NASA Facts Surveyor

8/7/2019 NASA Facts Surveyor

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N A S A ~ f f i ~ AN EDUCATIONAL PUBLICATION OF TH E

NATIONAL AERONAUTICS AND SPACE ADMINIS TRATIONNF-35/VO L. IV , NO . 6

OnSurveyor

On May 30, 1966, Surveyor I climbed away fromCape Kennedy, Florida , aboard an Atlas-Centaurrocket . On June 2, 1966, sixty-three hours andthirty- six minutes later, after traveling almost aquarter of a million miles, it landed within nineExact counterpart of the Su rveyor I spacecraft whic h madethe first U.S. " soft landing" on the moon June I , 1966.It is one of seven which will be sent to the moon t oin vestigate the surface environment prior t o manned landings expected to begin about 1970. It is iden ti ca l t oSurveyor , ,, which landed on the moon , April 19, 1967,

miles of its target in the Ocean of Storms close tothe lunar equator.During the six weeks following Surveyor's landing-while the sun set, rose again 14 earth dayslater and set a second time on Surveyor's landingexcept fo r t he surface sampler (see inset) fastened to ame tal extendable arm. About f ive inches lon g and twoinches wide the device, on radioed command , is able toex tend itself about f ive feet and scoop or dig into the lunarsurface. In the larger photo , the turret to the left of themast houses a television camera .


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site-the spacecraft transmitted to NASA earthstations 11 ,150 high-resolution pictures of thelunar surface. The pictures were excel lent in qualityand so clear in detail that scientists have been ableto measure and to count particles as small as onefiftieth of an inch in diameter. The reso lution ofthe pictures was 1,000 ,000 times better than couldbe obtained by the be st earth-based telescopes and1,000 times better than the best pictures takenby the Ranger spacecraft. The pictures recei vedacross the 247 ,000 -mile gulf separating the twocelestial bodies provid ed scientists with a view of

Fig. 1 Schematic diagram of launch phasetrajectory of Surveyor I.

ATLASCENTAURSEPARATIONPHASE

the lu nar surface of about one-and-one-half milessurrounding the spacecraft.

On July 13, during its 42nd day on the moon ,Surveyor I, after enduring the intense heat of thetwo-week lunar day (250 degrees F. maximum) ,and the cold of the two-week-Iong lunar night(minus 260 degrees F.), radioed 812 additio nalpictures to earth during its second lunar day onthe moon .

Surveyor I wa s the first of seven lunar soft landing missions planned for 1966 through 1968. Itstest objectives called for Surveyo r to accomplish

INJECTION INTOLUNAR TRANSFER ORBIT

SURVEYORSEPARATION PHASE(CENTAUR COASTRATESTABILIZED)

MAINENGINESIGNITION

ATLASSUSTAINERPHASE AJETI ISONNOSE FAIRING

INSULATION PANELS

--LAUNCH FROM CAPE KENNEDY

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an ex tremely difficult mission. Its AtlasCentaurlaunch vehicle had to launch it towa rd the moonwith such accuracy that a small correction of itsflight path by a mid-course maneuver would bringit to a spec ific spot above the moon 's surface.Then , Su rveyor wa s required to automatically fi reits main solid propellant retro engine and controlthree smaller l iquid engines to slow it s speed from6000 miles an hour to a land ing speed of only7.5 mph. This critical descent phase, under thecontrol of a completely automatic on -board softla nding guidance an d control system, had neverbeen accompli shed before and required precisiontiming and flawless exe cution .SURVEYOR FLIGHT

Surveyor I l ifted off Launch Pad 36-A at CapeKennedy within one second of its planned launcht ime- lOAl :01 a.m . Eastern Daylight Time-onMay 30, 1966 (See Fig. 1). Subsequen tly , alllaunch vehicl e and spaceflight events occur redsatisfactorily.

