Ranger 4 Press Kit

8/8/2019 Ranger 4 Press Kit

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N EWS RELEASENATIONAL AERONAUTICS AND SPACE ADMINISTRATION

A A 400 MARYLAND AVENUE, SW, WASHINGTON 25, D.C.TELEPHONES: WORTH 2-4155-WORTH 3 -1110FOR RELEASE: A.M., THURSDAYAPRIL 19, 1962RELEASE NO. 62-93RANGER 4 SPACECRAFT

Ranger 4 will be launched by the National Aeronauticsand Space Administration from the Atlantic Missile Range,Cape Canaveral, Florida, within a few days. It will repre-sent the second United States attempt to take closeup picturesof the moon, provide information on the composition of thelunar surface and learn more about its history by means ofan instrumented capsule designed to survive a landing onthe moon.The mission is so difficult that NASA scheduled threeflights (Rangers 3, 4 and 5) in the hope that one would besuccessful.Ranger 3, the first of these spacecraft, was launchedby an Atlas-Agena B rocket from Cape Canaveral on January 26,1962. A malfunction in the Atlas booster caused the space-craft to be injected into its lunar transfer path at excessivevelocity, and, as a result, Ranger 3 arrived in tiie area ofthe moon some 14 hours ahead of time. On January 28 at 3:23p.m., P.S.T., the spacecraft passed in front of its target,missing it by 22,862 miles, and then went into orbit aroundthe sun.Despite Ranger 3's nonstandard trajectory, an attemptwas made to carry out the lunar photography experiment whilethe spacecraft was approaching the orbit of the moon. Theattempt was unsuccessful, however, because the spacecraftdid not properly perform the terminal maneuver that wouldhave pointed its television camera at the surface of themoon. This was caused by a malfunction in a subsystem ofthe spacecraft. This also caused the spacecraft's direc-tional antenna to lose its orientation towards earth,resulting in a significant drop in signal strength.

Circuitry modifications in the Ranger 4 spacecrafthave been made.(OVER)


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Ranger 4 is a 730-pound gold and chrome-plated machinethat will be called uo,, in a 60-hour flight to the moon, toperform a complicated series o* events. It will be asked to:1. Leave the earth, achieve a parking orbit and reachescape velocity of 24,500 miles an hour.2. Perform a three-axis maneuver in space to lock onto

the sun and th e earth.3. Accept correction commands from the earth, changeits orientation in flight and fire a mid-course motor t3put itself on collision course with the moon.4. Reestablish its lock on the sun and the earth.5. Perform a terminal maneuver when it gets to within5000 miles of the moon.6. Take television pictures of the lunar surface asit approaches the moon.7. Make studies of the composition of the lunarsurface and its radar reflection characteristics.8. Separate a retro rocket and capsule system fromthe spacecraft when it is approximately 70,000 feet abovethe lunar surface.9. Fire the retro rocket to slow the capsule systemfrom 6000 miles an hour to zero velocity some 1100 feetabove the surface of the moon.

10. Detach an instrumented capsule containing aseismometer from the retro rocket so that it rough landsafter a free fall from approximately 1100 feet, survivesthe landing, positions itself and then sends. for 30 daysor more, informal:ion on moon quakes and meteoritic impact.The Ranger program is being carried out for the NASAby the Jet Propulsion Laboratory, operated for the NASAby the California Institute of Technology. In the Ranger 4spacecraft, the Aeronutronic Division of Ford Motor Company,Newport Beach, California, provided the lunar capsule andradio altimeter subsystems.Four scientific experiments carried on Ranger 4 are:the moon quake experiment, the lunar photography experiment,the gamma ray experiment, and the radar reflectivity experiment.

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SPACECRAFT D.C'CRIPT (411

The Ranircr 3, "I nd 5 design i, sicmilar in appearanceto their two precdecce,;.ors., Ranger I and 2, in that they usethe sainm basic hoxagonal. st;ricture and solar panels thatmarked those two ,pacecraft.. JPT. englneers. who designedthe Ranger series call the basic hexagon the bis, in th esense that It scrves a:; an omnibu.; to carry differentpar-sengers In the form of ( . iferent scientific andengincering instruments.Panger )'I is five fect In diameter at the base of th ehexagon in it.s; launch pos:lttion 'rl the solar panel.s folded

lip in the manner of butterfly wings, In its launch positionIt is 8.25 feot in height. In the cruise position, with Itssolar pancls extended and the hiph-gal.n directional. antennaJn It:: extended positi.on, it: is 17 feet across in span and10.25 feet in helght.The 730-pound weight of the spacecraft Includes 332.1pounds for che lunar capsule and retro rocket system. The:Lnstruinent capsul.e, designed to survive the landing on themoon, weighs 57.1. pounds and is covered by a balsa woodimpact limiter to cushlon the shock of landing.. The lmpactlimiter weighs 32.2 pounds, m'.eking the instrumented sphereand the limiter wei.gh a total of 89.3 pounds.The lunar capsule rests atop a retro motor which in turnsits on the top of the spacecraft hexagon. The retro motor,with a thrust of 5080 poundsl, weighs 214.1 4 pounds, togetherwith its small spin motor that rotates the assembly forstability just before the retro motor Is fired.Surrounding the sphere-retro-motor assembly is acylindrical h-at shield, designed to provide .thermalcontrol for the solid propellant retromotor. The shield,called 'he "'Yhower curtain", is made up of several layersof silvered plastic sheet and esctends from the equatorof the sphere dorn to the top cf the spacecraft hexagon.The shield is supported at the top by nylon lanyardswhich, in turn, are hooked to the spacecraft's omni-antenna on top of the sphere. When the omni-antenna:L s deployed during the terminal maneuver, these lanyardsare released and rubber eord.s pull the shield down to the

top of the hexagonal structure, thereby providing anunfettered exit path for the capsule's escape.Attached to the hezaagonal base are the two solar panelswhich in flight will. collect solar energy which in turn willbe converted in .o electrical power to rmn the spacecraft.

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The panels contain )134[0 solar cells each in approximntely 10square feet of each panel making a total of 8680 cells on thetwo nan.1,. They will pick uip enough solar energy to be con-verted into a minimum of 175 watts and a maximum of 205 watts,unregulated.In one of the six boxes around the base is a 25-pound

silver zinc launch and backup battery with a capac:i.tyof

1000 watt hours. This battery will be used to provide povwerfor Ranger 4 when the solar cells are not operatinp. such asprior to sun acquisition, in the mid-course manuever and priorto landing.Ranger 4 has three communication antennas--two on thespacecraft (or bus) and one on the top of the instrumentedsphere that w:il.]..l land on the moon. The lunar capsule trans-

mitter is powered by six silver cadmium batteries to run thetransmitter for at least 30 days to transmit moon quake andtemperature information from the sphere to the earth.

The two antennas on the spacecraft are the omnidirectionalartenna positioned at the forward end of the spacecraft and thefour-foot-in-diameter high-gain directional antenna which ishinged mounteA at the aft end,

Mounted in the hollowvied-out section in the middle of thehexagon is the mid-course motor -:!hich was developed by JPLseveral years ago and has since been used in other U.S. Spacetests.I-t is a liquid monopropellant engine that weighs, withfuel and the nitrogen pressure gas system, 35 pounds. The.hydrazine fuel is held in a rubber bladder contained insidea football-shaped container called the pressure dome. Whenthe mid-course motor receives the command to fire, nitrogen

under 300 pounds of pressure per square inch is admittedinside the pressure dome and squeezes the rubber bladderwhich contains the hydrazine fiuel.

The hydrazine is thus forced into the combustion'chamber, but because it is a monopropellant, it needs astarting fluidl to initiate combustion and a catalyst tomaintain combustion. The starting fluid used, in thiscase nitrogen tetroxide, is admitted into the combustionchamber by means of a pressurized cartridge. The intro-duction of the nitrogen tetroxide causes ignition, and theburning in the combustion chamber is maintained by thecatalyst, aluminum oxide pellets stored in the chamber.Burning stops when the valves turn off nitrogen pressureand fuel flow.

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At the bottom of the nozzle of the mid-course motor arefour jet vane-, whLch protrude into the rocket exhaust forattitude control of the spacecraft during the period of themid-course motor burn.

The mid-course motor is so precise that it can burn inbursts of as little as 50 milliseconds and can alter velocityin any direction by a-, little as one-tenth of a foot per secondor as much as 138 feet per second. It has a thrust of 50 poundsfor a maximum of 63 seconds.

