NASA Facts NASA's Ranger Program

8/7/2019 NASA Facts NASA's Ranger Program

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- - ~ - - . . . . - " - ~ _. - --. NASA FACTS (A-62) N63 1670 1 Page 1

NASA'S RANGER PROGRAM

The MOON-America's space goal of the 60 ' s: a manned landing. Yet today more is unknown than is knownabout that satellite.

THE REQUIREMENTTo land American astronauts on the moon,

the National Aeronautics and Space Administration (NASA) needs much more information aboutlunar composition, characteristics, and conditionsthan earth-bound scientists now have. NASA

has developed projects to land scientific instruments on the moon to relay precise data so thatthe practical aspects of man's lunar landing andreturn (Project Apollo) can be accurately planned.Project Ranger is th e first of NASA's severalunmanned space projects delving into the moon'ssecrets. The Ranger program represents Amer-

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--Page 2 NASA FACTS (A-62)ica's first attempt to obtain close-up and detailedphotographs of the moon and its topography,to secure scientific data on the composition ofthe lunar surface, and to learn more about lunarorigin, history and structure from an instrumented capsule, designed to survive a "roughlanding" on the moon.

DEVELOPMENT OF PROJECT RANGERInterest in the propulsion of scientific instru

ments to the moon antedates NASA's establish-

ment in November 1958, bu t the actual meansof propulsion were no t then available. Instrumented lunar landings were an integral part ofNASA's first planning. In 1960 the executionof the Ranger program was assigned to theJet Propulsion laboratory (JPl), a NASA facili ty operated by the California Institute ofTechnology.

Initial ly the Ranger program proposed fiveflights of instrumented packages during 1961and 1962, but four additional Ranger flightswere added fo r 1963, to insure more and betterdata about the moon.

RANGER- This is the intricate spacecraft in moon flight . It spans 17 feet and is 10.25 feet long , although it left the earth ina compact shroud , B feet high and 5 feet in diameter. It weighs 729 pounds and will depasit on the moon the instru-ment capsule weighing 92 pounds.

LUNAR CAPSULE

SOLAR PANELS - - . ~

HIGH-GAINANTENNA - - - - - ,

/ OMNIDIRECTIONAL/ ANTENNA

TV CAMERA

RADARALTIMETER

GAM MA RAY -----'SPECTROM ETER

RETROROCKET

MID-COURSEMOTOR

RANGER SPACECRAFT


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RANGER LAUNCH-TO- INJECTION SEQUENCESUN

I I I \> "I" 'i- - :Q CJ : l- ~ ~ ~ \ \ ~ ~ 4 8 79

1 . L A U N C H2. B OO S T ER SH U T OFF AN D SE P AR A T I ON3. SU ST A IN E R SHU TO F F /I AG EN A SE P A R A T I O N4 . SHRO U D E J EC T IO N5. F I RS T A G EN A I GNI T IO N6. F I RS T AGEN A S H U T O F F /I S T A R T O F COAS T7 . SEC ON D AG E NA IG N I TI O N8 . SE C ON D AGEN A S H U T O F F /I SP A C E C R A F T SE P A R A T I O N9. S P A C E C R A F T SU N A C Q U ISITION

10 . EARTH AC Q U IS IT IO N

The pri mary missi on of the first two Rangerflights, on August 23 , and November 18, 1961,was to prov ide engineering tests of the manyelements of the spacecraft system and NASA'sworld-wide tracking network. Neither flightwas aimed at impact but merely to make highlyelliptical earth orbits. However, the Agena Bbooster veh icle twice malfunctioned in its secondburning phase, when it should have restarted itsmotors an d projected the spacecraft from itsnear earth orbit into outer space. Rangers 1and 2 never did get into interplanetary space.Yet these tests had their positive side. Theinstrumentation in the spacecraft was tested andprovided telemetered data to the tracking network. It was also demonstrated that the space-

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INJECTION_8-7

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craft would execute commands received fromth e earth stations as well as its preass ignedtasks.