Both antennas and the spacecraft's three landinglegs were commanded by the Atlas-Centaur programmer, about 12 minutes after liftoff , to ex tendfrom thei r folded launch position to the flight andlanding position . Fli ght controllers re ceived telem etry information , however, indicati ng that AntennaA, one of Surveyor's two low gain antennas, failedto deploy.

Later , after Su rveyor I tou ched down on themoon , telemetry showed that the an tennas wereproperly ex tended. Television pictures from Surveyor's camera of t he antenna and its latchingmechanism provided verification of this.

Th e critical termina l descent began 31 minutesand 2000 miles from the moon with a series ofcarefully planned maneuvers to align Surveyor'sretrorocket with its approach direction , just fivedegrees from local lunar vertical.About 28 minutes later, Surveyor's altitudemarking radar sensed the nearness of the m o o n -59% miles away-and started the automaticsequence that fi red first its three small vernierengines and t hen its 9 ,000-pound-thrust mainretromotor . At that moment, Surveyor was 46 %miles above the moon and traveling at 5840 milesper hour.The powerful retrorocket blasted for 39 secondsand slowed the spacecraft to 267 miles an hour bythe time it had descended to 35 ,000 feet altitude.The rocket motor case automatically detached

itself from Surveyor at 31 ,000 feet , and threesmaller rocket engines which earlier powered themid-course maneu ver, continued to slow thede sce nt. These little rockets , called verniers ,reduced the spacecraft 's speed to 71.4 miles perhour by the time Surveyor was 1000 feet abovethe moon and finally to 2.8 miles an hour whenthey cut off about 10 feet above the lunar surface.Fig. 2 Schemat ic di ag ra m of terminal descentevents to moon 's surface.

\\ \\~ ""''' m""",

\\k PRERETRO MANEUVER 30 MINBEFORE TOUCHDOWN ALIGNSMAIN RETRO WITH FLIGHT PATH\\~ MAIN RETRO START BY ALTITU DEMARKING RADAR WHICH EJECTSFROM NOZZLE, CRAFT STABILI ZEDBY VERNIER ENGINES AT60MI ALTITUDE , 5 ,90 0 MPH\\\\\

I~

MAIN RETRO BURNOUT AND EJECTION,VERNIER RETRO SYSTEM TAKEOVER AT31 ,00 0 FT , 267 MPH

VERNIER ENGINES SHUTOFFAT 10 FT , 2.8 MPH

-_-:>- . .. ~ - . . , . " " , " , o w , , , " M ,"

~ ~ ' , ~ . , : : "':)~ .::>-::>

" ~ ... ' : ) -;.NOTE: ALTITUDES, VELOCITIES, AND

TIM ES ARE APPROXIMATE3


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Surveyor fell free the last 10 feet of the flight(See Fi g. 2) . Its landing speed at touchdown , wasabout 7.5 miles per hour. But telemetered readingsfrom the three landing legs recorded a "secondtouchdown" less t han one second later, ind icatingthat the spa cecra ft bounced about two to threeinches.SURVEYOR SPACECRAFT

Surveyor I stands about 10 feet high , and withits t ripod landing gear extended , cou ld be placedwithin a 14-foot circle. At launch f rom CapeKennedy with all it s fue l, engines and radar equipment, it weighed 2.194 pounds. But after jettisoning th e altitude marking radar , retrom oto r, andexpe nding the propellants and attitude control gas,the landing weight of Surveyor on the moon wa sabout 594 po unds. On the moon where gravity isabout one-sixth that of earth , its weight equalledabout 99 pounds.Fi g. 3 Surveyor I spacecraft conf igur ation

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SECONDARY SUN SENSOR

SOLAR PANEL3,960 CELLS

SIGNAL DATACONVERTER ANTENNA

OMNIANTENNA B

CANOPUS SENSOR

FLIG HT CONTRo.L SENSORGROUP

THERMAL COMPARTMENT BCOMMAND DE CODERSIGNAL PROCESSORAND DECODING UNITVERNIER ENGINE (3 )

