Planetary Atmosphere Experiments Test Press Kit

8/8/2019 Planetary Atmosphere Experiments Test Press Kit

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NEWS A NATIONAL AERONAUTICS AND SPACE ADMINISTRATION TELS WO 2-4155WASHINGTON,D.C. 20546 wO 3-6925FOR RELEASE: SundayJune 13, 1971

RELEASE NO: 71-99

p PROJECT: Planetary AtmosphereEx-teriments Test(PAET)

E Con ntsGENERAL RELEASE----------------------------------------1-4GENERAL BACKGROUND -------------------------- -- 5-6S MISSION PROFILE-------------------- ------------------ 7PAET SPACECRAFT-------------------------------------8EXPERIM ENTS ----------------------------------------------SCOUT LAUNCH VEHICLE----------------------------------10TRACKING AND DATA ACQUISITION------------------------ 11MISSION CONSTRAINTS----------------------------------12PROJECT OFFICIALS AND PROGRAM MANAGEMENT------------- 13SEOUENCY OF EVENTS-----------------------------------14

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N EWS NATIONAL AERONAUTICS AND SPACE ADMINISTRATION (202) 962-4155WASHINGTON,D.C. 20546 TELS: (202) 963-6925David Garrett FOR RELEASE: Sunday(Phone 202/962-3865) June 13, 1971RELEASE NO: 71-99

PAET LAUNCH SCHEDULED

The National Aeronautics and Space Administrationwill launch no earl ier than June 16, 1971, a probe vehiclethat will plunge back into the Earth's atmosphere at 15,000miles an hour.

The experiment will investigate means of determiningthe structurc: and composition of an: unknown planetary atmosphere.

The Planetary Atmosphere Experiments Test (PAET)is one step in providing the technical base necessary foradvanced planetary exploration to Mars, Venus, and eventaullythe outer planets. These planetary missions will requiremeasurements of atmospheric properties.

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-2-PAET will be launched from the NASA Wallops Station.

Wallops Island, Va. and will splash into th e Atlantic Oceanabout 702 miles (1,130 kilometers) down range an d 98 miles(158 km) nor theas t of Bermuda. Total flight time is approxi-mately 14 minutes.

Launch vehicle is th e NASA Scout, a four-stage solidpropel lant :rocket. The first two stages provide boost andcoast to a maximum altitude of 234 miles (377 km) some 287miles (462 km) down range. The Scout heat shield is separatedjust after reaching this altitude.

The third and fourth stages then accelerate th e 137-pound entry vehicle back into th e atmosphere at a speed of22,000 feet per second (15,000 miles per hour). Separat ionfrom th e fourth stage occurs 612 miles (985 km) down rangeat an altitude of 91 miles (146.5 km).

Instruments in th e probe vehicle will be subjectedto deceleration forces peaking ai: about 80 Gs (80 times th eforce of gravity) as th e craft slows to 140 feet per second(95 mph). Speed at splashdown is approximately 80 fp s (55mph).

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-3-The PAET entry vehicle is 36 inches (91.44 cm ) in

diameter and 25.2 inches (64 cm ) long. The nose is a blunted,flattened cone and the afterbody is hemispherical in shape.The circular center section of the nose is made of beryllium,and a silicon elastomer ablator covers the aluminum structureof the remainder of the nose. The beryllium section protectsa radiometer quartz window and a mass spectrometer inlet frombeing contaminated by ablation products. The afterbody structureis fiberglass honeycomb with a silicone elastomer ablatorfo r thermal protection.

Experiments aboard the PAET spacecraft will investigatemeans of determining planetary atmosphere structure andcomposition. Objectives of the atmosphere structure experi-ment are to determine the pressure, temperature, and densitychanges with altitude changes and the mean molecular weightof the encountered gas, or atmosphere. Zccelerometers,pressure sensors, and temperature sensors are included in theinstrument package.

By looking through a quartz window in the nose of thespacecr-ft, a raciometer will gather data on the composition ofthe atmosphere by measuring emissions from the hot shock layercreated in front of the craft. The amount of oxygen, nitrogen,arn carbon dioxide will be determined by detection of radiation.


