Repairing Solar Max the Solar Maximum Repair Mission

8/8/2019 Repairing Solar Max the Solar Maximum Repair Mission

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THESOLAR MAXIMUM REPAIR MISSION


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REPAIRINGSOLAR MAXTHESOLAR MAXIMUMREPAIR MISSION

NASANat iona l Aeronau t i c s a n dSpace Administrat ionGoddard Space Flight Center

by Tracy M cMahan a n d Valer ie Neal for the Office of Space Sc ience an d Appl icat ions , M ul t imiss ion M odular Sp a cecra f t F lighSupport Sy stem Project Off ice

ACKNOWLEDGMENTSWith appreciat ion fo r their contribut ions to this publicat ion: Frank CepollinaRobert Bridgers, Barbara Scott andJames Elliott of NASA-Godda rd SpacFlight Cen ter; Ro n McCul la r a n d Char les Redmond of NASA Hea dqua r te rs

For sale by the Superintendent of Documents, Robert Trevino, Thomas Woods, and M ichae l Gent ry of NASA-JohnsoU.S. Government Printing Office, Washington, D.C. 20402 Space Cen ter ; Ela ine M cGarry, Robert Womack and Brien O'Brien.

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ORIGINAL PAGE ISOF POOR QUALITYE

A new era in satellite operations - the era of orbital service andrepa ir-begins in the spring of 1984 on the STS-41C Space Shutt lemission. A team of ast ronau ts wi l l rep lace a fau l ty module on theSolar Maximum Mission satell i te, known as Solar Max.Repair isnecessa ry because three small fuse s in the at t itude con trol systemfailed, leaving Solar M ax una ble to point i ts instruments preciselya t targets of observation on the sun.Th e crew also wil l repairscientific instrumen ts aboard this orbiting solar observatory.Fortunately, Solar M ax is the f irst of a new breed of sa tell ites builtof standardized components a n d designed to be repaired in space.The fau lty at t itude con trol module is one of three replacea ble, box-like units that control power, commanding, a n d positioning of thesatellite. These un its are part of the mult imission modular spa cecra f tsystem, which makes up the lower portion of the Solar M a x satellite.The upper portion, the observatory, con tains seven dif feren t instru-ments fo r solar research.The Nat iona l Aeronaut ics and Space Admin is t ra t ion (NASA) wi l lint roduce daring technology a nd procedures to restore the sa telli tein a fea t never before at tempted in spa ce. Using a jet-powe redbackpack ca lled a manned maneuver ing un i t , one Shutt le crewmanwil l f ly 90 meters (100 yards) f rom the Shutt le cargo bay to theslowly spinning spacecraf t . The astronaut wil l not be connected tothe Shuttle by the usual tether line but will move freely throughspace. Although the maneuvering unit was tested by astronautsduring a previous Shuttle flight, this will be its first use in regu larmission ope rat ions.When the ast ronau t reaches the satell i te, he will capture it with a nat tachment device and stop its rotat ion by ac t ivat ing the man euver-ing unit 's thrusters. When Solar M ax is stabil ized, the Shutt le willmove 9 meters (10 yards) below it. Then, the remote man ipu la torsystem arm wil l grasp the satell i te and lift it onto a platform in theShuttle's cargo bay, the "workshop" for the repair operat ion.After Solar Max i s securely latched to the support plat form, theastronauts will begin the repa ir tas ks. They wil l use a special moduleservice tool to replace the malfunct ioning module with a n e w one,enabling scient ists once again to point the sophist icated instru-,ments on the solar observatory toward specif ic areas on the sun.The astronauts also wil l repair tw o accessible sc ien t i fic inst rumen tson the satell i te, bu t they will n ot attempt repair of a third malfunc-tioning instrument that is more diff icul t to reach.

The crew forSTS-41C, the Solar M aximum Repa ir M ission, includesCommander Robert Crippen; Pilot Francis R. (Dick) Scobee; andM ission Spe cial ists, Terry Hart , Dr . George D. Nelson an d Dr. Jamesva n Hoften. The crew rehearsed the repair mission at facilit ies a roundthe country. Although they are cross-trained and can assist eachother in various roles, each has been ass igned specif ic tasks du ringthe mission. As the commander, Crippen wil l be responsible forflying and maneuver ing the Shutt le during rendezvous, retr ieval,repair, an d redeployment of the satelli te. Scobee wil l assist Crippen,operate the fl ight support system an d coordinate the repair mission.Hart will operate the remote manipulator system. Nelson and vanHoften will share the repair tasks du ring two extravehicular act iv ities(EVA). *