Also in one of the six boxes around the hexagon is a solid-state ulgital computer called the Central Computer and Sequencer(CC&S). This :J.:; a system which allows commands to be stored inthe system for later transmission to subsystems of the space-craft, and which also allows specific ground commands to bestored in the CC&S after launch for later routing to performspecific functions.

Ranger 4 will use the parking orbit technique which is ameans by which geometry imposed on moon impact flights by thelocation of the Atlantic Missile Range at Cape Canaveral,Florida, is corrected by using the Agena B second-stagerocket as a mobile launching platform in space.

The Atlas booster lifts the Agena B and spacecraft to analtitude of approximately 105 statute miles above the earthand to a velocity considerably below orbital speed of 18,000miles an hour.

During the launch phase, the Ranger spacecraft is pro-tected against aerodynamic heating by a shroud, or nose cone,which covers it. After Atlas cutoff, at approximately 280seconds, the shroud is jettisoned by eight spring-loadedbolts which shove it ahead of the vehicle. At almost thesame time, the Agena B separates from the Atlas. At thistime, the Agena B pitches down from an attitude almost 15degrees above the local horizon to almost level with thelocal horizon.

In this horizontal attitude, the Agena B fires for thefirst time and burns for almost two and a half minutes toreach orbital speed of 18,000 miles an hour. After thisburning time, Agena B shuts down and coasts in a parkingorbit for more than 6 minutes until it reaches the optimumpoint in time and space in its orbit to fire for the secondtime.

After the second Agena B burn, the Agena B and Ranger 4,still as one unit, are injected at near escape velocity of24,500 miles an hour approximately over Ascension Island in-5- (OVER)


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the South Atlantic Ocean and approximately 16 minutes afterlaunch. Up to this time, the events of the launch, separa-tion of Agena from Atlas, operation of the Ranger spacecraftsystem and ignition and cutoff times of Agena have beentelemetered to ground tracking stations through the Agenatelemetry system.A little more than two minutes after second burn cutoff

(known as injection), Ranger 4 is separated from Agena, againby spring-loaded bolts. After this occurs, Agena does a 180-degree yaw and moves into a different and lower trajectoryfrom that held by Ranger 4 by means of firing a solid retrorocket on Agena. This is done for two reasons: it would notbe desirable for the unsterilized Agena to follow Ranger 4 onin and impact the moon, and if Agena B follows Ranger 4'tooclosely, the spacecraft optical sensors might mistake reflectedsunlight from Agena B for the sun or earth and thus confuse itsoptical sensor acquisition system.Ranger 4 now is on a trajectory that will take it fairly

close to the moon. The omnidirectional antenna is working andradiating its full three watts of power. Before and duringlaunch, the transmitter had been kept at half power of 1.5watts. This was done because as the launch vehicle passesthrough a critical low atmospheric density area between 150,000and 250,000 feet, there is a tendency for devices using highvoltage to arc over and damage themselves; hence, the trans-mitter is kept at half power until this area is passed. Thenecessary switching to accomplish this change is done by theCC&S at 23 minutes after launch.Now it is possible to describe the sequence of eventsthat Ranger 4 will conduct on its 60-hour flight to the moon.The second command is issued by the CC&S 31 minutes afterlaunch. Explosive pin pullers holding the solar panels intheir launch position are detonated to allow the spring-loaded solar panels to assume their cruise position. Atlaunch plus 34 minutes, the CC&S turns on the attitude con-trol system and Ranger 4 starts the process of looking forthe sun with its solar sensors. The same command extendsthe gear-driven high-gain antenna at the aft end of thespacecraft to a preset position.There are six sun sensors mounted on Ranger 4. There

are four primary sensors on four of the six legs of thehexagon, and two secondary sensors mounted on the backs ofthe solar panels. There are light-sensitive diodes whichinform the attitude control system--gas jets and gyros--when they see the sun. The two seoondary sensors on the6


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back>; of tiic .s.v. pa!,h(i; infirn th attitlut3Je contro] systemthat threy e tho -un, lbua; .:,-nt not to roo i t. Trhre atti tildecontrol -;ysteol rc::ponli.: tot thea .ni. tLby tilrnln;g theN space-craft in -;,ich a. ia'nner that tile l ongi twi tnal, or rol 1 a;ll ,points to ears the -,in. To-i-jwi )n,' theh -acocraft for thesem.aneiiver.-, is provI dlae by teen -1;i;-at,;Wc1clly rlocatrd m.aL; jet


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The spaeoci-aft now is stabilizeod on two axes--the solarpanel-sun axis and the earth--dii'ecUlonal antenna axis. Thereis so, ve danger that the earth sensor, during its search for theearth may see the moon anO. lock onto that. If this happens,the Goldstone and Johannesburg, South Africa, trackinC: stationshave the ability .o send an override command to the attitudecontrol system to tell it to look again for the earth.

Tle earth-sensor/high-gain antenna should have acquiredthe ear'th by 4 hours after launch. At that time, South Africawill a-rnd Ranger 4 a command to switch from the omnidirectionalanto an-ao the directional antenna. If the increase in receivedsigna- strength indicates that the directional antenna is lockedon the earth, no further commands in this area are necessary at ;the mordant. But if the signal strength drops, indicating thatthe directional antenna is not pointed at the earth, the over-ride roll command will be sent to Ranger 4 to look for the earthagain. If this is not sufficient, South Africa also has theability to send a hinge override command to change the positionof the antenna and stait the search for the earth again.

Four hours after launch, CC&S will turn on the gamma rayexperiment. This is a spectrometer contained in a 12-inch(diameter) ball mounted on a 40-inch-long arm on the hexagon.Later in the flight, pressurized gas will be vsed to extendthis telescoping arm to 72 inches away from the spacecraft inorder to avoid the measurement of secondary effects created bycosmic rays hitting the main bulk of the spacecraft.

It is not deemed desirable to extend the gamma ray boom atthis time, hcwever, since Ranger 4 must still perform its mid-course corrective maneuver to get on collision course with themoon. In order to perform this maneuver with precision, ofcourse, it is necessary to know the precise center of gravityof the spacecraft. If the gamma ray boom were ordered out toits extended position, and it did not for some reason obey thisorder, the center of gravity would be different from the calcu-lated point, and the precision of the mid-course maneuver wouldbe affected. So the boom staysin the retracted position untilthe mid-course maneuver is completed. Meanwhile, gammpa-ray datais obtained while the spectrometer is still retracted, for reasonsof calibration.

From that point on, four hours after l.unch, until thestart of the mid-course maneuver approximately 16 hours afterlaunch, most of the activity takes place at the three DeepSpace Instrumentation Facility stations--Woomera, Australia;Johannesburg, South Africa; Goldstone, California--and at JPL.

Tracking data from these three stations are fed into the7090 computer at JPL in Pasadena. The computer calculates theposition of the spacecraft as it is in fact in relation towhere it should be in order to hit the moon. If it is thecase, as it is likely uo oe, that guidance errors before injec--tion have put it off its optimum trajectory, the computer willprovide a set of figures that will tell the spacecraft how ithas to change its orientation in space in order to properly aimthe mid-course motor for its corrective maneuver.

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This Intelligence will be in the form of a foUr-word digitalcommand that w:.ll be sent to the spacecraft and stored in theCC&S. One word concerns the direction and amount of pitch needed,and another word concerns the direction and amount of roll nec-essary. With these two maneuvers, the spacecraft can be pointed:In any direction necessary to make a change in course, time offlight; or both. The third word is the amount of velocityincrement needed from the mid-course motor. These three wordsare sent from Goldstone to the Ranger 4 CC&S, where they arechecked to see if they are addressed to the proper places inthe spacecraft. CC&S takes no action, however, until. itreceives the "go" command from Goldstone. While walting forthat command, the spacecraft sends back to Goldstone, forrechecking, then words it received. If there are no changesto be made, 30 minutes after the Ranger )4 C&S has receivedand stored the. commands, it recieves, at 15 hours afterlaunch, the "go" command from Goldstonle.

Just prior to issuing the "go command, Goldstone willhave issued a command to Ranger Sljo switch from the direc-tional to the omni-antenna and to move its directional antennaout of the way of the exhaust of the mid-course motor.

