,,pione] ,,saturn ,,enc\nt] ,illu/ration3 ,,nasa ,,cont5ts ,=eword #a ,introduction #c ,pione] ,saturn #d ,saturn ,images #h ,sci5ce ,highlights #ba ,outw>d ,b\nd #bh ,,=eword ,! ,pione] #aj & #aa spacecraft1 laun*$ 9 #aigb & #aigc1 respectively1 7 well nam$3 !y made ! fir/ cross+s ( ! a/]oid belt & 7 ! fir/ to enc\nt] ,jupit] & its int5se radiation belts4 ,pione] #aa's trajectory1 b5t into a hairp9 curve by ,jupit]'s p[]ful gravitational field1 all[$ x to recross ! sol> sy/em to make ! fir/ flyby ( ,saturn almo/ a billion miles f ,e>? :]e x came )9 #ac1cjj miles ( ! cl\d tops4 ,assembl$ 9 ?is publication is a selection ( ! pictures return$ by ,pione] #aa ( ,saturn & its l>ge/ moon1 ,titan4 ,^! images are ( great beauty z well z ( great sci5tific int]e/1 s]v+ to :et our appetite = ! m detail$ obs]vations to be made by ,voyag] 9 #aihj & #aiha4 ,track+ ( bo? ,pione]s w cont9ue = _m m ye>s1 provid+ fundam5tal data on ! nature ( int]planet>y space 9 ! dep?s ( ! sol> sy/em4 ,! results ( ^! out]-planet ,pione] missions h f> exce$$ our hopes & expectations ( a decade ago :5 ! program 0 initiat$4 ,rob]t ,a4 ,fros*1 ,adm9i/rator ,national ,a]onautics & ,space ,adm9i/ration ,septemb] #aigi ,,nasa ,national ,a]onautics & ,space ,adm9i/ration ,ames ,rese>* ,c5t] ,m(fett ,field4 ,cali=nia #idjce ,illu/ration3 ,arti/'s draw+ ( ,saturn & its r+s %[+ ! ,pione] ,saturn spacecraft pass+ "u ! r+s & ne>+ close/ approa* to ! planet4 ,actual pictures c\ld n be obta9$ at ?is "t because ( ! high spe$ ( ! spacecraft4 ,,introduction ,we h ent]$ into a new era ( space exploration4 ,missions und]tak5 dur+ ! lun> exploration ( ! #aifj's typically la/$ a matt] ( days ) comm&s issu$ & c>ri$ out 9 ne> real "t4 ,n[1 a decade lat]1 planet>y voyages may la/ = _m ye>s z ! spiral+ trajectories ( ! spacecraft make p]iodic int]sections ) ! orbits ( ! planets4 ,communicat+ ) u across ! va/ness ( space1 ^! spacecraft report to u _! exp]i5ces z !y trav]se ! out] rea*es ( ! sol> sy/em4 ,among ^! deep space travel]s1 ,pione]s #aj & #aa are appropriately nam$1 = !y truly are pione]+ ! exploration ( ! out] sol> sy/em4 ,laun*$ 9 #aigb & 9 #aigc1 respectively1 !y 7 ! fir/ spacecraft to fly by ,jupit] 79 #aigc & #aigd74 ,at ,jupit]1 ,pione] #aa's trajectory 0 c>efully t>get$ to sw+ x t[>d ,saturn = an enc\nt] 9 ,septemb] #aigi4 ,we see "s ( ! e>ly results 9 ?is publication4 ,o!r spacecraft are foll[+ along ! trail blaz$ by ,pione] ,saturn4 ,voyag] #a pass$ by ,jupit] 9 ,m>* #aigi & w rea* ,saturn 9 ,novemb] #aihj4 ,voyag] #b has also pass$ beyond ,jupit] & w enc\nt] ,saturn 9 ,augu/ #aiha1 ) ! fur!r possibility ( travel+ on to ,uranus 7a #aihf enc\nt]74 ,"u developm5t are ! ,galileo orbit] & atmosph]ic entry probe1 de/9$ to j\rney to ,jupit] :]e ! orbit] w return m detail$ in=mation1 includ+ high-resolution pictures ( ! ,galilean satellites1 & ! probe w p5etrate deep bel[ ! ,jovian cl\ds4 ,9 ! com+ ye>s1 ea* ( ^! foll[-on missions w enri* our und]/&+ ( ! sol> sy/em1 greatly supplem5t+ ! obs]vations ( ,pione]s #aj & #aa4 ,b "o ?+ w nev] *ange4 ,! ,pione]s 7 fir/4 ,?omas ,a4 ,mut* ,associate ,adm9i/rator = ,space ,sci5ce ,national ,a]onautics & ,space ,adm9i/ration ,,pione] ,,saturn ,illu/ration3 ,pione] ,saturn spacecraft4 ,pione] ,saturn has giv5 u our fir/ close view ( ! spectacul> r+$ planet ,saturn & its sy/em ( moons4 ,! spacecraft began its j\rney to ! giant planets ,jupit] & ,saturn on ,april #e1 #aigc1 z ,pione] #aa4 ,x rea*$ ,jupit] on ,decemb] #b1 #aigd1 pass+ )9 #db1gfj km ( ! ,jovian cl\d tops & tak+ ! only exi/+ pictures ( ,jupit]'s pol> regions4 ,jupit]'s massive gravitational field 0 us$ to sw+ ,pione] #aa back across ! sol> sy/em t[>d ,saturn4 ,additional maneuv]s 7 execut$ 9 #aige & #aigf to place ! spacecraft on a suitable trajectory1 ) ! f9al aimpo9t select$ 9 #aigg4 ,f ! _m possible t>get+ options = ! fir/ ,saturn flyby1 two aimpo9ts 7 consid]$1 bo? ( :i* w\ld result 9 a ne>-equatorial flyby t w\ld give ! be/ mapp+ ( ! high-en]gy p>ticles & ! magnetic field ne> ! planet4 ,! diff]5ce betwe5 ^! two aimpo9ts1 :i* came to be kn[n z ! 