ranger 5 press kit

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NATIONAL AERONAUTICS AND SPACE ADMINISTRATION1520 H STREET. NORTHWEST * WASHINGTON 25. D. C.TELEPHONES: DUDLEY 2-6325 . EXECUTIVE 3-3260

FOR RELEASE: SUNDAY A, M.'SRELEASE NO. 62-213 October 14 , 1962RANGER SPACECRAFT

Ranger 5 will be launched by the National Aeronautics and SpaceAdministration from the Atlantic Missile Range, Cape Canaveral, Florida,between October 16 and 19 . It will represent the third United States attemptto take closeup pictures of the moon, gather information on the compositionof the lunar surface and land an instrumented capsule on the surface of themoon.If successful, the Ranger 5 flight will obtain scientific informationthat will add to our knowledge of the history and structure of the moon, andtechnical information that will help make successful future moon landingsby manned or unmanned spacecraft.

k1Ranger 5 is a 755-pound gold-and chrome-plated spacecraft that willbe called on to perform a complicated series of events in a 66 to 72 hourflight to the moon. It will be asked to:1. Leave the earth with a velocity of about 24,500 miles an hour,

directed on an orbit which will arrive at the moon.2. Perform a maneuver in space to lock onto the sun and then ontothe earth.3. Accept correction commands from the earth, change its orientationin flight and fire a mid-course rocket motor to put itself on collison coursewith the moon.4. Reestablish its lock on the sun and the earth.5. Perform a terminal maneuver when it comes to within 5000 milesof the moon.

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6. Take television pictures of the lunar surface as it approachesthe moon,

7. Observe the radar reflection characteristics of -he lunar sur-face.

8. Separate a retrorocket and capsule system from the spacecraftwhen it is approximately 68,000 feet above the lunar surface.9. Fire the retrorocket tc slow the capsule system from 6000 milesan hour to zero velocity some 1100 feet above the surface of the moon.

10 . Detach an instrumented capsule containing a seismometer fromthe retrorocket so that it rough lands after a free fall from approximately1100 feet, survives the landing, positions :self and ther sends, for 30days or more, information on moon quakes and meteoriric Impact.The assignment is so difficult that NASA scheduled three flights(Rangers 3, 4 and 5) in the hope that one would be successful.Ranger 3, the first of these spacecraft, was ladrnched by an Atlas-Agena B rocket from Cape Canaveral on January 26, 1962. A malfunctionin the Atlas booster caused the spacecraft to be injected into Ats lunartransfer path at excessive velocity, and, as a result. Ranger 3 arrivedin the area of the moon some 14 hours ahead of time. On January 28 at3:23 p.m. , PST. , the spacecraft passed in front of its target, missing it

by 22,862 miles, and then went on into orbit around the sunDespite Ranger 3's nonstandard trajectory, an attempt was made tocarry out the lUnai photography experiment while the spacecraft wasapproaching the orbit of the moon. The attempt was unsuccessful, how-ever, because the spacecraft did not properly perform zh e terminalmaneuver that would have pointed its television camera at the surface

of the moon. This was caused by a malfunction in a subsystem of thespacecraft. This also caused the spacecraft's directional antenna to loseits orientation towards earth, resulting in a significant drop in signalstrength.The launch of Raniger 4 on April 23, 1962, was marked by a perfect

performance of the Atlas-Agena B rocket, Through injection and separation- ,'a2

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from the Agena B, the spacecraft operated normally, BUL when the space-craft rose over the South African horizon, tracking stations in Johannesburgreported the absence of the spacecraft's telemetry commutation sequence.Later it was shown that the telemetry system itself was intact, but possiblydue to loss of power to the spacecraft's Central Ccrnputer and Sequencer,the spacecraft's master clock had stopped.In the absence of its primary program sequencer, Ranger 4 could notperform any of its timed functions and could no. accept commands Sincethe spacecraft's solar panels could not be extended so that solar energycould be converted to electrical energy, tracking of the spacecraft's trans-mitter was limited to the 10-hour lifetime of the Ranger 4 backup battery.During this 10-hour period, precise two-way Doppler tracking datawas obtained. After the battery became depleted stations of the Deep SpaceInstrumentation Facilit- tracked the self-powered lunar capsule transmitteruntil the spacecraft impacted the moon. Impac: occurred after a flight of64 hours at 4:49 a. m., PST. , on April 26. at 12.9 degrees south lunar latitude,12S.1 degrees west lunar longitude, on the far side of the moon.The Ranger project is being carried out for the NASA by the jet PropulsionLaboratory, operated for NASA by the California Institute of Technology. Inthe Ranger 5 spacecraft, the Aeronutronic Division of Ford Motcr Company,Newport Beach, Calif. , provided the lunar capsule and radio altimeter sub-systems.The four scientific experiments carried on Ranger 5 are: the moonquake

experiment, the lunar photography experiment, the gamma ray experiment.and the radar reflectivity experiment.SPACECRAFT DE..CRIPTION

The Ranger 5 spacecraft is identical in appearance to Ranger IIIand IV. JPL engineers who designed the Ranger series call the basic hexagonalstructure the bus, in the sense that it scrves as an omnibus to carry differentpassengers in the form of different scientific and engineering instruments.Ranger 5 is five feet in diameter at the base of the hexagon and in its

launch position with the solar panels folded up in the manner of butterfly wings.In its launch position it is 8.25 feet in height. In the cruise position, with

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Spacecraftits solar panels extended and the high-gain directional antenna in itsextended position, it is 17 feet across in span and 10.25 feet in height.

The 755-pound weight of the spacecraft includes 338.73 poundsfor the lunar capsule and retrorocket system. The instrument capsule,designed to survive the landing on the moon, weighs 57 pounds and iscovered by a balsa wood sphere to cushion the shock of landing. Thebalsa sphere weighs 35 pounds, making the complete instrumented cap-sule weigh a total of 92 pounds.The lunar capsule rests atop a retro motor which in turn sits onthe top of the spacecraft hexagon. The retro motor, with a thrust of 5080pounds, weighs 221.73 pounds, together with its small spin motor thatrotates the assembly for stability just before the retro motor is fired.Surrounding the sphere-retro-motor assembly is a cylindrical heatshield, designed to provide thermal control for the solid propellantretromotor. The 3.5 pound shield, called the "shower curtain," is madeup of several layers of silvered plastic sheet and extends from the equatorof the sphere down to the top of the spacecraft hexagon. The shield issupported at the top by nylon lanyards which, in turn, are hooked to thespacecraft's omni-antenna on top d'f the sphere. 'When the omni-antennais deployed during the terminal maneuver, these lanyards are releasedand rubber cords pull the shield down to the top of the hexagonal structure,thereby providing an unfettered exit path fo r the capsule's escape.Attached to the hexagonal base are the two solar panels which inflight will collect solar energy which in turn will be converted into electri-

cal power to run the spacecraft. The panels contain 4340 solar cells eachin approximately 10 square feet of each panel making a total of 8680 cellson the two panels. They will pick up enough solar energy to be convertedinto 142 watts, unregulated.In one of the six boxes around the base is a 25-pound silver zinclaunch and backup battery with a capacity of 1200 watt hours. This batterywill be used to provide power for Ranger 5 when the solar cells are no toperating, such as prior to sun acquisition, in the midcourse maneuver andprior to la ndi ng.

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Ranger 5 has three communications antennas--two on the space-craft (or bus) and one on the to , of the instrumented sphere that willland on the moon. The lunar capsule transmitter is powered by sixsilver cadmium batteries to run the transmitter for at least 30 days totransmit moonquake and temperature information from the sphere tothe earth.The two antennas on the spacecraft are the omnidirectionalantenna positioned at the forward end of the spacecraft and the four-foot-in diameter high-gain directional antenna which is hinge-mountedat the aft end.Mounted in the hollowed-out section in the middle of the hexagonis the mid-course motor developed by JPL several years ago and sinceused in other U. S. Space tests.It is a liquid monopropellant engine that weighs, with fuel andthe nitrogen pressure gas system, 38 pounds. The hydrazine fuel isheld in a rubber bladder contained inside a football-shaped containercalled the pressure dome. When the mid-course motor receives thecommand to fire, nitrogen under 300 pounds of pressure per square inchis admitted inside the pressure dome and squeezes the rubber bladderwhich contains the hydrazine fuel.The hydrazine is thus forced into the combustion chamber, bu tbecause it is a monopropellant, it needs a starting fluid to initiatecombustion and a catalyst to maintain combustion. The starting fluid

used, in this case nitrogen tetroxide, is admitted into the combustionchamber by means of a pressurized cartridge. The introduction of thenitrogen tetroxide causes ignition, and the burning in the combustionchamber is maintained by the catalyst, aluminum oxide pellets storedin the chamber. Burning stcps when the valves turn off nitrogen pressureand fuel flow.At the bottom of the nozzle of the mid-course motor are four jetvanes which protrude into the rocket exhaust for attitude control Af thespacecraft during the period of the mid-course motor burn.The mid-course motor is so precise that it can burn in bursts of aslittle as 50 milliseconds and can alter velocity in any direction by as littleas one-tenth of a foot per second or as much as 132 feet per second. Ithas a thrust of 50 pounds for a maximum of 63 seconds.

