NASA Facts Living in Space

8/7/2019 NASA Facts Living in Space

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Page 1NASA FACT SNASA FACTS Vol. III, No.5

An Educational Services Publication of theNational Aeronautics and Space Administration

LIVING IN SPACE .

.. .. . ....

(THRU)

(PAGES)I I

(C O DE ) . . " . . -O!:J(NASA CR OR TMX OR AD NUMBER ) (CATEGORY) Ij

Astronauts will some day live in space cabins similar to th e one pictured here . Th e test subject is checking th e status of th e equip-ment in this simulated space stat ion before removing hi s pressure suit.

In our earth-bound existence, the availabilityof the food we eat, the water we drink, and theair we breathe are pretty much taken fo r granted.Because of the absence of these elements inouter space, it is necessary to take them along orto create them within a manned spacecraft.

Man already has ventured into the hostile environment of space, carrying a small portion ofhis earth environment with him. Until now hehas been able to carry only enough to sustainhimself fo r short periods of time.

We ca n predict, with reasonable certainty,that men will orbit the earth in scientific labora-

tories, performing useful work for months. Tripsto the moon may lead to establishment of lunarscientific stations. It is not too great a stepbeyond this to imagine a new generation ofMagellans, enroute to th e near planets of oursolar system; a journey that may take a year orlonger.

LIVING ON EARTH

How will we support life in space over suchextended periods of time? What are the prob-


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Page 2 NASA FACTS Vol. III, No.5lems? What must we contain in the astronauts'spacecraft to ensure their s ~ v i v a l in comfort?

To pu t this into its simplest terms, let's takeon objective look at "l iving on earth," notingthe essentials to the existence of al l l ivingcreatures.

Life, as we know it, can survive only within acertain range of pressures. Deep-sea fish, fo rexample, cannot survive in shallow water. Ma nhas evolved in an atmosphere which compresseshim with a force of 14.7 pounds pe r square inch{one atmosphere}. If he moves too far awayfrom this pressure, his death is certain. Theminimum pressure under which man can live comfortably and function efficiently is about half onatmosphere (about 7.5 pounds per square inch).

A second need for l ife support is the righttemperature. Most creatures live within a limited range of temperature. Man's body temperature must stay pretty close to 98.6 degreesFahrenheit, or he won't function well.

Our third requirement for life support isoxygen: A fairly constant intake proportional tothe amount of energy we are expending at anygiven moment. Three minutes without oxygenrisks permanent brain damage; five minutes with-out oxygen spells death.

Water is the fourth. We can live less than aweek without it .

Fifth and last on our list of physical necessitiesis food. It is the fuel that keeps our machineryrunning, and at the right temperature.

Mother Earth provides all of these supplies inabundance. Man, though, has broken throughthe thin shell of his atmosphere into space,where they are lacking. He can remain thereonly as long as he can maintain an environmentlike the one from which he sprang.

BASIC ELEMENTS OF LIVING IN SPACE

Man in space must l ive within a pressurizedenclosure. The simplest form is the space suit,which can sustain him fo r a short time.

This is an airtight suit completely enclosing theastronaut, which is "pumped up" to provide himwith his own atmospheric envelope._

Pressure suited Astronaut enters the sp ace-sta t ion tes t bed.Once he is within th e pressurized atmosphere of his space station, an Astronaut will be able to shed th e clumsy space corset

far shirt sleeves.

More complex is the space capsule. The Mercury capsule had little room fo r movement, al imitation imposed by the restricted amount ofweight its booster could place in orbit. Becauseof the difficulty of movement, and other reasons,taking off and putting on a space suit wasinadvisable.

The Gemini capsule presents a similar butsmaller problem because it is more spacious.Gemini astronauts have spent extended periodsof time in their "long-Johns" . Beginning withthe Apollo capsule, the astronauts will have theadequate living and work space they need in acabin pressurized fo r comfort, in which they canmove about in shirt-sleeve freedom.

Heat is an essential bu t is not a " load factor".It is produced in excess by the operation of thecapsule in flight as a by-product of the generation of electrical power and by the human body.It must be continuously dissipated in space tomaintain the thermal balance of the spacecraft.