8inside0 & 8outside0 options1 0 _! relation%ip to ,saturn's unique r+ sy/em fir/ discov]$ by ,galileo 9 #afaj4 ,! 8outside0 option 0 f9ally select$ because x 0 consid]$ to be ( less risk to ! spacecraft & m valuable 9 plann+ ! subsequ5t enc\nt] ( ,saturn by ,voyag] #b1 :i* w rea* ,saturn 9 #aiha4 ,f9al t>get+ 0 complet$ dur+ e>ly #aigh1 :5 a s]ies ( tim$ rocket ?ru/s lock$ ,pione] into ! desir$ trajectory4 ,illu/ration3 ,pione] ,saturn voyage4 ,illu/ration3 ,enc\nt] trajectory4 ,on ,septemb] #a1 #aigi1 ! spacecraft1 n[ designat$ ,pione] ,saturn1 rea*$ ,saturn aft] #f ye>s 9 flight4 ,x pass$ ?r\gh ! r+ plane outside ! edge ( ,saturn's ,a-r+ & !n swung 9 "u ! r+s f #b1jjj to #aj1jjj km bel[ !m4 ,at ! po9t ( close/ approa*1 x atta9$ a spe$ ( #aad1ajj km_/h 7#ga1ijj mi_/h7 & came )9 #ba1djj km ( ! planet's cl\d tops4 ,:ile x 0 approa*+1 enc\nt]+1 & leav+ ,saturn1 ! spacecraft took ! fir/ closeup pictures ( ! planet1 %[+ #bj to #cj times m detail ?an ! be/ pictures tak5 f ,e>?1 & made ! fir/ close measurem5ts ( its r+s & sev]al ( its moons1 includ+ ! l>ge/ moon1 ! planet-siz$ ,titan4 ,titan1 along ) ,m>s1 has be5 consid]$ by _m sci5ti/s to be ! mo/ likely place to f9d life 9 ! sol> sy/em4 ,pione] ,saturn unravel$ _m my/]ies4 ,x det]m9$ t ,saturn has a magnetic field & trapp$ radiation belts1 measur$ ! mass ( ,saturn & "s ( its moons1 & /udi$ ! "* ( ,saturn's int]ior4 ,x confirm$ ! pres5ce & det]m9$ ! magnitude ( an int]nal heat s\rce = ,saturn4 ,its in/rum5ts /udi$ ! temp]ature di/ribution1 composition1 & o!r prop]ties ( ! cl\ds & atmosph]es ( ,saturn & ,titan1 & took photometric & pol>ization measurem5ts ( ,iapetus1 ,rhea1 ,dione1 & ,te?ys4 ,pione] may also h discov]$ a previ\sly unkn[n moon ( ,saturn4 ,! spacecraft measur$ ! mass1 /ructure1 & o!r *>act]i/ics ( ,saturn's r+s1 & pass$ safely ?r\gh ! out] ,e-r+1 :i* pos$ a pot5tial haz>d = ,pione]4 ,x also discov]$ new r+s4 ,"o ( ^! r+s1 call$ ! ,f-r+ by ! ,pione] team1 lies j outside ! ,a-r+4 ,! gap betwe5 ! ,f-r+ & ! ,a-r+ has be5 t5tatively designat$ ! ,pione] ,division4 ,! o!r new r+ has be5 call$ ! ,g-r+1 :i* lies well outside ! ,f-r+4 ,pione] c>ries a sci5tific payload ( #aa op]at+ in/rum5ts2 ano!r in/rum5t1 ! a/]oid_/meteoroid detector1 0 turn$ (f 9 #aige4 ,two o!r exp]im5ts1 cele/ial me*anics & ,s-b& occultation ( ,saturn1 use ! spacecraft radio to obta9 data4 ,pione] ,saturn is a sp9n+ spacecraft1 :i* gives its in/rum5ts a full-circle scan #g4h times a m9ute4 ,x uses a nucle> s\rce = electric p[] because ! sunlight at ,jupit] & beyond is too weak = a sol>-p[]$ sy/em4 ,two booms project f ! spacecraft to deploy ! nucle> p[] s\rce ab\t #c met]s f ! s5sitive spacecraft in/rum5tation4 ,a ?ird boom positions ! magnetomet] s5sor ab\t #f met]s f ! spacecraft4 ,six ?ru/]s provide velocity1 attitude1 & sp9-rate control4 ,a di% ant5na is locat$ along ! sp9 axis & looks back at ,e>? ?r\gh\t ! mission1 adju/+ its view by *anges 9 spacecraft attitude z ! spacecraft & ,e>? move 9 _! orbits ar\nd ! sun4 ,track+ facilities ( ,,nasa's ,deep ,space ,network1 locat$ at ,gold/one1 ,cali=nia1 & 9 ,spa9 & ,au/ralia1 support$ ,pione] ,saturn dur+ int]planet>y flight & enc\nt]4 ,pione]'s radio signals1 travel+ at ! spe$ ( light1 took #he m9utes to rea* ,e>? f ,saturn1 a r\nd-trip "t ( almo/ #c h\rs1 some:at complicat+ gr\nd control ( ! spacecraft4 ,almo/ #aj1jjj comm&s 7 s5t to ! spacecraft 9 ! #b-week p]iod be=e close/ approa*4 ,cont9u$ communications %\ld be possible ?r\gh at lea/ ! mid #aihj's4 ,aft] ! spacecraft pass$ ,saturn1 x head$ out ( ! sol> sy/em1 travel+ 9 ! direction ! sol> sy/em moves ) respect to ! local />s 9 our galaxy & 9 approximately an opposite direction f its si/] spacecraft1 ,pione] #aj4 ,bo? spacecraft h plaques atta*$ to !m :i* conta9 a message f ,e>? = any intellig5t species t may int]cept ! spacecraft dur+ _! endless j\rneys ?r\gh int]/ell> space4 ,pione] ,saturn ,sci5tific ,in/rum5ts ,in/rum5t ,pr9cipal ,inve/igator ,exp]im5t ,objective ,helium vector ,edw>d ,j4 ,smi? ,magnetic fields magnetomet] ,jet ,propulsion ,laboratory ,fluxgate ,m>io ,acua ,magnetic fields magnetomet] ,godd>d ,space ,flight ,c5t] ,plasma analyz] ,john ,h4 ,wolfe ,sol> plasma ,ames ,rese>* ,c5t] ,*>g$ p>ticle ,john ,a4 ,simpson ,*>g$ p>ticle ,univ]sity ( ,*icago composition ,cosmic ray telescope ,frank ,b4 ,mc,donald ,cosmic ray en]gy ,godd>d ,space ,flight ,c5t] spectra ,geig] tube ,james ,a4 ,van ,all5 ,*>g$ p>ticles telescope ,univ]sity ( ,i[a ,trapp$ radiation ,r4 ,walk] ,fillius ,trapp$ radiation detector ,univ]sity ( ,cali=nia1 ,san ,diego ,a/]oid_/meteoroid ,rob]t ,k4 ,sob]man ,a/]oid_/meteoroid detector#a ,g5]al ,electric ,co4 & a/ronomy ,philadelphia ,drexel ,univ]sity ,meteoroid detector ,william ,h4 ,k9>d ,meteoroid detection ,langley ,rese>* ,c5t] ,radio transmitt] ,john ,d4 ,&]son ,cele/ial me*anics & ,,dsn ,jet ,propulsion ,laboratory ,ultraviolet ,d>rell ,l4 ,judge ,ultraviolet photomet] ,univ]sity ( ,s\!rn photometry ,cali=nia ,los ,angeles ,imag+ ,tom ,gehrels ,photo imag+ & photopol>imet] ,univ]sity ( ,arizona1 ,tucson pol>imetry ,infr>$ radiomet] ,&rew ,+]soll ,infr>$ !rmal ,cali=nia ,in/itute ( /ructure ,te*nology ,radio transmitt] ,arvydas ,j4 ,kliore ,s-b& occultation & ,,dsn ,jet ,propulsion ,laboratory #a,n curr5tly op]ational4 ,,saturn ,,images ,saturn1 call$ ! wond] ( ! heav5s by e>ly a/ronom]s1 has be5 /udi$ f ,e>? = _m c5turies4 ,:5 ,galileo fir/ focus$ 8 telescope on ,saturn 9 #afaj1 he realiz$ t ! appe>ance ( ! planet 0 unusual1 b he nev] knew its real "* because ! p[] ( 8 homemade telescope 0 f> too l[4 ,he ?\ght he 0 look+ at ?ree globes1 "o l>ge & two small1 :i* seem$ to *ange sl[ly 9 appe>ance4 ,9 #afee1 ,huyg5s1 aft] ye>s ( obs]v+ ! planet1 f9ally realiz$ t ^! projections 7 actually a flat r+ slightly sep>at$ f ! ma9 globe4 ,illu/ration3 ,fir/ sket* ( ,saturn 7,galileo1 #afaj74 ,illu/ration3 ,fir/ sket* %[+ a division 9 ! r+s 7,cass9i1 #afge74 ,9 #afge1 ,cass9i f\nd ! fir/ brea* 9 ! suppos$ly solid1 rigid1 & opaque r+ :5 he discov]$ t x 0 divid$ into two p>ts by a d>k l9e1 n[ kn[n z ,cass9i's ,division4 ,9 lat] ye>s he also detect$ "s ( ,saturn's moons4 ,illu/ration3 ,fir/ successful photograph ( ,saturn 7,&rew ,common1 #ahhc74 7,discov]+ ! ,univ]se1 ,col9 ,a4 ,ronan1 ,copyright #aiga by ,col9 ,a4 ,ronan1 ,basic ,books1 ,inc41 ,publi%]s1 ,new ,york47 ,! e>lie/ successful photograph ( ,saturn 0 tak5 9 #ahhc by ,&rew ,common4 ,9 #ahie1 ,james ,keel] sugge/$ t ! r+s are 9 fact a sw>m ( p>ticles 9 ne>-indep5d5t orbits4 ,^! r+s1 until ! rec5t discov]ies ( fa9t r+ sy/ems ar\nd ,jupit] & ,uranus1 7 consid]$ unique 9 ! sol> sy/em4 ,s9ce ,galileo fir/ us$ 8 homemade telescope to view ,saturn1 !re h be5 _m obs]v]s4 ,!re h also be5 major advances 9 telescopes2 a result+ mod]n view ( ,saturn is %[n on ! next page4 ,! correspond+ sket* %[s ! nom5clature ( ! brighte/ r+s4 ,n[ ! planet has be5 se5 = ! fir/ "t n f ,e>?1 b 9 mu* clos] views by an in/rum5t on a spacecraft1 ! imag+ photopol>imet] on ,pione] ,saturn4 ,! in/rum5t sep>ately measures ! /r5g?s ( ! r$ & blue compon5ts ( sunlight scatt]$ f ! cl\ds ( ,saturn & conv]ts ?is in=mation into numb]s4 ,! data are transmitt$ to ,e>? z "p ( ! spacecraft telemetry4 ,! signals are !n conv]t$ by comput] into %ades ( gray on photographic film1 & ! two compon5ts plus a syn!siz$ gre5 image c be recomb9$ into a color image t approximates ! planet's true color4 ,"s ( ! result+ images are %[n on ! pages foll[+ ! ,e>?