Solar Maximum Repair Mission "Firsts"First Shuttle rendezvous and capture operation

with a free-flying spacecraftFirst Shuttle era spacecraft repairFirst Shuttle era instrument repairFirst Shuttle reboost of a free-flying spacecraftFirst direct ascent launch of the Space Transportation SystemFirst operational use of the Manned Maneuvering UnitFirst operational use of the Multimssion

Modular Spacecraft Flight Support SystemFirst operational use of the Manipulator FootRestraintFirst use of the EVApower toolsFirst extensive checkout of a spacecraft berthed to the ShuttleFirst use of a Pay oad Operations Control Center at aremote

location from the Mssion Control CenterFirst return of spacecraft hardware that has been in space

for several years


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SOLAR MAXIMUM RE

Magnetic field loops in a solar flare, as revealed by theSolar Maximum Mission Ultraviolet Spectrometer Polar/meter

ORI GI NA L PAGECOLOR PHOTOGRAPH


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R MISSION ORIGINAL PAGECOLOR PHOTOGRAPHStudying the Sun Launched high above the clouds andfi ltering atmosphe re on Februa ry 14. 1980. the Solar M a ximumobservatory was a source of very detai led information about thesun. For the f i rs t nine months of the plan ned two-year miss ion, thesatel l i te co l lec ted spectacu lar n ew data Hundreds o f sc ient is tsgathered at NA SA s Goddard Space Flight Center in Greenbelt.Mary land, and at ground observator ies around the wor ld to watchthe s u n a n d study so lar f laresThese solar f lares are tremendous explosions that rack the sun.sending radiat ion a n d matter toward Earth. Within hours after a f lareerupts, solar matter bombards the Earth, often interrupting radiocommunicat ions or cau s ing br il liant a uroras Flares occur most f re-quently during the sun's active cycle, which peaks every 11 years .Scient ists dec lared 1980 the So lar Maximum Year and launchedSolar M ax in an e f fo r t to learn more a bout f lares and the sun dur ingthis ac tive period.Flares, l ike thunderstorms on Earth, are complex; no single i ns t r u -ment can moni to r a l l the i r features . The So lar Max observatorycarr ies severa l dif ferent i ns t r uments tha t ca n observe f lare featuressimultan eously. Six of the ins t rumen ts mon i to r f lare rad iat ion in par tsof the electromagn etic spectrum from visible l ight through ultra violeta n d X- ray emission to gamma rays . S c ient is ts c an u s e data f romthese ins t ruments to unders tand bet te r ho w f l a res s ta r t , ho w theyre lease their energy, and how they a f fec t the Earth. A seventhins t rument on board the satel l i te monitors the sun's total radiat ion.Smal l chan ges in the sun 's rad ian t ou tput could drama t ica l ly a f fec tthe Ear ths wea the r a n d c l imate . Af ter t rack ing hundreds of f laresbefore the satel l i te lost its f ine pointing control, scientists madenumerous d iscover ies and ra ised many new quest ions about thesun .Repair Mission Rationale There are many reasons forrepair ing Solar Ma x and extending its mission. Solar M ax is the on lysolar observatory cur rent ly in orbit. A successful repair wil l restorethe $77-mil l ion satel l i te at an estimated one-fourth of i ts replace-ment cost a n d wil l extend the ope ra t iona l life of the observatory fo rseveral years .M a n y pieces of the solar f lare puzzle a re sti l l missing, a nd scien tistsneed cont inu ous an d very precise mea suremen ts o f f lares to deter -mine how they a f fec t the Earth. Using the insight gained from ninemonths of pr ior Solar Max observations and three years of dataana lys is , scien tists ca n pinpoint wha t they need to wa tch. Resu ltsfrom the earlier observations will guide plans for the renewed mission

By the time Solar M ax is restored, the solar cycle wil l have progressed four years to a quie ter phase, pu nc tu ated by s t rong buless frequent f lare activity Scientists will have an u nforeseen chancto focus on the quie ter sun an d compare d i f fe ren t phases o f so laactivity. Solar scientists ca n renew their search fo r so lar - te r res tr iconnect ions . As a rev ived So lar M ax beams more in fo rmat ion Earth, they may unders tand more c lear ly why explos ions on thsun bombard the Earth with energetic part ic les that disrupt commun icat ions , endanger orb it ing spa cecra f t , dama ge power s tat ionan d alter the chemistry of the a tmosphereSolar scientists wil l not be the only ones to benef i t if the f a u latt i tude con trol module is replaced an d the solar observatory is oncagain working properly. The scientific community at large will nlonger be virtua l ly helpless to save equipmen t tha t malfun ctions ispace. The mission wil l demonstrate that the Shutt le can be usea s a space repair vehicle supplied with crews and parts to servicsatellites. No longer will it be necessary to abandon mul t imi l l iodollar spa cec ra fts becau se of local ized hardware problems.During the Shutt le era of orbital repa ir and modu lar design, sa te l l i tma y no longer have to re ly on expens ive, back-up componentdesigned into systems to prevent their f a i l u re. Other ma jor observator ies designed with replacea ble modu les for orbital servic ingincluding Spa ce Telescope, the Lan dsat se r ies of satel l i tes, and thGamma Ra y Observatory, can be as s u r e d of miss ion successhost of f u tu re satel l i tes can be expected to benefit from the procedures a n d hardware demonstrated in the Solar Maximum RepaMission.

