nasa facts simulators

8/7/2019 NASA Facts Simulators

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AN EDUCATIONAL PUBLICATION OF THENATIONAL AERONAUTICS AND SPACE ADMINISTRATION

NF-3 6 / VOL . IV , NO .8

- c2Simulators ~ ~ What may be the fastest gun in the West islocated at Ames Research Center, Mountain View,California . It is called a light gas gun because itemployes the ignition of ordinary gunpowder todrive a piston down a tube which contains hydro-gen, a gas lighter than air. Heated by compression,the hydrogen drives a spacecraft model or anotherkind of project i le into a test section at 20 ,000 milesper hour. At the same time, a mixture of hydrogen,oxygen , and helium , started from the opposite end,rushes past the model at about 10,000 mph , pro-ducing a simulated speed of 30,000 mph.

The gun is used to study spacecraft entry intothe atmospheres of ea rth and other planets such asMars and Jupiter. It is also employed to study theeffects of micrometeoroids (microscopic particlesof matter, larger than atoms, speeding throughspace) on spacecraft.

The Ames light gas gun is one of many simula-tors by which NASA exhaustively tests on theground all elements and situations that materialsand man are expected to face in earth 's atmosphereor in interplanetary space. To simulate has been

defined as " to assume the appearance of , withoutreality." This is exactly what NASA simulators aredesigned to do.

Using simulators, NASA finds out how proposedairplanes, spacecraft, launch vehicles, and theircomponents will function on missions. Worthwhilefeatures are incorporated in the actual flight craft;those that fail the tests are modified or discarded.Thus, time is saved and costs are held down indevelopment of airplanes and spacecraft.NASA has developed simul ators in which pilotsperfect the techniques they will use during flight .When astronauts practice in these simulators, theyare made to feel that they are on actual spacemissions. As a result , when they head into space ,they are already familiar with almost every detailof their mission and have had advance preparationfor possible emergencies .

In the not too distant future , th ree Americanastronauts are scheduled to pi lot an Apollo space-craft into lunar orbit. Two will Iclnd a section of itcalled the Lunar Module (LM) on the moon. Afterexploring, taking pictures, co ll ecting rock samp les,

Fastest gun in the West. l i ght gas gun ,Am es Research Center, can fire a pro -jectile at a simulated speed of 30,000mph.


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and performing other tasks, the landing party isto launch the LM to lunar orbit where they will re -join the parent Apollo spacecraft. Th en, they returnto the parent craft, cast the LM adrift , and rocketApollo out of lunar orbit to earth.

The mission calls for operations never beforedone by man . For example , the astronauts mustuse rocket power alone to land on the airless moon.They must guide their spacecraft through tracklessspace to the moon and back to earth, using thestarfield for navigation. They will be travel lingthrough an airless va cuum and their spacecraft willbe subjected simultaneously to baking tempera-tu res on one side and subzero cold on the other.

NASA has simulators for training Apollo flightcrews at two of its facilities: Manned SpacecraftCenter, Houston , Texas, and the John F. KennedySpace Center, Kennedy Space Center, Florida .

The astronauts sit in a crew compartment withinstrument panels th at duplicate the interior of theApollo command module. The command module isthe astrona uts ' living quarters during their flightto and from the moon. Surrounding the crew com-partment is a battery of television and motion pic-t ure screens and planetarium projection equipment.These provide the views that the crew is expectedto see during their mission-such views as thestarfield , the growing moon (as the astronautsapproach it ) , and the Lunar Module, both connectedto and separated from the craft.

Realism is accentuated by sound effects such asreco rdings of the thunder of the great Saturn Vengines at launch from earth and of the thumpsheard when the Apollo thrusters fire to maintain2

Rendezvous and Docking Si m ulator, Langley Research Center.

Technician using sextant takes sightings of makebelievestars and moon in naviga tion simulator at Ames Resea rchCenter.

orientation. The Apollo crew is familiarized withboth operating and emergency procedures beforeleaving the ground .Heart of thi s Apollo Mission Simulator is aunit consisting of three great computers. The simu-lator can duplicate almost every detail of themoon mission except weightlessness.