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Also in one of the six boxes around the hexagon is a solid-statedigital computer called the Central Computer and Sequencer (CC&S).This is a system which allows commands to be stored in the systemfor later transmission to subsystems of the spacecraft, and which alsoallows specific ground commands to be stored in the CC&S after launchfor later routing to perform specific functions.Ranger 5 will use the parking orbit technique. This techniquecompensates fo r the penalty in launching lunar impact flights from theAtlantic Missile Range at Cape Canaveral, Florida.The Atlas booster lifts theAgena B and spacecraft to an altitudeof approximately 105 statute miles above the earth and to a velocityconsiderably below orbital speed of 18, 000 miles an hour.During the launch phase, the Ranger spacecraft is nrotectedagainst aerodynamic heating by a shroud, or nose cone, which coversit. After Atlas cutoff, at approximately 280 seconds, the shroud isjettisoned by eight spring-loaded bolts which shove it ahead of thevehicle. At almost the same time, the Agena B separates from the Atlas.At this time, the Agena B pitches down from an attitude almost 15 degreesabove the local horizon to almost level with the local horizon,in this horizontal attitude, the Agena B fires for the first time andburns for almost two and a half minutes to reach orbital speed of 18,000miles an hour. After this burning time, Agena B shuts down and coastsin a parking orbit for more than 25 minutes until it reaches the optimumpoint in time and space in its orbit to fire for the second time,After the second Agena B burn, the Agena B and Ranger 5, stillas one unit, are injected at near escape velocity of 24, 500 miles anhour approximately over Ascension Island in the South Atlantic Oceanand approximately 35 minutes after launch. Up to this time, the eventsof the launch, separation of Agena from Atlas, operation of the Rangerspacecraft system and ignition and cutoff times of Agena have beentelemetered to ground tracking stations through the Agena telemetrysystemA little more than tw o minutes after second burn cutoff (known asinjection), Ranger 5 is separated from Agena, again by spring-loaded bolts.

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After this occurs, Agena does a 180-degree yaw and moves into adifferent and lower trajectory from that held by Ranger 5 by means offiring a solid retrorocket on Agena. This is done for two reasons:it would not be desirable for the unsterilized Agena to follow Ranger5 on in and impact the moon, and if Agena B follows Ranger 5 tooclosely, the spacecraft optical sensors might mistake reflected sun-light from Agena B for the sun or earth and thus confuse its opticalsensor acquisition system.Ranger 5 now is on a trajectory that will take it fairly close tothe moon. The omnidirectional antenna is working and radiating itsfull three watts of power. Before and during launch, the transmitterhad been kept at half power of 1.5 watts. This was done because asthe launch vehicle passes through a critical low atmospheric densityarea between 150,000 and 250,000 feet, there is a tendency fordevices using high voltage to arc over and damage themselves; hence,the transmitter is kept at half power until this area is passed. The

necessary switching to accomplish this change is done by the CC&Sat 23 minutes after launch.Now it is possible to describe the sequence of events that Ranger5 will conduct on its 65-hour flight to the moon.The second command is issued by the CC&S 48 minutes after launch.Explosive pin pullers holding the solar panels in their launch positionare detonated to allow the spring-loaded solar panels to assume theircruise position.At launch plus 51 minutes, the CC&S turns on the attitude controlsystem and Ranger 5 starts the process of looking for the sun with itssolar sensors. The same command extends the gear-driven high-gainantenna at the aft end of the spacecraft to a preset position.There are six sun sensors mounted on Ranger 5. There are four primarysensors on four of the six legs of the hexagon, and two secondary sensorsmounted on the backs of the solar panels. These are light-sensitive diodeswhich inform the attitude control system when they see the sun. The twosecondary sensors on the backs of the solar panels inform the attitude con-trol system that they see the sun, but want not to see it. The attitude control

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system responds to these signals by turning the spacecraft in sucha manner that the longitudinal, or roll axas, points toward the sun.Torquing of the spacecraft for these maneuvers -s provided by tenstrategically located gas jets which are fed by four bottles of nitrogengas containing a total of 2.64 pounds of nitrogen under pressure of3000 pounds per square inch. This is calculated to be enough nitrogento operate the gas jets to maintain attitude control for a minimum of50 days and a maximum of 100 days in a cruise mode.

The gyros have first acted to cancel out the residual separationrates which affected Ranger 5 after it left Agena BL The sun sensorsthen, working on the valves controlling the gas jets, jockey the space-craft about until its long axis is pointed at the sun, thus fully illuminatingthe solar panels Both the gyros and the sun sensors can activate thegas jet valves, In order to conserve gas, the attitude control systempermits a pointing error toward the sun of one degree, or 5 degree oneach side of dead on. The mixing network in the attitude control systemis calibrated to keep Ranger 5 slowly swinging through this one degreeof arc pointed at the sun. The swing takes approximately 60 minutes.As Ranger 5 nears the .5 degree limit on one side, the sensors signalthe gas jets and they fire again. This process is repeatea hourlythrough the effective life of Ranger 5. It is calculated that .he gas jetswill fire one-tenth of a second each 60 minutes to keep the spacecraft'ssolar panels pointed at the sun.

The sun acquisition process is expected o- o take between 5 and 29minutes. When it is completed, the secondary sun sensors on the backsof the solar panels are turned off to avoid having light from the earthconfuse them. After the solar panels are locked on the sun, the powersystem now recognizes that it is getting electric power from the solarpanels, so it switches from the silver zinc battery and uses the solarpower to feed the power demands of Ranger. The solar panels on Rangerare not used to charge the battery.

Three and a half hours after launch, the CC&S commands Ranger5 to start the earth acquisition process, which requires from 5 to 30 minutes.The spacecraft maintains its lock on the sun, but with ts high-gain direc-tional antenna pointed at a preset angle, it rolls on its long axis and starts

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to look for the earth. It does this by means of a three-section photo-multiplier-tube-operated earth sensor which is mounted to look parallelto the main axis of the high-gain antenna. During the roll, the earthsensor will see the earth and inform the gas jets. The jets will fireto keep the earth in view of the sensor and thus lock ontc the earth.A slight correction in the preset hinge angle may also be required, whichis also earth sensor controlled.

The spacecraft now is stabilized on two axes--the solar panel-sunaxis and the earth-directionai antenna axis. There is some danger thatthe earth sensor, during its search for the earth, may see the moon andlock onto it. If this happens, tracking stations at Goldstone in Califor-nia and Johannesburg in South Africa have the ability to send an overridecommand to the attitude control system to tell it to look again for theearth.The earth-sensor/high-gain antenna should have acquired the earth

by 4 hours after launch. At that time South Africa will send Ranger 5a command to switch from the omnidirectional antenna to the directionalantenna. If the increase in received signal strength indicates that thedirectional antenna is locked on the earth, no further commands in thisarea are necessary at the moment. But if the signal strength drops,indicating that the directional antenna is not pointed at the earth, theoverride roll command will be sent to Ranger 5 to look for the earth again.If this is not sufficient, South Africa also has the ability to send a hingeoverride command to change the position of the antenna and start thesearch for the earth again.Four hours after launch, CC&S will turn on the gamma ray experi-mient. This is a spectrometer contained in a 12-inch-in-diameter ballmounted on a 40-inch-long arm on the hexagon. Later in the flight,pressurized gas will be used to extend this telescoping arm to 72 inchesaway from the spacecraft in order to avoid the measurement of secondaryeffects created by cosmic rays hitting the main bulk of the spacecraft.It is not deemed desirable to extend the gamma ray boom at thistime, however, since Ranger 5 must still perform its midcourse correctivemaneuver to get on collision course with the moon. In order to perform

this maneuver with precision, of course, it is necessary to know the pre-cise center, of gravity of the spacecraft. If the gamma ray boom were

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ordered out to its extended position, and it did not for some reasonobey this order, the center of gravity would be different from the cal-culated point and the precision of the mid-course maneuver wouldbe affected. So the boom stays in the retracted positron antil the mid-course maneuver is completed. Meanwhile, gamma-ray data is obtainedwhile the spectrometer is still retracted, for reasons Of calibration.