The roll maneuver requires 9.5 minutes of time, includingtwo minutes of settling time, and the pitch maneuver requiresapproximately 17 minutes. Two minutes after the pitch maneuveris completed, the mid-course motor is turned on and burns untilthe commanded velocity increase has been effected. The attitudecontrol gas jets are not powerful enough to maintain the stabil-ity of the spacecraft during mid-course maneuvering, so jet-vanpi extending into the exhaust of the mid-course motor con-trol the attitude of the spacecraft in this period. Thejet-vanes are controlled by an adjucnt to the attitude con-trol system known as the autopilot.

After the mid-course maneuver has put Ranger 4 on thedesired collision course, the spacecraft goes through thesun and earth acquisition modes again. The double acquisi-tion is not so difficult this time, however, because gyrosin the attitude control system provide a reference back tothe attitude position it used before the mid-course maneuver,and it quickly moves back to that position.Ranger 4 now is at the limit of the range at which the

omni-antenna can provide useful information,however, and

Ranger 4 has been transmitting through the omni during themid-course maneuver. A ground command is issued to trans-fer back to the high-gain antenna and thii condition willremain for the rest of the flight.9 -(OVER).


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Two and one-half hours after :tnit:iat;.on of the mid-coursemaneuver, CC&S commands the gamma ray boom to extend, by meansof pressurized gas, to -its limit of '(2 inches awray from thespacecrait. The gas contained in the boom is not allowed tovent, since its quick escape undoubtedly would perturb theattitude of the spacecraft. It may leak out, however, butnot at a rate that would affect the spacecraft att'"ude.For the next 48 hours, Ranger 4 continues on its course

to the moon, telemetering conti.nuous engineering data and alsosending gamma ray reports back once every eight minutes. Track-Ing data from all three DSIF stations are sent to JPL and the7090 computer calculates when impact will occur.WIhen the exact time of impact is computed, it then willbe possible to. ack off in time and determine where the space-craft ':ill. be 65 minutes before impact. The computer, usingthis position of Impact minus 65 minutes, will determine thekind of commands that have to be sent to the CC&S in orderfor it to perform its terminal maneuver at that time.These commands will. be sent by Goldstone to Ranger 4a half hour before the spacecraft reaches this point intime and space, or 95 minutes before impact.The commands will be similar in nature to those sent togovern the mid-course maneuver, with the difference that thistime there will be no motor burn. The three commands, sentto the CC&S and stored there against the time it receivesthe "go" command,.are: direction and amount of pitch turnidirection and amount of yaw turn, direction and amount ofa secohd pitch turn. These three turns are necessary tokeep the directional antenna aimed at the earth and yet

position the spacecraft properly for its lunar approach.The "go" command sent in real time from Goldstone 65minutes before impact initiates a series of events whichsees the spacecraft using its attitude control system gyrosand gas Jets to turn around and' orient its television camerato the surface of the moon. When this sequence is initiated,'Ranger 4 will be approximately 5,000 miles above the lunarsurface. In the attitude required for the terminal maneuverthe solar panels are not pointed at the sun, and from now onpower is provided by-the battery. Initiation of the terminalmaneuver also turns on the television camera for warmup; itwill not start to take pictures until later.The last maneuvering command of the CC&S, which is tostop the second pitch maneuver, also accomplishes threeother switching functions. These are: (1) to switch froman engineering data telemetry mode to a scientific telemetry 0

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mode, [or acquisition of the television picturcs and anincreased rate of gamma-ray data, (2) initiate a 2 minutetime delay to deploy the radio altimeter antenna, (whichis necessary for It to be looking at the lunar surface),and to remove the protective cover from in front of thetelevision camera telescope and (3) to initiate a 21minute time delay to deploy the omni-antenna which makesan exit path for the separation of the lunar survivalcapsule. The time delays for the deployments are necessaryto allow the spacecraft to stabilize from its last pitchmaneuver before introducing the motion of the deployments.The radio altimeter antenna is deployed 30 seconds beforethe omni-antenna to allow it to be out of the way at thetime the retro-motor heat shield comes dorm. the latterhappening when the omni-antenna is deployed. The tele-scope cover, mentioned above, is used to prevent micro-meteorite damage and as a radiation shield to husbandthe heat in the television camera assembly. All of thedeployments mentioned above are operated by captivesprings, which are released by pyrotechnic "pih-pullers"or explosive bolts.

At 2400 miles from the surface of the moon, just 40minutes before impact, the television camera starts takingpictures of the lunar surface and transmitting them, oneevery 13 seconds, to Goldstone.

The gamma ray telemetry also is shifted from low tohigh rate so that instead of sending reports once everyeight minutes, it now sends reports once every 52 seconds.The radar altimeter, ranging its signal against thesurface of the moon and receiving the echo, initiates thenext command. At approximately 68,000 feet above thelunar surface, and 8.1 seconds before the main spacecraftis due to crash and destroy itself, the delay time betweenthe radar pulse and echo is such that the altimeter willgenerate a fusing signal.This fusing signal starts the lunar capsule launchsequence, in this order of events:The bus power source, the large battery, will explodefour bolt cutters on the clamp that holds the retro motorand the lunar capsule assembly to the spacecraft. Theclamp flies out.Simultaneously the bus power source will blow a squibswitch whi 3h activates a battery and sequencer in a smallcookie-shaped container located between the retro rocket

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and the lunar capsule. From that point on, the events thatoccur to the retro rocket and the lunar capsule are governedby commands from this cookie-shaped sequencer.When the squib switch is closed, the sequencer powersthree timers. The first timer, with a built-in delay of 135milliseconds, ignites the small spin motor in the nozzle ofthe retro rocket motor. This delay is programmed so that theclamp which holds the assembly to the spacecraft has time tofly free before the capsule starts to spin.The spin motor, with a thrust of 20 pounds, has three

nozzles tilted down fronm the horizontal at an angle of 10degrees, so that when it ignites and spins the retro rocketand the lunar capsule assembly up to 300 revolutions perminute, the downward tilt results in the entire assemblylifting itself by approximately two and a half feet aboveits cradled position in the spacecraft. The spacecraftgoes on to crash into the moon and destroy itself.The retro motor, with a thrust of 5080 pounds, thenfires. As it fires, it ejects the spin motor rocket thatwas contained in'its nozzle. The retro motor, with thelunar capsule positioned on top, fires for 10 seconds and

cancels out approximately 6000 miles an hour velocity fromthe capsule assembly.When the retro rocket fires, it is expected to severelyaffect the operation of the main spacecraft so that probablythe telemetry system will lose its lock on the earth. Theconsequence of this, of course, will be a sudden loss oftransmission of television pictures.This retro rocket ignition is initiated at 52,000feet above the surface of the moon and comes to an endafter burnout of the retro motor so that the entire assembly

would normally come to zero velocity when it is approximately1100 feet above the lunar surface. The 1100 foot altitude ischosen to provide allowance for'the normal dispersions in thesystem in order to insure that the retro rocket will havetime to complete its Job of removing the v locity.After burnout, a separation timer in he sequencerexplodes a clamp holding the lunar capsul to the retromotor, and the two units, now separated, oth start tofree fall into the moon.The separation of the two units will be such that theburned-out retro motor is expected to lan four or fiveseconds ahead of the lunar capsule. Thislevent will occursome 24 seconds after the main spacecraft'has 'crash landed.

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The balsa wood-covered instrumented capsule is expectedto land with a speed of less than 150 miles an hour.After it has landed, the instrument container in thebalsa wood covering will erect itself to point its antennaback to earth and prepare to record and telemeter back tnearth lunar body tremors it picks up from moon quakes ormeteoritic impacts. This process of preparation is expectedto take 20 minutes.

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RANGER 4 SCIENTIFIC EXPERIMENTS

There are four scientific experiments on Ranger 4. Theyinvolve scientists and engineers at seven institutions: TheCalifornia Institute of Technology, Columbia University, theJet Propulsion Laboratory, Los Alamos Scientific Laboratories,University of Arizona, United States Geologic Survey, and theUniversity of California at San Diego. Scientific aspects ofthe instrument system were the responsibility of Dr. Harold W.Washburn of JPL, project scientist, and Raymond L. Heacock ofJPL was the project engineer responsible for the engineeringof the scientific hardware.