NASA's Project Gemini , which laid a sound basefor Apollo , demonstrated among its many achieve-ments that astronauts can maneuver spacecraft torendezvous (navigate to the vicinity of) and dock(link up) with another craft in space . Even beforeleaving the ground, Apollo astronauts-like the

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Huge rotor fo r centrifuge (motion generator) of the SpaceNavigation Simulator at Ames Research Center. Note sizeof men nearby.

Gemini astronauts before them-wil l prac ti cerendezvous and docking time after time in si mula-tors. One of these is the Space Vehic le Rendezvou sDocking Simulator at the Langley Research Cen ter,Hampton, Virginia. The simulator duplicates thelast two hundred feet of maneuvers leading todocking. Pilot manipulations of Lunar Modu le instruments are converted into spacecraft motion.In addition , emergencies requiring rapid correctiveaction are sprung on the pilot.

Housed in a 135 foot diameter circu lar room atthe Ames Research Center is a Space Navigat ionSimulator, which duplicates every known fac tor ofcontrol and navigation during space flight. Th efacility contains two spacecraft models. One is athree-man model to conduct simulated lu nar andinterplanetary missions. The other is a one-manmodel for study of physiological and psycho logicalfactors of prolonged flight in space. The modelsare eq uipped with systems such as may be used onlong-du ration fl ights; for exam pie, Iife-su pport (a i r ,temperature control, food , etc.), na vi ga ti on, guid ance, and power. A feature of t he faci lity is itsmotion generator-a carefu lly contr olled centrifugethat provides the acceleration an d decelerationforces associated with li ft -off from earth, firing of

Lunar Landing Research Vehicle, Flight Research Center.

rockets during flight path adjustments (mid-coursemaneuvers), and entry into the atmosphere of earthon return f rom the moon and planets. Such entrymay be at a speed of 42 ,000 mph, or more thantwice that of entry from earth orbit . The simulatoris primarily used for study of future manned missions into space , not astronaut training.

Severa l simulators help perfect techniques forland ing safely, using only rocket power , on theair less moon. Original research for one such craftwas conducted at the Flight Research Center,Edwa rds, California . This Lunar Landing ResearchVehicle has a jet engine that is automatically regulated and controlled to counter balance five-sixthsof the earth's gravity (the vehicle 's weight) . Thistakes into account the gravitational force of themoon which is one-sixth that of earth . A IBOpoundman on ea rth, therefore, would weigh only 30po unds on t he moon . The Lunar Landing ResearchVehicle uses hyd rogen peroxide gas jets to lower,ra ise, and balance itself in the same manner as theLunar Modu le is expected to operate as it descendsto t he moon's surface. An improved version of thiscraft, looking like the Lunar Module, is 'called theLu nar Landing Training Vehicle.Langley Research Center employs a saw horseshaped Lunar Landing Research Facility to dupli ca te vehic le dynamics (how the vehicle will act)during t he crit ical last 200 feet of moon la nding.Th e fac il ity is 250 feet high, 400 feet long, and300 feet wide at the base. A vehicle representingthe Lunar Mod ul e is suspended by cables thatcounte ract f ive-sixths of its weight. The pilot con

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Lunar Land ing Research Fa c i l ity, Lan gley Res earch Center.

VTOL c raft used at Ames Resea rch Center fo r study of lunar landing.

t rois his landing speed by varying the thrust ofhydrogen peroxide rockets .Ames Research Center is stu dying lunar landingby means of a VTOL (Vertical Take-Off and Landing)aircraft. The ai rplane neither looks nor is poweredl ike a space ship , but applies power in the sameway. The airplane's je t exhaust is directed downward to allow it to rise or descend vertically liket he Lunar Module.The tallest of the NASA simulators is the SaturnV test stand at Marshall Space Flight Center,Huntsville , Al abama. The 360-foot high stand isequipped to shake, bend, and vib rate Saturn V, theApollo launch vehicle, duplicating the stresses onit as it lifts off through earth's turbulent atmosphere. The great booster never leaves the stand .It is filled with water rather than rocket fuel. Elec-4

trodynamic devices create the effects of the violentair pressures that are built up dur ing the booster'soutbound flight from earth.