The amount of oxygen needed depends uponthe number of crewmen, and the duration of the

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NASA FACTS Vol. III, No.5 Page 3

LIFE SUPPORT MATERIAL BALANCE

InOxygen consumptionFood requirement (dry basis)Carbon in food converted into CO,Hydrogen in food converted into H20H,O derived from foodNet water intake for drinking an d food

preparat ionTOTAL

Ibs/day2.01.320.6150.0460.994.467.78

miSSion. A four-man crew in an orbiting spacelaboratory on a year-long mission will consumeabout 2700 pounds of oxygen. At the sametime, they would be exhaling about 3300 poundsof carbon dioxide. This gas must be kept be-low .5% of the total capsule atmosphere or theefficiency an d health of the crewmen will be im-paired. If allowed to accumulate it wouldasphyxiate the astronauts.

The breathing air is subject to other forms ofcontamination which also must be controlled.Machines, men, and chemical reactions betweenvarious compounds will give off minute quantitiesof gas or floating particles which, over a longperiod of t ime, could present a hazard to thecrew.

Of the consumables that must be carried,water offers the most serious weight problem.Four men, over a one year period, will consume16,000 pounds of it .

This amount of water is based on a daily allotment of 1V2 gallons of water a day fo r eachcrewman; much less than the average earth mannormally uses.

A year's supply of food for four men, carefully selected for nutrition, taste, and minimumweight, with al l the moisture removed would tipthe scales at 2400 pounds.

The grand total fo r oxygen, water, and foodexceeds ten tons .

OutWater vapor generationCarbon dioxide generationMetabol ic water generat ionUrine productionFecal outputFecal water (at 75%)Solid waste from foodTotal H2 0 outputTOTAL

Ibs/doy2.202.250.413. 00.330.250 .085.457.78

Even though we may be able to launch thismuch weight with our advanced boosters, it isat great cost. The more we carry, the greaterthe booster required, the larger storage spacewe need, and fo r every pound of supplies carried, we may have to sacrifice a pound ofexperimental equipment.

REGENERATIONBy the process of "regeneration," we can re-

duce the basic amount of water and oxygen fo rour theoretical mission from 18,700 pounds-toaround 400 pounds with a corresponding savingin storage space.

Literally, regenerate means to restore a material to its original strength or properties.Another definition is "to make use, by means ofspecial devices, of heat, or the l ike, that wouldotherwise be lost."

The development of regenerative systems fo rlife support in space has not been easy, but thefirst demonstration of the capabil ity has beenaccomplished.

A GROUND-BASED SPACE STATION"l iving in Space" experiments are now under

way. The first experimental working model o


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Page 4an orbiting space laboratory is already in operat i o ~ at NASA's Langley R e s ~ a r c h Center.

This space station will never leave the ground,but men will live within the sealed hull fo r extended periods of time, under conditions whichsimulate l iving conditions in space. They willl ive only on the supplies sealed in with them atthe beginning of each test.This space laboratory is a cylinder measuring18 feet 4 inches in diameter and 18 feet inlength. It contains three compartments: A livingarea with a volume of 2840 cubic feet, a laboratory /work area with a volume of 1910 cubicfeet , and an airlock entry/exit area comprisinganother 90 cubic feet.

There are seven main subsystems comprisingthe l ife support system which are undergoingrigid and exhaustive tests. Atmospheric controlis the subsystem which regulates pressures, re-covers oxygen from carbon dioxide, an d re-moves atmospheric contaminants. The watermanagement subsystem includes means fo r stor-ing, testing, distributing, and for regeneratingwater from wastes. Food management i n c l u d e ~ techniques fo r storing, heating, chilling, preparing, an d serving food under zero-gravity conditions. The thermal control subsystem maintains cabin air temperature and humidity at crewchoice, provides hot and cold operating temperatures for equipment, and dissipates excessheat. Waste management includes collection,transfer, processing, and storage or disposal ofall unwanted materials. Personal hygiene isprovided for by another subsystem developed tokeep the astronauts healthy and clean. Threading through al l of these subsystems is a seventhsubsystem, instrumentation and control, which"measures" and controls the distribution ofphysical factors such as pressure, flow, electricalpower, temperatures, etc. This last subsystemincludes "status" display panels and alarms towarn of malfunctions of any of th e subsystems.

The space station and its life support systemare designed to support four men. However,the principles and techniques of the station canbe "sized" to a larger or smaller crew.