Hydraul ic sh ock absorbers and crushable aluminum honeycomb footpads attached to each landingleg eased th e touchdown as Surveyor landed lightlyonto the moon (See Fig. 3) . Blocks of crushablealuminum honeycomb were also attached to thebottom of the spaceframe at each of the th reecorn ers to absorb part of th e land ing shock if itst ripod gear broke or was damaged.Each of th e unmanned Surveyors to follow Surveyor I during t he ne xt two -year pe riod , althoughprogrammed for a specific series of moon topographic explorations, is basically similar in appearance and design.ELECTRONIC EQUIPMENT

Sensitive electronic apparatus requiring tempera t ure contro l for proper operat ion are housed intwo thermal compart ments. The eq uipment ismounted on thermal trays which distributes heatthroughout both compartments.

HIGH GAIN ANTENNA

THERMAL COMPARTMENT ARECEIVERSTRANSMITTERSMAIN BATTERYTV AUXILIARYMAIN POWER SWITCH

OMNIANTENNA A

ATTITUDE JET (6)


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Compartment A, which is designed to maintainan internal temperature between 40 degrees and125 degrees F., contains two radio receivers , twotransmitters , th e main battery, battery chargeregu lator, ma in power switch and some auxiliaryequipment.

Compartment B, which is designed to maintaintemperatures between zero and 125 degrees F. ,houses the central command decoder, boost regulator, centra I signa I processor , signa I processi ngauxiliary, engineering signa l processor, and lowda ta rate auxiliary.

Both compartments contain sensors whi ch t elemeter temperature measurements to earth.Solar cells are the spacecraft's primary power

so urce dur ing flight and duri ng operations in thelunar day. The Surveyor's sola r panel consists of3,960 solar cells arranged on a thin , flat surface.Th e so lar cells are co nnected in parallelser ies th atgua rd against comp lete fail ure in t he even t th atone or even a few of the cells mal funct ion. Thepanel is able to generate a total of about 89watts-ample power for operation of all on- bo ardequipment.

A 14-cell rechargeable, silver-zinc mai'n batteryis the spacecraft's power reservoir. It stores electrica l energy gathered from the solar panel duringthe lu nar day. When fully charged, the battery isable to provide 3,800 watt-hours at a di schargerate of 1.0 amperes.Augment ing the primary power source is a nonrechargeab le silver-zinc battery contained in asea led magnesium cannister. It also acts as a powerbackup for both the main battery and the solarpane l under peak power load conditions. Thi sbattery has a capacity of from 800 to 1,000 watthours, depending upon power load and operationtemperature.TELECOMMUNICATIONS

Surveyor communications equipment servesthree funct ions: transmission and reception ofradio signa!s; decoding commands sent to th espacecraft ; and selecting and convert ing engineering and telev ision data into a form suitable fortransmission. Three antennas, one high-gain directioni:ll antenna, and two low-gain omn idirectionantennas serve two t ransmitters and two receivers.

Fig. 4Close-up view of the 210 foot-indiametertracking and communicat ion s antenna oft he world-wide NASA Deep Space Network.The antenna and its supporting membersweigh approximately five million poundsand float on an oi l bearing the th icknessof a sheet Of paper.

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This historic photo is the f irs t 600-scan-l ine picture takenby Surveyor I of the moon's surface. Easily identified areone of the three landing legs, one of its footpads , anomni-directional antenna boom and, at lower left, the topof the helium gas container. Notice the d isturbance of thelunar surface by the landing pad.

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The high -gain antenna is used to transmit 600-lin e television data . The low-gain anten nas receiveground commands and transmit other data including 200 -line television pictures from the spacecra ft.Either low-gain antenna can be co nn ected to eith erreceiver.SURVEYOR I LUNAR OPERATIONS

After a series of engineeri ng interrogations toconfirm that all spacecraft systems had surv ivedthe landing, Surveyor I took its fi rs t fourtee n 200-line pictures beginning at 2:53 p.m. (lunar time),June 2. These were tra nsmitted to the GoldstoneCa lifornia , Deep Space Network station . (See Fig.4). Th e solar panel was then positioned for powerco nversion and Surveyor's high-ga in antenna waspositioned at the earth for transmission of higherquality 600-line pictures.