The experiments are designed to obtain scientific informa-tion that will increase our knowledge of the history and forma-tion of the moon and technical information that will help makemore successful future moon landings by-manned or unmannedspacecraft. The instruments for these experiments are a vidiconcamera system, a gamma ray spectrometer, a radar altimeter anda seismometer. The main section of the spacecraft, carryingthe television camera and telescope, the gamma ray spectrometer,and the radar altimeter, will impact the moon at approximately6000 miles per hour and be destroyed. The capsule containingthe seismometer and its radio transmitter will rough land at avelocity between 80 and 120 miles an hour.

In the history of man's search for knowledge concerningthe moon, since Galileo first turned his telescope on the earth'ssatellite in the 15th century, there is relatively little thatis known as hard fact. We know with some certainty that themoon is 2160 miles in diameter, it has a mass one eightiethof the earth's mass, it rotates around the earth approximatelyonce every 28 days, it has a temperature range at its surfaceof approximately plus 260 degrees to minus 230 degrees Fahrenheit,it is at a mean distance of 238,000 mi]es from the earth.

There are, of course, other things known about the moon,such as the approximate number,'position arnd appearance of thecraters and seas, the incidents of slopes and valleys, but anylist of known facts concerning the moon would be relativelyshort compared to a list of known facts concerning the earth.What we have learned concerning the moon in the pastseveral centuries we have learned, not by much better observa-tion, but rather by improving our understanding of geology andby interpreting new discoveries made in this field. So, bylooking more closely at the eartii, we have understood betterthe forces that are brought into play to shape a large bodysuch as the earth, and which probably also affected theformation of the moon.

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Our studies of geochemistry have told us more about thei nature of rocks which might be on the moon. But despite allthese advances, detailed observations of the moon are as dif-f cult. to. make now-.as they ever have been. The filtering effectof the earth's atmosphere has had an adverse effect on the qual-

ity of photographs taken by earth-based telescopes, even underthe best conditions of seeing. Consequently, we have neverseen the moon from the earth with better than a kilometer, orsix-tenths of a mile, of resolution. This means that objectssmaller than this in size cannot be distinguished on the lunarsurface.There are many controversies among scientists concerningthe formation of the moon arn the history of the forces whichsubsequently have changed it3 structure and appearance. It isclear that the moon :1.s diffcr-c-iA In appearance from the earth,but the cause of these differences is the heart of the contro-

versy.Centuries ago, most astronomers believed the moon'scraters were giant extinct volcanoes and the vast.darkplains--called maria, the Latin word for seas--were thoughtof as fiel.ds of lava. Thus, these astronomers pictured themoon as a hot body with molten rock ready to spew out onto

the surface.As geologists began to look at the moon, however, and

turn to this riddle their knowledge Of the earth, they sug-gested that the craters really were the result of impacts.Of meteorites on the surface of the moon. They even sug-gested the vast, dark plains were really the result ofimpact by large meteorites. Thus, the astronomers turnedto a geologic explanation--volcanism--to describe the sur-face of the moon, and the geologists turned to astronomy--meteorite falls--for their description.

Very few scientists now believe that all the features ofthe rmooh are the result of volcanism. Most believe that thecraters are the result of meteorite impacts and the maria areindeed lava flow from volcanoes. Theire are a few who believethat the moon never was hot enough t6 have lava on it surface.and that all features of the moon are the result of meteoriteImpacts, dust particles and unfiltered sunlight.

Several of the crucial problems in this controversy areconcerned with the details of the lunar surface. Is it finelybroken up with small markings characteristic of lava flows hereon earth? Is it covered completely with shattered rock result-ing only from impact, and is it without lava? Has the surface-15- (OVER)


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been eroerld by the tinfi- iterod high energy of sunlight .;o thatSt .1 covered wl.th a layer of fine rock dust? We cannot tellwhich of those pos:ih ll.ties (or which unexpected unforeseenpossibillty) 's true by looking at the moon from the earth,no matter hew clever and ingenious scientists are at Inter-pret;ing the observational data. Only closeup, detailedobservation vrll]. Solve the rI.d.dle.It Is to some of these scientific questions that Ranger I1addresses itself. 'The four scientific experiments on ehe space-craft are expected to provide critical answers to some of thepressing problems that block our path to understanding the moon.

Clearly, this understanding is an essential part of the programto place a man on the moon in this decade.The experiments:

LUNAR PHOTOGRAPHYMost'of the useful lunar information has been obtainedfrom pictures of the moon's surface. One objective of theRanger 4 mission is to obtain pictures that contain more

deta:i.l than pictures now available, since the television-telescope instrument on the spacecraft will be in a positionto photograph the moon's surface free of the distortingeffects of the earth's atmosphere.From a scientific point of view, better quality pictureswill indicate 'the type of surface on which the seismometer willland and thus will assist in performirg a better evaluation ofthe seismometer data. The pictures also will give some geolog-ical information concerning coarse surface structure, smallscale selenological land forms and features, and altitudesand slopes of surface features. The same pictures will pro-vide invaluable information to help in the discovery ofpossible landing sites for future unmanned and manned lunarlandings.Whereas the best earth-based moon photos taken to datehave a resolution of approximately one kilometer---meaningobjects smaller than that in size cannot be distinguished--the Ranger 4I television camera and telescope is expected,if it is working within its limits, to provide pictures thatwill show an area a little more than 800 feet square in whichobjects 12 feet in diameter can be seen, under favorableconditions.The difference will be comparable to the ability todistinguish between an object the size of a large battle-

ship and an object the size of an automobile when both areon the surface of the moon.At Impact minus 65 minutes, a ground command will be sentfrom the Goldstone Tracking Station in the Mohave Desert ofCalifornia-to perform two functions. These are: To initiate .the terminal maneuver and to turn on the television camera.ystem. This occurs when Ranger 4 is 5000 miles from the3urface of the moon. - 16 -


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Although the television camera system will. be turncd onat that time, :it will not Send the telemetery unt3l Impactminus 40 minutes. This delay occurs for two reasons: It isnecessary to allow the tclevi.Sion system some time to warmup and also to allow the spacecraft to stabilize itself againafter the oscillations that have occurred during the terminalmaneuver when the spacecraft turned around and started to backdown to the surface of the moon.

At Impact minus 40 minutes, some 2500 miles above thesurface of the moon, the TV camera system signal will be fedinto the spacecraft telemetry and the picture-sending sequencefrom the spacecraft to Goldstone will commence. This sequencewill continue in an automatic mode until the destruction ofthe spacecraft.by impact at approximately 6000 miles an hour,but pictures are not expected to be received up to impact.

Each picture received at Goldstone from the spacecraftwill consist of 200 lines which are built up over a period of10 seconds. When the picture is built up, another three secondsis required to erase the picture and prepare for the next one.This three second interval also is used to transmit gamma rayand radar data. These are the steps in sequence: (1) A space-craft command signals that a frame should start. This causes ashutter solenoid to actuate a 20-millisecond exposure and simul-taneously begin a slow scan of the image on the televisionfaceplate. (2) Ten seconds later, a second spacecraft commandindicates cessation of the readout and diverts the telemetryinput to interrupt the signal. At this time, the TV camerabegins an erase and prepare mode to restore the televisionfaceplate to a blank condition in preparation for the nextimage. (3) Three seconds after the second command, the firstcommand is repeated, thus completing the cycle.

Several safety features have been incorporated in thecamera design. They are: (1) Should no spacecraft commandbe sent, the camera will sequence itself automatically. How-ever, spacecraft commands have'.priority and will, if present,override the internal sequence command. (2) The spacecraftclock is used to dictate the exact time that each line ofscan begins. This clock is always in control of the line,even when the erase process is taking place. The clock isin the form of a 400-cycle sine wave, and is also telemeteredback to Goldstone. This makes it possible to know preciselywhen each line should begin. If the telemetry link becomesnoisy at any time, then, it will be possible to maintainsynchronization on an absolute reference basis, thus keepingthe pictures in a format which allows the 7090 computer atJPL to later remove noise while searching for redundant pictureelements.

Ranger 4, from the time the TV system starts transnmitting,will send one TV picture to Goldstone every 13 seconds, a total-17- (OVER)

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of more than 100 pictures. At approximately 15 miles fromthe surface of the moon, and 8.1 seconds before bus impact,the capsule will be separated from the bus. The disturbanceresulting from this event is expected to disturb the attitudeof the spacecraft to the point where the high-gain antenna willlove its lock on Goldstone; thus transmission of TV pictures isexpected to end at this point.