NASA scientists, in performing experimentaltests with the working model laboratory, willaccu mulate data that will guide the design of

NASA FACTS Vol. III, No.5

Exterior view of a model space laboratory developed by NASAand General Dynamics Corporation, and now in us e a t th e

Langley Research Center in Virginia.

actual space vehicles. They will develop programs of work, rest, exercise, and recreation.They will refine the menu an d seek to improveequipment.

The major ingredient mission in the test program will be zero gravity except for very briefperiods. The real test will come when theoperational laboratory assumes its orbital pathin space, and becomes a home an d place ofwork for four men in long-term isolation.

LIFE SUPPORT PROCESSESEarly orbital laboratories may be launched

with their crews riding in re-entry capsules attached to th e larger structures. However, forthe long-term orbital observatories it is most practical to launch without the crew.

After the crewless la b attains its orbit, groundstations will test its systems, to assure that everything is in good working order. Then, membersof the scientist/ astronaut team will ride to their


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NASA FACTS Vol. III, No.5 Page 5

Life suppor t functions are symbolized to show inter-dependence: ( I) oxygen recovery (2 ) air pressure (3 ) wate r (4 ) contaminantremoval (5 ) food (6 ) waste disposal (7 ) power (8 ) hygiene (9 ) thermal control (10) instrumentation and control.

new home in space in transport vehicles similarto the Gemini spacecraft, thrust into a matchingorbit by smaller boosters.

Their first task, after they enter the lab, willbe to check out all functions. If everything isworking right, they will then be ready fo r th erelative freedom of th e shirt-sleeve environment.It is then that the men will enter into the life support loop-i .e . , become a part of the total life

support system cycle. The life support systembegins to function when the astronauts lift theirvisors and take a first breath of the lab air.ATMOSPHERIC CONTROL-When you inhale

and use oxygen, it isn't lost. It merely gets"tied up " within the body. Some of the oxygenyo u breathe combines with carbon, and is exhaled as carbon dioxide (C0 2 ), If you could

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Page 6 NASA FACTS Vol. III, No.5

A wide-angle view of th e equipment and laboratory deck shows th e actual operating equipm ent now in us e to regenera te oxygenan d water fo r re-use. Living quarters are on th e deck above this.

separate th e oxygen in CO 2 from its carbonatoms, you could use it again. So, the oxygenpresent in a small room will sustain yo u fo r a lifetime, if it is reclaimed fo r use over and overagain.Oxygen recovery, as you may recall, IS apart of the atmospheric control subsystem.

In the space cabin, air continuo.usly flowsthrough a number of devices which cleanse andpuri fy it . There is a set of filters in the livingarea, an d a duplicate set in the laboratory. Ateach of these stations, air first passes throughfiber-glass filters which remove visible-size particles. The air then flows through charcoalfilters, which remove odors and certain unwantedgasses.

Beyond the filter, air is passed through a de-vice called a catalytic burner which changes anytrace quantities of toxic gases into harmlesscompounds. Then al l the ai r flows through thecabin heat exchanger which cools the air to atemperature which maintains the cabin at a com-fortable range. In passing through this unit,most of the moisture contained in the ai r changesto tiny droplets of water which are siphoned of f

into water storage tanks fo r later purification andreuse.

The ai r also passes through a continuous ~ y c l e of oxygen recovery. There are three elementsin th e system: The CO 2 concentrator, the CO 2reduction unit, an d a water electrolysis unit.

The CO 2 concentration unit is comprised oftwo separate filtering devices. One removesal l water from the air as th e air flows throughthe concentrator. The second filter is composedof Zeolite, a chemical composition that has avery great attraction for carbon dioxide. Asthe air flows through this second filter, the molecules of carbon dioxide are captured by thegranules of Zeolite. The airstream, thus relievedof CO 2 returns to the main ai r circuit.

The CO u captured in the Zeolite filter, is thenextracted by a combination of heat and a vac-uum pump. It is then mixed with hydrogenan d is passed into a device called a "BoschReactor." Here, the mixture is raised to a tem-perature of 1200 degrees Fahrenheit, in thepresence of iron, which acts as a catalyst. Inthe reaction which follows, some of the hydrogen atoms combine with atoms of oxygen in the


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NASA FACTS Vol. IJI, No . 5CO 2 to form water. The carbon atoms adhereto the iron catalyst.