The sun's outer atmosphere, the corona, a s revealed by the SolMaximum Mission Coronagraph Polar/meterLeft: the quiet corona, with streamers of outflowing gasAbove: aneruptive prominence of cooler, denser material from thlower atmosphere


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ORIGINAL PAGECOLOR PHOTOGRAPHSOLAR MAX RENDEZ

Retrieval


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\PHUS& RETRIEVALScient ists and technic ians at NASA-Goddard commanded SolarM a x du rin g i ts nine m onths of su cces sfu l solar stu dy They wil l playan importan t role in helping the Shu tt le rendezvous with the sa tel l i teSixty days before launch, a miss ion team work ing in the N A S A -Goddard con trol cen ter wil l pinpoint the satel l i te s exact location a n dbegin to prepare So lar M ax for the Shut t l es approach . After th elaunch, they wil l advise the Shutt le crew of the satel l i tes exactrotation rate and incl ination, and they wil l position Solar Max forrendezvous and cap tu reIt is predicted that Solar M a x will be orbiting the Earth a t approxi -mately 50 0 kilometers 37 kilometers (270 * 20 nautical miles) a ta n incl ination of 28.5 degrees above the Ear th Th e Shutt le wil lreach this high orbit by the f irst direct ascen t l aunch in the historyof Shutt le operat ions .Besides a satel l i te payload that wil l be deployed dur ing the secondda y of the mission, the Shu tt le will ca rry the i tems needed to repairSolar M a x : the f l ight support system, th e replacement a t t i tude con-trol system module, instrum en t repair parts, the module se rvice tool,repair tools, an d the manne d man euver ing un i t . Before approachingthe sa tel l i te, the crew will activate an d perform sy ste m checks onthe flight support sys tem and the remote man ipulato r sys tem Bothsystems are essent ia l to the suc cess fu l re t r ieva l a n d berthing ofSolar M a x .Equipment Checkouts After l aunch, on the f i rst day ofth e seven -day mission, th e crew w i l t checkout the equipment. Animportant piece of equ ipment is the f l ight suppor t sys tem, a mount -in g plat form for the sate l l i te dur ing repai rs . This suppor t sys temmates with th e mult imiss ion modu lar spa cecra f t base of the satel l i te.Th e f l ight support system is a U-shaped s t ruc tu re tha t fil ls the widthof the 4 5-meter -wide (15-foot) cargo bay. It cons is ts of three cradles(ca l led A B. an d A-pr ime) an d a c i rcu la r berthing ring to which thesatellite will be an chored This sys tem can be u sed again and aga in

BerthingLa tchBerthingRing

Cradle A PrimeCradle B

on service an d repair missions Simulations at Johnson Space Ce nte r using ful l-scale models of the f l ight support system . Solar M axand the Shutt le proved that the satel l i te could be berthed to thsupport system successfu l ly . During training on these models, tha s t r o n a u t s d e m o n s t r a t e d t h a t t he y hav e ad e qu a t e r o o m anmaneuverabi l i ty to repair the sate l l i te .The f l ight support system has 12 motor-dr iven mechanisms thaprovide mechanical an d electr ical con ne ctions between the sa tel l ian d the orbiter dur ing the repairs. A berthing r ing a t tached to c rad lA-prime is stored vertically inside the crad les dur ing launch but pivoted into horizonta l posit ion for satel l i te repairs. A rotator on thr ing can be used to turn the sa te l li te , an d a pivo ter can be used ttilt the sate l l i te to any pos i tion f rom u pr ight (90 deg.) down to horzon ta l within the cargo bay (0 deg.) If the r epa i r s to the spacec rashould fa i l , the so lar pane ls c an b e je t t isoned an d the satel l i te cabe lowered to the horizontal stowed posit ion and locked into thflight suppor t sys tem fo r re turn to Earth.To secure the satel l i te to the plat fo rm r ing, three jaw- l ike ber th inlatches will c lamp onto pins near the bottom of Solar Max on thmult imission modular spacecraft base. Nearby two umbil icals wplug into the sate l l i te to provide S hutt le powe r an d heat to SolaM a x during the repai rs . Th e as t r o nau t s will turn o n a n d check thmotor-driven un i ts in the f l ight suppor t sy s tem before they rendezvous with the satel l i te.