Du r ing the night of June 1 and th e morninghours of June 2 (earth time) when Surveyor tookits first 144 pictures, commercial television networks re layed the live lunar program throughoutthe nation. The Early Bird satellite carried thepictures even fur ther- to Eu rope.More than 82 ,000 ground commands to Surveyor were transmitted from the Goldston e stationfrom May 30 to June 14 , Du r ing its most productive session over Goldstone , June 10 , Su rveyortook 1758 pictu res of the moon an d received andac ted upon more than 12,000 command s. Si xhours and 37 minutes of Surveyor's 10-hour, 20-minute period over Goldstone were devoted topicture transmission.

On June 6, an attempt was made to photographa port ion of the earth , but the planet was ju st outof view, above the elevation range of the tiltin gmirro r of the camera.

Several attempts were made to di sturb thelunar surface or create a sma ll dust cloud nearone of the spacecraft 's three landing fee t by firingbursts of nitrogen gas from Surveyor 's attitudecontrol jets. However, no disturbance or dust wa sdiscern ib le in TV pictures taken during and afterthe firing s.Becau se of the exce llent condition of the spacecraft after it had operated on the moon for morethan a week , there was speculation that Surveyormight survive the lunar night. Thi s possib ility wastaken into account during formulation of plans forthe spacecraft's operati on on the final day of sunl ight-June 14.

Atl as / Centaur/Surveyor spa ce vehicle configuration .

NOSE FAIRING

EQU IPMENTCOMPARTMENT

LIQUID HYDROGENTANK

LIQUID OXYGENTANK

CE NTAURMAIN ENGINE (2)

ADAPTER

LIQUID OXYGENTANK

LIQUID OXYGENDUCT

FUEL TANK

VERNIER THRUSTCHAMBER (2)

BOOSTER THRUSTCHAMBER (2 ) CHAMBER

SURVEYORSPACECRAFT

CE NTAURSTAGE

TLASSTAGE

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As th e Sun sa nk lower on th e horizon the came rarecorded another 523 pictures. Many of the pictures taken with the low Sun behind the spacecraftshowed perfect si Iho uett es of Su rveyor shadowedagainst the moon 's surface.

At lunar sunset, 12: 18 p.m. EDT June 14, thecamera was commanded to point toward that por tion of the horizon where the Sun disappeared anda number of pictures were taken of t he solarcorona , the Sun's upper atmosphe re.Aft er taking 10 ,338 pi ctu res during 121/2 daysof operation on t he lunar surface, Surveyor'sca mera was shut down for th e duration of thenight. Temperat ures began dropping rap idly on thesp acecraft. The battery , however , was nea rly fullycharged . Fo r the following two days, the spacecra ft was queried periodically concerning its cond i t ion-voltages, tem peratu res and battery powercapac i ty-by ro und -the-world stations of the DeepSpace Network.END OF THE FIRST MOON DAY

Surveyor went deeper into hibernation on June16, co nserving it s stored electrica l energy, expending only enough to keep itself warm during thelong, co ld night. The only systems fu nct ioning inthe power-conservi ng fa shion were the two radioreceivers and th e co mmand decoder to acceptcomma nd s from space communications stationson earth .

The so lar pane l had bee n positioned so that atdawn t he Sun would not strike the power -convertingce ll s too qu ickly, sending a sudden surge of curren t into the ch illed electronics system s. The planwas that several earth days time would be requiredto warm Surveyor to the point where it cou ld besa fely operated.