A Lunar Orbit and Landing Approach (LOLA)simulator at Langley Research Center enables thepilot to practice flying from a height of 100 milesto 200 feet above the moon. The pilot 's contro lsare linked to a computer that controls a battery oftelevision cameras. These in turn are pointed atthree-dimensional relief maps of the moon's sur face . (The maps are made of molded fiberglass.)Through closed-circuit TV , the pilot gets the im pression that he is dropping toward or climbingaway from the moon .

Wh en the astronauts leave their Lunar Module towalk and work on the moon , they will be repeatingmany tasks they have done on the make-believe

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moon at the Manned Spacecraft Center. Selenologists (lunar geologists) have created here a smallpiece of the moon complete with craters as muchas 64 feet across and 16 feet deep. On this makebelieve moon is a mock-up of the Lunar Module.Clothed in their space suits, the astronauts climbout of th e Lunar Module and perform assignedtasks. Not only does this give the astronautsneeded practice but also it enables scientists tostudy their performance and capabi lities.

Th e X-I5 Research Airplane is a winged rocketpropelled craft th at has provided much information of significance to ae ronautic and space technologies and to science. It has been flown at morethan 4200 miles per hour and to altitudes of morethan 67 miles. Th e X-I5 is launched from a B- 52aircraft about 45,000 feet above earth. The powered part of its flight lasts about two minutes. Theremainder is spent coasting to the peak of itstrajectory and then in a long glide to earth. Landingspeed is about 220 miles per hour.

Before any flight, the X-I5 pilot rehearses hismission in a computer-driven ground model equipped with repl icas of the X-I5 instruments and

Engineer with equipment thatelim inates five -sixths of hisweight trudges on makebelieve moon surface at Man ned Spacecraft Center.

controls. In this simulator, the pilot plans, checks,and analyzes each flight from launch to landingand develops and practices procedures for emergencies. The X-I5 program is managed by FlightResearch Center.The best known of all simulators is the windtunnel. In a wind tunnel, gases, such as air, areblown at different speeds at a model that is usuallytethered . The effect of the air flowing past themodel is the same as if the model is speedingthrough the air. The wind tunnel ha s contributedmuch to the advancement of aeronautic and spacetechnologies.

Almost every aircraft, from propeller-drivenmodels to supersonic jets , owes part of its development to the wind tunnel. Models of future VjSTOL(Vertical and Short Take-Off and landing) craftare being tested tod ay in wind tunnels . Varioustests of helicopter equipment, such as the rotor,are refining existing th eory and contributi ng toimproved designs. Research on rotors is helpingto develop high-performance helicopters that canfly in any weather.The Un ited States tested in wind tunnels many

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Massive blades of a wind tunnel fan frame a scale model of a variable-sweep a ircraft. The variable-sweep design, chosenfor Amenca's supersonic ai r transport, permits the win gs to be straight out (as shown) for subsonic fl ight or be sweptback for supersonic flight_designs fo r a supersonic commercial air transportbefore deciding on the most promising. This airliner is designed to fly as fast as 2000 miles perhour, about three times the speed of today's commercial jet airliners.

Wind tunnel tests have contributed to the Mercury , Gemini , and Apollo manned spaceflight programs. As recently as 1966, wind tunnel tests of ascale model of the 365-foot-tall Apollo-Saturn Vvehicle provided information which led to important- b u t minor-design modifications. The testsshowed that the tall vehic le would sway as much asfive feet in the normal ocean breeze at Cape Kennedy as it awa its tanking. Among the effects of suchmovement are stresses on th e vehicle and tie-downmechanisms, interference with launch operations,and oscillation on lift-off. Engineers designed asystem to curtail the swaying.

In addition , NASA uses simula tors to study otherphases of airp lane flight. For example, NASA hasbuilt an actual cockpit for a supersonic air linerat Langley Research Center. The controls in thecockpit are programmed by computers to duplicate6

the handling qualities of the craft. In one program,the simulator at Langley is used to examine factorsrelating to traffic control for supersonic transportsarriving at and departing from commercial airports.