Flight Support System Configuration forthe Solar Maximum Repair MissionSolar Max model used in engineeringevaluations and training


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ORIGINAL PAGECOLOR PHOTOGRAPHThe remote man ipu la tor sys tem or robot arm. which wi l l be used tograpple the sa tel l i te, also wi l l be checked ou t The 15 2-meter (50foot) Canadian-bu i l t a rm has been tested a n d used on prev iousShutt le missions to deploy, grapple, and retr ieve var ious objectsDur ing this mission, the arm will be used to ret rieve Solar M ax.place it in the orbiter payload bay on the fl ight support system, a n dlater redeploy i t when the repa irs are completed Having performedthe var iou s equ ipment checkouts before beginning th e rendezvousopera t ions , the crew wil l complete their f i rst day's act iv i t ies.On the second day of the mission, at an al t i tude of 482 ki lometers(260 na ut ical miles), the crew wil l deploy an other sa tel l i te locatedin the f ron t end of the cargo bay. Launching the additional sate l l i teal lows NASA to accomplish two ta sks on one Shutt le f l ight. Follow-ing this operat ion, the Shutt le wi l l maneuver to an al t i tude of 502ki lometers (270 na ut ica l miles) to rendezvous wi th Solar M ax M is-sion teams a t NASA-Godda rd s cont ro l center wi l l do a remotecheckout to ensu re tha t Solar Max i s sa fe a n d ready fo r cap tu r eAfter th e ast rona uts s ight Solar M ax. they wil l report their observa -t ions, sta t ion the orb iter 90 meters (100 ya rds) awa y, and then beginprepar ing for their busy schedule the next dayCapturing Solar Max After mission control informs thecrew that Solar Max i s ready fo r c a p t u r e , tw o ast ronauts wi l l p repareto leave the Shut t le crew compar tment an d work outs ide in spaceThey must a wa ke ear l ier than usua l to prepare thei r bodies for theext raveh icu la r act iv i ty , during which they wi l l breathe pure oxygen.Before suit ing up. they wi l l breathe pure oxygen for four hours tof l ush the ni trogen from their b lood After they don their space s u itsin the Shutt le's middeck air lock, they wi l l depressur ize the air lock,open the outer hatch, and use handra i ls to move to the manned

EVA ITimelinenun iuhuu

Manned Maneuvering Unitman euver ing un i t, which is s towed in the cargo bay . After one c rewma n dons the manned man euver ing un i t, he wi ll per form a b r icheckou t f l ight in the ca rgo bay.Th e manned man euver ing un i t is a 149-k i logram (330 poun d), seconta ined mob i l ity un i t tha t is a s pa cec ra f t in i tsel f . Powered by twsets of 12 gaseous n i t rogen t h r us t e r s . it will move the a s t r o n a u tSolar M ax a t a max imum speed of .6 meter s pe r second (1.5 milpe r hour ) . The backpack was tested for the f i rs t time during ST11B when an ast ronaut f lew approx imate ly 90 meters (100 yardwithout a tether. Th e maneuver i ng un i t s r ange is cur rent ly 30

1 un/ niriuuK ^HOURSAstronauts enterairlock anddon mannedmaneuvering unit

MMUcheckoutflightAstronaut capturesSolar MaxManipulator armholds satellite andberths it to flightsupport system inShuttle cargo bay


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ORIGINALC OL OR P H OTOGRA tmeters (1.000 feet) . While the Shutt le is parked 90 meters (100yards) from Solar Max. one astronaut wil l f ly the distance to thesatellite and u se the manned maneuver ing un i t to stop its rotationIn the unlikely event of a malfunction, the maneuvering unit an dcontingency procedures a re designed to protect the as t r o nau t ssafety. The orb i te r would move toward the s ta l led c rewman andscoop him into the open cargo bay.This precision maneuve r i ngcapabi l i ty ha s al ready been demonstrated in fl ight.Grabbing a moving satel l i te is a chal lenge, because even a weight-less sa tel l i te retains a l l the momentum of i ts spinn ing. Practic ing ina manned man euver ing un i t s imulator , the c rew demonstrated thatthe backpack s 1.7-poun d thrus ters can be used to stabi l ize objectsrotating faster than Solar M a x. The sa tel l i te is predicted to be rotat-ing at 1 degree per secon d or 1 rotation every 6 minu tes. Thea s t r o n a u t wi l l match th e s a t e l l i te s r o t a t i o n , using th e mannedmaneuver ing un i t to maintain his position while he docks with thesatell ite. To dock, he wi ll conn ect a t runnion pin a t t achment dev ice ,cal led a T-PAD. that is ca r r ied between the ma neu ver ing un i t handcontro ls to a t runn ion pin pro trud ing f rom Solar M ax. The a s trona utwill remain docked to So lar Ma x. us ing the maneu vering un i t thrus-ters to stabi l ize the sa tel l i te un til the Shutt le 's remote man ipulatorarm can grapple i t.