From that point on, four hours after launch, un-il the start ofthe midcourse maneuver approximately 16 hours after la inch, most ofthe activity takes piace at the three Deep Space InstrumentationFacility stations--Woomera, Australia; Johannesburg, South Afrnca;Goldstone, California--and at JPL.

Tracking data from these three stations are fed into the 7C90computer at JPL in Pasadena. The computer calculates the pcsition ofthe spacecraft as it is in fact Jn relat.on to where it should be in orderto hit the moon. If it is the case, as it is likely to be, that guidanceerrors before injection have put it off Its optimum trajectory, the com-puter will provide a set of figures that will tell the spacecraft hcw ithas to change its orientation in space in order to properly aim th3 mid-course motor for its corrective maneuver.

This intelligence will be in the form of a four -word digital commandthat will be sent to the spacecraft and stored in the CC&S. One wordconcerns the direction and amount of pitch needed and another word con-cerns the direction and amount of roll necessary. With these two maneu-vers, the spacecraft can be pointed in any direction nezessary to makea change in course, time of flight, or both. The third word is t.he amountof velocity increment needed from the midcourse motor. rhese threewords are sent from Goldstone to the Ranger 5 CCocS where they arechecked to see if they are addressed to the proper places in the spacecraft.CC&S takes no action, however, until :t receives to "go" command fromGoldstone. While waiting for that command, the spacecraft sends backto Goldstone, for rechecking, the words it received. If there are no changesto be made, 30 minutes after the Ranger 5 CC&S has r-iAved and storedthe commands, it receives, at 16 hours after launch, the "go" commandfrom Goldstone.

Just prior to issuing the "go" command, Golastone will send acommand to Ranger 5 to switch from the directional to the omni-antenna.

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After the "go" command is sent, the directional antenna is fully ex-tended automatically so that it will be out of the way of the exhaustof the midcourse motor.The roll maneuver is allotted 9. 5 minutes of time, including twominutes of settling time, and the pitch maneuver is allotted approxi-

mately 15 minutes. Two minutes after the pitch maneuver is completed,the midcourse motor is turned on and burns until the commandedvelocity increase has been effected. The attitude control gas jetsare not powerful enough to maintain the stability of the spacecraft duringmidcourse maneuvering, so jet vanes extending into the exhaust of themidcourse motor control the attitude of the spacecraft in this period.The jet-vanes are controlled by an adjunct to the attitude control systemknown as the autopilot.After the midcourse maneuver has put Ranger 5 on the desiredcollision course, the spacecraft goes through the sun and earth acquisi-tion modes again.Ranger 5 now is at the limit of the range at which the omni-antennacan provide useful information, however, and Ranger 5 has been trans-mitting through the omni during the midcourse maneuver. A ground com-mand is issued to transfer back to the high-gain antenna and this conditionwill remain for the rest of the flight.Two and one-half hours after initiation of the midcourse maneuver,CC&S commands the gamma ray boom to extend, by means of pressurized

gas, to its limit of 72 inches away from the spacecraft. The gas con-tained in the boom is not allowed to vent since its quick escape un-doubtedly would perturb the attitude of the spacecraft. It may leak out,however, but not at a rate that would affect the spacecraft attitude.For the next 48 hours, Ranger 5 continues on its course to the moon,telemetering continuous engineering data and also sending gamma rayreports back once every eight minutes. Tracking data from all three DSIFstations are sent to JPL and the 7090 computer calculates when impactwill occur.When the exact time of impact is computed, it then will be possibleto back off in time and determine where the spacecraft will be 65 minutes

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before impact. The computer, using this position of impact minus65 minutes, will determine the kind of commands that have :o besent to the CC&S in order for it to perform its terminal maneuver atthat time.These commands will be sent by Goidstone to Ranger 5 a half

hour before the spacecraft reaches this point in time and space, or95 minutes before impact.The cofimands will be similar in nature to those sent to governthe midcourse maneuver, with the difference that this time there willbe no motor burn, The three commands, sent to the CC&S and storedthere against the time it receives the "go" command, are: directionand amount of pitch turn, direction and amount of yaw tu-n, directionand amount of a second pitch turn. These three turns are necessary tokeep the directional antenna aimed at the earth and yet position thespacecraft properly for its lunar approach.The 'go" command sent in real time from Coldstone 65 minutesbefore impact initiates a series of events which sees the spacecraftusing its attitude control system gyros and gas jets to turn around andorient its television camera to the surface of the moor. When thissequence is initiated, Ranger 5 will be approximately 5 COG miles abovethe lunar surface. In the attitude required for tne terminal maneuver thesolar panels are not pointed at the sun, and from now on power is pro-vided by the battery. Initiation of the terminal maneuver also turns onthe television camera for warmup; it will not start to take pictures untillater.The last maneuvering command of .he CC&S, which is to stopthe second pitch maneuver, also accomplishes three other switchingfunction. These are: (1) to switch from an engineering data telemetrymode to a scientific telemetry mode, fo r acquisition of the televisionpictures and an increased rate of gamma-ray data, (2) initiate a 2minute time delay to deploy the radio altimeter antenna, (which isnecessary for it to be looking at the lunar surface), and to remove theprotective cover from in front of the television camera telescope and(3) to initiate a 22 minute time delay to deploy the omni-antenna whichmakes an exit path for the separation of the -rnar survival capsule. The

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time delays for the deployments a.a necessary to allow the space-craft to stabilize from its last pitch maneuver before introducingthe motion of the deployments. The radio altimeter antenna isdeployed 30 seconds before the omni-antenna to allow it to be outof the way at the time the retro-motor heat shield comes down, thelatter happening when the omni-antenna is deployed. The telescopecover, mentioned above, is used to prevent micro-meteorite damageand as a radiation shield to husband the heat in the television cameraassembly. All of the deployments mentioned above are operated bycaptive springs, which are released by pyrotechnic "pin-pullers" orexplosive bolts.

At 2600 miles from the surface of the moon, just 35 minutesbefore impact, the television camera starts taking pictures of the lunarsurface and transmitt! .,l them, one every 13 seconds, to Goldstone.The gamma ray telemetry also is shifted from low to high rate sothat instead of sending reports once every eight minutes, it now sendsreports once every 52 seconds.The radar altimeter, which is turned on-one minute before impact,ranges its signal against the surface of the moon and receiving theecho, initiates the next command. At approximately 64,000 feet abovethe lunar surface, and 8.1 seconds before the main spacecraft is dueto crash and destroy itself, the delay time between the radar pulse

and echo is su:ch that the altimeter will generate a fusing signal.This fusing signal starts the lunar capsule launch sequence, inthis order of events.The bus power source, the large battery, will explode four boltscutters on the clamp that holds the retro-motor and the lunar capsuleassembly to the spacecraft. The clamp flies out.Simultaneously the bus power source will blow a squib switchwhich activates a battery and sequencer in a small cookie-shaped con-

tainer located between the retrorocket and the lunar capsule. From thatpoint on, the events that occur to the retrorocket and the lunar capsuleare 9overned by commands from this cookie-shaped sequencer.

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When the squib switch is closed, the sequencer powers threetimers. The first timer, with a built-in delay of 215 milliseconds,ignites the small spin motor in the nozzle of the retrorocket motor.This delay is programmed so that the clamp which holds the assemblyto the spacecraft has time to fly free before the capsule starts to spin.

