NASA Facts Manned Space Flight Apollo

8/8/2019 NASA Facts Manned Space Flight Apollo

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1 Source of Acquisition' NASA Contractor/Grantee

AN EDUCATIONAL PUBLICATION OF THE

NATIONAL AERONAUTICSAND SPACE ADMINISTRATION

NF-23/VOL. IV, NO. 7 %

Manned Space Flight : ADOIIOApollo is the third step in NASA's manned space

flight program. Its goals:* To land American explorers on the moon and

bring them safely back to earth.:% To establish the technology required to meet

other National interests in space.* To achieve for the United States pre-eminence

in space.Apollo was preceded by Project Mercury which

pioneered the technology and man's capabilitiesfor manned space flight and by Gemini which sig-nificantly extended the technology and experience-gained through Mercury Both Mercury and Geminiwere programs in which astronauts test pilotedspacecraft which were largely experimental, Apollo,on the other hand, calls for an operational space-craft capable of carrying astronauts safely to andfrom another body in the solar system.LUNAR ORBIT RENDEZVOUS

Three methods were considered to accomplishthe manned lunar landing mission. They were: 1)direct flight of a full-size spacekhip from the earth

to the moon and back, 2) launching two separatesections of a spaceship from earth into orbit,joining them together, and sending them as asingle spacecraft to land on and take off fromthe moon; and 3) launching the whole spacecraftfrom earth to lunar orbit and landing a sectionof the craft on the moon while the other partwaits in orbit for the landing craft to return.

The third method, called lunar orbit rendezvous,was chosen after careful study. This method re-duced significantly the rocket power required forlanding on and taking off from the moon. More-over, a craft using the earth-orbital rendezvousmethod (2) would weigh more than twice as muchas the one using the lunar-orbit rendezvous meth-od, mainly because of additional fuel.

APOLLO SPACECRAFT

The Apollo spacecraft assembly is 82 feet talland weighs about 45 tons. It is composed of threemodules (separable units or "blocks"), plus anadapter and a launch escape system (LES).

Lunarby twdown

Module,o astroron the

of Apollo space~auts, momentsmoon.

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* REPLACES VOL. Ill, NO . 1


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COMMAND MODULE

The Command Module (CM) is the only m odulewhich will return to earth from the lunar mission.It contains the crew's living compartment and allthe controls for the various in-flight maneuvers.Similar in shape to a cone, this module has abottom width of 13.8 feet and stands about 12feet high. It consists of two shells: a pressurizedinner crew compartment and an outer heat shield.Launch weight is about 12 ,000 pounds. Moreelaborately equipped for human com fort than eitherthe Mercury or Gemini spacecraft, the Apollo CM

contains a pilot cockpit for three astronauts. Ithas two side windows, a crew hatch window, andtwo rendezvous' windows w hich face tow ard th enose of the CM.

The Apollo Environment Control System (ECS) issimila r to that of the G emini spacecraft. It suppliespure oxygen in the cabin at 5 psi (pounds persquare inch), a tem pera ture of approxima tely 75 "with a hu midity index between 40 % and 70% .2

LAUNCH ESCAPE SYSTEM

On top of the Command Module at launch is theLaunch Escape System (LES) tower, with rocketmotors s imilar to those used on the Mercury escapesystem. The LES is 3 3 feet tall and weighs about8,20 0 pounds. With this tower and motors, thelaunch pad Apollo spacecraft (without its booster)has a total height of 82 feet. It is almost as tallas the com bined Mercury-A tlas vehicle tha t placedJohn Glenn in orbit on America's first mannedorbital f light in 1962.

The LES is designed to separate the command

module from the rest of the launch vehicle shouldan emergency occur on the launch pad or shortlyafter lift-off. The system rockets the commandmodule a safe distance away from the launchvehicle and to an altitude high enough for para-chutes in the modu le to function for descent toearth. The LES is jettisoned about 3 5 seconds afte rignition of the launch vehicle's second stage.