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-4-In a separate, secondary experiment using two of the

radiometer's nine channels, the amount of water vapor ptesentin the Earth's atomsphere will be determined by measuring theabsorption of infrared radiation in sunlight reflected fromthe surface of the Earth.

During entry, atmospheric samples will be drawn intothe spacecraft through an orifice in the nose where a massspectrometer will determine the gas composition present.

Primary data gathering station fo r the PAET missionis Bermuda. The Apollo Tracking Ship USNS Vanguard, theWallops telemetry ship Range Recoverer, and two telemetry air-craft will provide additional support. Wallops Station willtrack from launch to entry. Bermuda tracking will acquiresoon after first stage burnout and continue into the entryperiod. The USNS Vanguard will also be used to insure postblackout tracking.

Recovery of t3h. spacecraft is not required.The PAET is che responsibility of NASA's Office of

Advanced Research and Technology. The spacecraft and mostof the instrument systems were designed, fabricated and testedby the NASA Ames Research Center, Mountain View, Calif. TheMass Spectrometer Composition instrument was supplied by theNASA Goddard Space Flight Center, Greenbelt, Md. The ScoutLaunch Vehicle program is managed by the NASA Lanyley ResearchCenter, Hampton, Va.

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,(EN OF C.N..AL RELEASE: BACKGROUND INFORMATION FOLLOWS)


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-5-GENERAL BACKGROUND

The current NASA planetary exploration program includesmissions to Mars and Venus that will require survivableatmospheric entry. The exploration of Jupiter and Saturnwill also require atmospheric entry during later missions tothese planets.A major objective of these earlier missions to Marsand Venus, and the later entry missions to the outer planetswill be to make measurements of atmospheric properties. Bymeasuring the motion of the planetary entry vehicle and neasure-ments obtained from on-board instrumentation, the structure andcomposition of the unknown atmosphere can be determined.For the past eight years, Ames Research Center hasconducted research on atmospheric measurements from entryprobes. This program has included analysis of various tech-niques for determining atmospheric characteristics from measure-ments made during entry; the development of special instrumenta-tion to make the measurements; determination of the character-istics which an entry vehicle must incorporate to carry out theexperiments with maximum accuracy, and finally, low-speed flighttests of an atmosphere structure experiment using payloads

launched from high altitude balloons. This last effort demon-strated the capability for accurately determining the atmos-pheric structure from measurements of acceleration, pressureand temperature.Goddard Space Flight Center has been engaged in develop-ing atmospheric composition measurement techniques using massspectrometers and has been conducting measurements of the Earth'satmosphere by both rocket and satellite using the instruments.In addition, there has been a parallel program specificallyoriented toward the development of mass spectrometers foratmospheric composition measurement during planetary entry.The development has emphasized reliability, l ight weight andefficient data transmission.PAET will extend this technology and experience bydemonstrating in the Earth's atmosphere selected planetary entryexperiments and instrumentation. PAET is a project of theEntry Technology Office of NASA's Office of Advanced Researchand Technology which has the major responsibili ty for planetaryentry probe technology.

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-6-Several secondary experiments are planned. The problemof planetary relay communications will be studied by inves-tigation of VHF radio transmission through the wake of thespacecraft and the effect of planetary probe motion on signalacquisition and bit synchronization. Atmospheric water /aporrofile with changing altitude will be determined from absorp-tion measurements of reflected sunlight in the infrared.The PAET fl ight test will be conducted under conditionsthat provide a simulation of the entry conditions fo r a plan_-tary mission. Exact simulation is not necessary since theprincipal effect of varying trajectory conditions is to changethe range of the quantities to be measured. Fo r example, peakdeceleration during the PAET flight will be about 80 Gs (80times the force of gravity), whereas the Viking vehicle willexperience approximately 15 Earth Gs durinc Mars entry. AVenus probe could experience decelerations as hiah as 400Gs. In each case, however, the same technique can be used todetermine a -nospheric characteristics from these accelerations.