The television electronics are contained in a circularpackage seven inches'in diameter and three inches deep. Theelectronics and tube design of the television camera wereespecially developed by the Radio Corporation of America forRanger 4, and Jet Propulsion Laboratory scientists developeda special optical telescope that provides the equivalent of a40-inch focal length instrument in a package that is only 14inches. long. General Electro Dynamics Corporation developedthe electron gun structure.

In the Ranger 3 flight, although the spacecraft did notprovide the television camera with the position it needed toconduct a successful lunar photography experiment, it waspossible to determine from telemetry that the televisioncamera equipment operated normally. Several of the frames)received clearly show the reticle on the face of the camera,by illumination from reflected sunlight.Experimenters on the lunar photography experiment are

Dr. G. P. Kuiper, University of Arizona; Dr. E. M. Shoemaker,U. S. Geologic Survey; Dr. H. C. Urey, University of Californiaat San Diego; Dr. A. R. Hibbs, R. L. Heacock and E. F. Dobies,Jet Propulsion Laboratory. Dobies is the JPL cognizant scientistfor the experiment, and Richard Heyser is the cognizant engineer.

GAMMA RAY EXPERIMENTStudies extending over several decades have shown thatthe earth possesses a thin surface layer, or crust, the com-

position of which is markedly different from that of theremainder of the earth. This difference shows up in thedistinct enrichment or depletions of many elements in thiscrust as a result of chemical and physical processes thathave taken place in the earth's history.One theory that has been widely accepted for years iothat the mean composition of the earthts mantle, excludingthe crust, is roughly the same as a class of undifferentiatedmaterial found in meteorites and known as the chondrites.

Strong evidence to support this hypothesis is found in thefact that the estimated heat loss of the earth is in closeagreement with the heat loss that could be expected from anearth of chondritic composition.-18- (')

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iI

Presumably the conditions that produced the earth arecon-Iderably different from those which acted upon the moon,but; the Dame quostions of differentiation and heat balanceare pertinent to the moon. The surface of the moon generally.in cons;idered to be older than the earth, but it seems l:i.kelythat the same processes of separation that are known to haveoccurred in the earth's crust may have taken place to a limitedextent in the moon.

Elements found In the earth's crust include, among others,uranium, thorium, radium and potassium. All of these possessradioactive isotopes and put out penetrating and characteristicradiations called gamma rays which are physically similar tohigh energy, monochromatic X-rays. Thus, by detecting thesecharacteristic gamma rays it is possible to tell how many ofthese elements are :I.n the rock. Geochemists have discoveredthat the rocks in the crust of the earth contain much morepotassium 40, which emits these X-rays, than does thechrondritic material of meteorites..Conequently, a measurement of the gamma ray spectrumfound in lunar surface rocks and dust will provide directinformation for the first time concerning the compositionof this material. Since the heat production of a body suchas the moon is largely determined by its radioactive content,C)#and since those elements which possess natural radioactivityare indicative of differentiation at least on the earth, gammaray spectroscopy on the moon appears to be capable of contribut-ing evidence to both problems.This radioactive technique of analysis has many advantagesover the ordinary chemical analysis process in which the rockwould have to be ground up, dissolved in acid and then subjectedto a series of chemical tests. For the gamma ray method, ofcourse, the rock sample need not be ground up or dissolved.Another advantage of this application is that.it measures theaverage composition of a large part of the moon's surface,rather than that of a particular sample which may differwidely from the average. Also,'the experiment can be con-ducted without landing delicate equipment on the lunar.surface.With these potassium 40 gamma ray data from Ranger 4, itwill be possible to determine in a broad sense if the surfaceof the moon looks like the surface of the earth or if it looksmore like meteoritic material. If the surface of the moon isindeed similar to the surface of the earth, this means that the

moon has had extensive volcanic or melting action in its historyand may be partially covered with lava. If, on the other hand,the lunar surface material appears similar to that of meteo-rites, this implies that a low level of volcanic activity orthat whatever volcanoes may have existed in the past have beeninactive for so long that the surface now is well covered bymeteorites.19 (OVER)


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The gamma ray detector writh Its hi.gh voltage supp].y .1.slocated at the end of a telescoping boom mounted on the space-craft. The detector in a thin aluminum sphere at the end ofthe boom Is extended by pressurized gas to a distance of saxfEe;t away from the spacecraft in order to reduce the effectof' The secondary gamma rays which are produced by the inter-action of cosmic rays with the bulk of the spacecraft. Thi.sevent is performed after Ranger 4 has undergone its mid-coursegruidance maneuver in order to preserve a known center of gravitywhich is required for the guidance maneuver calculations.Four hours after launch, the central computer and sequencerwill turn on the gamma ray experiment. As mentioned, the boom:i not extended at this time for several reasons. First, thecounting rate of secondary gamma rays produced by interaction.,'f osmic rays with the spacecraft is needed in order to providecalibration data.Another reason has to do with the precision required fortine mid-cQursc maneuver of the spacecraft. The mid-course motorthrust must, of course, be through the center of gravity of thespacecraft. If the gamma ray spectrometer boom were commandedto the extended position before the mid-course maneuver, and iffor some reason it did not reach that position, the center ofgravity would be different form the calculated point and wouldaf'ect the precision of the mid-course maneuver. Consequently, sthe boom Is kept in the retracted position until after completionof the mi.d-course maneuver.From the time that it is turned on until.40 minutes beforeimpact with the moon, the spectrometer sends information to theearth once every eight minutes. At 40 minutes before impact,when it is in a position to detect lunar surface gamma radia-tion, it starts to send data once every 52 seconds. When itshifts to this more rapid mode of' transmission, the spectro-meter uses the three-second erase mode on the televisionpicture channel of telemetry once in every four intervals.The gamma ray spectrometerd., mounted on'the spacecraft,wrill continue to send data up to the moment of separation ofthe lunar capsule from the bus.The gamma ray experiment hardware weighs a little morethan 12 pounds and occupies a volume of 850 cubic inches.The power required is less than two watts.In the Ranger 3 experiment, the gamma ray spectrometerperformed well. It obtained space radiation data that willbe of great value as a measure of the background upon whichany lunar signal must be superimposed. These data are nowbeing analyzed for Information that may be of intrinsic value.

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E~xpori.lentor8 arc ADA. J. R. Arnold, Un.l.vor..i.ty orCalifornla at 8..n nDlcgo; Dr. E. C. Anrlerzoln and Dr. 1. . A.Van Dilla, of the Lorz A]amorno Sci enti :tc laaboro.lor;.n-IDr. A. E. Met,'zror of the Jot Proputl si on Laboratory.Dr. Dct:.ger is the cognI7iant -,cicnt;ist In(1 cngincor fo rJPJ..MOON(2UAKE EXPE:RIM'4ENT

The determination of lunar body activity, either bymoonquakes which send raves through the lunar mass, or bythe impact of meteorites will provide important new infor-mation concerning the thermal history of the moon and thestructural proceoses which now may be taking place. Thebody wave data which may result either from moonquakes orimpact by meteors will provide information on the presenceor absence of 'a olid or liquid core at the center of themoon, and also will give information on the depth at whichmoonquakes occur and the amounts of energy released.by suchquakes.

In addition, the presence or absence of a lunar crust,similar to the crust which is known to exist on the earth,can be determined by the presence or absence of a particularkind of moonquake wave which could result from quakes ormeteorites.The instrument which will perform this experiment onthe surface of the moon is a small, highly sensitive seis-mometer, many times more sensitive than any tsehat is usedfor earthquake recording, yet constructed so as to be ableto withstand an impact with granite at a speed of 200 miles,an hour--a shock the equivalent to a deceleration of 3000times earth gravity--and continue to operate after such animpact.The seismometer was designed and fabricated by theCalifornia Institute of'Technology Seismological Laboratory,in cooperation with the Lamont iGeophysical Observatory ofColumbia University.It is a single-axis instrument 5.27 inches long and 4.37inches in diameter and weighs 7.8 pounds. Six silver cadmiumbatteries will provide power for a period between 30 to 60days to transmit moonquake or meteorite impact data to earth.The seismometer is contained in a sphere slightly less

than 12 inches in diameter, and weighing 57.). pounds. Thisinstrumented capsule is covered by a protective balsa woodcover designed to help absorb the iNpact energy when theassembly lands on the moon at a velocfty' omewhat less than- 21 - (OVER)


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1.50 miles per hour. The entire a.ssjmbly, in ;trurmcnted sph;leroand iva].aood covering and as,.;ocia.te(d harcdwiare w-eighls a totaloC89.3 pounds. The instrumented sphere, containing theMomocicr, the soi-;mometer amplifier and the batteries and a50-milliwratt radio transmitter, fits in the balsa wood cavity:t.n a thin layer of o:1 1 between the sphere and the balsa woodso that the sphere is free-floating in the cavity.