On June 28 , a few hours be fore sunrise onSurveyor , commands to turn on the spacecrafttransmitter were sen t f rom th e tracking station atGo ldston e. No response was rece ive d. For se veralhours each day th erea fter , Go ldstone sent the samecommands. Th e stat ion at Canberra took over t hewake-up duties on July 3 and fina lly aroused Surveyor from its power-conservin g sleep on July 6.

The moon's hOrizon in this photo taken by Su rveyor seemstilted. Th is is becau se Surveyor's camera is tilted andpointed directly at the sun which is ou t of view. Bri ghtcirc les in t he sky are reflections of t he sun caused bythe camera 's mirror.8


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POWER TROUBLEIn preparation for picture-taking activities duringthe second lunar day, engineers and scientists sentcommands via Goldstone on July 7 to operate Sur

veyor's camera. Twenty-four pictures were takenand th e camera proved to be in good workingcondition. But , two days later, Surveyor's batterytemperature began rising rapidly , and by afternoonJuly 9 had reached 129 degrees F., just 12 degreesbelow the maximum design limit . By 7:00 p.m.EDT, July 9 , the temperature was at 134 degreesbut rising at a lower rate . Emergency measureswere taken to take advantage of what was thenbelieved to be the la st few hours of Surveyor I'soperational life. Responding to commands fromthe Deep Space Net station at Ca nberra , the TVcame ra took 38 pictures of the lunar surface .

An attempt was made to fire the th ree liqu idprope llant rocket engines at a low thrust level tostir up moon dust or dig a hole in the surface justbelow the rocket nozzles. The attempt was unsuccessful because of the inability to turn on , byground command, power circuits that opera ted theengine valves to release propellants into t he thrustchambers.

By the time operations were concl uded on July9, the battery tempe ra ture had leve led off at 139.8degrees. Then, inexplicably by afternoon on thefollowing day (July 10) , Surveyor's temperaturefell to 130 degrees, and 24 hours later, to 115degrees, well within the operating range of th ebattery. Reason for the battery 's brief recovery isnot known .

With the battery problem unsolved but lesscri tical , picture-taking was resumed on the morning of July 12 when 257 TV photographs of thelunar surface were rece ived at the Goldstone stat ion . A number of the pictures revealed visually forthe first time lunar environmental da mage toSurveyor .

The picture showed that 13 pa rt of the mirroredglass atop Compartment A, used to dissipate heatfrom temperature-sensitive electronics shatteredduring the long, cold night in temperatures about260 degrees below zero F. At these temperatures,th e 1/ 5th-inch-thick segments of glass were subjected to large stresses.

The compartment, covered by 36 of the glassra diators , houses two radio recei ver s, two transmitters, the main battery and other equipmentde signed to operate between 40 and 125 degrees F.10

None of 24 glass radia tors on a seco nd compartment were damaged by the extreme cold. Engineerses timated that the shattered segment of glass,representing less than one-sixtieth of the totalrad iator area , had little effect on spacecraft performance.When control of Surveyor passed to theJohan nesburg station just a few hours before lunardark fell on the landing site, the spacecraft'scamera was made ready for 200-scan-line picturesof the so lar corona . Sunset was expected at 10:30p.m . EDT on July 13. At ten 0 ' clock as a few testpictures were transmitted from Surveyor, its telemetry showed large battery voltage drops indicatingthat the battery, already operating without the support of so lar power, was dying.

Communications with Surveyor were lost at afew minutes before 11 :00 p.m . EDT after the ninth200-line picture was recorded . Unfortunately , contact with Surveyor I was lo st before the coronacou ld be photographed.

Surveyor I was not expected to survive its secondlunar night, which lasted for two weeks at temperatures approximating minus 250 degrees F. However , the spacecraft surprised the world scientificco mmunity when it briefly reawakened in Octoberand November 1966 for short peri ods at earthco mmand. Although , on each occas ion , SurveyorI was able to provide scientists with a brief electronic account of it s status, it shortly lapsed againinto silence.