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-7-MISSION PROFILE

The first two stages of the Scout provide the PAETspacecraft with boost and coast to a peak altitude of about1,236,000 feet or 234 miles (376,700 meters), some 287 miles(462 km ) down range.Just after reaching the maximum altitude the Scoutheat shield is separated and the third stage ignition occurs.

After third stage burnout, the Scout guidance system willpitch the vehicle about 60 degrees nose down to the flightpath. The Scout then provides spin-up to about 150 revolutionsper minute, separation of the third stage and ignition of thefourth stage.At fourth stage burnout, the spacecraft attitude willbe 30 degrees nose down to the fl ight path. Then the spacecraftdespin system will reduce the spin race of the fourth stage-spacecraft 'configuration to 30 rpm.Entry vehicle separation will occur at an altitude ofabout 478,500 feet or 91 miles (146.5 km), velocity of about15,000 mph (22,000 fps, 6.7 kilometers per second) and about612 miles (985 km ) down range.The splash point will be 702 miles (1,130 km ) down rangeand 98 miles (158 km ) northeast of Bermuda.Entry vehicle recovery is not required, but may beattempted. If it does not break on impact, the spacecraftcould float fo r as long as a half hour. A -ye marker to aidvisual sighting will be deployed and the VHF telemetry systemwill continue to give off a signal acting as a homing beacon.

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A:titude MISSION PROFILErim300 x

Scout ShroudSeparationt A10 sec 3rd IGNt~=4I2 sec 3rd 8.0. 3,d Separationt 449 sec t " 484 sec200 Spin-up 4th IGNT 483 sec 489 sec

4th B.O. t = 524 secDespin t = 534 sec100 Entry Vehiclo Separation

t = 538 sec4th Separationt = 548 sec2nd B.O.

t --116 sect54seVHVHFIst B.O. 2nd IGN Blackout

= 75 sec s 'tDData layback0 IMPACT t 890 se('00 200 300 400 500 600 700RANGE, NM


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-8 -PAET SPACECRAFT

The PAET spacecraft consists of two major assemblies,the entry venicle and the entry vehicle separation system.Combined weight of the spacecraft is 296 pounds (134 kilograms).The entry vehicle contains the experiment instrumentationnecessary to carry out the mission objectives. At separationit weighs 137 pounds (62 kilograms). The entry vehicle primarystructure is a ring-stiffened aluminum shell on which is mountedthe experiment instruments, the digital data handling andradio system, engineering data system, C-band radar transponder,

pyrotechnic system, rate gyro and power system.The entry vehicle nose is a blunted, flattened coneand the afterbody is hemisperhical in shape. The spacecraftis 36 inches (91.44 cm ) in diameter and 25.2 inches (64 cm )long.The spher-cal center section of the nose is made of

beryllium to provide a surface around a quartz window for theradiometer and the inlet fo r the mass spectrometer where measure-ments can be made free from contamination by ablation products.Tw o small ports for pressure sensors are also located in theberyllium nose. A silicon elastomer ablator covers the alum-inum structure of the remainder of the nose. The afterbodystructure is fiberglass honeycomb with a silicon elastomerablator fo r thermal protection.

The entry vehicle separation system is designed tohold the entry vehicle in the proper attitude on the launchvehicle throughout the fl ight to separation; to despin theScout fourth stage and the attached PAET spacecraft; and finally,to separate the entry vehicle from the fourth stage.

A yo-yo despin system is used to reduce the spin fromapproximately 150 rpm to 30 rpm. Despin weights are deployedby redundant cable cutters. After despinning, a spring separatesthe entry vehicle from the Scout fourth stage.