Berthing Solar Max The Shutt le wil l then move into postion 9 meters (10 yards) below Solar Max. and the robot armmove upw a r d a n d grapple a n exis t ing f ix tu re between th e sa te l l i t esolar observatory an d the mul t imiss ion modular sp ac ecra f t basDur ing the re t r ieval operat ion, the a s trona ut operat ing the arm f roinside the Shutt le must avoid hitting a n d damag ing the delicate solar rays tha t power the satel l i te.When the robot arm ha s a secure hold on the satel l i te, the astronawill remove his a ttachmen t device a nd move clear of Solar M awhile the arm br ings the sa tel l i te to the f light support sy stem in threar of the Shutt le 's cargo bay.The berthing ring will be in thhorizontal posit ion when the arm moves the satel l i te to the suppoplatform Crew members inside the Sh u tt le wil l c lose the ja w-l ikberthing latches located on the ring around p ins on the sa te l l i tWhen the la tches have secured So lar Max in p lace, the arm wrelease the satel li te. Then Solar M ax w il l be rota ted into the correposition for repairs. During this operation, the r ing must be t i l tslightly to keep the satel l i te 's so lar a r ra ys f rom hi tt ing the orbi teMeanwhi le , the astronaut who is using the manned maneuverinunit will return to the orbiter a n d stow the backpack in the cargbay.Before the repairs begin, special ists a t NASA-Godda rd wi ll turn oSolar M ax s power. The cre w can con trol power f low to the sa tel l ionce it is connected wi th the fl ight support system. Space Shuttheaters wil l be used to keep the satel l i te at the proper temperatuan d provide power for the sa tel l i te as neededNASA intends to berth the satel l i te dur ing dayl ight, which lasts f60 minutes dur ing each 100-minute orbit of the Earth. Some of threpairs wil l be performed as the Shutt le moves through half-honights, but orbiter l ights an d astrona ut helmet l ights wil l al low repaito cont inue

'HOURS HHOURS SHOURSAstronaut removesold attitude controlmodule

Astronaut installsnew attitudecontrol moduleand vent cover

Equipmentstowage


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ORIGINAL PAGECOLOR PHOTOGRAPHRESTORING SOLAR M

Repairs


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Servicing the Spacecrafta re performed in low Earth orbit with the Shutt le s cargo ba y doorsopen. The two repa ir crewmen wi l l be anchored to the Shutt le by156 mete r (5 0 foot) safety te thers O n e astronaut wil l insert a workstat ion in the end of the remote man ipu la tor a rm This work stat ionha s han dholds an d foot restrain ts to hold the astrona ut in place ,tether attach points, a n d tool boards w here va rious tools a re mountedO n e ast rona ut wi ll opera te f rom the work stat ion, while the othermoves freely a round the ca rgo bay The ast ron au ts wil l move to atool locker loca ted at the base of the horseshoe-shaped flight sup-port system Various tools a n d equipment necessary for the repairtasks a re stowed in the locker. Before serv ic ing the spacecra f t , theas t ronau t s will cover the att itude control module's sensit ive start rackers which help poin t the satel l i teThen, they will remove the module service tool, designed especial lyfor exchanging modules in the mult imiss ion modular spa cecra f tsystem The tool is cont ro l led by two handles and two swi t ches . Tw olatches on the tool fit into oblong ho les on the module a n d hold it inplace as the socket wrench on the end of the tool loosens a re ten -tion bolt Each box-l ike module is a t t ached to the mult imission mod-u la r spacecra f t by two bolts. If the as t rona u t used a regu lar wrenchto remove these bolts, he would tu rn whi le they remained un moved.The a s t r o n a u t will disengage the lower bolt of the f au l ty moduleThen, he will disengage the upper bolt a n d slide the module off thesatell ite, us ing the serv ice tool to hold th e module. Th e man ipu la to ra rm will then move him to a temporary storage area, where he willplace the old module.Th e as t r onau ts mu st work slowly while moving the modules around.Although they a re weight less in space , the modules are 1.2 metersby 1 2 meters by 5 meters (4 feet by 4 feet by 1.7 feet) large an dweigh 225 kilograms (500 poun ds) on Earth If they were set inmotion, they would be hard to con t ro l