The spin motor, with a thrust of 20 pounds, has three nozzlestilted down from the horizontal at an angle of 10 degrees, so that whenit ignites and spins the retrorocket and the lunar capsule assembly upto 285 revolutions per minute, the downward tilt results in the entireassembly lifting itself by approximately two and a half feet above itscradled position in the spacecraft.The retro-motor, with a thrust of 5080 pounds, then fires. As itfires, it ejects the spin motor rocket that was contained in its nozzle.The retro-motor, with the lunar capsule positioned on top, fires for 10seconds and cancels out approximately 6000 miles an hour velocityfrom the capsule assembly.When the retrorocket fires, it is expected to severely affect theoperation of the main spacecraft so that probably the telemetry systemwill lose its lock on the earth. The consequence of this, of course,will be a sudden loss of transmission of television pictures.This retrorocket ignition is initiated at 52 ,000 feet above thesurface of the moon and comes to an end after burnout of the retro motorso that the entire assembly would normally come to zero velocity whenit is approximately 1100 feet above the lunar surface. The 1100 footaltitude is chosen to provide allowance for the normal dispersions inthe system in order to insure that the retrorocket will have time to com-plete its job of removing the velocity.After burnout, a separation timer in the sequencer explodes aclamp holding the lunar capsule to the retro-motor, and the two units,now separated, both start to free fall into the moon. The spacecraftgoes on to crash into the moon and destroy itself.The separation of the two units will be such that the burned-outretro-motor is expected to land foui or five seconds ahead of the lunar

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capsule. This event will occur some 24 seconds after the main space-craft has crash landed.

The balsa wood-covered instrumented capsule is expected to landwith a speed of less than 150 miles an hour.

After it has landed, the instrument container in the balsa woodcovering will erect itself to point its antenna back to earth and prepareto record and telemeter back to earth lunar body tremors it picks upfrom moon quakes or meteoritic impacts. This process of preparationis expected to take 20 minutes.KEY PERSONNEL

Ranger 5 is part of the National Aeronautics and Space Adminis-tration's lunar and planetary programs and is the responsibility of theOffice of Space Sciences. The Jet Propulsion Laboratory, Pasadena,California, operated for NASA by the California Institute of Technology,is the prime contractor for Ranger 5 and other currently authorizedlunar and planetary projects.

NASA Headquarters personnel associated with Ranger 5 are:Dr. Homer E. Newell, Director, Office of Space Sciences;E. M. Cortright, Deputy Director, Office of Space Sciences; Oran W.

Nicks, Director of Lunar and Planetary Programs; Newton W. Cunningham,Chief, Ranger Program, Walter Jakobowski, Ranger Program Engineer; andDr. Urner Liddel, Chief of Sciences, Lunar and Planetary Programs.

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RANGER 5 SCIENTIFIC EXPERIMENTS

EXPERIMENTS DESCRIPTION EXPERIMENTERSLunar Photograph To photograph lunar surface Dr. G. P. Kuiperfrom altitude of 2600 miles Univ. of Arizona;down to altitude of 15 miles. Dr. E. M. Shoemaker,U. S. Geological

Survey; Dr. H. C, Urey,University of Calif.at San Diego; Dr. A. R.Hibbs, R, L, Heacockand D. E, Willingham,JPL.Gamma Ray To determine the approxi- Dr. JO R. Arnold,Measurement mate concentration of University of Calif.

different radioactive mate- at San Diego;rials in the surface of the Dr. 1. C. Andersonmoon. and Dr M. A. VanDilla, Los AlamosScientific Labs; andDr. A. E. Metzger, JPL.Radar Reflectivity To provide information W . E. Brown, Jr., JPL.regarding the characterof the moon's surface.Lunar Seismic To measure the presence Dr. Frank PressAct vity or absence of moon quakes, California Institute ofand meteoritic impact on Technology; Dr, Mauricethe moon. Ewing, Columbia Univ.

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RANGER 5 SCIENTIFIC EXPERIMENTS

There are four scientific experiments on Ranger 5. They involvescientists and engineers at seven institutions: The California Instituteof Technology, Columbia University, the Jet Propulsion Laboratory, LosAlamos Scientific Laboratories, University of Arizona, United StatesGeologic Survey, and the University of California at San Diego. Scien-tific aspects of the instrument system were the responsibility of Dr.Harold W . Washburn of JPL, project scientist, and Raymond L. Heacockof JPL was the project engineer responsible for the engineering of thescientific hardware.

The instruments for these experiments are a vidicon camera system,a gamma ray spectrometer, a radar altimeter and a seismometer. Themain section of the spacecraft, carrying the television camera and tele-scope, the gamma ray spectrometer and the radar altimeter, will impacton the moon at approximately 6000 miles per hour and be destroyed.The capsule containing the seismometer and its radio transmitter willrough land at a velocity between 80 and 120 miles an hour.

In the history of man's search for knowledge concerning the moon,since Galileo first turned his telescope on the earth's satellite in the 15thcentury, there is relatively little that is known as hard fact. We knowwith some certainty that the moon is 2160 miles in diameter, it has a massone eightieth of the earth's mass, it revolves around the earth appro-d-mately once every 28 days, it has a temperature range at its surfaceapproximately 260 degrees to minus 230 degrees Fahrenheit, it is at amean distance of 238,000 miles from the earth.

There are, of course, other things known about the moon, suchas the approximate number, position and appearance of the craters andseas, the incidence of slopes and valleys, but any list of known factsconcerning the moon would be relatively short compared to a list ofknown facts concerning the earth.What we have learned concerning the moon in the past severalcenturies we have learned, not by getting much better observation, butrather by improving ou r understanding of geology and by interpreting ne w

discoveries made in this field. So, by looking more closely at the earth,we have understood better the forces that are brought into play to shapea large body such as the earth, and which probably also affected the for-mation of the moon.

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Scientific Experiments

Our studies of geochemistry have told us more about the natureof rocks which might be on the moon. But despite all these advances,detailed observations of the moon are as difficult to make now as theyever have been. The filtering efiect of the earth's atmosphere has hadan adverse effect on the quality of photographs taken by earth-basedtelescopes, even under the best conditions of viewing, Consequently,we have never seen the moon from the earth with better than a kilometer,or six-tenths of a mile, of resolution, This means that objects smallerthan this in size cannot be distinguished on the lunar surface.

There are many controversies among scientists concerning theformation of the moon and the history of the forces which subsequentlyhave changed its structure and appearance. It is clear that the moonis different in appearance from the earth, but the cause of these dif-ferences is the part of the controversy.Centuries ago, most astronomers believed the moon's craterswere giant extinct volcanoes and the vast dart plains--called maria,the Latin word for seas--were thought of as fields of lava. Thus, theseastronomers pictured the moon as a hot body with molten rock ready tospew out onto the surface.As geologists began to look at the moon, however, and turn tothis riddle theih knowledge of the earth, they suggested that the cratersreally were the result of impacts of meteorites on the surface of the moon.

They even suggested the vast, dark plains were really the result ofimpact by large meteorites. Thus, the astronomers turned to a geologicexplanation--volcanism--to describe the surface of the moon, and thegeologists turned to astronomy--meteorite falls--for their description.Very few scientists now believe that all the features of the moonare the result of volcanism. Most believe that the craters are the resultof meteorite impacts and the maria are indeed lava flow from volcanoes.There are a few who believe that the moon never was hot enough to havelava on its surface, and that all features of the moon are the result ofmeteorite impacts, dust particles and unfiltered sunlight.Several of the crucial problems in this controversy are concernedwith the details of the lunar surface. Is it finely broken up with smallmarkings characteristic of lava flows here on earth? Is it covered completely


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Scientific Experimentswith shattered rock resulting only from impact, and is it withoutlava? Has the surface been eroded by the unfiltered high energy ofsunlight so that it is covered with a layer of fine rock dust? We!cannot tell which of these possibilities (or which unexpected unfore-seen possibility) is true by looking at the moon from the earth. Onlycloseup, detailed observation will solve the riddle.

It is to some of these scientific questions that Ranger 5addresses itself. The four scientific experiments on the spacecraftare expected to provide critical answers to some of the pressingproblems that block our path to understanding the moon. This under-standing is an essential part of the program to place men on the moonin this decade.The experiments:

LUNAR PHOTOGRAPHYMost of the useful lunar information has been obtained frompictures of the moon's surface. One objective of the Ranger 5 missionis to obtain pictures that contain more detail than pictures now avail-able, since the television-telescope instrument on the spacecraft willbe in a position to photograph the moon's surface free of the distortingeffects of the earth's atmosphere.From a scientific point of view better quality pictures will indicatethe type of surface on which the seismometer will land and thus will

assist in performing a better evaluation of the seismometer data. Thepictures also will give some geological information concerning coarsesurface structure, small scale selenological land forms and features,and altitudes and slopes of surface features. The same pictures willprovide information to help in the discovery of possible landing sitesfor future unmanned and manned lunar landings.Whereas the best earth-based moon photos taken to date have aresolution of approximately half a mile--- meaning objects smaller thanthat in size cannot be distinguished--the Ronger 5 television camera and

telescope is expected, if it is working within its limits, to provide picturesthat will show an area a little more than 800 feet square in which objects12 feet in diameter can be seen, under favorable conditions.