The water created in the Bosch Reactor istaken into an electrolysis unit where it is mixedwith a chemical liquid that will conduct electricity.The liquid is contained in a material that will allow hydrogen ions and oxygen ions to passthrough its walls, but holds back liquids. Onone side of the container is another compartmentwhich contains a positive electrode. A thirdcompartment contains a negative electrode.When electric current is applied, hydrogen atomswith a positive charge move towards the negative electrode in one compartment. The oxygenatoms, with a negative charge, move towardthe positive electrode in the other compartment.As the oxygen accumulates it returns to the cabinatmosphere, ready for reuse. The hydrogengas is returned to the Bosch Reactor, where it isused again, mixing with CO 2 to create morewater fo r electrolysis.

Thus, by regeneration, the same oxygen present in the cabin ai r when the spacecraft goes intoorbit is used over and over in an endless cycle.Theoretically, in a space cabin such as the onewe have described, i f there were no losses ofai r to the vacuum of space, 80 pounds of oxygenwould be enough to sustain four men for thelifetime of each. However, some loss is inevitable, so additional supplies will have to be onboard to make up fo r it. No material is "leakproof" when the pressure on one side is greaterthan that on the other. Engineers have calculated that a minute quantity of gases will leakthrough the cabin wall into space. To offsetthis leakage a reserve supply equal to about 100pounds of air for each 90 days of space travelmust be carried.

During the same period, astronauts will beusing the airlock for entering and leaving thespacecraft. We can estimate that they will useit about five times every 90 days. Each time,90 cubic feet of air will be lost.

As a safety factor, we will provide enoughadditional gases to replenish completely thecabin once every 90 days. This reserve is tomeet any possible emergencies; a leak in thecabin wall, or serious contamination of the atmosphere as a result of equipment malfunction.

Page 7If one of these conditions were to occur, thecrew would make necessary repairs, drain theatmosphere from the cabin and refill it with thereserve supplies. During this process, theywould be protected by their space suits, drawingfrom air supplies included in each space suit"bio-pack. "

Reserve supplies of gases will be stored asliquids or in high-pressure containers.

THE WATER CYCLE-When we drink water,it doesn't necessarily change its form. It becomes contaminated by the waste products ofour biological processes. We consume it in itspure form, in beverages, and in the food we eat.

We reject it as water vapor in breathing, asperspiration, as urine, or in solid wastes (feces).

The recovery of a part of this was covered inthe description of the ai r circuit. Perspirationevaporates, and with vapor in th e breath, becomes suspended in the atmosphere, increasingthe humidity level within the cabin. This humidity is concentrated by cooling in the cabin heaexchanger, and recovered in the water separator

Man's biological processes produce morewater than he consumes. This is becauseoxygen he breathes combines with hydrogenfrom hydrocarbons in food to produce about apint of water per day. With this net gain, itwon't be necessary to recover water from solidwastes-as long as leakage and loss of atmosphere due to use of air-lock fo r extra-vehicularactivities are minimal.

Wash water and urine are the other twosources of water which is purified fo r re-use.The process begins in the collection tanks.

The collection tanks hold the waste water untithere is enough to process. Here, speciachemicals are added. These inhibit bacteriagrowth an d formation of objectionable gases.From here, the waste water begins its flowthrough the recovery circuit.To "regenerate" water, the prototype lifesupport system uses a combination of evaporation and f i ltration. The main unit is a sealedcontainer enclosing a special wick over whichflows a stream of hot air. With this, we can"hold" water in zero-gravity.

Waste water, in a carefully regulated flow,saturates the wick. The ho t air flowing past the


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Brushing teeth in zero-gravity is not much different. It is bestdone while strapped to a bunk. Astronauts will have to becareful no t to squirt pas te, and must keep mouth closed whilebrushing.

wick evaporates th e water, leaving th e majorpart of th e contaminants in the wick. Thesewicks are replaceable, and are changedperiodically.

The air stream carries th e evaporated waterthrough a charcoal filter which removes odorsand contaminants which may have escaped inthe evaporative process.

Leaving the charcoal filter, the hot air entersa heat exchanger which cools it, condensing thewater to droplets. These move on with the ai rstream to a centrifuge type water separator,where the precious l iquid is recovered.