The two ast rona uts wi l l then remove the stowed replacemen t attude control module by grasping it with the module service tooThe astron au t on the en d of the a rm wil l be moved up to the site the att itude control module a n d will use the module service toolsecure the ne w module to the spa cec raf t The old module will thebe placed in its proper storage locat ion fo r return to EarthTh e next task will be to place a baf f le , or cover, on the satell i te s Xra y Polychromator un it, which me asu res X - r a y emission f rom solf lares and shows sc ient is ts how par t ic les are moving an d changinin the hot solar f lare gases Plasma, the electr if ied ga s tha t f lowthrough space , is leaking into the ins t rument a n d distorting the da tit sends to Earth. Th e ast ron au t wi l l remove the baff le f rom the tolocker a n d then be moved on the manipulator work stat ion to thi n s t r umen ts exhau st vent , located above a solar a r ray on one sidof the satell i te. Th e 6.9-cent imeter (2 .7 5 inch) baff le s n a p s on thvent with spring clips; n o ext ra tools a re needed to a t t a c h it.When the f irst repair operat ions a re completed, the crew wil l storall equipment and go inside the orbiter The mission team at thNASA-Goddard cont ro l center will t u rn on Sola r M a xs power a nperform an eight-hour remote checkout of the satel l i te's systemShould there be someth ing cruc ia l ly wrong with the sate l l i te , isolar panels can be je t t isoned and i t can be lowered into the Shut le's cargo bay and returned to Earth.

Module Service Tool


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ORIGINAL P/ "COLOR PHOTOGI

Repairinga Scientific Instrument If he checkout indi-ca tes that the satel l i te s systems a re functioning properly, th e astro-nau ts wil l repair another scienti f ic instrument on the f i f th day of themission The crew wil l spend the fourth day of the mission restingand servic ing their space suits. Before the second extravehicularactivity begins, the Shutt le wil l maneuver to a higher orbit if it hasadequate fue l . Solar Max was l aunched in to a n orbit of 574 kilo-meters (310 nautical miles), a n d scientists would like for it to beredeployed at an alt i tude n ear i ts or igina l orbit.The as trona uts wi l l do n their space suits again a n d move throughthe air lock into the cargo bay to repair the observa tory s Corona -graph Polan meter One crewman wi ll operate f rom the man ipulato rfoot restrain t work stat ion . The other crewman wil l move between aworksite near the tool locker a n d a works i te at the CoronagraphPolarimeter. which is located near the bottom of the solar observa-tory. He will hand tools to the astronaut mounted on the robot arma n d assist him as needed.The a s tronau ts wi ll be replacing the main e lec tronics box in theCoronagraph Polar imeter. a n i ns t rument that is used to study th esun's outer atmosphere or corona by creating art i f ic ial ecl ipses.Unlike the mult imission modular spa cecra ft un its that provide theutilities for the satellite, the scientific instruments on board SolarM ax were n ot designed to be replaced or repaired in space. Th ecoronagraph's main electronics box is mounted inside the insulatedshell of the observatory, but its location is access ib le enough tomake a repair attempt feasible. This repair operation is est imatedto take three hours a nd is more complicated than the removal of thefau l ty at t i tude contro l module .Th e tool kit for this repair includes scissors, adhesive tape strips, aratchet tool, a n d a bat te ry-operated screwdr iver for use on screwsa n d bolts. Th e ratchet tool wil l be avai lab le a s a subs t i t u te for theelectric screwdriver.To remove the electron ics box. which is ab o u t the size of a br ie fcase,an d ins ta l l a new one. the as trona ut w i l l open a pan e l in the observ-atory shel l at the location of the box. He must cu t through the foi linsulation a n d remove screws that secure a protective thermal blan-ke t over the box. After taping the thermal b lanket a n d i nsu lat ion ou tof the way . he wil l instal l a hinge a n d remove the remain ing screwsto open the panel that covers the mam electronics box.Next, he wil l unplug cables from th e electronics box. remove th ebox a n d pass it to his partner, wh o wil l hand him the replacementelectronics box from the tool locker. The new box wil l be instal led.a ll connectors wil l be remated. the door closed a n d secured, a n dthe protective nsu lat ion reattached.EVA IITimeline