-bas$ view4 ,^! pictures 7 produc$ by a sci5tific team f ! ,univ]sity ( ,arizona4 ,^! images1 :ile help+ to unravel "s ( ! my/]y surr\nd+ ! planet1 h creat$ ev5 m int]e/ reg>d+ x4 ,we are really j beg9n+ to "k ,saturn4 ,x is up to future spacecraft to m completely reveal h] secrets & solve h] my/]ies4 ,illu/ration3 ,high-quality contempor>y ,e>?-bas$ view ( ,saturn 7,photo3 ,catal9a ,obs]vatory1 ,univ]sity ( ,arizona74 ,illu/ration3 ,nom5clature ( bright r+s4 ,,out] 7,a7 ,,r+ ,,cass9i ,,division ,,middle 7,b7 ,,r+ ,,crepe 7,c7 ,,r+ ,illu/ration3 ,pione] ,saturn image ( ,saturn & its r+s f a di/ance ( #h1djj1jjj km 7,augu/ #bb1 #aigi1 #aj days be=e close/ approa*74 ,resolution has n yet rea*$ ,e>?-bas$ quality4 ,fa9t b&+ is visible on ! disk ( ! planet4 ,! silh\ette ( ! r+s c be se5 9 front ( ! planet4 ,slightly above ?is silh\ette is ! %ad[ ( ! r+s on ! disk4 ,beyond ! disk1 /ructure c be se5 9 ! r+s4 ,! r+s h a di/9ctly diff]5t appe>ance 9 ?is & subsequ5t images ?an 9 ,e>?-bas$ pictures because !y are illum9at$ f bel[ r ?an f above z we view !m f ,e>?4 ,! ,a-r+ & ,c-r+ are bright1 & betwe5 !m ! ,b-r+ is d>k4 ,! ,cass9i ,division at ! inn] edge ( ! ,a-r+ is also bright1 b is bl5d$ ) ! r+ at ?is di/ance4 ,illu/ration3 ,pione] ,saturn image ( ,saturn & its r+s f a di/ance ( #e1ejj1jjj km 7,augu/ #bf1 #aigi1 #f days be=e close/ approa*74 ,resolution ( features is beg9n+ to be approximately equal to t ( ,e>?-bas$ pictures4 ,belts on ! planet are becom+ m di/9ct1 & consid]able /ructure c be se5 9 ! r+s4 ,! small blue spot at ! bottom ( ! planet is due to incomplete data & w be correct$ by fur!r process+4 ,a not* appe>s at ! top left ( ! planet1 :i* may be a data transmission problem or ! %ad[ ( "o ( ,saturn's moons4 ,illu/ration3 ,pione] ,saturn image ( ,saturn & its r+s f a di/ance ( #b1hjj1jjj km 7,augu/ #bi1 #aigi1 #gb h\rs be=e close/ approa*74 ,! ,cass9i ,division at ! inn] edge ( ! ,a-r+ is cle>ly resolv$ & is bright4 ,! ,a-r+ is d>k outside ! ,cass9i ,division because x has m p>ticulate matt] !re4 ,pol> belts are becom+ m visible on ! face ( ! planet4 ,irregul>ities t appe> 9 ! r+ silh\ette & %ad[ are due to /epp+ anomalies 9 ! imag+ photopol>imet] & w be remov$ 9 fur!r process+4 ,! small r\nd image t appe>s above ! planet is ! moon ,titan4 ,illu/ration3 ,^! pictures ( ,saturn & its r+s 7 tak5 by ,pione] ,saturn f a di/ance ( #b1ejj1jjj km 7,augu/ #bi1 #aigi1 #eh h\rs be=e close/ approa*74 ,! imag+ photopol>imet] ga!rs data us+ ! r$ & blue compon5ts ( ! light reflect$ f ,saturn4 ,^! two views are f ! two color compon5ts 7upp]1 blue2 l[]1 r$74 ,! b&$ /ructure on ! planet is p>ticul>ly evid5t 9 ! upp] image4 ,because ! spacecraft is ne>+ ! planet1 ! r+s are p>tially outside ! field ( view ( ! in/rum5t4 ,! speck ( light bel[ ! planet is ,saturn's moon ,rhea1 :i* is #adej km 9 diamet]1 ab\t "o-half ! size ( ,e>?'s moon4 ,illu/ration3 ,saturn & its r+s3 r$ compon5ts4 ,illu/ration3 ,?is image 0 produc$ by comb9+ ! two images on ! fac+ page1 add+ a syn!siz$ gre5 compon5t1 & adju/+ ! int5sity ( ea* to obta9 an approximation to ,saturn's true color4 7,! same process 0 us$ 9 all ( ! ,pione] color images ( ,saturn %[n "h47 ,al?