,manag] ,pet] ,t4 ,lyman1 ,deputy ,project ,manag] ,ri*>d ,p4 ,laes]1 ,mission ,director ,george ,p4 ,textor1 ,deputy ,mission ,director ,*>les ,e4 ,kohlhase1 ,mission ,plann+ ,(fice ,manag] ,james ,e4 ,long1 ,sci5ce ,directorate ,manag] ,*>les ,h4 ,/embridge1 ,deputy ,ar?ur ,l4 ,lane1 ,assi/ant ,project ,sci5ti/ = ,jupit] ,francis ,m4 ,/urms1 ,sequ5ce ,design & ,integration ,directorate ,manag] ,rob]t ,k4 ,wilson1 ,deputy ,mi*ael ,j4 ,s&]1 ,developm5t1 ,integration & ,te/ ,directorate ,manag] ,rob]t ,g4 ,polansky1 ,deputy ,mi*ael ,w4 ,devirian1 ,space ,flight ,op]ations ,directorate ,manag] ,raymond ,j4 ,amorose1 ,deputy ,m>v9 ,r4 ,traxl]1 ,track+ & ,data ,sy/em ,manag] ,kurt ,heftman1 ,mission ,control & ,comput+ ,c5t] ,manag] ,cali=nia ,in/itute ( ,te*nology1 ,pasad5a1 ,cali=nia ,edw>d ,c4 ,/one1 ,project ,sci5ti/ ,,additional ,,read+ ,,te*nical ,jupit]1 ,t4 ,gehrels1 ,ed41 ,u4 ( ,arizona ,press1 ,tucson1 #abed pages 7#aigf74 ,space ,sci5ce ,reviews1 special ,voyag] in/rum5tation issues1 ,vol4 #ba1 ,no4 #b1 pgs4 #ge-bcb 7,novemb] #aigg72 ,vol4 #ba1 ,no4 #c1 pgs4 #bcd-cgf 7,decemb] #aigg74 8,melt+ ( ,io by ,tidal ,dissipation10 by ,s4 ,j4 ,peale1 ,p4 ,cass51 & ,r4 ,t4 ,reynolds1 ,sci5ce1 ,vol4 #bjc1 pgs4 #hib-hid 7#b ,m>* #aigi74 ,sci5ce1 special ,voyag] #a issue1 ,vol4 #bjd1 pgs4 #ide-ajjh 7#a ,june #aigi74 ,nature1 special ,voyag] #a issue1 ,vol4 #bhj1 pgs4 #gbe-hjf 7#cj ,augu/ #aigi74 8,jupit]'s ,r+10 by ,t4 ,ow5 et al41 ,nature1 ,vol4 #gha1 pgs4 #ddb-ddf 7#aa ,octob] #aigi74 ,sci5ce1 special ,voyag] #b issue1 ,vol4 #bjf1 pgs4 #ibe-iif 7#bc ,novemb] #aigi74 ,geophysical ,rese>* ,lett]s1 special ,voyag] issue1 ,vol4 #g1 pgs4 #a-fh 7,janu>y #aihj74 ,,nonte*nical 8,! ,sol> ,sy/em10 special issue ( ,sci5tific ,am]ican1 ,vol4 #bbc1 ,no4 #c 7,septemb] #aige74 8,! ,galilean ,satellites ( ,jupit]10 by ,d4 ,p4 ,cruik%ank & ,d4 ,morrison1 ,sci5tific ,am]ican1 ,vol4 #bcd1 ,no4 #e1 pgs4 #ajh-aaf 7,may #aigf74 ,pione] ,odyssey1 by ,r4 ,o4 ,fimmel1 ,w4 ,sw9dell1 & ,e4 ,burgess1 ,,nasa ,,sp-#cif1 #bag pages 7#aigg74 ,murmurs ( ! ,e>?3 ,! ,voyag] ,int]/ell> ,record1 by ,c>l ,sagan et al41 ,r&om ,h\se1 ,new ,york1 #aigh4 8,jupit] & ,family10 by ,j4 ,eb]h>t1 ,sci5ce ,news1 ,vol4 #aae1 pgs4 #afd-agc 7#ag ,m>* #aigi74 8,! ,f>-,out ,worlds ( ,voyag]10 by ,j4 ,k4 ,beatty1 ,sky & ,telescope1 ,vol4 #eg1 pgs4 #dbc-dbg 7,may #aigi7 & pgs4 #eaf-ebj 7,june #aigi74 8,return to ,jupit] & ,co410 by ,j4 ,eb]h>t1 ,sci5ce ,news1 ,vol4 #aaf1 pgs4 #ai-ba 7#ad ,july #aigi74 8,voyage to ! ,giant ,planet10 by ,c4 ,sutton1 ,new ,sci5ti/1 ,vol4 #hc1 pgs4 #bag-bbj 7#ai ,july #aigi74 8,voyag] ,views ,jupit]'s ,dazzl+ ,realm10 by ,r4 ,gore1 ,national ,geographic1 ,vol4 #aeg1 ,no4 #a1 pgs4 #b-bi 7,janu>y #aihj74 8,! ,galilean ,moons ( ,jupit]10 by ,l4 ,a4 ,sod]blom1 ,sci5tific ,am]ican1 ,vol4 #bdb1 ,no4 #a1 pgs4 #hh-ajj 7,janu>y #aihj74 8,! ,great ,r$ ,spot10 by ,d4 ,s*w>tz5burg1 ,a/ronomy1 ,vol4 #h1 pgs4 #f-ac 7,july #aihj74 8,f\r ,new ,worlds10 by ,d4 ,morrison1 ,a/ronomy1 ,vol4 #h 7,septemb] #aihj74 ,illu/ration3 ,national ,a]onautics & ,space ,adm9i/ration ,transcrib]'s ,notes --,reta9$ publication in=mation f ! pr9t$ edition3 ?is e,book is public-doma9 9 ! c\ntry ( publication4 --,sil5tly correct$ a few palpable typos4 --,mov$ captions ne>] ! relevant images2 tweak$ image ref]5ces )9 captions accord+ly4 --,9 ! text v]sions only1 text 9 italics is delimit$ by und]scores4