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The difference will be comparable to the ability to distinguishbetween an object the size of a large battleship and an object thesize of an automobile when both are on the surface of the moon.At Impact minus 65 minutes, a ground command will be sentfrom the Goldstone Tracking Station in the Mohave Desert of Californiato perform two functions. These are: To initiate the terminal maneuverand to turn on the television camera system. This occurs when Ranger5 is 5000 miles from the surface of the moon.Although the television camera system will be turned on atthat time, it will not send the telemetry until Impact minus 35 minutes.This delay occurs for two reasons: It is, necessary to allow the tele-vision system some time to-warm up and also to allow the spacecraftto stabilize itself again after the oscillations that have occurred duringthe terminal maneuver when the spacecraft turned around and startedto back down to the surface of the moon.At Impact minus 35 minutes, some 2600 miles above the surfaceof the moon, the TV camera system signal will be fed into the space-craft telemetry and the picture-sending sequence from the spacecraftto Goldstone will commence. This sequence will continue in an auto-matic mode until the destruction of the spacecraft by impact at approxi-mately 6000 miles an hour, but pictures are not expected to be rece.vedup to impact.Each picture received at Goldstone from the spacecraft will con-sist of 20C lines which are built up over a period of 10 seconds. Whenthe picture is built up, another three seconds is required to erase thepicture and prepare for the next one. This three second interval alsois used to transmit gamma ray and radar data. These are the steps insequence: (1) A spacecraft command signals that a frame should start.This causes a shutter solenoid to actuate a 20-millisecond exposureand simultaneously begin a slow scan of the image on the televisionfaceplate. (2) Ten seconds late, a second spacecraft command indicatescessation of the readout and diverts the telemetry input to interrupt thesignal. At this time, the TV camera begins an erase and prepare mode

to restore the television faceplate to a blank condition in preparation forthe next image. (3) Three seconds after the second command, the firstcommand is repeated, thus completing the cycle.

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Several safety features have been incorporated in the cameradesign. They are: (1)Should no spacecraft command be sent, thecamera will sequence itself automatically. However, spacecraft com-mands have priority and will, if present, override the internal sequencecommand. (2) The spacecraft clock is used to dictate the exact timethat each line of scan begins. This clock is always in control of theline, even when the erase process is taking place. The clock is inthe form of a 400-cycle sine wave, and is also telemetered back toGoldstone. This makes it possible to know precisely when each lineshould begin. If the telemetry link becomes noisy at any time, thenit will be possible to maintain synchronization on an absolute referencebasis, thus keeping the pictures in a format which allows the 7090computer at JPL to later remove noise while searching for redundantpicture elements.

Ranger 5, from the time the TV system starts transmitting, willsend one TV picture to Goldstone every 13 seconds, a total of moreth, a 100 pictures. At approximately 15 miles from the surface of themoon, and 8.1 seconds before bus impact, the capsule wili be separatedfrom the bus. The disturbance resulting from this event is expectedto disturb the attitude of the spacecraft to the point where the high-gain aatenna will lose its lock on Goldstone; thus transmission ofTV pictures is expected to end at this point.

The television electronics are contained in a circular packageseven inches in diameter and three inches deep. The electronicsand tube design of the television camera were especially developedby the Radio Corporation of America for Ranger 5, and Jet PropulsionLabore,~or- scientists developed a special optical telescope that pro-vides the equivalent of a 40-inch focal length instrument in a packagethat is only 14 inches long. General Electrodynamics Corporationdeveloped the electron gun structure.

In the Ranger 3 flight, although the spacecraft did not providethe television camera with the position it needed to conduct a success-ful lunar photography experiment, it was possible to determine fromtelemetry that the television camera equipment operated normally.Several of the frames received clearly show the reticle on the face of

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the camera, by illumination from reflected sunlight. A spacecraftfailure prevented activation of the television camera on the Ranger 4flight.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 that theearth possesses a thin surface layer, or crust, the composition ofwhich is markedly different from that of the remainder of the earth.This difference shows up in the distinct enrichment or depletionsof many elements in this crust as a result of chemical and physicalprocesses that have taken place in the earth's history.One theory that has been widely accepted for years is thatthe mean composition of the earth's mantle, excluding the crust, isroughly the same as a class of undifferentiated material found inmeteorites and known as the chondrites. Strong evidence to supportthis hypothesis is found in the fact that the estimated heat loss of

the earth is in close agreement with the heat loss that could beexpected from an earth of chondritic composition.Presumably the conditions that produced the earth are considerablydifferent from those which acted upon the moon, but the same questionsof differentiation and heat balance are pertinent to the moon. The sur-face of the moon generally is considered to be older than that of theearth, but it seems likely that the same processes of separation thatare known to have occurred in the earth's crust may have taken placeto a limited extent in the moon.Elements found in the earth's crust include, among others,uranium, thorium, radium and potassium. All of these posses radio-active isotopes and put out penetrating and characteristic radiations

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called gamma rays which are physically similar to high energy,monochromatic X-rays. Thus, by detecting these characteristicgamma rays it is possible to tell how many of these elemenits arein the rock. Geochemists have discovered that the rocks in thecrust of the earth conmain much more potassium 40, which emits theseX-rays, than does the chondritic material of meteorities.Consequently, a measurement of the gamma ray spectrum

found in lunar surface rocks and dust will provide direct informationfor the first time concerning the composition of this material. Sincethe heat production of a body such as the moon is largely determinedby its radioactive content, and since those elements which possessnatural radioactivity are indicative of differentiation at least on theearth, gamma ray spectroscopy on the moon appears to be capableof contributing evidence to both problems.This radioactive technique of analysis has many advantagesover the ordinary chemical analysis process in which the rock wouldhave to be ground up, dissolved in acid and then subjected to a series

of chemical tests. For the gamma ray method, of course, the rocksample need not be ground up or dissolved. Another advantage ofthis application is that it measures the average composition of a largepart of the moon's surface, rather than that of a particular samplewhich may differ widely from the average. Also, the experiment canbe conducted without landing delicate equipment on the lunar surface.With these potassium 40 gamma ray data from Ranger, it willbe possible to determine in a broad sense if the surface of the moonlooks like the surface of the earth or if it looks more like meteoriticmaterial. If the surface of the moon is indeed similar to the surfaceof the earth, this means that the moon has had extensive volcanic ormelting action in its history and may be partially covered with lava.If, on the other hand, the lunar surface material appears similar tothat of meteorites, this implies that a low level of volcanic activityor that whatever volcanoes may have existed in the past have beeninactive for so long that the surface now is well covered by meteorites.The gamma ray detector with its high voltage supply is locatedat the end of a telescoping boom mounted on the spacecraft. The detectorin a thin aluminum sphere at the end of the boom is extended by pressurized

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gas to a distance of six feet away from the spacecraft in order toreduce the effect of the secondary gamma rays which are producedby the interaction ;f cosmic rays with the bulk of the spacecraft.This e ent is performed after Ranger. 5 has undergone its midcourseguidance maneuver.

Four hours after launch, the central computer and sequencerwill turn on the gamma ray experiment. As mentioned, the boom isnot extended at this time for several reasons. First, the countingrate of secondary gamma rays produced by interaction of cosmic rayswith the spacecraft is needed in order to provide calibration data.Another reason has to do with the precision required for themidcourse maneuver of the spacecraft. The midcourse motor thrust

must, of course, be through the center of gravity of the spacecraft.If the gamma ray spectrometer boom were commanded to the extendedposition before the midcourse maneuver, and if for some reason itdid not reach that position, the center of gravity would be differentfrom the calculated point and would affect the precision of the mid-course maneuver. Consequently, the boom is kept in the retractedposition until after completion of the midcourse 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 35 minutes before impact, whenit is in a position to detect lunar surface gamma radiation, it startsto send data once every 52 seconds. When it shifts to this morerapid mode of transmission, the spectrometer uses the three-seconderase mode on the television picture channel of telemetry once inevery four intervals.The gamma ray spectrometer, mounted on the spacecraft,will continue to send data up to the moment of separation of thelunar capsule from the bus.The gamma ray experiment hardware weighs a little more than12 pounds and occupies a volume of 850 cubic inches. The power re-quired is less than two watts.