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SERVICE MODULEBeneath the Command Module at launch is the

Service Module, a cylindrical unit 12.8 feet indiameter and 22 feet tall, weighing 55,000 pounds.It contains the spacecraft's electrical power supplyequipment and its primary propulsion system,which produces 22,000 pounds of thrust. Thisstop-and-restart engine will be used for several im-portant maneuvers while the spacecraft is moon-bound. It will also be used to slow the spacecraftto go into lunar orbit, to make midcourse correc-tions while earth-bound.

Having fulfilled all these functions during theround trip, the Service Module will be jettisonedprior to the Command Module's reentry into theearth's atmosphere.

ADAPTER

Under the Service Module, at launch, is theadapter section which connects the Apollo space-craft to the third stage of the Saturn V launch

2 Techniques considered fo r thelunar landing mission.

3 Apollo Command Module.4 Apollo spacecraft.

vehicle and serves as the housing for the LunarModule (LM), the lunar landing vehicle.

The adapter section is a fairing 28 feet tall.It is 12.8 feet in diameter at the top to matchthe width of the Apollo spacecraft. At the bottomit flares out t o a diameter of 2 2 feet in order tomatch the width of the Saturn V booster's thirdstage (S-IVB). Weight of the adapter section isabout 4,000 pounds.

LUNAR MODULE

The Lunar Module (LM), which weighs approxi-mately 35,000 pounds, is the flight unit that willdetach from the orbiting Command and ServiceModules and desend to the moon's surface withtwo of the th ree astronauts aboard. Called the "bug"because of its appearance, it has two windows thatwi ll serve as "eyes" fo r the land ing maneuvers, atubular "mouth" for entry and exit, and fourspidery "legs" for steady support after lunartouchdown.


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The LM has its own complete guidance, propul-sion, computer, control, communications, and en-vironmental control systems, all with at least oneand sometimes two backup systems. These pre-cautions are necessary because landing on themoon will be the lunar mission's most criticalphase.

The LM's descent propulsion system has a throt-tle control-its rocket engine's thru st power canbe varied from low to high (1,050 pounds to 10,500pounds) in order to control the lunar touchdownflight w ith great precision. The pilots will use thisengine to provide brak ing thrust for the moonlanding.

The final descent can be slowed to 3 mph at analtitude of 15 feet, but i f the LM should drop attwice this speed, i ts four jointed steel-truss legscan absorb the landin g shock without harm t o thecra ft or crew. The legs are also designed to lan d

on slopes up to 1 2 degrees in slant, o r to retainbalance if one or two legs sink into a layer of dustas much as 12 inches deep.

The LM is a two-stage vehicle. The botto m stagecontains the rocket engine and legs for lunar land -ing. For the retu rn trip , this stage also serves asthe "launch platform" for the upper stage, whichincludes the cabin for the astronauts and the ascentengine. The ascent engine propels the up per stagefrom the lunar surface for rendezvous and dockingwith the CSM (combined Command and ServiceModules) which had remained in lunar orbit.

GUIDANCE AND NAVIGATION

The Apollo space navigation system includes tworelatively conventional units-inertial guidanceplatform and fl ight pattern computer. A third un itis an optical space sextant with which th e astronautswill take sightings of the earth, moon, and referencestars to check out their position before eachmaneuver.

ASTRONAUT WARDROBE

The Apollo crewmen will have a changeable

wardrobe for wear at different times. On the trip,two of the men (in rotation with the third) mayrelax in their "constant wear garment," a two-piece,close-fitting garment which covers all the body ex-cept the head and hands.

The thir d m an will be in the Apollo space suit,with "accordion" joints (bellows principle ) forflexible ease in walking, bending, o r m oving hislimbs, and a helmet that has a pivoted visor for4


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5 Model of Apollo Lunar Module.6 The Apollo launch vehicles. (see text page 7)


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7 Wearing an Apollo pressure su it an d buoyed by app aratus that cancels out five-sixths of his weight, an engineercarries out an experiment in a simulated lunar crater.