Deploying Solar Max When the astronauts have completed this repair, they will stow a ll equipment. Special ists at thNASA-Goddard contro l center w i ll turn on So lar M a xs power anperform a remote systems check for. the last t ime. Th e manipulatoa rm wil l grapple Solar M a x a n d move it outside the cargo bapointing it toward the sun .While it is on the arm outside the Shutt le , miss ion tea ms a t NASAGoddard will remotely deploy the satellite s high gam an tenna Than tenna wi ll a l low th e satel l i te to send d a t a to Earth through NAS An ew Tracking an d Data Relay Sate l l i te System The two extravehicular activity crewmen wil l watch the antenna deployment fromthe forward bulkhead of the cargo ba y an d then return inside througthe air lock.While the crew rests overnight. Solar M a x will remain attachedthe arm outside the cargo bay. On day six. the arm will release thsatell ite, and the Shutt le wil l back away. Th e crew wil l spend threst of this da y performing checks on the flight suppor t sys tem a npreparing to deorbit. On the seventh day. the Shutt le wil l land aKennedy Space Center w i th So lar M ax 's f a i l ed pa rts, which wil l breturned to NASA-Goddard fo r engineer ing analys is .

n umIDCunuuKj HOUR 8 HOURSAstronauts enterairlock and preparefor repair

ReplaceelectronicsboxReplaceelectronicsbox


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ORIGINAL PAGECOLOR P H O T O G R A P H

Mission Spec ial ist Dr. George Nelson pract ices removing the mam electronics box of the Corona grapin the Neu t ra l Buoyan cy Simulator at NASA-M arsha l l Space Flight Center

anmeter underwate

H HOUR* innoc1UU\-IReplaceelectronicsbox

Checkout satellitefor deployment Checkout satellitefor deployment


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ORIGINAL PAGE"COLOR PHOTOGRAPHSIGNIFICANCE OF SO

Deployment


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M AX REPAIR ORIGINAL PurrCOLOR PHOfO ?

Space Telescope. Landsat-4 and the Gamma Ra y Observatory belong to a new family of satellites designed fo r orbital repairWhen the Shut t le lan ds at NASA-Ken ne dy, the Solar M aximumMission will begin a n e w phase. A revived Solar M a x wil l be mon-i tor ing act iv i ty on the sun an d re turn ing new data to Ear th. M ean-whi le, th e f i r s t a s t r o n a u t s to repai r a sate l l i te in s pac e will re turnhome wi th prac t ica l in fo rmat ion about serv ic ing sate l l ites .Renewing Solar Science Besides learning many prac t i -ca l lessons in servic ing satel l i tes. NASA will ex tend the life of SolarM ax and enable scientists to cont inue their studies of the sun froma sophisticated orbital observatory. M ajor a dvan ces in groun d-basedmicrowave a n d opt ica l ins t rumenta t ion will make n ew collaborativeobservat ions possible. An swe rs may be fou n d to some of the qu es-t ions raised by Solar M ax da ta col lected previously.Th e ren ewa l of the Solar M ax i mum Mission offers several majorbenefi ts to solar physics a n d so la r - te r res t r i a l stud ies . Cont inuedobservat ions should help to solve the f lare puzzle and give us newinsight into the processes of energy bui ld-up and release on thesun and other stars. Better un derstan ding of the flare process shouldenab le better prediction of f lare events and the disruptive radiat ionthat ma y af fect spacec ra f t or vulnerable electronic equipment onthe ground . An extended mission wi l l ena ble lon ger- te rm measu re-ments of tota l solar output, which a re necessary fo r cor re lat ingchanges in Earth s wea ther an d cl ima te with chan ges in solar ra dia-tion. Final ly, coordinated observations of the atmosphere wil l revealho w ozone a n d other const i tuen t ga ses vary wi th so lar ac t iv i ty .The Era of Orbital Repair If the Solar Maximum Repai rMission is successful, investigators on f u t u re projects need n otworry about missions being cu t short before they have met p lannedscientif ic objectives. A blown fuse or a short circuit in a sate l l i te n olonger wil l end its l i fe. With modular design and replaceable parts,scient ists will be able n ot only to repai r mal func t ions bu t also to t akeadvan tage of new technology to replace instruments and to improvetheir observations. The l i fe of the satel l i te may be lengthened a n dits operat ion enhanced becau se i t can receive n ew state-o f- the-ar tcomponen ts , subsystems, a n d exper iments .Some new observator ies, such as the Advan ced X - R a y Astrophys-ics Facil i ty an d the Space Telescope, wil l have modu lar in strum en tsdesigned to be replaced or repaired in space. These n ew designswill make tasks similar to replacing the electronics box in Solar M axa s easy as changing the modules on the satel l i tes base. Modu l a rdesign wil l also al low scientists to use instruments which requirespecia l coolants or f luids that must be replenished fo r cont inuedoperationBecause the Shutt le wil l carry the used att i tude control module a n d