Air discharged from the separator passesthrough the blower which keeps it circulating; thenthrough a heat exchanger which heats it again;and returns again as hot, dry air, passing overthe wick to pick up more water.

Water from the centrifugal air/ l iquid separator passes out through another l ine to anothercharcoal fi lter, and finally into the recovery holding tank. It remains in this tank until it can betested fo r pu rity.

For space crews, the standard of purity ishigher than that applied to the water you use inyour home.

For psychological reasons, however, waterrecovered from urine is processed through aseparate unit reserved fo r this, and is used only


In zero-gravi ty , bathing is with a sponge, filled an d squeezedwith a mechanical device. Exercise must be of those kindswhich do not depend on gravity. Push-ups an d weight-liftingare out .

for washing. Potable water for drinking andfood preparation is processed in the first unit, andis derived from humidity condensates and washwater.

FOOD-Scientists are working on techniquesto reconstitute food from waste products, bacteriaand algae. There has been progress but acceptable methods will take some time to develop.For the next generation of astronauts, we willhave to settle fo r improvements in products thathave already been tested in space flight.

NASA, working with industry, has developedtechniques of freeze-drying foods in vacuumpackages . Using this technique, we can preserve almost any food, providing a menu bothtasty and nutritious.

Space meals, in individual, sealed plastic containers, will be stored in cabinets aboard thespacecraft. At meal-time, an astronaut willselect his balanced intake, and place the package on "zero-gravity" trays. They must beheld down, or they would f loat away at theslightest movement of the tray.

To prepare food for eating, crewmen will setan automatic dispenser control to the amount ofwater required. A water nozzle fits into a valveon each food bag, an d delivers the right amount

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MealNo . 1

MealNo . 2

MealNo.3

MealNo . 4

DAYS 1, 5 and 9Apricot NectarGrapenutsBread Wafers 111Mocha BeverageCoff

Fruit CocktailShrimp Casserol.Bread Wafers ILemon Gelat inJordan AlmondsCoffee

Beef SaladBread Wafers IIApplesauceSp ice Squa re sMilkCoffee

Pineapple JuiceBreast of ChickenMashed PotatoesGlazed CarrotsCorn Meal WafersStrawberry Dessert BitesTea

SAMPLE MENUDAYS 2, 6 and

Prune BitsScramb l ed EggsBread Wafers IMilkCoffee

Cream SoupTornato AspicCheese SandwichesRice PuddingHoney SquaresCoffee

Blended JuicesBeef and GravyMashed PotatoesPeasPecan BitesTea

Vegetable SoupHam PattiesBread Wafers IIBanana Milk ShakeNougats

10 DAYS 3 and 7Orange JuiceWhea t ChexBread Wafers 111Chocolate MilkCoffee

Swiss SteakMashed PotatoesCornApple PuddingToffeeTeaCream of Mushroom SoupGelatin Fruit SaladCorn Meal WafersCheese Cake BitsMilkCoffee

Grapefruit JuiceChicken a 10 kingRiceBread Wafers IIPearsCoffeeAlmond Wafers

DAYS 4 and 8Peach BitsScrambled EggsBread Wafers IIIMilkCoffee

Tomato ConsommeHamburger PattiesBread Wafers ICoffee Milk Shake

Grape PunchTurkey and GravyWinter Sq u as hSpinachBread Wafers II IRaspberry DessertTeaBlended JuiceHam CasseroleCorn Meal WafersPineapplePeppermint WafersCoffee

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Th e nex t generat ion of space men wil l us e f reeze-dr ied foods in vacuum packages. They reconst i tute these foods by adding cer ta ' "amounts of hot or cold water , through a self-seal ing valve. Food is eaten by squeezing contents in to mouth .


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. ... _ ................ . . . . . .. __ .. . _ . . . . _ ..... __ .. _ ..... _ _ ._ -:-;;-:-__ .. _____ ; .. _ _ - - ; - . - ; - _ ~ .; ._ . . . . _ _ .. __ . . . . .. ; .... . . ____ . ______ . . . . . __ ..... _ W- ii __ . . . ' ~ ' - - " - " . R - f t . 1 w = ~ __ __Page 10of water fo r reconstituting the food. There areseparate nozzles fo r ho t and cold.