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8 Test of Apollo pressure suit.

quick closing and sealing.The same type of space suit will be worn by the

two LM astronauts who explore the moon. Under-

neath the pressure suit will be a special under-garment interwoven with a fine network of water-circulating tubes to carry away body heat. Coveringthe entire space suit will be a "thermal garment,"or a white coverall with hood, to protect the astro-

') naut from blis terin g sunshine on the airless moon.Finally, a "meteoroid cape" on his back will p rotecthim from micrometeoroid dust which may rain downon the moon at high speed. Meteoroids that wouldpenetrate the cape are calculated to be rare.

An imp ortant u nit of the Apollo space suit systemis the strap-on backpack for lunar exploration which

includes a 4-hour oxygen supply, two-way radio,heat-dumping radiator, and dosimeter (radiationgauge). Partial radiation protection is built into thespace suit fabric .

LAUNCH VEHICLESThe Apollo launch vehicles are the Saturn I,

Uprated Saturn I, and the Saturn V.(1) The Saturn I developed 1.5 million pounds

of thrus t in its first stage (S-1) through the cluster-ing of eight H -1 rocket engines burn ing RP-1(refined kerosene) and LOX (liqu id oxygen). Its

second stage (SIIV) ad six RL-10 -A3 enginesbur ning liquid hydrogen and LOX, pro ducing 90,0 00pounds tota l thru st. With a diameter of 21.5 feet

and standing 125 feet tall (without spacecraft), thistwo-stage vehicle delivered a payload of 22,000pounds into low earth orbit.

The Saturn I has placed the Command andService Modules of the Apollo spacecraft into orbitin unmanned test flights and has been used tolaunch the Pegasus micrometeoroid technologysatellites. The Saturn I program was completed in1965 with ten successes in as many launches.

(2) The Uprated Saturn I has an improved ver-sion of the Saturn I first stage and a new andmore powe rful second stage-the S-IVB. The Up-

rated Saturn I is designed to launch the firstmanned Apollo flights into earth orbit.

The second stage (S-IVB) has one J-2 enginewhich bu rns liqu id hydrogen and LOX and produces200 ,000 pounds thrust. Low earth-o rbit payloadfor the Uprated Saturn I is 40,000 pounds.

(3) The Satu rn V is a vehicle of gigantic size andpower. The first stage (S-IC) has a diameter of 3 3feet and is powered by a cluster of five F-1 engines,each developing 1.5 million pounds of thrust, for atotal of 7.5 million pounds.

The Saturn V second stage (S-ll) has a cluster


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9 Space flight simulator, with image of the moon on left, shows what man can and cannot do in controlling space-craft d uring actual missions.

10 An Apollo-Saturn V test vehicle.

of five J-2 engines that furnish a total of 1 millionpounds of thru st. The Saturn V's th ird stage(S-IVB) is identical with the Uprated Saturn 1'ssecond stage and produces 200,000 pounds ofthrust.

This immense three-stage booster is 2 8 1 feettall. The entire Apollo-SaturnV assembly will stand365 feet high at the launch pad and will weigh 6million pounds fueled before a moon flight. It willfurnish the power to boost the Apollo Command,

Service, and Lunar Modules into b oth manned earthorbital and lunar flights.The mighty Saturn V launch vehicle willbe able

to launch 14 0 tons into a low earth orbit a t a speedof 5 miles per second (mps), and accelerate 47.5tons of payload to an escape velocity of 7 mps.This means that both the Apollo spacecraft and theSaturn V thir d stage will go in to pa rking orbit, afterwhich the S-IVB will re-ignite and add speed of 2

mps to send the spacecraft on its way to th e moon.

UNMANNED MOON EXPLORATION

Three manned spacecraft programs are contrib-uting to p lanning for manned landings by providingclose-range pictures and other information aboutthe moon. The first o f these was Ranger, completedin 196 5, which telecast close-ups of selected lunarareas before crashing as intended on the moon.