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Scientific Ekperiments

In the Ranger 3 experiment, the gamma ray spectrometerperformed well. It obtained space radiation data that will be ofgreat value as a measure of the background upon which any lunarsignal must be superimposed. These data are now being analyzedfor information that may be of intrinsic value. A failure in thecentral clock on Ranger 4 prevented the experiment from energizingon that flight.Experimenters are Dr. J. R. Arnold, University of Californiaat San Diego; p)r. E. C. Anderson and Dr. M. A. Van Dilla, of theLos Alamos Scientific Laboratories, and Dr. A. E. Metzger of theJet Propulsion Laboratory. Dr. Metzger is the cognizant scientistand engineer for JPL.

SEISMOGRAPH EXPERIMENTThe scientific objectives of the seismograph experiment are:1. To determine the presehce of absence of lunar seismicity(frequency of tremors,.2. To obtain preliminary information on the presence orabsence of a lunar crust and the presence of lava layers or dust layers.3. To obtain preliminary information on the nature of the lunarcore (solid or liquid), the depth of focus of moonquakes, and roughestimates of their energy release.4. To obtain preliminary information on the mechanical pro-perties of the materials which make up the moon,The data which will be obtained from the first lunar-basedseismograph station will yield a limited amount of information com-pared +o a conventionaL Earth-bound station since only one singleaxis (vertical) spismometer will be used. However, within thebounds of its limitations, the seismograph will determine the presence

or absence of lmnar seismic disturbances, thus providing an importantclue to the thermal history of the Moon and an insight into the tectonicstructure-making processes which might be operative. If the Moon should-m.. - COver)


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prove to be seismically active, approximate travel-time curvescan be assumed for the purpose of rough calculation of distancesto the seismic source. With this information it may be possibleto determine the presence or absence of a lunar crust and thepresence of lava layers or dust layers.

Seismic body waves can contribute very rough estimatesof seismic energy release, indication of seismic wave absorptionas a clue to the nature of the Moon's interior, and informationon the presence or absence of a major shadow zone as a manifes-tation Of a solid or liquid lunar core. Depth of focus can be obtainedfrom a comparison of body-wave and surface-wave amplitudes aswell as from the time interval between the principal seismic phasesand their images on the surface above the focus. Comparison ofwave spectra among the different phases of lunar seismic d] -turbances,as well as with the corresponding phases on Earth, will yield a roughestimate of absorptivity in lunar rocks. This data will provide infor-mation on the mechanical properties of the materials which make upthe moon.

The device which will perform this experiment on the surfaceof the moon is a small seismometer with a highly sensitive amplifierthe combination of which make an instrument approximately 10 timesmore sensitive than those used for earthquake record-ng. In additionthe instrument is constructed to withstand an impact with rock at aspeed of 200 feet persecond-a shock equivalent to a deceleration of3000 times earth gravity-and continue to operate after such an impact.

The seismometer is a single axis instrument 5. 25 incheslong and 4.37 inches in dioneter and weighs 8.2 pounds, It containsa self cal'brating device which is powered by six n.ckel cadmiumbatter'es designed to last the lifetime of the experiment. The interiorof the seismometer is filled with a fluid (n-heptane) to prevent rapidmovement of its inertial mass during impact with the moon.The fluid filled seismometer is contained in a instrumentedsphere 12 inches in diameter and weighing 57 pounds. This instru-

mented sphere is covered by a protective balsa wood sphere, Theassembly then constitutes the lunar landing capsule. The balsa woodcover is designed to help absorb the impact energy when the assembly-26


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lands on the moon at a velocity of somewhat less than 150 feetper second. The entire assembly, instrumented sphere and balsawood covering weighs a total of 92 pounds. The instrumentedsphere, containing the seismometer, the seismometer amplifier,batteries, a 50-milliwatt radio transmitter and a turnstile antennais suspended in the balsa wood sphere by a thin layer of Freonbetween the sphere and balsa wood so that the instrumented capsuleis free floating in the impact limiting outer sphere. The instrumentedsphere is designed with its center of gravity a half inch below itsgeometric center, This was done so that when the capsule lands onthe lunar surface and stops rolling, the inner instrumented spherewill right itself in the manner of heavy bottom toys with the antennaon the top and pointed in the general direction of the earth.

In the process of assembling the sphere, the 50 milliwatttransmitter was turned on four weeks before the launch date. Thetransmitter, however, is controlled by a mercury switch, so thatduring normal handling and before launch, the transmitter could beturned off by turning the sphere upside down. Mercury switches,however, are not reliable in zero gravity fields, so an inertialswitch which closes under five gravities was installed as a safetyprecaution. During lift-off, this inertial switch will be closed bythe acceleration encountered during powered flight, and thus theseismometer transmitter will be turned on permanently at that time.It is essential for the seismometer transmitter to be turned on, eventhough it is, of course, not recording moonquakes data during flight,so that ground operators will know that it is operating. With thisknowledge, it then will be possible to determine if the shock ofthe retro rocket firing causes any disturbances in the seismometertransmitter. The batteries inside the sphere are designed to pro-vide power for operation on the moon for approximately 30 days.

During flight, the instrumented sphere is locked to the balsawood impact limiter by a set of caging pins. During the terminallanding maneuver on the moon the thrust of the retro rocket closesan acceleration-sensitive switch starting a timer and releasing thecaging pins.It is not expected that the balsa wood impact limiter will

split on impact and fall away from the sphere, but the balsa woodis transparent to the rada signals from the transmitter in the sphere.After the landing takes , he sphere with uts low center of gravity

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may take as long as 15 minutes to position itself with the antennapointing toward the earth. The operation requires that much timedue to the weak lunar gravity and the viscosity of the Freonseparating the instrumented sphere and impact limiter.

However, now that the sphere is in position for the seis-mometer to operate, another hurdle must be overcome. That isto get ride of the Freon between the inner sphere and the impactlimiter and the n-Heptane inside the seismometer lest they act -as insulators to the shocks the seismometer is designed to detect.Accordingly, 15 minutes after impact on the lunar surface the instru-mented sphere is rigidly caged within the impact limiter by threepost-impact caging pins. One minute later the impact limiter ispunctured by two pyrotechnic venting squibs permitting the fluids tovent off. The reduction of pressure with the seismometer actuatesa pressure switch and activates the seismometer self calibratingdevice. Thirty minutes after impact a servosystem is energizedby the capsule timer which centers the inertial mass within theseismometer. This initiates the seismograph experiment.

Another problem, relating to the great temperature rangewhich is expected on the moon--from approximately plus 260 degreesto minus 230 degrees Fahrenheit is now resolved by an ingenioussolution. The survival sphere contains 3. 6 pounds of water whichis heated by the dissipation of electrical energy inside the sphereuntil it reaches the boiling point of water under lunar vacuum con-ditions, which is about 75 degrees Fahrenheit. Since it is impos-sible to superheat water beyond the boiling point, this serves tostabilize the upper limit of the temperature range at this 75-degreelevel. As the 14-day long lunar night arrives, the water temperaturefalls from this peak but never really becomes completely frozen be-cause of the heat dissipation inside the capsule and the time involved.Consequently, the water control system serves to keep the spheretemperature within operating limits for the electronics and batteries.The seismometer was designed and fabricated by theCalifornia Institute of Technology Seismological Laboratory incooperation with the Lamont Geological Observatory under a JPL

work order. The capsule including the seismometer amplifier, wasI


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designed, developed and fabricated by Aeronutronics, Divisionof Ford Motor Company, under a JPL subcontract. JPL conductedenvironmental tests on the seismometer, sterilized it and moni-tored the operations of both CIT and Aeronutror.ics to insure properintegration of the seismometer in the capsule and integration ofthe capsule into the Ranger spacecraft. The seismograph groundsupport data processing system was developed and assembledjointly by the co-experimenters and JPL.

The scientists participating in the moonquake experimentare Dr. Frank Press, California Institute of Technology SeismologicalLaboratory, and Dr. Maurice Ewing, Lamont Geophysical Observa-tory, Columbia University. Dr. R. L. Kovach, JPL, is the cognizantscientist for JPL, and Donald Adamski is the JPL cognizant engineer.

