Suited for Spacewalking pdf - Virtual Astronaut

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Exploration BriefO 2 —How Much?ContextA typ i cal extra vehicular activity (EVA) lasts about 7h o u r s . Du ring that time, an astronaut perf o rms anumber of activities, s ome of which are ve ry stre n u-o u s . To make it possible to accomplish the mission ,the spacesuit has to provide a steady and re l i a b l eoxygen supply for breathing and suit pre s s u ri za t i on .The oxygen supply in the pri m a ry life - s u p p o rts ystem (PLSS) is contained in four oxygen tanks.Two of the tanks are used as the pri m a ry ox y g e ns u p p ly and two for an emergency secon d a ry supply.The two pri m a ry tanks each have a volume of 3,980c m 3 . T h ey contain a total of 0.55 kilograms ofoxygen at a pre s s u re of 5,860.5 kilopasca l s . As thisoxygen circulates through the suit, it passes thro u g ha re cycling system that re m oves ca rb on diox i d e,o d o r s , and humidity. The two secon d a ry ox y g e ntanks have a volume of 1,460 cm3 and contain atotal of 1.19 kilograms of oxygen at a pre s s u re of41,368.5 kilopasca l s .This supplies on ly enough ox y-gen for about 30 minutes because this oxygen is notc on s e rved and re cycl e d .Although the Shuttle spacesuit is used in Eart ho rbit where the suit is in effe c t , w e i g h t l e s s , t h eoxygen tanks still have to be con s t ructed froml i g h tweight materi a l s . Weight is not a problem ino rb i t , but it is a problem for Shuttle lift o f f. T h eSpace Shuttle can ca r ry on ly so mu ch mass too rb i t . Lighter tanks means that additional payl o a dcan be ca r ri e d .To reduce their weight tanks are made from thinwa ll metal shells that are wrapped with Kevl a r ®filaments and resin for stre n g t h .Objective• To measure the quantity of oxygen a person willneed under varying levels of activityMaterials and Tools ChecklistTwo-liter soft drink bottle1 meter of flexible plastic tubing(from a hardware or aquarium store)Permanent markerPaper stripsCellophane tapeWaterLarge pot or aquariumSuited for Spacewalking An Activity Guide for Technology Education, Mathematics, and Science, EG-1998-03-112-HQ • 8 3
ProcedureStep 1. Obtain the materials in the material list andbegin by calibrating the 2 liter soft drink bot -tle. Stand the bottle upright and pour mea -sured amounts of water into the bottle with abeaker. Add 100 ml and mark the side of thebottle at the top surface of the water. Repeatthis procedure until the bottle is filled.Step 2. Make paper mouthpieces by rolling a strip ofpaper around one end of the tube. Use a smallstrip of tape to hold the mouthpiece together.Make a new mouthpiece each time a differentperson uses the apparatus.Step 3. Partially fill a large pot or aquarium withwater. Fill the bottle with water and invert itin the aquarium. Support the bottle by hold -ing it with one hand around the neck. Insertthe air hose into the bottle neck. Attach amouthpiece to the other end of the tube andhave a student fully exhale a normal breath ofair through the tube. Water will be driven outof the bottle. Read the volume of air trappedinside the bottle from the calibration marksplaced on the bottle's side in step 1.ActivityStep 4.Measure the air quantity required in normalb reathing by several vo l u n te er stu d e n t s .Begin with the students at rest. With a freshmouthpiece on the tubing, have a studentinhale a normal breath of air and exhale theair through the tube. The student should dothis several times. Measure the amount of airin the bottle and divide this quantity by thenumber of breaths.Record the quantity for "atrest" on a data table or computer spread sheet.Also measure and record how long it took forthe test.Step 5. After recording "at rest" breathing require -ments, refill the bottle with water and haveeach student perform a moderate amount ofactivity such as lifting small barbells for aminute or two. After exercising, repeat the airStep 6.Step 7.q u a n t i ty re q u i rement measurements andrecord the numbers in the data table for "mod -erate work."Repeat the procedure a third time, but havethe students run in place for a minute or twobefore taking the measurements. Record theresults under "strenuous exercise."Discuss possible ways to determine how muchair an average "student astronaut" will needon a 7-hour spacewalk in which the worklevel will range from moderate to strenuousand calculate an answer from the data collect -ed. Make sure the students realize that notonly will the quantity of air taken in witheach breath changes but the breathing ratewill change with exercise. Determine whatthe quantity would be if, instead of a normalair mixtu re, p u re ox y gen would be used.