Launch vehicle stages and future unmannedsatellites are also tested in a variety of simulators.Among other things, they are shaken , spun , baked ,and frozen in tests that frequently are more severethan conditions they are expected to meet in spaceflight. In this way, faults can be discovered andeliminated before launch.

During its launch and flight through earth 'satmosphere , a space vehicle is subjected to manyforces , such as noise and its associated pressuresand the turbulent air pressures generated by thevehicle's own speed. These may cause the vehicleto vibrate at such levels that it is damaged orthrown off course.

The problems that could be created are simulated ill a Launch Phase Simulator at the GoddardSpace Flight Center, Greenbelt, Maryland . Th e facil ity can simultaneously subject vehicles to variablelevels of acceleration, vibration, noise, and vacuum


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Simulated cockpit fo r supersonic air transport permitsstudies of operations. The simulator is at Langley ResearchCenter.

occurring during launch from earth into space.The simulator is an immense rotating structure

116 feet long. It ca n create forces as high as 23times the pull of earth's gravity. The simulator ishoused underground in a huge covered pi t to isolate it from extraneous effects in the surroundingen vironm ent. It is big enough to test the largestavailable unmanned satellites such as the OrbitingGeophysical Observatory.

When the satellite has passed the launch phasetest, it goes to Goddard's Space EnvironmentalSimulator. This huge chamber, 60 feet in heightand 35 feet in diameter, can hold the biggest craftbuilt for America ' s unmanned satellite programs.In the chamber, a spacecraft is not only subjectedto the vacuum of space but also to the cold anddarkness of space as well as the heat and otherradiation which the sun pours on objects in space.

The dark and cold of outer space originate froma temperature-controlled black inner wall . The solarradiation is created by 127 arrays made up of ahigh intensity Mercury Xenon lamp, an aluminizedreflector, and four fused silica lenses that direct theradiation on to the tested spacecraft. The range ofelectromagnetic radiation (such as visible light andultraviolet and infrared rays) produced by the 127units closely matches that which the sun pours into

Launch Phase Simulato r, Goddard Space Flight Center.

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High-intens ity Xenon mercu ry lamps and a lumin ized ref lectors, part of the artifici al sun of the Space Environ me ntal Simulato r, Goddard Space Flight Center . Threeunits (r ight ) are turned on .

space outside of earth 's atmosphere. Th e artificialsun is located in th e dome of the Space Environmental Simulator.Special eq uipment is required fo r testing adva nced rockets powered by nuclear or oth er highlyvol at ile fuels and fo r checking nuclear devices designed to ge nerate sustained flows of electricity athigh levels for prolonged periods. The Lewi s Re-sea rch Center, Cleveland, Ohio, and its Plum BrookStation, Sandusky, Ohio , are responsible for muchof th i s work. At Plum Brook, a vacuum tank th atis 100 feet in diameter and 120 feet high providesthe pressure and temperatu re conditions of spacefor tes ting components and complete systems. Theta nk is inclosed by a six-foot-thick concrete shield.

Al so at Plum Brook is a nuclear reactor which

Hydroge n-fueled second stage of th e Atlas-Centaur launchvehicle is lowe red in the vacu um chamber of Lewis Research Center fo r testing.

provides a me ans for study of space radiation andhow man and mac hine can be protected against it.A reactor creates radiation wh en it splits atoms .The resulting protons, elec trons, and other atomicparticles, accelerated to high speeds, are similarto particles hurled into space by our sun and otherstars and to th ose making up the dangerous VanAll en Radiation Region.

NASA uses many more si mulators to br ing outerspace down to ea rth . Th ese are supplemented andtes ting is reinforced by th e extensive sim ulatorfac ilities of NASA con tr ac tors . The NASA-industryuniversity team has found simulation to be an important contributor to reliab ility of space veh icles,tr aining of as tronauts , and th e ad vance of America's ae ronaut ic and space programs.

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