RADAR REFLECTIVITYThe radar altimeter on Ranger 5 serves a dual purpose. Itsengineering function is to initiate the capsule separation from the

bus and the retrorocket ignition at a preset altitude above the moon'ssurface. Its scientific function is to conduct a radar reflectivityexperiment on the surface of the moon in order to provide informationon the nature of the lunar surface in the impact area and to establishmore information on lunar radar reflection properties.Many earth-based radar experiments have been conducted inan attempt to establish something about the properties of the lunarsurface by reflection coefficient of the returned signal. By necessity,however, the area on the lunar surface covered by the earth-basedradar is large, in most cases about 60,000 square miles, and thereturns allow estimates to be made for the average reflection coeffi-cients for areas of this size.The Ranger 5 radar altimeter, however, will view an area ofapproximately 60 square miles or less of the lunar surface, and theresults may serve to establish a standard area for the calibration ofmore complex earth-based radar systems to be used in lunar work.

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The instrument is a standard pulse-type radar. Th e trans-mitter is a magnetron with a peak power output of 150 to 400 watts.Pulse width is two microseconds, pulse repetition rate is 500 to600 pulses per second, and the frequency is 9400 megacycles.The altimeter will be turned on by ground command fromGoldstone at a distance from the lunar surface of approximately100 miles.During the Ranger 3 terminal maneuver, the radar altimeterwas successfully turned on, but the reflectivity experiment wasnot attempted. On Ranger 4, a spacecraft clock failure preventedactivation of the altimeter.W. E. Brown, Jr., is the experimenter in the radar reflec-tivity experiment and also serves as the cognizant scientist.H. E. Wagtrr is the JPL cognizant engineer.


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DEEP SPACE INSTRUMENTATION FACILITY

The Deep Space Instrumentation Facility (DSIF) consists of threepermanent space communication stations, located approximately 120 de-grees apart around the earth, a mobile station which can be located to suitthe purpose of a particular mission, and a launch tracking station at CapeCanaveral. The three permanent stations are Goldstone, California;Woomera, Australia; and near Johannesburg, South Africa.

The DSIF is under the technical direction of the California Instituteof Technology Jet Propulsion Laboratory for the National Aeronautics andSpace Administration. Dr. Eberhardt Rechtin is JPL's DSIF Program Director.

In the lunar and planetary programs, the mission of the DSIF is totrack, receive telemetry from and send commands to spacecraft from thetime they are injected into orbits until they complete their missions.Since they are located approximately 120 degrees apart around theearth, the three stations can provide 360 degree-coverage around the earthso that one of the three always will be able to communicate with a distantspacecraft.In the case of Ranger, the mobile station, under a crew headed byPaul Jones, of JPL, is located at a position approximately one mile eastof the DSIF station near Johannesburg.The mobile station will be used in that location because it has the

advantage of having a lQ-foot-in-diameter dish with a 10-degree beam width-ten times as wide as the 85-foot-in-diameter dish-and it can track at arate of 20 degrees per second, better than 20 times as fast as the big dishes.On the other hand, since its antenna is not so large as the big dishes, itcannot match the big dishes in communication range and consequently willbe used only in the initial part of the flight.Based on nominal performance and a nominal trajectory, the initialRanger 4 acquisition and loss times for the DSIF stations are:Mobile Station, South Africa -- Acquires 32 minutes after launch, and

tracks for 5 minutes. Reacquires 316 minutes after launch andtracks for i0.7 hours.(over)

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DSIF, Johannesburg -- Acquires 316 minutes after launch andtracks for 10. 7 hours.DSIO, Woomera -- Acquires 42 minutes after launch and tracksfor 7. 3 hours.DSIF, Goldstone -- Acquires 14.5 hours after launch and tracks

for 12 . 5 hours.The midcourse and terminal maneuver commands will be sent byGoldstone, which also will send other commands as needed to the space-craft, Goldstone will acquire Ranger 5 approximately 63 hours after launchto hold it through the terminal maneuver and impact.Each DSIF station thereafter will work a 14-hour day for the lengthof the battery life in the moon capsule, estimated to be at least 30 days.Each station will receive telemetry from the lunar capsule for approxi-

mately eight hours and then pass it on to another station as the rotationof the earth and of the moon bring it within range.Each deep space station of the DSIF is equipped with an 85-foot-in-diameter antenna and receiving, data handling, and interstation com-munication equipment. In addition, the stations at Gol-dstone andJohannesburg have command capability.Goldstone is operated for JPL by the Bendix Radio Corporation.JPL's engineer in charge is Walter Larkin.The Australian DSIF is 15 miles from Woomera Village in SouthAustralia. It consists of an 85-foot-in-diameter receiving antenna andsupporting equipment and buildings. The Woomera station is operatedby the Australian Department of Supply, Weapons Research Establishment.Dr. Frank Wood represents the WRE. JPL's resident engineer isRichard Fahnestock.The South African station, like the Woomera station, consists ofan 85-foot-in-diameter receiving antenna and supporting equipment andbuildings and is located in a bowl-shaped valley approximately 40 miles

northwest of Johannesburg. The South African station is operated by theSouth African government through the National Institute for Telecommunica-tions Research, Dr. Frank Hewitt, Director. NITR is a division of theCouncil for Scientific and Industrial Research. JPL's resident engineer isPaul Jones.-32-


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The two overseas stations and Goldstone are linked by a com-munications network which allows tracking and telemetry informationto be sent to the JPL Communication Center in Pasadena for processingby JPL's IBM 7090 computer.

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S UBCONTRACTORS

Twenty-eight subcontractors to the California Institute ofTechnology Jet Propulsion Laboratory provided instruments and hardwarefor Ranger 3, 4 and 5 program. These contracts amounted to $8 million.

Aeronutronic, Division of Ford Lunar Rough Landing CapsuleMotor Co., Newport Beach,Calif.

American Missile Products CC & S Flight Subsystem andLawndale, Calif. Ground Support Equipment;Power Switching and Logic;Antenna Change-Over Switch

Barry Controls Solar Panel FramesGlendale, Calif.Bell Aerosystems Company Digital Accelerometer ModulesCleveland, OhioBendix Corporation Deep Space InstrumentationOwings Mills, Maryland FacilityGoldstone, Calif.California Institute of Seismometer

TechnologyPasadena, Calif.Electric Storage Battery Co. BatteriesMissile Battery DivisionRaleigh, North CarolinaElectro-Optical Systems, Inc. Booster RegulatorPasadena, Calif.General Electrodynamics Scan-Converter SystemGarland, TexasGroen Associates Actuators for Solar Panels and

Omnidirectional Boom, GammaRay Telescoping Boom

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Subcontractors

Hercules Powder Company Capsule Retro MotorBacchus, UtahHoffman Electronics Solar PanelsEl Monte, Calif.Horkey-Moore Ranger Spacecraft SystemTorrance, Calif. Test Stand, Pin PullersInternational Telephone & Static Power Converter ModulesTelegraphIndustrial Products DivisionSan Fernando, Calif.Lockheed Aircraft Sterilization of Agena ShroudVan Nuys, Calif.Minneapolis -Honeywell GyroscopesRegulator CompanyAero DivisionMinneapolis, Minn.Motorola Flight Transponder,Military Elec. Division Flight Data EncoderScottsdale, ArizonaNortronics Attitude Control and MidcourseHawthorne, Calif. Aitopilot Electronic Subsystems;Sun Sensors and Earth Sensors;AttiLude Control Gyro ModulesOrdnance Associates SquibsSouth Pasadena, Calif.Radiation Instrument Division Gamma-ray Pulse Height AnalyzersLaboratory and Associated Ground SupportNorthlake, Illinois EquipmentRadio Corp. of America Lunar Impact TV CameraPrinceton, New Jersey

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SubcontractorsRansom Research Data Display EquipmentSan Pedro, Calif.Space Electronics Corp. C iund Command SystemGlendale, Calif. Demodulators;

Data Encoder Ground SupportEquipmentTE Company Optical Collimator for TestingSanta Barbara, Calif. Lunar TelescopeTexas Instruments Ranger Flight Command SubsystemDallas 9, Texas and Ground Support EquipmentTinsley Laboratories Optical Telescope for Lunar ProbeBerkeley 10, Calif.Wiley Electronics Radio AltimeterPhoenix, Arizona

In addition to these subcontractors, there were 1200 indus trial firmswho contributed to the Ranger. Th e cost of these supplies was in excess of$5 million, which covers all three spacecraft.