electronics box home in the cargo bay. scientists can check theseold parts for contamination and determine the effects of long-termspace exposure on hardware. The att i tude control module f romSolar Ma x will be refurbished for reuse on a Lan dsat sa tel l i te. Sci-entists wil l learn wha t kinds of equipment an d resources a re n eededto refurb ish used s atel l i te parts. Th e magn i t ude a n d cost of reworking the Solar M ax parts will help to esta bl ish guidel ines for designingand bui ld ing f u t u re spacecraf t par ts .As repair missions help perfect the modula r conce pt of sta nda rdizedspacecra f t , par ts may be mass-produced and bulk-purchased tocreate an inventory of a vai la ble spare pa rts. Then money a n d designefforts can be focused on the scienti f ic instruments required for thedif ferent missions instead of on bui lding the entire satel l i te fromscratch.The cost-e ffective use of the Shutt le a s a repa ir vehicle for satel l i teswill become a real i ty. The Solar M aximu m Repair M ission wil l giveNASA prac t ica l in fo rma t ion about des igning sate l l i tes more ef fectively fo r re t r ieval and repai rs by Shut t le c rews. New hardwarei tems, such a s the mann ed man euver ing un i t , the f l ight sup por tsys tem, and the module service tool, wil l prove the i r usefu lnessa n d wil l be ava i l ab le fo r other missions using th e mult imissionmodular spa cecra f t sys tem.Solar Max is only the f i rst of the n ew breed of sate l l i tes . NASA plan sto build many satellites with modular, replaceable components. Othersatel l i tes that may be repairable in space include the Landsat ser iesthe Space Telescope, the Upper Atmosphere Research Satel l i tethe Gamma Ray Observatory , and the Advan ced X-Ra y Astrophysic s Facil i ty.A suc cessfu l Solar Ma ximum Repair M ission not only wil l restorethe world 's only orbit ing solar observatory but also wil l open a brandn ew era in the practical ut i l i za t ion of spac e. This mission blazes thetrail for a promising new venture - commerc ia l manufac tur ing inspace - by demonstrat ing the use of Amer ica 's Space Tran spor ta-tion System for scheduled servic ing of orbital fa ci l i ties.Through the confidence estab l ished by this pioneering mission insatellite rendezvous, c a ptu re , repai r, redeploymen t, a n d ha r d w a r eretr ieval , compan ies wil l be encouraged to assume the high r isks ocommerc ia l manufac tur ing in space Pharmaceut ica l companiesfo r example, should be ab le to man ufa c ture bet te r medicines economical ly in space in the very near futureAs the Solar Maximum Repair Mission opens this new opportunity,c itizens ca n look forwa rd to man ifold b en efits from their in vestmentin space. *


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REPAIR MISSIONCREW

ORIGINAL PAGECOLOR P H O T O G R A P H

A. Robert L. Crippen.STS-41C CommanderVeteran of two previous Shutt le missiona s Pilot fo r STS-1 a n d Commande r fo r STS7.

B. Francis R. (Dick) Scobee,S T S - 4 1 C PilotAerospace Engineer and instructor pi lot foth e NASA Boeing 747 Shu t t le car r ie r p laneC. Dr. George D. Nelson,S TS - 41 C Mission SpecialistAstronomer with exper ien ce in astronomicresearch, deve lopment of the Shutt le -erspace suit, and mission support for the STS3 an d STS-4 miss ions.D. Dr. James D. van Hoften.S T S - 4 1 C Mission SpecialistHydraul ic E ng i ne e r a n d leader of the Astro

n a u t Support Team responsible fo r S pacShutt le tes t ing a n d f l ight prepa rat ions , w i texper ience i n Shu t t le gu idance , n av iga t iona n d f l ight contro l .E. Terry J. Hart.S T S - 4 1 C Mission SpecialistM e c h a n i c a l and E lec t r i c a l Eng inee r w i texper ience as a suppor t c rewman for th

STS-1. STS-2. STS-3 a n d STS-7 m iss ions

Modular Spacecraf t- The New GenerationSolar Maximum MissionSpace TelescopeGamma Ray ObservatoryAdvanced X-Ray Astrophysics FacilityShuttle Infrared Telescope FacilityLarge Deployable ReflectorAdvanced Solar ObservatorySystem-ZLandsat seriesUpper Atmosphere Research SatelliteLeasecraft and other commercialspacecraft


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Repairing Solar Max the Solar Maximum Repair Mission

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