Fin al ly, in its 220th day on the moon , on command from NASA's Canberra , Au stralia , trackingstation, Surveyor came to life for t he last time at1:22 a.m . EST , January 6, 1967 . Although thesignal received from the spacecraft was very faint ,the tracking station did manage to remain in contact with th e craft for about twelve hours. Duringthis per iod important Doppler Effect data on themotion of the moon was radioed by the spacecraftto earth. But no attempt was made to order it stelevi sion camera into operation because of itsheavy power requirements. Contact was finally lostwith Surveyor I at sunset on the moon at 2:22 a.m.EST, Saturday January 7, 1967 .Surveyor's TV picture total now reads: Firstluna r day, 10 ,338; second lunar day, 812 .INFORMATION INVALUABLE

Information transmitted by Surveyor I concerning lunar co ndit ions will continue to be studied for


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This 600-scan -line photo transmitted by Surveyor on June2, 1966 shows a moon rock about six inches high andtwelve inches in diameter_ Bri ght spots at the left arereflections of the sun. A small crator can be seen in thebackground and the horizon is visible in the upper leftcorner of the pictu re.

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years . Of con siderable interest were color photographs of the moon 's surface which showed themoon , at least at the landing site, to be a darkgrey in color.

Project Apollo offic ials have al ready been able todetermine f rom the weal t h of photographic evi-dence obtained by Surveyor, that an astronaut cansafely set foot on the moon 's su rface-a t least inthe vicinity of the Surveyor landing site . Prev iouslythere had been some doubt that the luna r surfacecould support the we ight of the Apo llo spacecraftor even the weight of the astronaut who wouldemerge from it.

Some sc ienti st s had believed th at the airlessluna r surface might be covered with a thick layerof powdery dust, like fine loose sand . Othersbel ieved that the moon 's surface might be rockhard . Either condit ion , of course , could make thelanding of the Apollo spacecraft extremely hazardous, if not impossible.Surveyor I, with it s safe touchdown and subsequent pictures proved that the lunar surface conformed to neith er of th ese beliefs. Now, with thepicture facts sent to earth by Su rveyor I, mostscient ists are confident that th e moon surface isreasonably stable and can suppo rt a we ight of atleast five pounds per square inch .

Wh i le, of course, lunar surface soil may vary atdifferent location s on the moon , conditions at Surveyor 's landing site ind icate that t he fine granularsoil is slightly compress ible. It is sim ilar , scien tist sbe lieve f rom photo studi es , to that which might be

ex hibited on earth by damp, fin e-grained soil .But , it was a pi cture from Surveyor that providedevidence fo r th e st re ngth ch aracterist ics of thelunar surface. Surveyo r , according to evidence froma self -made port rait of one of it s own feet , sankone and on e- half to th ree inches into the moonsurface when it dropped the last few feet to itsluna r landing.SURVEYOR PROGRAM OBJECTIVES

The ov erall object ives of NASA's Surveyor program are: to accomplish successful soft landingson the moon as demonstrated by ope ration s of thespacec raft subsequent to landings; to provide basicda ta in support of Apollo; and to perform opera t ions on the lunar surface wh ich will contributenew sc ientific knowledge about the moon and provi de fu rther info rmation in support of Apollo .The fi rst four Surveyor missions were plannedto sa t is fy th e fi rst object ive and the last threeSurveyo rs were planned to meet the second objecti ve . The highly success ful Su rveyor I mi ssionsa ti sfi ed both object ive s and ha s contributed signifi ca ntly to the attainment of obj ective three .Pla nni ng and eng in ee rin g are now under way foradd ition al Su rveyor mis sions to fully meet objective three.

By the tim e Apollo astronauts set foot on themoon, le ssons gleaned by NASA sc ientists fromSurveyor I and others of its cl ass to follow willhave done much to make th eir landing safer andtheir work more rewa rd i ng.

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u. S. GOVERNMENT PRI TlNG OF F ICE , 1967 0 - 269-560