~ f t e r removing th e bag, an astronaut willknead it to mix properly dried food and water.

To eat, you just squeeze the contents into yourmouth and chew, careful to keep your mouthclosed. Biscuits, cookies, and the like are packaged in edible wrappers. They are eaten package and all.

PERSONAL HYGIENE-Those who will volunteer for lonely, long-term vigils in space will havesome adjustments to make in terms of personalhygiene. They will sacrifice warm tub-baths andinvigorating showers fo r the zero-gravity sponge.

Even the squeezing of their sponge will become a mechanical task-since it must beenclosed-or the cleansing fluid, instead of running out, would gather into a glob of moisture,to go floating about the cabin with the slightestmotion.

The spaceman's razor will mast l ikely be electric, but it musthave a special attachment; a built-in vacuum sweeper thatpicks up whiskers as it shaves. We cannot allow loose

whiskers floating about.

NASA FACTS Vol. III, No.5"Tooth-brushing" won ' t be too much different,

but spacemen will have to learn to keep theirmouths closed during the process.

Shaving could become a minor problem, sinceordinary blade or electric razors would contaminate the atmosphere with floating shavingcream and bristles. Yet the spaceman needs toshave, or his space helmet might eventually closehim in like the man in the iron mask. To solvethis problem, engineers have developed an electricrazor that vacuums as it shaves.

Nail clippers will be enclosed in plastic bagsinto which an astronaut must insert his f inger.The common haircut would require spec ial precautions. It is highly probable that crewmen will shave their heads . Dandruff is a bigproblem.

Wash day may consist of simply discardingused or soiled clothing in to the waste collectorand slipping into new disposable outfits.

A special program of exercises is needed tokeep spacemen fit. The absence of gravitytakes the exercise ou t of th e conventional chinups and push-ups because there is no load onthe muscles.

Instead, crewmen will use well-planned regimens of isometrics, chest pulls, and other similardevices which do not depend on a gravity environment. Gemini crews have done valuablework in developing exercise programs.

In the year-long mission, there will very likelybe a small centrifuge between decks. Astronauts will spin-up in these devices fo r a set~ e r i o d on a regular basis. This will help keepmuscles from deteriorating .

WASTE MANAGEMENT-Waste co l lectionequipment and facilities are designed to overcome the no-gravity problem . For example,the commode uses forced air as a transportforce instead of water.

The commode ' s receptor con tains a ba gmade from special material that allows air topass through, but captures solids an d liquids .An object entering th e bag is caught by a continuous f low of air which forces it to the bottomand holds it there.


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The "Men's Room" aboard a space station is designed to overcome th e problems of zero-gravi ty. All wastes must be driedand stored in th e large container on th e left. Waste dr ier is

a t upper left center .

To dispose of the bag, the astronaut carefullycloses it, removes it and places it in the wastedrier. When the li d is closed, this container issealed off from the cabin. Heat is then providedinside the container, and a valve is opened whichexposes the materials to the vacuum of space.Between th e container and the exit to space,there is a filter which captures bacteria and othercontaminants.

After drying, waste products are removedfrom the drier and stored in collector "trashbarrels." Into these also go the used filters fromvarious components, such as the carbon filtersfrom the Bosch Reactor, and wicks from theevaporative water recovery units.

It would be simpler to dump the waste intospace, but scientists of most nations have agreedthat space missions should not clutter space withdebris or bacteria. All waste will eventua lly bebrought back into the earth's atmosphere.

An alternate proposal suggests that we couldsend waste rockets hurtling back into the atmosphere, where the objectionable materials insidethem would burn up during re-entry.

THERMAL CONTROL-Heat control is neededto maintain a comfortable temperature within thespacecraft, and to provide controlled temperatures for the various machines.

All the energy that is generated on the spacevehicle for operating equipment ends up in the

Page 11form of heat. If it were allowed to accumulate,it would become intolerably hot fo r the crew, sothe excess heat must be radiated to space.