In the process of assemb).ing the sphere, the 50-mil.liw:ratttransmitter Was turned on four weeks before the launch date.The tranomitter, hotievor, is controlled by a mercury switch,so that duringr normal handling and before launch, the trans-mitter could be turned off merely by turning the sphere upsidedomrn. Mercury siw:1.tches, however, are not reliable in zerogr-avi.ty fields, so an inertial switch which closes under fivegravities was installed a.s a safrety precaution. Du.ring l.ift-oCf, til:t incrtia. swin:;tch will be closed by the gravitiesencountered during powered flight, and thus the seismometertransmitter wil). be turned on permanently at that time. It:i . cs. sntial fo r the seismometer transmitter to be turned on,even though it is, of course, not recording moonqualce dataduring flight, so that ground operators will know that itis operating. Wilth this knowledge, it then will be possibleto determine if the ohu;k of the retro rocket firi.ng causesany disturbance i.n the seismometer transmitter.

Also :i.n the instrumented sphere is a voltage controloscillator which is temperature-sensitive. This oscillatorhas been calibrated to its temperature sensitivity, andconsequently the data it sends by telemetry will enablecalculations to be made as to the range of temperaturesencountered during the 3.4-day lunar day and the 14-daylunar night.On top of the instrumented sphere is a turnstile antenna.The sphere is deliberately designed writh its center of gravitya half inch below its geometric center. This was done so thatwhen the capsule lands on the lunar surface and stops rolling,the sphere will right itself, in the manner of heavy bottomedtoys, with the turnstile antenna on the top and pointed at theearth.During flight, the instrumented sphere is held.in a rigidpos.Ltion in the balsa wood cavity by a set of caging pins whichimpinge on the outside of the sphere. During the thrust of theretro rocket during the terminal landing maneuver, a gravity-

sensitive switch will respond to the buildup of gravity whichthe sphere will undergo and will start a timer which willrelease the caging pins holding the sphere in place.-22- . I.


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It is not expected that the protective balsa wood cover-ing will split on impact, and fall away from the sphere., butthe balsa wood is transparent to the radio signals from thetransmitter in the sphere. Wfhen the caging pins release thesphere inside the balsa wood capsule and after the landingtakes place, the sphere with its low center of gravity willtake 20 minutes to position itself with the turnstile antennapointed toward the earth. The operation .requires that muchtime because of the weak lunar gravity and the viscosity ofthe oil which had served to insulate the sphere inside thebalsa wood covering.

However, now that the sphere is in position for theseismometer to operate, another hurdle must be overcome.That is to get rid of the oil film between the sphere and'the balsa wood, lest it act as an insulator to the shocksthe seismometer is designed to detect. Accordingly, afterthe sphere has righted itself, two pyrotechnic slugs areblown out of the assembly and the oil is vented off..

Another problem, relating to the great temperaturerange which is expected on the moon--from approximatelyplus 200 degrees to minus 230 degrees Fahrenheit--is nowresolved by an ingenious solution. The survival sphere

n contains 3.6 pounds of water which is heated by theV dissipation of electrical energy inside the sphere untilit reaches the boiling point of water under lunar vacuumconditions, which is 75 degrees Fahrenheit. Since it isimpossible to superheat wrater beyond the boiling point,this serves to stabilize the upper limit of the temperaturerange at this 75-degree level. As the 14-day-long lunarnight arrives, the water temperature falls from this peakbut never really reaches the freezing level because of theheat dissipation inside the capsule and the time involved.Consequently, the water control system serves to keep thesphere temperature within operating limits for the electronicsand batteries, seeing to it that they neither freeze nor melt.

The scientists participating in the moonquake experimentare Dr. Frank Press, California Institute of Technology Seis-mological Laboratory, and Dr. Maurice Ewing, Lamont GeophysicalObservatory, Columbia University. Dr. R. L. Kovach, JPL, isthe cognizant scientist for JPL, and Donald Adamski'is theJPL cognizant engineer.

RADAR REFLECTIVITYThe radar altimeter on Ranger 4 serves a dual purpose.Its engineering function is to initiate the capsule separa-

tion from the bus and the retro rocket ignition at a preset( altitude above the moon's surface. Its scientific function-23-


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I, to COllC t; n i';.via raC]' ci; v: 'dty e;:pcrilme^nt; on h;lv 8ur'faceof t~ho m1loonl .I.n O1-11(:P t;o pi'ovi Jce '1infoTiu'.t3;; n)n n the rnature ofthe l lnaina' ;;ii'U.? 'In th(e m'1p.P.c t arclr. ;). to e.;nh] ,;h mor(*n.'OrI;iai 6n 0on lunn' ;'a(-h-.r reJf1. cC.Ion propertXl";.iatyllr eartlh-,.bAc rar h,icnts have been conl.Thctedin an attempt 1to ctaol h ;;owethl.ng about the propcrtL c,; of'the Iiinar -;ijrm'acc by rf lectlIon cooUlcic nt of the rotnlrncA'r,signal. Dy nccc;;z 7,J, ho ever, thc arcna on the lulnar m;urfacecovorod by the oairti'-ba.ed racar :.is large, i;n most ca,,c., al)out60,000 zquare and the returns, al].o r eistimate. to bemade for the average re'lection coefficl.cnt3 (or arcas. of th; ss~i.ze .The Ranger 11 adar al imeter, ho'.-rever, vri].l. vievr an areaof approximately 60 sqiuare miles; or lcr;s of the l.unor surface,and the resul.ts may serve to cstabllsh a sl,andard area for th ecallbration of1 more comilple.: earth-ba:,ed radar systems to beused in lunar .ork.The instrument is a ;tandard pulsectype radar. The trans-

mitter is a magnetron with a peak porer output of 150 to p400vwatts. Pu.lse width is l;;o Microseconds, pulse repetition rateis 500 to 600 pulses per sccond, and the frequency i:s 94I00megacycles.The alt:tmeter wiill be turned on by ground command fromGoldstone at a distance from the lunar surface between 1.22and 3)4 miles.During the Ranger 3 terminal maneuver, the radar a].ti-meter.vwas successfully turned on, but the reflectivityexperiment was not attempted.W. E. Brown, Jr., is the experimenter in the radarreflectivity experiment and also serves as the cognizant

-scientist. H. E. Wagner is the JPL cognizant engineer.2.

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DEE13P SPACE, INSTRUMENTATION FACI.LITYThe Dcep Space Tn-t;truniontat; on Facl.ity (TDXIF) con. sict;of three space communication stat-ion3-, located approxi matcly:1.20 degrees apart around the earth, and a mobile station whichcan be located to suit the purpose of a particular miss:ton.The three permanent stations arc Gol(lotone, California; Woomera,Australia; and near Johannesburg, South Africa.The DSIF is under the technical direction of the CaliforniaInstitute of Technology Jet Propulsion Laboratory for the NationalAeronautics and Space Administration. Dr. Eberhardt Rechtin isJPL's DSIF Program Director.In the lunar and planetary programs, the mission of theDSIF is to track, receive telemetry from and send commands tospacecraft from the time they are :injected into orbits untilthey finish their missions.Since they are located approximately 120 degrees apartaround the earth, the three stations can provide 360 degree-

coverage around the earth so that one of the three alwayswill be able to communicate with a distant spacecraft.In the case of Ranger, the mobile station, under a crewheaded by Earl Martin of JPL, will locate its 10-foot-in-diameter tracking station at a position approximately onemile east of the DSIF station near Johannesburg.The mobile station will be used in that location becauseit has-the advantage of having a 10-degree beam width--tentimes as wide as the 85-foot-in-diameter dish--and it cantrack at a rate of 10 degrees per second, also ten times as

fast as the big dishes. On the other hand, since 'its antennais not so large as the big dishes, it cannot match the bigdishes in range and consequently will be used' only in theinitial part of the flight.Based on nominal performance and a nominal trajectory,the initial Ranger 4 acquisition and loss times for the DSIFstations are:Mobile Station, South Africa--Acquires 10 minutes afterinjection, holds for 12 hours.DSIF, Johannesburg--Acquires 15 minutes after injection,holds for 12 hours.DSIF, Woomera--Acquires 65 minutes after injection, holdsfor 2.5 hours.