Ranger 3 was th e first test a imed at i mpacting the moon an d " rough-landing " a scientificinstrument package upon it . It was the first of3 identical NASA spacecraft launched to perform a series of most complicated operations.Ranger 3 and its two identical sisters each consists of a 729-pound gold an d silver spacecraftcontaining four scientific experiments; lunar televised photography, gamma ray detector, radarreflectivity of th e moon and a moonquakeseismometer, the latter to land on th e moonand transmit seismographic data for 30 days.On a successful launch, Ranger would be lifted

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Page 4into space by an Atlas "0 " booster and putinto a near earth orbit by an Agena-B secondstage, which would then shut off while only par-tially burned out . When Ranger and itsattached Agena-B had coasted to the "spacewindow" selected as the best trajectory to themoon, the Agena engines would restart, accel-erate Ranger to the earth-escaping velocity ofthe 24,500 miles per hour and pu t it on animpact course to the moon. The Agena boosterwould then drop off and be deflected by its ownretrorockets, to prevent its following the spacecraft to the moon. The Ranger would then beon its own for its 66-hour fli ght to moonimpact.

RANGER FLIGHT PLANA summary of Ranger operations and activities

on its flight to, and just before its impact onthe moon, indicates why this is one of America's

NASA FACTS (A-62)most complicated satellites an d why NASAdetermined on three identical craft to insure thescientific purpose of this mission. While inlunar flight, Ranger has th e following missionsequence:

1. At 30 minutes after launch, on signalfrom its own computer, unfolds two solarpanels. Using cold nitrogen jets, theRanger aligns its flight axis so that thesesolar panels are aligned to face the sun,in a "sun-lock," to produce electricalpower for the spacecraft's operations.Having locked on th e sun, Ranger thenextends its "high-gain antenna," forclearest telemetry and television transmission to earth stations, and withoutlosing the "sun-lock," jets itself and theantenna onto an "earth-lock." Finally,the gamma ray spectrameter is turned onand relays radiation data to earth every8 minutes.

MAKING SUN-LOCK AN D EARTH-LOCK-Drawing of maneuver to put solar panels in linewith sun and "high gain " antenna in line with the earth .


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NASA FACTS (A-62)

1' / / GAMMA RAY 100M OUT1 IARTH UACQUIS/TION) , / SUN UAQUISITION_.I' 0 \ / ANNl1NAI"OSmON/) _ l ~

\ MOTOR tURN/ PITCH MANNVn/ lOl l MANIUvnANnNNA UP0,.-r . , ~ ~ ) . /RANGER

J l)lt i)\MIDCOURSE MANEUVER )) ) ~ .

/ IARTH"2. Changes its flight orientation, 16 hours

after launch, following orders transmittedby NASA's Goldstone (Calif.) tracking sta-tion, utilizing computer course correctionsfrom the flight data received from three

Deep Space Instrumentation Facility stations:California, South Africa and Australia.Ranger obeys by firing a mid-course motorin the spacecraft's base and puts itself oncollision course with the moon.

RANGERTERMINAL M A N E U V E R

FIRST PilCH M ~ N E VER

YAW MANEUVEI?

SECOND PITCH MANEUVU

- - - OMNI .ANTENNA DEPLOYEDCAJlSl,.Ill SEPARATESREno M010R FIRES

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Page 63. Re-establishes its solar panels' lock to the

sun and its "high-gain antenna" lock onthe earth, which would have been lost inthe mid-course maneuver and the firingof its own engine. The gamma rayspectrometer is then extended by a gasoperated boom, some 72 inches from thespacecraft, to obtain more accurate data.4 . Performs a terminal maneuver I about 65hours after launch, at 5,000 miles fromthe moon. Upon previously transmittedcom mands from Goldstone Station,Ranger maneuvers itself into proper position for televising pictures of the moon,and receiving radar reflections from themoon as well as posit ioning the lunarcapsule and its retroactive motor fo rproper separation. The TV cameras arewarmed up and the lid moves from the

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lens. The radar antenna extends andradar impulses to the moon are startedto report on the reflective characteristicsof its surface with telemetry transmissionto earth tracking stations.

5. Commences taking telescopic televisionpictures of the lunar surface about 2,400miles from the moon. The spacecraft'scamera will produce one 200- l ine (ascontrasted with a 525- l ine on domesticTV) transmitting image, every 13 secondsuntil 8 seconds before the Ranger vehicleimpacts. The expected 100 picturesshould have a clarity, or an identifyingcapability, from 3 to 20 times better thanmoon photographs taken from the earth.