\gh n evid5t on ?is reproduction1 sci5ti/s believe t1 f detail$ /udy ( bo? ! uncomb9$ & ! comb9$ images1 !y c beg9 to see evid5ce ( jet /reams 9 ,saturn's upp] atmosph]e4 ,! slight blue edge is an artifact f ! comput]-enhancem5t proc$ure4 ,illu/ration3 ,pione] ,saturn view %[+ ! /ructure ( ,saturn's r+ sy/em 9 detail nev] be=e se54 ,! image 0 tak5 f a di/ance ( #idc1jjj km 7,augu/ #ca1 #aigi1 ab\t #dd h\rs be=e enc\nt]74 ,! moon ,te?ys1 se5 at ! top ( ! image1 is #abjj km 9 diamet]4 ,!re is a v fa9t unid5tifi$ ,saturnian moon at ! l[] "r1 j (f ! tip ( ! bright ,a-r+ 7may n be visible 9 ?is pr9t74 ,! newly def9$ ,f-r+ appe>s fa9tly j outside ! bright edge ( ! ,a-r+4 ,! region betwe5 ! ,a-r+ & ! ,f-r+ has be5 t5tatively nam$ ! ,pione] ,division4 ,?is pr9t has be5 process$ to enhance detail ( ! ma9 r+s4 ,illu/ration3 ,a color pr9t ( a v]sion ( ! same image z %[n on ! fac+ page4 ,! blue dot at ! out] edge ( ! ,c-r+ is an artifact4 ,?is image has n be5 comput] process$ to ! same ext5t z ! fac+ image4 ,te?ys1 = example1 is only fa9tly visible1 & ! ,f-r+ _c be se54 ,illu/ration3 ,close-up image f ,pione] ,saturn ( ,saturn f a di/ance ( #djj1jjj km 7,septemb] #a1 #aigi1 a few h\rs be=e close/ approa*74 ,inset %[s ! location ( ! image on ! planet4 ,! "p ( ! disk %[n is ab\t #be1jjj by #gj1jjj km4 ,! sawtoo? patt]n is an artifact4 ,! v]tical /ripe on ! disk is due to a ga9 *ange 9 ! in/rum5t4 ,! image has n _h its f9al corrections = %ape4 ,! r+s & _! %ad[s cut diagonal swa?s across ! image ) ! upp] swa? be+ ! %ad[4 ,! r+s1 se5 f ! unlit side1 are visible 9 ! =egr\nd4 ,! r+ %ad[ %[s cle>ly t ,saturn's r+s h two major divisions3 ! ,cass9i ,division divid+ ! out] ,a-r+ f ! middle ,b-r+1 & a second division 7previ\sly controv]sial7 divid+ ! ,b-r+ f ! inn] ,c-r+4 ,^! divisions %[ z p>allel p9/ripes 9 ! broad black b& ( ! r+s' %ad[1 ) ! upp] /ripe be+ ! ,cass9i ,division4 ,"s %e>+ 9 ! b&s & belts on ,saturn's disk is beg9n+ to appe>1 al?\gh ! l[ contra/ on ! planet 7due to its high-altitude haze7 does n make ?is highly evid5t4 ,illu/ration3 ,po/-enc\nt] image ( ,saturn f a di/ance ( #hej1jjj km 7,septemb] #b1 #aigi1 #ae h\rs aft] enc\nt]74 ,z plann$1 dur+ ! enc\nt] ,saturn's gravitational field turn$ ! spacecraft's trajectory beh9d ! planet & out t[>d ! edge ( ! sol> sy/em at approximately a "r angle to ! inb\nd trajectory4 ,?us1 ! planet is n[ illum9at$ f ! side1 & ! view is ( a cresc5t ,saturn ) ! t]m9ator on ! "r ( ! picture4 ,! r+s appe> dim :5 comp>$ ) ! previ\s inb\nd pictures because ( ! diff]5t angle betwe5 ! sun1 ! r+s1 & ! spacecraft4 ,:5 ?is picture 0 tak51 ! spacecraft1 z se5 f ,e>?1 0 ab\t to pass beh9d ! sun1 & sol> activity 0 int]f]+ ) spacecraft communications4 ,! image quality1 !re=e1 is n z good z = pictures tak5 inb\nd4 ,) ?is f>ewell image f ,pione]1 ,saturn waits = ! ,voyag] spacecraft 9 #aihj & #aiha4 ,illu/ration3 ,?is image ( cl\d-cov]$ ,titan is "o ( ! 8fir/s0 = ! ,pione] ,saturn mission4 ,titan is ! l>ge/ ( ,saturn's moons4 ,because ( its great di/ance f ,e>?1 h[ev]1 ,titan c be se5 only z a po9t ( light 9 ,e>?-bas$ pictures4 ,! ,pione] trajectory c\ld n be adju/$ to all[ passage close to ,titan1 & imag+ ( ! planet f ! spacecraft 0 at ! out] range ( capability ( ! imag+ in/rum5t4 ,?us1 ! fuzzy edges & contra/ v>iations on ! moon %\ld n be con/ru$ z surface features4 ,titan 0 imag$ 9 ! _s ( exploration & discov]y4 ,) ?is image1 :i* is n[ a "p ( record$ hi/ory1 our visual in=mation on ,titan is mat]ially increas$1 b is /ill only r\ghly equal to ,galileo's in=mation on ,saturn itself 9 #afaj at ! "t t he prep>$ 8 fir/ sket*4 ,bett] images ( ,titan w be obta9$ by ! ,voyag] spacecraft4 ,,sci5ce ,,highlights ,pione] ,saturn has already greatly exp&$ our k ( ,saturn1 its r+s & moons4 ,we n[ "k t ,saturn1 9 _m ways1 repres5ts an int]m$iate case betwe5 ,jupit]1 ! l>ge/ planet 9 ! sol> sy/em1 & ,e>?4 ,! composition ( ,saturn's int]ior is ess5tially ! same z ,jupit]'s1 diff]+ only 9 ! size & ext5t ( ! v>i\s int]nal lay]s4 ,measurem5ts = ,saturn are consi/5t ) a c5tral core ( molt5 heavy elem5ts 7probably mo/ly iron7 :i* is ! approximate size ( ! entire ,e>?1 b ab\t ?ree times m massive4 ,surr\nd+ ! c5tral core is an out] core ( highly compress$ hot1 liquefi$ volatiles su* z me?ane1 ammonia1 & wat]4 ,?is out] core is equival5t to approximately n9e ,e>? masses4 ,^! core regions1 h[ev]1 repres5t a v small fraction ( ! planet1 :i* is compos$ prim>ily ( ! v lighte/ gases1 hydrog5 & helium1 & is almo/ #ajj times ! mass ( ! ,e>?4 ,because ( ! high pressure 9 ,saturn's int]ior1 ! hydrog5 is trans=m$ to its liquid metallic /ate4 ,above ?is metallic hydrog5 %ell are liquid molecul> hydrog5 & ,saturn's gase\s atmosph]e & cl\ds1 :i* make up ! re/ ( ! planet4 ,electrical curr5ts set up )9 ! metallic hydrog5 %ell produce ,saturn's magnetic field1 :i* 0 measur$ by ,pione]4 ,9 spite ( ,saturn's l>ge size1 ! magnetic field at ! cl\d tops is only slightly weak] ?an ! field at ! ,e>?'s surface4 ,saturn is unique 9 t its magnetic axis is ne>ly align$ ) its rotation axis1 unlike ,e>? & ,jupit]4 ,saturn's magnetic field is also mu* m regul> 9 %ape ?an ! fields ( ! o!r planets4 ,at l>ge di/ances f ,saturn1 ! magnetic field is de=m$ by ! inw>d pressure ( ! sol> w9d4 ,ne> ! noon m]idian 7close to ! inb\nd ,pione] trajectory71 ! sol> w9d causes a compression ( ! field2 9 ! dawn m]idian 7close to ! outb\nd trajectory71 ! field is swept back & presumably =ms a long magnetic tail4 ,9 bo? cases1 ,pione] ,saturn cross$ ! out] b\nd>y ( ! magnetic field sev]al times z ! field mov$ 9 & out1 respond+ to *ang+ sol> w9d pressure4 ,pione] also obs]v$ inw>d & outw>d b\nd>ies4 ,! magnetic envelope surr\nd+ ,saturn is int]m$iate 9 size & en]getic p>ticle population betwe5 ^? ( ! ,e>? & ,jupit]1 ! only two o!r planets kn[n to be /rongly magnetiz$4 ,! ?ree o!r planets inve/igat$ ?us f> 7,v5us1 ,m>s1 & ,m]cury7 & ,e>?'s moon h little or no magnetism4 ,virtually all our k ( ,saturn's magnetic environm5t has be5 obta9$ by ,pione]4 ,! spacecraft f\nd r+s ( p>ticulate mat]ial & sev]al small moons ne> ! r+s1 :i* /rongly affect ,saturn's trapp$ radiation4 ,^! features provide important diagno/ic capabilities4 ,a unique f9d+ is ! ne>ly total abs5ce ( radiation belt p>ticles at di/ances clos] to ! planet ?an ! out] edge ( ! visible r+s4 ,! inn] region ( ! ?ick magnetic envelope ( ,saturn1 call$ ! magnetosph]e1 conta9s trapp$ high-en]gy electrons & protons1 ) "s evid5ce = heavi] nuclei4 ,! ov]all =m ( ! magnetosph]e is simple & compact1 m simil> to t ( ,e>? ?an ( ,jupit]4 ,! unique measur+ capabilities ( ! ,pione] ,saturn radiation detectors l$ directly to ! discov]y ( a diffuse new r+ ( p>ticulate matt] 9 ! region f ab\t #aj to #ae planet>y radii 7#a ,saturn radius #fj1jjj km7 f ,saturn4 ,?is r+ has be5 t5tatively designat$ z ! ,g-r+4 ,! ,g-r+ cle>ly causes p>ticle absorption ne> ! equatorial region4 ,moreov]1 ,pione] discov]$ ano!r region inside #g or #h planet>y radii 9 :i* ! radiation belt p>ticles 7 subject$ to a /rong loss or absorption1 presumably caus$ by ! pres5ce ( an ext5sive cl\d ( plasma corotat+ ) ! planet4 ,inside ab\t #aj planet>y radii1 ! trapp$ radiation %[s a high degree ( axial symmetry ar\nd ,saturn & is consi/5t ) ! c5t]$ dipole magnetic field obs]v$ by ,pione]4 ,saturn's r+s annihilate all trapp$ radiation at ! out] edge ( ! ,a-r+1 leav+ a %ield$ region close to ! planet 9 :i* ! radiation int5sity is ! l[e/ s f> enc\nt]$ 9 ?is mission4 ,?is %ield+ prev5ts ! fur!r buildup ( electron int5sities at l[] altitudes1 :i* o!rwise w\ld h be5 pres5t & w\ld h made ,saturn a /rong radio s\rce obs]vable f ,e>?4 ,pione] f\nd t sev]al ( ,saturn's moons absorb trapp$ p>ticles f ! radiation belts1 produc+ prom95t dips 9 ! int5sity4 ,! effectiv5ess ( absorption at ! moons ,te?ys & ,enceladus is p>ticul>ly a/oni%+1 & supports ! idea t radiation belt p>ticles are drift+ inw>d sl[ly across ! moons' orbits4 ,a precipit\s decrease 9 p>ticle int5sity1 la/+ only = ab\t #ab seconds1 0 obs]v$ ov] a wide range ( en]gies = bo? protons & electrons at a di/ance ne> #b4ec ,saturn radii1 #bc m9utes aft] ,pione] cross$ ! ,saturn r+ plane inb\nd4 ,at ab\t ! same "t1 an anomaly 0 also obs]v$ 9 ! magnetic field measurem5ts4 ,^! ph5om5a h be5 t5tatively int]pret$ z indicat+ ! pres5ce ( a ne>by massive body absorb+ ! trapp$ radiation & p]turb+ ,saturn's magnetic field4 ,! e/imat$ radius ( ?is object lies 9 ! range ( #ajj to #cjj km1 bas$ on ! effectiv5ess ) :i* x absorb$ ! high-en]gy radiation4 ,! total radiation dose receiv$ at ,saturn 0 equival5t to only #b m9utes 9 ! ,jovian radiation belts because ,saturn's radiation belts 7 s mu* weak]4 ,9 addition to images ( ,saturn1 ! brightness1 color1 & pol>ization ( ! reflect$ light 7 also measur$ by ! imag+ photopol>imet] on ,pione] ,saturn4 ,^! measurem5ts are us$ to /udy ! cl\d lay]s ( ,saturn & ,titan & to model ! v]tical /ructure ( ! atmosph]es ( ^! two bodies4 ,9 ! scans t made ! images1 ! b&$ /ructures ( ,saturn & ( ! r+s 7 obta9$ 9 f9e detail4 ,^! are ess5tial 9 /udy+ ! atmosph]e1 r+s1 & moons4 ,a new ,saturnian r+1 :i* has be5 t5tatively designat$ ! ,f-r+1 0 discov]$ 9 ! images4 ,x is n>r[] ?an #ejj km 9 wid?1 b is important because x =ms an outside b>ri] to ! bright ,a- & ,b-r+s4 ,! gap betwe5 ! ,f- & ,a-r+s has be5 designat$ ! ,pione] ,division by ! ,pione] team4 ,a small moon1 :i* ei!r 0 previ\sly unkn[n or _h be5 previ\sly discov]$ f ,e>? b lo/ aga91 0 f\nd 9 ! ,pione] ,saturn images4 ,aft] its initial discov]y1 ?is new moon cont9u$ on its #ag-;h\r orbit ar\nd ! planet & pass$ ne> ,pione] z ! spacecraft ent]$ ! r+ sy/em4 ,x is q conceivable t ?is moon is ! same "o t p]turb$ ! radiation belt p>ticles & produc$ ! anomaly 9 ! magnetic field measurem5ts4 ,infr>$ obs]vations obta9$ dur+ ! ,saturn flyby reveal$ ! temp]atures 9 ! atmosph]es ( ,saturn & ! r+s & 9 ! atmosph]e ( ,titan4 ,x 0 f\nd t ,saturn has a temp]ature ( ab\t #ajj ,k 7ab\t #bhj;,f bel[ z]o7 &1 accord+ to ^! obs]vations1 has an int]nal heat s\rce ( en\gh /r5g? t ! planet emits approximately #b4e times z mu* en]gy z x absorbs f ! sun4 ,! equatorial yell[i% b& obs]vable 9 _m ( ! images 0 f\nd to be sev]al degrees cold] ?an ! planet at o!r latitudes & is probably a zone ( high cl\ds resembl+ simil> zones on ,jupit]4 ,z expect$1 ! r+s 7 extremely cold1 #fe to #ge ,k 7ab\t #ccj;,f bel[ z]o71 at ! "t ( enc\nt]4 ,! temp]ature diff]5ces betwe5 ! illum9at$ & unillum9at$ sides ( ! r+s1 & ! rate ( cool+ z ! r+ p>ticles g into ,saturn's %ad[1 sugge/ t ! r+ p>ticles are at lea/ sev]al c5timet]s 9 diamet] & ! r+s !mselves are _m p>ticle diamet]s ?ick4 ,! v m9or p]turbation to ,pione]'s trajectory1 z x pass$ "u ! visible r+s1 indicates t ! r+s probably consi/ ( ices4 ,z ,pione] pass$ ?r\gh ,saturn's r+ sy/em1 v s5sitive meteoroid detectors obs]v$ ! impact ( five p>ticles on ! spacecraft1 p>ticles t 7 ab\t #aj micromet]s 7#j4jjje in*7 9 diamet]4 ,two impacts occurr$ :ile ! spacecraft 0 above ! r+s & ?ree :ile ! spacecraft 0 bel[ ! r+s4 ,no impacts 7 detect$ go+ ?r\gh ! r+ plane1 b ! ,pione] in/rum5t _c detect individual impacts t occur less ?an #gg m9utes ap>t4 ,?is *>act]i/ic w\ld h prev5t$ detection ( r+ p>ticles because ( ! impacts detect$ j be=e bo? r+ plane cross+s4 ,x is unc]ta9 :e!r ! micrometeoroids detect$ by ,pione] ,saturn 7 /ray r+ p>ticles deflect$ out ( ,saturn's r+ plane or :e!r !y 7 p>ticles f int]planet>y space drawn inw>d t[>d ,saturn by its /rong gravitational field4 ,close to ! po9t ( close/ approa* to ,saturn1 ! spacecraft's radio transmissions 