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DSIF, Goldstone--Acquires 12.5 hour:; after injection,holds 11 hours.The mid-cource and terminal maneuver commands will be sentby GoJdstone, which also will send other commands as needed tothe spacecraft. Goldstone will acquire Ranger 3 approximately61 hours after launch to hold it through the terminal maneuverand Impact.Each DSIF station thereafter will work a 141-hour day forthe length of the battery life in the moon capsule, estimatedto be at least 30 days. Each station will receive telemetryfrom the lunar capsule for approximately eight hours and thenpass it on to another Station as the rotation of the earth andthe movement of the moon bring it within range.Each deep space station of the DSIF is equipped with an8 5-foot-in-diameter antenna and receiving, data handling, andinterstation communication equipment. In addition, the sta-tions at Goldstone and Johannesburg have command capability.Goldstone is operated for JPL by the Bendix Radio Corpora-tion. JPL's engineer in charge is Walter Larkin.The Australian DSIF is 15 miles from Woomera Village inSouth Australia. It consists of an 857f'oot-in-diameter receiv-ing antenna and supporting equipment and buildings. The Woomerastation is operated by the Australian Department of Supply,Weapons Research Establishment. Dr. Frank Wood represents theWRE. JPL's reqident engineer is Richard Fahnestock.The South African station, like the Woomera station,consists of an 85-foot-in-diameter receiving antenna andsupporting equipment and buildings and is located in a bowl-

shaped valley approximately 40 miles northwest of Johannesburg.The South African station is operated by the South Africangovernment through the National Institute for Telecommunica-tions Research, Dr. Frank Hewitt, director. NITR is a divisionof the Council for Scientific and Industrial Research. JPL'sresident engineer is Paul Jones.The two overseas stations and Goldstone are linked by acommunications network which allows tracking and telemetryinformation to be sent to the JPL Communication Center inPasadena for processing by JPL's IBM 7090 computer.

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K1.Y PERSONNEL

Rangcr 4 i.. art of the National Aeronautics and SpaceAdmtitratIZii' I niiiar and planetary progrdmin3 and is theresronsi bli:tty of the Office of Space Sciences. The JetPropulsion Laboratory, Pasadena, California, operated forNASA by the Cal:1fornia In-t;ilttct of Technology, is theprime contractor for Ranger 4 and other currently author-ized lunar and planetary prI,,jects.

NASA Headquarters personnel associated with Ranger 4are:Dr. Homer R. New-,ell, Director, Office of Space Sciences;E. M. Cortright, Deputy Director, Office of Space Sciences;Oran W. Nicks. Director of L:unar and Planetary Programs;Newton W. Cunningham, Chief. Ranger Program; Walter Jakobowski.

Ranger Program Engineer, and Dr. Charles P. Sonett, Chief,Sciences,0.Lunar and Planetary Program,.Key Jet Propulsion Laboratory personnel are:Clifford I. Cummings, Lunar Program Director; James D.Burke, Ranger Project Manager; Allen E. Wolfe, Ranger Space-craft Systems Manager; Dr. Nicholas A. Ienzetti, DSIF SystemsManager; Phillip A. Tardani. DSIF Operations Manager; MarshallS. Johnson, Data Operations and Control System Manager;Raymond L. Heacock, Project Engineer; Dr. Harold W. Washburn,Project Scientist; Edwin F. Dobie3, Scientist.for TV experl-

ment; Dr. Robert T...ovach, Scientiot for the seismometerexperiment; Walter E. Brown, Jr., Scientist for the radarreflectivity experiment; Gregory P. Cushing, Lunar CapsuleProject Engineer; Robert L. Crabtree, Spacecraft LaunchOperations; 14. Richard Mesnard, Ranger 4.project engineer;and Dr. Albert E. Metzger, Scientist for the gamma rayspectrometer experiment.

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SUBCONTRACTORS

Twenty-eight subcontractors to the California Instituteof Technology. et Propulsion Laboratory provided instrumentsand hardware for Ranger 3, 4 and 5 program. These contractsamounted to $8 million.

Aeronutronic, Div. of Ford Motor Lunar Rough LandingNewport Beach, California CapsuleAmerican Missile Products CC&S Flight SubsystemLawndale, California and Ground Support Equip,ment; Power Switching andLogic; Antenna Change-Over SwitchBarry Controls Solar Panel FramesGlendale, CaliforniaBell'Aerosystems Company Digital AccelerometerCleveland, Ohio ModulesBendix Corporation Deep Space Instrumenta-Owings Mills, Maryland tion Facility, Goldstone,CaliforniaCalifornia Institute of SeismometerTechnologyPasadena, CaliforniaElectric Storage Battery Company BatteriesMissile Battery DivisionRaleigh, North CarolinaElectro-Optical Systems, Inc. Booster RegulatorPasadena, CaliforniaGeneral Electrodynamics Scan-Converter SystemGarland, TexasGroen Associates Actuators for SolarPanels and Omnidirec-tional Boom, Gamma Ray

Telescoping Boom

Hercules Powder Company Capsule Retro MotorBacehus, UtahHoffman Electronics Solar PanelsEl Monte, California

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Ilorkey Moore Ranger Spacecraft SystemTorrance, California Test Stand, Pin PullersInternati.one.1.Telephone & Stati.c Power ConverterTelegraph ModulesIndustrial Products DivisionSan Fernando; CaliforniaLockheed Aircraft -Sterilization of AgenaVan Nuys, California ShroudMinneapolis-Honeywrell cgulator GyroscopesCompanyAero DivisionMinneapolis, MinnesotaMotorola Flight Transponder,Military Elec. Division Flight Data EncoderScottsdale, ArizonaNortronics Attitude Control andHawthorne, California Midcourse Autooilot

Electronic Subsystems;Sun Sensors and EarthSensors; Attitude Control?Gyro ModulesOrdnance Associates SquibsSouth Pasadena, CaliforniaRadiation Instrument D:ivision Gamma-ray Pulse HeightLaboratory Analyzers and AssociatedNorthlake. Illinois Ground Support EquipmentRadio Corp. of America Lunar Impact TV Camera* Princeton, New JerseyRdnsom Research Data Display EquipmentSan Pedro, CalifbrniaSpace Electronics Corp. Ground Command SystemGlendale, California Demodulators; DataEncoder Ground SupportEquipmentTE Company Optical Collimator forSanta Barbara, California Testing Lunar TelescopeTexas Instruments Ranger Flight CommandDallas 9., Texas Subsystem and GroundSupport Equipment

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Tinsley Laboratories Optical Telescope forBerkeley 10, California Lunar ProbeWiley Electronics Radio AltimeterPhoenix, ArizonaIn addition to these subcontractors, there were 1200

industrial firms who contrzbuted to the Ranger. The costof these supplies W&S in excess of $5 million, which coversall three spacecraft.

70

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LAUNCIT VEIICLE

tTASA s-Tainralrvehicle for the Ranger 4- unar landingmission is. the Atlas Agena-B--a combination of two rockets.The Atl.as D" serves as the booster and the Agena-B asthe vehicle's second stage.The launch vehicle is provided to NASA by the Air ForceSystems Command's Space SystamQ Division which functions asa "prime contractor" to the NASA vehicle group--the MarshallSpace Flight Center, Huntsville, Alabama.The unique relationship is spelled out in the NASA-USAFagreement which provides for NASA procurement through the AirForce of a number of veiicles consisting of modified Atlasboosters with modified Agena-B's serving as second stages.The Agena was developed for the Discoverer satellite programin which ft has achieved a significant reliability record.Major contractors Involved in the vehicle operation areLockheed Missile and Space Company and General Dynamics/Astronautics. The vehicle is launched by these companiesunder the direction of NASA's Launch Operations Center.

FLIGHT PLANAll engines Qf the Atlas booster, sustainer and vernier,are burning at liftoff. The booster is programmed to burn

approximately 2-1/2 minutes; the sustainer about 4-1/2 minutesand the verniers about five minutes. At Atlas burnout, thevehicle should be about 80 miles high.

Prior to sustainer cutoff, the Atlas ground guidancecomputer determines the velocity when vernier cutoff occursand coast'begins. Acting on these data, the computer estab-lishes the time when a signal to the Atlas airborne guidancesystem starts a timer aboard the Agena. This timer and anauxiliary timer in the Agena, control the sequence of eventswhich occur after separation from the Atlas.