6. Separates the lunar seismometer capsulewith its braking rocket from the spacecraft when radar reflections indicate an

LUNAR SEISMOMETER SPHERE AN D BRAKING ROCKET

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- NASA FACTS (A-62)altitude of about 70,000 feet from themoon's surface. Three small rocketmotors spin the retrorocket from the lunarcapsule some four feet above and awayfrom the spacecraft which then impactsin 8 seconds and is destroyed.

7. Fires the retro or braking rocket for 10seconds at 5,080 pounds of thrust toslow the capsule system from 6,000miles per hour to zero velocity of 1,100feet .

8. Detaches seismometer capsule from braking rocket so that th e former under thepressure of the moon's gravity falls freeth e last 1,100 feet and "rough-lands"on th e moon, at a speed of about 150miles pe r hour, some four seconds afterth e braking rocket, and twenty-four seconds after the spacecraft had impacted.

PROTECTIVE BALSA SHIELD

9. Positions th e seismometer capsule bycounter-balanced weights so that it is inthe best position to transmit to earth dataon moonquakes and meteor impact for 30days. The seismometer s phere floats inan oil film inside an oval balsa woodprotective shield, tested to withstand a200-mph impact on rock. Since the oilfilm might deaden lunar sounds, two ex-

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Page 7ploding sl ugs pierce th e bottom of thebalsa casing to permit the oil to drainou t when the capsule rights itself.America's first scientific instrument on themoon is then ready to transmit data tothe earth.

RANGER 3 LAUNCH-JANUARY 26, 1962


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THE RANGER 3 TESTAt 3:30 p.m . on January 26, 1962, the

Atlas-D Agena B rocket carrying Ranger 3,blasted off from NASA's Atlantic Missile Rangeat Cape Canaveral, Florida. The launch hadbeen scheduled for January 22, the beginningof a 5-day period when th e lunar surface isproperly l ighted by the sun fo r televisionphotography . The Atlas engines burned toolong and gave the entire assembly an excessivespeed of about 275 feet per second fo r whichthe Agena-B booster was not programmed tocompensate . Agena-B pu t Ranger into itsearth " coasting" orbit and then refired to placethe spaceship into its moon trajectory. However, the velocity was so great that the space-craft would arrive at lunar impact point about1 4 hours before the moon reached the samespot. A lunar miss was evident within an hourafter launch.

Ranger operated almost perfectly within theIi mits of its capabilities as verified by telemetered data. Its solar panels were posit ioned. It made its lock on th e sun and itslock on the earth. It executed its mid-coursecorrection maneuver within the capabil i t ies ofits motor ' s strength, and then regained a lockon both sun and earth. It commenced its ter-minal maneuver, pitching and yawing to pointits camero at the moon some 31,000 milesaway . The TV warmed up and the lens un-covered and at 12:52 p .m. on January 28,Ranger attempted to take pictures. However,the " high-gain" antenna, previously positionedperfectly for earth reception, lost its lock on the

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NASA FACTS (A-62)earth during terminal maneuvers due to an excessive pitch motion. While TV pictures weretransmitted, the misdirected antenna could notprovide the tracking stations with a sufficientlyclear and powerful TV transmission to providedistinguishable pictures.

At a speed of 4,188 miles pe r hour, Ranger'sclosest approach to the moon was 22,862 milesat 6:23 p.m . EST January 28, only 51 hoursafter launching. Ranger was too far from themoon to accomplish a landing of the lunarcapsule, and this experiment was no t attempted.Ranger has gone into an orbit of the sun, joining Pioneer IV (launched March 1959) andPioneer V (March 1960).

CURRENT STATUS OF THERANGER PROGRAM

One of the more significant achievements ofRanger 3 was the successful accomplishment ofits solar panels lock on th e sun, simultaneouswith the earth-orientated lock of i ts high-gainantenna. This was truly a space "FIRST " andwill contribute enormously to improved reception of telemetered scientific data from space-craft. The gamma ray detector, operating for50 hours, provided some 350 reports on theenvironment through which Ranger passed on itsway toward the moon. Finally, the experienceand the results of Ranger 3 operations providethe engineers an d scientists with invaluable information, which will be utilized to improve theprospects fo r success in other Ranger fl ights tothe moon .

u.s. GOVERNM ENT PRI NTING OFFICE : 1962 OF' - 637077

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NASA Facts NASA's Ranger Program