Another spacecraft is Lunar Orbiter which takes

sharp close-range photographs of extensive areasfrom relatively low orbits around the moon. Thephotographs are be ing used prim arily to select sitesfor manned landings. In a closely coordinated effort,Surveyor spacecraft are soft-land ed on the moon totransmit pictures and other information about theluna r surface in their vicinity. These are coor-dinated with the broader overhead views providedby Lunar Orbiters..


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TRAlNlNG

Astronaut training for the Apollo program in-cludes the "basic space train ing" of the Mercuryand Gemini programs along with the new Apollospecialties which are added from time to time,among them:

* "Moon T rips" in trainers tha t provide a realis-tic simulation of travel through space, descent tothe m oon, and return to earth.

* "Lunar Obstacle Course," a 32 8-fo ot-w idesimulation of the moon's rugged surface, completewith craters up to 50 feet wide and 15 feet deep,large boulders, a d ust layer, an d fissures over whichto jump. A suspension harness reduces an astro-naut's weight to the moon's value (1/ 6th earthweight).

* "Space Su it Workouts," du ring which astro-nauts wear experimental Apollo pressure garmentsto practice walking, bending, opening of visor, and

other operations.MOON FLIGHT TRACKlNG SYSTEM

A network of tracking stations around the worldwas established for Project Mercury, augmentedfor Gemini, and redesigned and rebuilt for Apollo.

One group of network stations will follow theApollo spacecraft at launch, during earth orbit, andagain at the end of the flight after the moon tripis finished.

As the spacecraft leaves earth orbit and startstoward the moon, it passes from range of these

stations. Trackin g then switches to a second grou pof stations whose powerful transmitters and sensi-tive receivers are dependable for communicationsat great distance.

These stations have huge 85-foot diameter dish-shaped antennas and are similar in appearance tothose which communicate with spacecraft, such asMariner, millions of miles away in the vicinity ofMars or Venus or orbiting the sun.

Located at Goldstone, California; Madrid, Spain;and Canberra, Australia, they stand approximatelyone -third of the earth's circumference (120") apart.

As the rotating earth cut offs one station's directline of contact wit h the spacecraft on its way to themoon or back, the next station rises above thehorizon and takes over.

When the returning Apollo, speeding towardearth at 25,000 mph, enters the range of theearth-orbital tracking chain, these stations go intooperation again and monitor the vital reentry andrecovery.


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11 Rendezvous docking simulator enables astronauts to practice the last 200 feet of lunar orbit rendezvous and docking.


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Sequence of major events in Apollo lunar landing mission.

FLIGHT TO THE MOON

The first U.S. manned flight to the moon willtake place sometime before the end of this decade.The mission will begin with launch of the 365-footApollo-SaturnV vehicle. The first and second stageswill be jettisoned afte r burn ing all the ir propellants,but the third stage will burn only enough to placeitself and the three-module Apollo spacecraft in"parking" orbit about 10 0 miles high.

Later, when the lunar "launch window" (bestperiod of tim e for takeoff) is open, the thi rd stagewill refire and add enough speed for the Apollospacecraft to escape from earth orbit.

On the way to the moon, the crew will reorientthe combined Command and Service Modules(CSM) and dock (lin k-up) the nose of the Comm andModule with the nose of the Lunar Module (LM).

The CSM then extracts the LM from the adaptersection and the t hir d stage of the launch vehicle.Mid-c ourse maneuvers may be made if the lu nar

trajectory, or flig ht path, requires adjustment. Themaneuvers are accomplished by firing the ServiceModule's 22,000-pound-thrust rocket engine.

By about 54 hours after launch, earth's gravitywill have slowed the spacecraft gradually fromabout 25,000 rnph to about 2,500 mph. When itenters the area where the m oon's gravitational fieldis dominant, the spacecraft will be accelerated to-ward the moon.

About 64 hours after launch, the spacecraft willnear the moon at a speed of about 5,200 rnph andthe astronauts will apply the retro power of theService Module propulsion system for about 6minutes to slow the spacecraft down to about 3,600mph. This will cause the craft to swing into a lunaror bit about 8 0 miles high. For the lunar landing,two men will transfer into the LM.