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PAET SPACECRAFT AEATHROUDWITH SCOUT SHROUD CGUILLOTINEAND FOURTH STAGE VEHICLE CABLE CUTER

ENTRY VEHICLERESTRAINT SYSTEM(CLAMPS & CABLE )CLAM SHELLHEAT SHROUD . ENTRY VEHICLE42-INCH DIA. SEPARATION SYSTEM

-- SPACECRAFT DESPIN coSPACECRAFT 1 SYSTEMSEPARATION PLANE

A PSCOUT "E" SECTIONADAPTER

ALTAIR III (FW-4 S)MOTOR


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LAUNCH VEHICLE ADAPTERSUPPORT STRUCTURE

SEPARATION SPRING (RELEASED)

PUSHER PLATE-DESPIN SYSTEM

SRETRO SYSTFM GAS BOTTLES

GUIDE ENTRY VEHICLERODS (4) RESTRAINT CLAMPS

ACCESS/DOOR

SEPARATION RETROSPRING (COMPRESSED) NOZZLESEPARATION SYSTEM

ENTRY VEHICLE

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EXPERIMENTE

Atmosphere StructureThe objective of th e atmosphere structure experiment isto determine th e changes with altitude in pressure, temperatureand density and th e mean molecular weight of th e encounteredgas, or atmosphere. This is accomplished by measuring vehicledeceleration from atmospheric entry to ocean impact, andpressure and temperature from Mach 2 (twice th e speed of sound)to impact.Stagnation pressure (pressure in front of th e spacecraftwhere the atmosphere diverges to pass on either side) will hemeasured using Ames-developed vibrating diaphragm sensors.The temperature of the gas flowing around the entry vehiclewill be measured with a special temperature sensor developedfor the PAET project. The sensor will remain inside the space-carf t unti l the high heating portion of the entry has passedand then will be deployed into the airstream by actuation ofa spring.

Atmosphere CompositionData on the composition of the atmospheric gases will beobtained by measuring emissions from the hot shock laver(created directly in front of the spacecraft) in selected wave-length regions. This is done by a nine-channel radiometerobserving the shock layer through a quartz window in the noseof the entry vehicle. Each radiometer channel is essentiallya narrow-band optical filter passing light on to a siliconphotodiode. Electronics are provided in the instrument toprocess the output signal from the photodiodes.In a separate experiment using two of the radiometerchannels, the amount of water vapor present in the atmospherewill be determined by measuring the amount of absorption ofinfrared radiation from the Fun reflected from the Earth'ssurface in the 0.92 micron band and comparing it with ameasurement of adjoining micron bands unaffected by watervapor absorption.

Mass SpectrometerDuring atmospheric entry, gas samples will be drawn intoth e eli ry vehicle throuah a tiny openina in the nose and fedinto the mass spectrometer to determine the gas species presentin the atmosphere. The system employs an adaptive scancharacteristic which ,measures mass concentrations.

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EXPER IMENT EVENTS

7(00 A4tI,, Stage Burnout

500Entry Vehicle Sepaoraion

Data Period Begins - StartAtmosphere Stru:ztvce Experiment

'o Start Mass Spectromneter - Atmosphere Composition Experiment300 Begin VHF Start RadiometerBlockouT-"

End Data Fer'oaEnd VHFBlackout --

IcO~Start Data to oaiometer p~ Ir' pc;tPlaybackDeploy TemperaturePFobes

20 4C 60 30 100 120 140 160 380Time, sec from 4th B.O.


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-10-SCOUT LAUNCH VEHICLE

Scout is NASA's only solid propellant launch vehicle withorbital capacity. The first developmental Scout was launchedJuly 1, 1960. The PAET mission will be the 73rd Scout launch.Since being recertified in 1963, the Scout launch vehicle hasattained a 94 per cent success record. The PAET launch follows17 successive, successful Scout launches.

Scout B is a four-stage solid propellant rocket system.The four Scout motors -- Algol II, Castor II, Antares II, andAltair III -- are interlocked with transition sections thatcontain guidarce, control, ignition, and instrumentationsystems, separation mechanics and the spin motors needed tostabilize the fourth stage. Control is achieved by aerodynamicsurfaces, jet vanes and hydrogen peroxide jets.

The launch vehicle is approximately 73 feet (22.25 meters)long and weighs about 40,000 pounds (18, 144 kilograms) atliftoff.

The Scout program is managed by NASA's Langley ResearchCenter, Hampton, Va.

The launch vehicle is built by Ling-Temco-Vought, Inc.,Dallas.