When vernier cutoff occurs, the entire vehicle goes intoa coast phase of about half a minute. First the shroud pro-tecting the Ranger spacecraft during its exit through theearth's atmosphere is separated by a series of springs.Next small explosive charges release the Agena carrying thespacecraft from the Atlas. Retrorockets on the booster fire,slowing its upward flight and allowing the Agena to separate.

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Then the Agena pneumatic control system begins a pitch maneuverto orient the vehicle into an attitude horizontal to the earth.This pitch maneuver is programmed to be completed before thetimer. ignalsignition of the Agena engine.At engine start the hydraulic control system takes over,keeping the vehicle horizontal during the approximately 2/1/2minutes the engine is operating. The infrared horizon sensingdevice sends minute corrections to the control system.At Agena engine cutoff the vehicle and its Ranger payloadwill be in a near circular orbit at an altitude of about 100miles. This first orbit is called a "parking orbit."The Agena now coasts in its parking orbit for approximately14 minutes. The pneuma>-4 control system again takes over, main-taining the vehicle in the proper attitude with respect to theearth. At the proper instant, the timer again signals the Agenaengine to begin operation. This second burn is programmed forapproximately 1-1/2 minutes.About 2-1/2 minutes after the finai engine shutdown, theRanger spacecraft is separated from the Agena by springs. Thisoccurs about 25 minutes after liftoff.At separation from the Agena, the Ranger spacecraft shouldbe traveling about 23,800 miles per hour. This velocity willplace it in a trajectory that will carry it to the moon. Thetrip, from liftoff, will take about 60 hours.On the Ranger III flight, January 26, 1962, excess velocitywas-imparted to the spacecraft by the Atlas Agena B vehicle. Itwas not possible, even with the spacecraft's midcourse trajectory

correction capability, to take out enough velocity to achieve alunar impact.AGENA-B SECOND STAGE

The Agena-B stage of the lhunch vehicle is an improvedand enlarged version of the Agena-A, which was used in theDiscoverer satellite program.The Agena-B vehicle has integral, load-carrying propel-lant tanks with twice the capacity of Agena-A tanks and ispowered by a Bell Aerospace turbopump-fed engine. It burnsunsymmetrical dimethylhydrazine (UDMH) as fuel and inhibitedred fuming nitric acid (IRFNA) as the oxidizer.The new engine develops substantially higher performancethan prioi Agena engines and has a dual start capability.

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The'Agena's guidance system is capable of establishingattitude references and aligning the vehicle with them duringthe coast and engine operation phases. It also initiatesprogrammed~aignaas..for the starting, stopping and maintainingof various equipment during flight.Here is .a des5cription of the Agena B:Propulsion: Single rocket engine using liquid propel-]ant--inhibited red fuming nitric acid and unsymmetricaldimethlhydrazine;Thrust: 15,000 pounds at altitude.Size: Approximately 22 feet long including Ranger space-craft adapter.Control Systems: Pneumatic using high-pressure gas meteredthrough external jets for use during coast phases. Hydraulicthrough gimballing rocket engine for pitch and yaw control dur-

iliAg powered portions of flight. Both fed by programmer initiatedby airborne timers. Corrections provided by airborne guidancesystem.Guidance: The guidance system--which is made up of timingdevices, an inertial reference system, a velocity meter and aninfrared horizon sensing device--is entirely self-contained.Contractors: Lockheed Missile and Space Company, primecontractoJ'; Bell Aerosystems Co., engine.-

ATLAS "D" BOOSTERHere is a description of the Atlas "D" space booster:Propulsion: Three rocket engines--two boosters, onesustainer; uses liquid oxygen and kerosene propellants.Speed: Approximately 12,0bo statute miles per hour forthe Ranger missions.Thrust: Total nominal thrust at sea level more than360,000 pounds.Size: Approximately 78 feet high including adapter for

Agena; 16 feet wide across flared engine nacelles. Ten feetwide across tank section.Weight: Approximately 260,000 pounds at moment of launch,fully loaded with propellants.

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Guidance: Radio command guidance. Airborne elementssense velocity and vector transmitting this data to groundcomputer. Computer determines corrections necessary andtransmits information to airborne unit which signals controlsystem. Control accomplished through engine gimbelling andengine burning time.Contractors: Airframe and assembly--General Dynamics/Astronautics; propulsion--Rocketdyne Division of North AmericanAviation; radio command guidance--Defense Division of GeneralElectric Company; ground guidance computer--Burroughs Corporation.

KEY MANAGEMENT PERSONNELAgena-B direction at NASA Headquarters is provided throughDr. Homer E. Newell's Office of Space Sciences. The Agena pro-gram manager is Dick Forsythe.The field installation charged with managing the vehicleprogram is the NASA Marshall Space Flight Center.The Marshall Center's main responsibilities in the pro-gram are: control of changes in the system to meet NASAmission requirements, resolving of problems encountered inthe integration of launch vehicles and spacecraft, launchoperations and overall project management. Hans Hueterheads the Center's light and medium vehicles office.Friedrich Duerr is the Agena systems manager.Major John G. Albert is the director of the NASA Agena-Bprogram for the AF Space Systems Division, assisted by MajorCharles A. Wurster.Harold T. Luskin is the Lockheed Missile and SpaceCompany manager of NASA programs.Dr. Kurt H. Debus heads the Launch Operations CenterWhich directs launchings. Charles Cope of LOC performsliaison between Huntsville and Canaveral with respect tolaunch activities.

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RANGER 4 FACT SHEET

LAUNCH V.E.ICL...... . Atlas-Agena BDIMENSIONS LAUNCH VEHICLE,

Total height, with Ranger spacecraft, plus shroud . . 100 plus feetAtlas . . . . . . . . . . . . . . . . . . . . . . . . 66 feetAgena B . . . . . . . . . . . . . . . . . . . . . 22 feetRanger with shroud . . . . . . . . . . . . . .. . 12 feet

DI1MENSIONS RANGERIn launch position, foldedDiameter . . . a . * . a . . . . . . . , . 5 feetHeight . . . . . . . . . * . . . . . . . . . . . . 8.25 feetIn cruise position, panels unfoldedSpan . . . . . . . . . . . , . . . . . . . , . . , . 17 feetHeight . . . a. . . . . . . . . , . . . . 10.25 feet

';.TIGHT RANGERStructurer.. ...... ,,.. . . . .. 79.25 poundsSolar Panels . . . . . . . . . . . . . 42.65Electrondes . . . . . . . . . . . . . ... . 108.12Propulsion . . . . . . . . . . . 35.00Launch-Backup Battery . . . . . . . . . . . . . . . 24.64Miscellaneous Equipment . . . . . . . . . . . . . . 77.39Scientific Experiments . . . . . . . . . . . . . . 30.85Lunar Capsule Subsystem . . . . . . . . . . . . . 332.10

Lunar Capsule ........ 89.3Retrorocket Equipment 220.8Bus Mounted Equipment 22.0332.1

GROSS WEIGHT . . . . . . . . . . . . . . . . . . 730.00 pounds35

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RANGER 4 LUNAR CAPSULE SUBSYSTEM WEIGHT SUMMARYA. LUNAR CAPSULE Weight (pounds)

1. Survival sphere assemblya) Electronics, antenna, batterieswiring, structure, insulation 41.1b) Seismometer 7.8c Flotation fluid and outer shell 8.2

Survival sphere total ......... 57.12. Balsa impact limiter 32.2

Lunar Capsule Total .89.3B. RETROROCKET EQUIPMENT

1. Retrorocket motor and igniter 214.42. Spin motor, igniter and attachment 2.33. Vibration damper and clamp 1.24. Ballast 0.95. Control timer, batteries, wiring 1.46. Spin balance allowance 0.6Retrorocket Equipment Total ....... 220.8

C. BUS-MOUNTED EQUIPMENT1. Radar altimeter and antenna 6.62. Radar altimeter support and deployment 2.03. Motor support structure and separation 4;14. Electrical Junction box and connectors 0.85. Retrorocket heat shield 3.56. Spin motor vent cowling 5.0

Bus-mounted Equipment Total ........ 22.0LUNAR CAPSULE SUBSYSTEM TOTAL ... 332.1

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Ranger 4 Press Kit

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