7 affect$ by ,saturn's ionosph]e4 ,! mann] 9 :i* ! radio signals 7 absorb$ indicates t ,saturn has an ext5sive ionosph]e compos$ ( ioniz$ atomic hydrog5 ) a temp]ature ( ab\t #abej ,k 9 its upp] regions4 ,?is high temp]ature requires an ext5sive en]gy s\rce o!r ?an ! sun4 ,?is ph5om5on 0 also obs]v$ at ,jupit]4 ,pione] measur$ ultraviolet gl[ ?r\gh\t ! ,saturnian sy/em4 ,?is ultraviolet gl[ is due to ! scatt]+ ( ! light f ! sun by atomic hydrog54 ,! obs]vations ( ultraviolet emission f an ext5sive cl\d ( hydrog5 gas surr\nd+ ,saturn's visible r+s are especially int]e/+4 ,! r+s !mselves are presumably ! s\rce ( ?is hydrog54 ,on ! planet's disk1 ! ultraviolet obs]vations %[ significant latitude v>iations1 sugge/+ ! possibility ( aurora ne> ,saturn's pol> regions4 ,a simil> ext5sive cl\d ( hydrog5 0 also se5 p>tially surr\nd+ ,titan's orbit4 ,^! v prelim9>y f9d+s by ,pione] ,saturn repres5t only a small fraction ( :at w ultimately be le>n$ ab\t ,saturn & its environm5t z ! spacecraft data are analyz$ 9 great] detail ov] ! weeks & mon?s ahead4 ,illu/ration3 ,s*ematic ( ! sol> w9d int]action ) ,saturn's magnetosph]e4 ,! sol> w9d arrives f ! direction ( ! sun1 is deflect$ at ,saturn's b[ %ock1 & fl[s ar\nd ,saturn 9 ! magneto%ea? 7orange region71 z indicat$ by ! arr[s4 ,! sizes ( ! magneto%ea? & radiation belts *ange 9 response to ! ext]nal sol>-w9d pressure1 becom+ small] :5 ! ext]nal pressure is l>g] & vice v]sa4 ,illu/ration3 ,diagram ( ,saturn's inn] trapp$ radiation belts4 ,! en]getic p>ticle fluxes g5]ally become m int5se clos] to ,saturn4 ,decreases 9 p>ticle flux at ! locations ( ,saturn's moons are due to ! sweep+ up ( ! en]getic p>ticles caus$ by p>ticles /rik+ ! moons & be+ absorb$ by !m4 ,also1 !re are decreases 9 p>ticle flux at ! out] edge ( ! r+s1 :]e ! en]getic p>ticles are also absorb$1 s t a region free ( trapp$ radiation is creat$ f ! out] edge ( ! r+s to ,saturn4 ,illu/ration3 ,infr>$ radiomet] image ( ,saturn & its r+s4 ,brightness 9 ! image is relat$ to temp]ature1 ) ! brighte/ areas at ab\t #ajj ,k 7ab\t -#bhj;,f74 ,! left v]sion %[s contra/ 9 ! cold] regions 7! r+s74 ,! "r v]sion %[s contra/ 9 ! w>m] regions 7! planet74 ,! image conta9s _m sep>ate scans f top to bottom4 ,ea* scan is displac$ to ! "r f ! "o be=e by ! motion ( ! spacecraft4 ,! spacecraft 0 bel[ ! r+ plane dur+ mo/ ( ! #c-;h\r obs]vation p]iod & 0 mu* clos] to ! planet at ! end ( ! p]iod 7"r ( image7 ?an at ! />t 7left ( image74 ,?us1 ! images are q di/ort$4 ,! small-scale patt]n is in/rum5t noise4 ,9 ! left image1 ! w>m infr>$ radiation f ! planet is se5 ?r\gh ,cass9i's ,division betwe5 ! ,a- & ,b-r+s4 ,! brightness level 9 ! "r image implies t ,saturn emits heat at a rate t is #b4e times ! rate t x absorbs en]gy f ! sun4 ,,outw>d ,,b\nd ,illu/ration3 ,aft] increas+ our k ( ! ,saturnian sy/em manyfold1 ! spacecraft is n[ outw>d b\nd4 ,x c>ries a message1 engrav$ on a plaque1 f ,e>? to any inhabitants ( ano!r /> sy/em :o might discov] ! spacecraft4 ,) its j\rney f> f ov]1 ,pione] ,saturn travels on--to ! out] rea*es ( space4 ,! ,pione] ,project is manag$ by ! ,ames ,rese>* ,c5t] = ! ,national ,a]onautics & ,space ,adm9i/ration4 ,! spacecraft 0 built by ,,trw ,sy/ems1 ,r$ondo ,bea*1 ,cali=nia4 ,national ,a]onautics & ,space ,adm9i/ration ,ames ,rese>* ,c5t] ,m(fett ,field1 ,cali=nia #idjce ,(ficial ,bus9ess ,p5alty = ,private ,use1 #cjj ,po/age & ,fees ,paid ,national ,a]onautics & ,space ,adm9i/ration ,,nasa-#dea ,illu/ration3 ,,nasa ,transcrib]'s ,notes --,reta9$ publication in=mation f ! pr9t$ edition3 ?is e,book is public-doma9 9 ! c\ntry ( publication4 --,sil5tly correct$ a few palpable typos4 --,add$ a ,table ( ,cont5ts4 --,9 ! text v]sions only1 text 9 italics is delimit$ by und]scores4