After about 68 hours of mission time, the LMwill separate from the CSM with a difference in12

velocity of about 3 rnph and will move away about73 5 feet. The descent engine will then p ut the LMinto a transfer orbit at a velocity of 3,500 mph.The LM will coast until an altitude of about 49,500feet is reached; then powered descent will begin.Powered descent will take the LM to the hoveraltitude of 20 0 feet, where either a manual or auto-matic hover-to-touchdown procedure will be initi-ated. In either m ethod, the engine will be cut offat LM altitude of about 15 feet, giving the LM alunar impact speed of about 3 mph.

ASTRONAUT EXPERIMENTS ON THE MOON

&

Plans call for the a stronauts to stay on the m oonabout 18 hours. Of this time, they will workonexperiments for two separate 3-hour periods, inbetween which they will have about 6 hours of

sleep. The remaining time will be spent on suchmatte rs as equipment checks, meals, mak ing readyfor experiments, p ost-land ing nspection, and prepa-ration for take-off.

The most important parts of the astronauts'duties are their radioed descriptions, photographs,and direct telecasts of the moon and the 6 0 poundsof assorted rock samples they are to bring homein vacuum-sealed containers. In addition, the astro-nauts are to set up a group of Lunar Surface Ex-periments which will continue to radio their infor-matio n to earth for as long as a year. The experi-ments are designed to report on such scientificphenomena as temperature changes, radiationlevels, moonquakes, and micrometeoroids (tinyparticles of matter in space).

RETURN FLIGHT TO THE EARTH

When the time arrives for leaving the moon'ssurface and joining the orbiting CSM, the lowerstage of the LM will be used as a launching padand left behind on the moon.


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1 Lift Off. 2 Jettison Launch Escape System

3 S-ll Stage Separation, S-IVB Stage Thrusting. 4 Earth Orbit Insertion of the S-IVB Stage and Spacecraft

5 Translunar Injection. 6 Turnaround of CSM. 13


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7 Docking and Separation of Spacecraft From S-IVB 8 Lunar Orbit Insertion

9 Transfer to L M l o LM Separation

1 1 Final Descent 12 Exploration of Luna r Surface


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13 Ascent Stage Liftoff 14 LM Ascent-CSM Docke d

15 LM Jettison

With launch timed for rendezvous with the o rbit-

ing CSM, the LM ascent stage will ascend to analtitude of 80 miles and dock with the CSM. Afterthe two astronauts have transferred to the CSM,the LM will be jettisoned and left in moon orbit.The Service Module's rocket engine will be ignitedto build up lunar escape velocity of 5,460 mph.About 29,000 miles outward, the spacecraft willreach the point where the earth's gravitational in-fluence becomes dominant. Then, subject to theearth's pull, the CSM will return at ever-increasingspeed until it reaches the same velocity at whichthe spacecraft left earth-about 25,000 mph.

After using its propulsion for final course cor-rections, the Service Module will be jettisoned, leav-ing the C ommand Module to plunge into the earth'satmosphere.

At the velocity of 25,000 mph, reentry will betrickier for the Apollo spacecraft than it was forthe Gemini or Mercury spacecraft. The CommandModule must enter the top of the earth's atmos-phere and transfer into an earthbound ballisticpath. The safe "reentry c orridor".will be only40miles wide, while the angle of attack (slant towardearth horizontal) must be kept between 5%' to

7 1/2O.Apollo's reentry temperature will be about

5,000F. As in M ercury and Gem ini, the heat shieldwill protect the crew as air resistance rapidly cutsvelocity to a safe point for parachute deploymentand landing.

From earth launch to earth touchdown, the tota lmoon trip t ime w ill be approximately198 hours, orabout 8 days.

16 Transearth Injection 15


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17 CM.SM Separat ion 18 Entry into Earth Atmosphere

19 Main Parachute Deployment 20 Spacecraft Recovery

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NASA Facts Manned Space Flight Apollo

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