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-11-TRACKING AND DATA ACQUISITION

The primary data-gathering (telemetry and radar) stationfo r the PAET mission is the Bermuda station of NASA's MannedSpace Flight Network (MSFN). The MSFN Tracking Ship USNSVanguard and three telemetry aircraft (Advanced Range Instru-mentation Aircraft and one Wallops telemetry aircraft) locatednear the nominal imDact area will provide additional telemetrycoverage and will be especially important fo r receiving trans-mission of stored telemetry data after the entry vehicle hasemerged from radio signal blackout.

The Wallops telemetry ship, Range Recoverer, will beabout 230 miles (370 km) up range of the impact point toreceive information radioed through the wake of the space-craft . This will provide a simulation of the communicationsgeometry between a spacecraft and a probe that has been released intoan unknown planetary atmosphere and which is relaying databack to the soacecraft.Wallops will track from launch until the PAET entryvehicle enters the data gathering region. Bermuda trackinawill acquire soon after first stage burnout and continuethrough the mission. The USNS Vanguard will be used toinsure post blackout tracking.Meteorological measurements of atmospheric densityand temperature in the region of the PAET entry flight.will he made hv Arcas-Sonde and Viper-Dart soundina rocketslaunched from Bermuda before and after the PAET flight.In addition, high altitude weather balloons will be launchedfrom Bermuda and standard weather balloons, radiosondes, willbe launched from the USTS Vanguard.

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TRACKING AND DATA ACQUISITIONWA I LOPS iSLAND

FIRST AND SECOND STAGE BOOST

THIRD STAGE THRUSTING

FOURTH STAGE THRUSTING. / ETR T/M AIRCRAFT

// N/COA-3I

SENTRY VEHICLE SEPARATIONO / S DATA REGIONCOAST

USNS RANGE RECOVERER(WALLOPS T M SHIP )

TRACKING USNS VANGUARDT/M (APOLLO TRACKING SHIP)

SOUNDINGS ETR T/M AIRCRAFTBERMUDA


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PROJECT OFFICIALS AND PROGRAM MANAGEMENTThe Planetary Atmosphere Experiments Test Project ispart of the program of the Entry Technology Office of th eOffice of Advanced Research and Technology (OART). TheTechnology Applications Office of OART has th e managementresponsibility fo r PAET. Project management has been assignedto Ames Research Center. The Office of Launch Vehicle andPropulsion Programs of the Office of Space Science and Appli-cations (OSSA) is responsible for the Scout Launch VehicleProject and Scout project management has been assigned tothe Langley Research Center. Tracking and Communicationsare managed by Goddard Space Flight Center fo r NASA's Officeof Tracking and Data Acquisition (OTDA).Leaders of the PAET Project Team are:

W. A. Guild NASA Headquarters Chief, FlightOART ProjectsJ. Levine NASA Headquarters Program Manager,OART PAET ProjectJ. E. Greene NASA Headquarters Technical AssociateOART Atmosphere Stru--ure& Radiometer Expts.Dr. R. F. Fellows NASA Headquarters Technical AssociateOSSA Mass. Spectrometer.xperimentD. E. Reese Ames Research Center Project ManagerPAETP. E. Goozh NASA Headauarter? Manager, ScoutOSSA ProgramR. D. English Langley Research Project ManagerCenter Scout Launch Vehicle

Principal Investigators of PAET are:N. Soencer Goddard Space Mass SpectrometerFlight CenterH. B. Niemann Goddard Space Atmosphere StructureFlight CenterS. C. Sommer Ames ReseFrc;. Centec Atmosphere StructureP. P. Whitina Apes Research Conter Radiometric Composition


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SEQUENCE OF EVENTS

EVENT TIME (Sec.)Liftoff 0.00First Stage burnout 75Second stage ignit ion 75Second stage burnout 116Scout Shroud Separation 410Third stage ignition 412Third stage burnout 449Spin-up 483Third stage separation 484Fourth stage ignit ion 489Fourth stage burnout 524De-spin 534Entry vehicle separat ion 538Pass through 400,000 feet (121,900 m.) 544Begin blackout 552End blackout 564Splash 890

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Planetary Atmosphere Experiments Test Press Kit

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