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LAUNCH VEHICLE

The Atlas-Agena-B--NASA's launch vehicle for its Ranger 5 lunarlanding mission--is a combination of two rcckets.The Atlas "D" serves as the booster and the Agena-B as thevehicle's serond stage. The rocket is provided to NASA by the Air Force

Syptems Command's Space Systems Division which functions as a"prime contractor" to the NASA vehicle group--the Marshall Space FlightCenter, Huntsville, Alabama.The unique relationship is spelled out in the NASA-USAF agree-ment which provides for NASA procurement through the Aiu Force of anumber of vehicles consisting of modified Atlas boosters with modifiedAgena-B's serving as second stages. The Agena was developed for AirForce satellite programs in which it has achieved a significant reliability

record.Major contractors involved in the vehicle operation are LockheedMissile and Space Company anu General Dynamics-Astronautics. Thevehicle is launched by these companies under the direction of the MarshallCenter's Launch Operations Directorate.All engines of the Atlas booster, sustainer and vernier, are burii-ing at liftoff. The booster is programmed to burn approximately 22 minutes,the sustainer about 4 minutes and the verniers about 5 minutes. AtAtlas burnout, the vehicle should be about 80 miles high.Prior to sustainer cutoff, the Atlas ground guidance computer deter-mines the velocity when vernier cutoff occurs arnd coast begins. Actingon these data, the computer establishes the time when a signal to the Atlasairborne guidance system starts a timer aboard the Agena. This timer andan auxiliary timer in the Agena control the sequence of events which occurafter separation from the Atlas.When vernier cutoff occurs, the entire vehicle goes into a coastphase of about half a minute. First the shroud protecting the Ranger space-c,-aft during its exit through the earth'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 up-ward flight and allowing the Agena to se.irate. Then the Agena pneumatic

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Launch Vehicle

control system begins a pitch mdneuver to orient the vehicle into anattitude horizontal to the earth. This pitch maneuver is programmedto be completed before the timer signals ignition of the Agena engine.

At engine start, the hydraulic control system takes over, keep-ing the vehicle horizontal during the approximately 2' minutes theengine is operating. The infrared horizon-sensing device sends minutecorrections to the control system.

At Agena engine cutoff, tne vehicle and its Ranger payload willbe in a near circular orbit at an altitude of about 100 miles. This firstorbit is called a "parking orbit."

The Agena now coasts in its parking orbit for approximately 15to 30 minutes depending on the day and hour of launch. The pneumaticcontrol system again takes over, maintaining the vehicle in the properattitude with respect to the earth. At the proper instant, the timeragain signals the Agena engine to begin operation. This second burn isprogrammed for approximately 1I minutes.

About 21 minutes after the final engine shutdown, the Rangerspacecraft is separated from the Agena by springs. This occurs about 25to 40 minutes after liftoff, depending on the day and hour of launch.

At separation from the Agena, the Ranger spacecraft should betraveling about 23 , 800 miles per hour. This velocity will place it ina trajectory that will carry it to the moon. The trip, from liftoff, willtake from 66 to 72 hours.

AGENA-B SECOND STAGEThe Agena-B stage of the rocket is an improved and enlarged version

of the Agena-A, which was used in the Discoverer satellite program.The Agena-B vehicle has integral, load-carrying propellant tanks

with twice the capacity of Agena-A tanks and is powered by a Bell Aero-space Turbopump-fed engine. It burns unsymmetrical dimethylhydrazine(UDMH) as fuel and inhibited red fuming nitric acid (IRFNA) as the oxidizer.

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Launch Vehicle

The new engine develops substantially higher performance thanprior Agena engines and has a dual start capability.

The rocket's guidance system is capable of establishing attitudereferences and aligning the vehicle with them during the coast andengine operation phases. It also initiates programmed signals for thestarting, stopping and maintaining of various equipment during flight.

Here is a description of the Agena-B:Propulsion--Single rocket engine using liquid propellants--in-

hibited red fuming nitric acid and unsymmetrical dimethylhydrazine.Thrust--15,000 pounds at altitude

Size --Approximately 22 feet long, including Ranger spacecraftadapter.Control Systems--Pneumatic, using high-pressure gas meteredthrough external jets fcr use during coast phases. Hydraulic, through

gimballing rocket engine for pitch and yaw control during powered por-tions of flight. Both fed by programmer initiated by airborne timers.Corrections provided by airborne guidance system.Guidance--The guidance system, which is made up of timingdevices, an inertial reference system, a velocity meter and an infrared

horizon-sensing device, is entirely self-contained.Contractors--Lockheed Missileand Space Company, prime con-tractor; Bell Aerosystems Company, engine.Here is a description of the Atlas "DI Space Booster:Propulsion--Three rocket engines--two boosters,. one sustainerusing liquid oxygen and kerosene propellants.Speed-Approximately 12,000 statute miles per hour for the Ranger

missions.Thrust--Total nominal thrust at sea level more than 360,000 pounds.

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Launch VehicleSize--Approximately 78 feet high, including adapter for Agena;

16 feet wide across flared engine nacelles. Ten feet wide across tanksection.

Weight--Approximately 260,000 pounds at moment of launch,fully loaded with propellants.Guidance--Radio command guidance. Airborne elements sense

velocity and vector, transmitting these data to ground computer. Com-puter determines corrections necessary and transmits information toairborne unit which signals control system. Control accomplished throughengine gimballing and engine burning time.

Contractors---General Dynamics-Astronautics, airframe andassembly; Rocketdyne Division of North American Aviation, propulsion;Defense Division of General Electric Company, radio command guidance;Burroughs Corporation, ground guidance computer.

KEY MANAGEMENT PERSONNELAgena-B direction at NASA headquarters is provided through

Dr. Homer E. Newell's Office of Space Sciences. The Agena programmanager is Dick Forsythe.

The field installation charged with managing the vehicle programis the NASA Marshall Space Flight Center.

The Marshall Center's main responsibilities in the program are:control of changes in the system to meet NASA mission requirements,resolving of problems encountered in the integration of launch vehiclesand spacecraft, launch operations and overall project management. HansHueter heads the Center's light and medium vehicles office. FriedrichDuerr is the Agena systems manager.

Major John G. Albert is the director of the NASA Agena-B programfor the AF Space Systems Division, assisted by Major Charles A. Wurster.

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Launch Vehicle

Harold T. Luskin is the Lockheed Missile and Space Companymanager of NASA programs.

Dr. Kurt H. Debus head the Launch Operations Center whichdirects launchings. Charles Cope of LOC performs liaison betweenHuntsville and Canaveral with respect to launch activities.

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RANGER 5 FACT SHEET

LAUNCH VEHICLE.......................................... Atlas-Agena BDIMENSIONS LAUNCH VEHICLE

Total height, with Ranger spacecraft, plus shroud . 100 plus feetAtlas....................................................................... 6 feetAgena B ........................................... 22 feetRanger with shroud ................................ 12 feet

DIMENSIONS RANGERIn launch position, foldedDiameter ............................................ 5 feetHeight..........................................................................25 feetIn cruise position, panels unfoldedSpan ........... .. ........ . . . . . . . . . . . 17 feetHeight............. ..................... 10.25 feet

WEIGHT RANGERStructure ......................................... 93.45 poundsSolar Panels ................. *. ...... 42.1Electronics .............. ....................... . 111.31Propulsion .................................... 38.11Launch-Backup Battery ... .................... . 24.64Miscellaneous Equipment ......................... 76.35Scientific Experiments ...................... ... 30.31Lunar Capsule Subsystem............ *............ 338.73

Lunar Capsule .............. . .92Retrorocket Equipment ....... 221.73Bus Mounted Equipment ....... 25.0

338@ 73

GROSS WEIGHT ............................................ 755 pounds

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RANGER 5 LUNAR CAPSULE SUBSYSTEM WEIGHT SUMMERY

A. LUNAR CAPSULE Weight (pounds)1. Survival sphere assembly

a) Electronics, antenna, batterieswiring, structure,insulation 41.2

b) Seismometer 7.6c) Flotation fluid and outer shell 8.2Survival sphere total ........... O. 57.0

2. Balsa impact limiter 35Lunar Capsule Total ........ ....... ....... 92

B. RETROROCKET EQUIPMENT1. Retrorocket motor and igniter 214.92. Spin motor, igniter and attachment 2.33. Vibration damper and clamp 1.24. Ballast 1. 35. Control timer, batteries, wiring 1.46. Spin balance allowance .5

Retrorocket Equipment Total ............... 221.73C. BUS-MOUNTED EQUIPMENT

1. 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 .85. Retrorocket heat shield 3.56. Spin motor vent cowling 5.07. Spin restraint 3.0

Bus-mounted Equipment Total ............... 25

LUNAR CAPSULE SUBSYSTEM TOTAL ........... 338.73

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ranger 5 press kit

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