(Normal air contains 20 percent oxygen.)Extensions• D e t e rmine the actual volume of oxygen ca r ried inthe Shuttle spacesuit pri m a ry and secon d a ryoxygen supplies. Ox y g e n , under standard con d i-t i on s , has a mass of 1.327 kilograms per cubicm e t e r. (The pri m a ry and secon d a ry oxygen systemscontain a total of 1.74 kilograms of ox y g e n .Divide that number by 1.327 to get the volume ofoxygen in cubit meters. Although the volume mayseem small , remember that oxygen is re cycl e d . )8 4 • Suited for Spacewalking An Activity Guide for Technology Education, Mathematics, and Science, EG- 1 9 9 8 - 0 3 - 1 1 2 - H Q
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National Aeronauticsand Space Admin
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National Education StandardsThe act
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National Mathematics StandardsNatio
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M e a s u r e m e n tThis activity
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need to be able to move arms, hands
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out in the vacuum of space.Dissolve
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Project MercuryEarly spacesuit desi
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to occur for the first time. As wit
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crew, an additional portable heat s
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and reentry, special orange-colored
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The SCU contains lines for power, c
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17.Communications Carrier Assembly
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settings to be read. Setting number
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digital display on the chest-mounte
Page 32 and 33: Astronaut Joe Tanner works on the H
Page 34 and 35: humidity when oxygen is flowing fro
Page 36 and 37: The problem of picking up rocks and
Page 38 and 39: Bruce McCandless II pilots the MMU
Page 40 and 41: Mark C.Lee test flies the Simplifie
Page 42 and 43: STS-76 astronaut Michael R. Cliffor
Page 44 and 45: Spacesuit technicians test the mobi
Page 46 and 47: Future spacewalkers will roam the s
Page 48 and 49: Introduction:The steps spacesuit en
Page 50 and 51: Design BriefC o n t ex t :Spacesuit
Page 52 and 53: Interface Control DocumentPage 1 Of
Page 54 and 55: Pulley close-upviewthe buck e t . T
Page 56 and 57: to them. Use a metric ruler for mea
Page 58 and 59: steel would make an excellent micro
Page 60 and 61: d ay or tw o, Ap o llo spacesuit ma
Page 63 and 64: Sleeve and Leg TesterInflated segme
Page 65 and 66: ity alone.If a scale were present,
Page 67 and 68: Exploration BriefMicrometeoroids an
Page 69 and 70: InvestigationPotato Astronaut—Par
Page 71 and 72: Exploration BriefKeeping Your CoolC
Page 73 and 74: AssessmentHave students design a gr
Page 75 and 76: InvestigationInsulating LayersIn th
Page 77 and 78: e nv i ronment experienced in Earth
Page 79 and 80: Arm Range of Movement Data SheetSub
Page 81: Body Size Range MeasurementsBased o
Page 85 and 86: Magnified view oftire valve and cla
Page 87 and 88: Extensions• Compare the stiffness
Page 89 and 90: 2. Tethers4. Connector Seal TestPla
Page 91 and 92: 9. Vacuum Experiment - 1Obtain an e
Page 93 and 94: You can investigate neutral buoyanc
Page 95 and 96: MMUMercuryORUPLSSRegolithRMSSCUSkyl
Page 97 and 98: NA S A’s Central Ope ra tion of R
Page 99: Suited for Spacew a l k i n gA Te a
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