The amount to be radiated is constantlychanging. Heat given off by the human bodyvaries with the activity of th e individual. Heatgenerated by electronic and processing equipment, operated intermittently, fluctuates withdemands placed upon them. A spacecraft designed fo r earth orbit may pass in and out of sunl ight and earth shadow many times a day, exposing th e cabin to constantly changing temperature extremes. Instruments must detect thechanging conditions and automatically regulatethe flow of air an d fluids to dissipate the excessheat at just the right rate.

l i fe support system processing uses energy intwo forms-as heat and as electricity. If itsonly source were electricity, it would require upto 9,000 watts during peak l oads- for a fourman system. However, scientists designed theequipment to uti l ize heat energy in place ofelectricity whenever possible. The use of heatreduces the electrical energy required to about2600 watts. This leaves a greater amount ofelectricity with which to operate electronic equipment and perform experiments.

A fluid picks up heat from the power generato r by means of a heat exchanger. This fluidcirculates to the equipment which requires heat.

Its energy is used to desorb the CO 2 concentrator, for CO 2 reduction, in th e water recoveryunits, in the waste drier, and in heating waterfor food preparation and washing.

Al l of this thermal energy must eventually beradiated into space, or the space cabin wouldbecome intolerably hot. This is accomplishedby means of space radiators.

The power generator has its own radiator.Al l operating energy fo r the spacecraft originatesas heat in an atomic isotope. This heats aworking fluid which dr;ves a turbine to produceelectricity. The hot fluid, no longer hot enoughto drive the turbine, is then used to heat anotherworking f lu id-by means of a heat exchanger.It is this second fluid which is used to operate thespacecraft's l ife support equipment. The powersystem fluid f lows from th e heat exchanger totubes outside the cabin walls.


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----------------------------------------------------------------.... o. - 0 0 0 0 o. - _ 00 0 0 0 - - 0 _.0. _. 0 0 0 - 0 0 0 0 0 0.0 0 0 00 0 _ _ 0 0.0 - O Page 12 NASA FACTS Vol. III, No.5..

Test volunteers must keep an eye onth e s ta tus panel , which keeps theminformed of th e candition of al l syst ems in thei r sealed chamber . If acomponen t beg ins to go bad , lightswill warn th e occupants. There are

also audible signals.

r=-""'" .,. . ... .

There, it gives up (o r radiates) its heat load tospace. The cooled fluid returns to the atomicisotope to repeat the cycle.

There is another radiator which is used fo r thecoolant system. The f luid in this radiator ischilled to a lo w temperature. It then passesthrough the various components of the life support system-chi l l ing water, condensing waterfrom the air, picking up heat from the air whichpasses through th e cabin air conditioner, andcooling the various items which become heatedin operation.

As the coolant moves through its pickup points,it heats up. It then flows back through the radiator to discard al l of the excess heat, and returns through the life support equipment to ge tsome more.

Thermal control is a thread which runs throughevery station in the spacecraft. In a sense, itties everything together, providing high temperatures where needed, and rejecting heat at lowertemperatures when it is no longer useful.

Briefly, we have described the major problems

NASA FACTS fo rmat is designed fo r bullet in-board displayuncut or fo r 8 x lO X loose leaf no tebook inser t ion whencu t along dotted l ines and folded along solid lines. Fo rnotebook ring insertion, punch a t solid dots in th e margins.

of living in space. Every component or subsystem in th e spacecraft has a backup. If aunit should malfunction, there would be an identical unit to take over, or a substitute method ofperforming the same operation.

Crew safety and reliabil ity are factors whichhave been paramount in the design of all equipment, and development of procedures.

The developfTIent of l i fe support systems fo rl iving in space is in its infancy. The system described here is th e finest NASA scientists, andtheir contemporaries in industry, have thus fa rbeen able to devise for conserving air, water,and energy in an orbiting spacecraft.

As improvements are made, they will be in corporated into the system. More and more usewill be made of materials and energy now discarded. Even as late as 1960, the mannedspace flight realities of today would have seemedl ike fanciful dreams. NASA research and development on regenerative systems today maymake it possible to extend man's space goalsbeyond the solar system.

NASA FACTS is an educat ional publication of NASA's Educational Programs an d Services Office. It will be mailedto addressees who request it from: NASA, Educatianal Publications Distribution Center, FAD, Washington, D:C., 20546.

u.s, GOVERNMENT PRINTING OFFICE : 1966 OF-218-584For sale by the Superintend e nt of Documen ts, U.S . Governmen t Printing Office

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