Suited for Spacewalking pdf - Virtual Astronaut

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Exploration BriefGetting the Right FitContextIn spite of many decades of experience in developingand evaluating spacesuits,they are still fatiguingto wear. The internal pressure of the suit createsresistance to movements of the arms, hands,or legs.Consequently, astronauts training for a spacewalkare encouraged to stay in excellent physical conditionby training on the ground for endurance andstrength. After a spacewalk, crew members areallowed a day of rest before going out again.That iswhy missions,such as the multi-day servicing of theHubble Space Telescope, have two EVA crews thatalternate spacewalk days.p re s s u ri ze d .An unpre s s u ri zed suit is slightly small e rthan when it is pre s s u ri ze d .The suit must fit ri g h twhen the crew member is in space. The micro g ra v i tyThe exhaustion factor of spacesuits can be mitigateds om ewhat by insuring that the suit the crew memberwill wear in space fits pro p e rly. It is essential thatthe position of suit joints pre c i s e ly match the positi on of shoulders, e l b ow s , wri s t s , k n u ck l e s , k n e e s ,and ankles. A misalignment of a mere centimeter inthe arm length, for example, can lead to achingfingers after a seve ral-hours spacew a l k i n g.Getting the right fit is com p l i cated by a number off a c t o r s . It is important that the suit fits when it isSuited for Spacewalking An Activity Guide for Technology Education, Mathematics, and Science, EG-1998-03-112-HQ • 7 7
e nv i ronment experienced in Earth orbit affects thehuman body in many ways . One effect is spinel e n g t h e n i n g. In one G (gra v i ty ) ,the ve rt e b rae of thespine are close together but are kept separate byru b b e ry disks that act as shock absorb e r s . In space,without the perc e i ved dire c t i onal force of gra v i ty, t h edisks expand slightly, causing the ve rt e b rae to moves l i g h t ly farther apart than they are when the crewmember is standing upright on Eart h . This spinelengtheningcauses the astronaut to get tall e r, re s u l t-ing in arm joint misalignment. Spine lengthening inm i c ro g ra v i ty has to be accounted for when astron a u t sa re measured for their suits. The typ i cal astron a u tw i ll gain between 2 and 3 centimeters in height whilein space.To avoid the expensive and time-consuming pro c e s sof creating custom-made suits for astron a u t s , a sNASA did during the Ap o llo mission s , suits withi n t e rchangeable parts are used. D i f fe re n t - s i ze dupper and lower torsos are available, but arm andleg lengths are still difficult to match. NASA hassolved this problem for the Shuttle EMU by creatingsizing inserts that are added or removed fromthe restraint layer in the arms and legs to achievethe right fit.The inserts are fabric rings of differentlengths that are laced into the arms and legs.Selecting the right combination of inserts insuresthe best fit possible.Objective• To experience the measurement process used insizing a spacesuit arm to fit different wearers.Materials and Tools ChecklistPVC thin-wall sewer pipe (4 in. dia.)Saw (crosscut or hacksaw)Measuring tape or ruler (metric)Duct TapeVinyl clothes-dryer hoseScissorsThick rubber glovesSand paper or knifeProcedureStep 1. Construct a variety of spacesuit arm segmentsby sawing off measured lengths of PVC plas -tic thin wall sewer pipe. (See the tip sectionfor information on where the sewer pipe andother needed materials can be obtained.) Cutthe pipe into segments 25, 50, 75, and 100mm long. Cut two of each size. Cut threeadditional segments of the 50 mm length.Step 2. Create a suit elbow joint by connecting two ofthe 50 mm segments with a 25 cm piece ofvinyl clothes dryer hose. Slip the hose endsover one end of each ofthe segments.It will benecessary to the hose a small amount to accom -plish this task. Fasten the hose to the segmentswith duct tape.Step 3. Slip the cuff of one ofthe gloves over a 50 mmpipe segment. The fit may be tight but try toslide the ring in so that it just reaches the posi -tion of the wrist. Trim off the excess of the cuffso that the glove can be affixed to the ringwith duct tape.ActivityStep 4.Provide the rings, joint, glove, measuringtape, and duct tape to a group of students. Tellthe students to select one member of theirgroup to serve as the astronaut. Their objec -tive is to fit a suit arm to that astronaut.Thestudents should begin by measuring the armand mapping the range of movement of thearm without the suit. Use the Arm Range ofMovement Data Sheet for recording data.Step 5. The students should select the right combina -tion of segments to use to construct the arm.PVC rings are joined with pieces of duct tape.Step 6. After completing the arm, the student groupshould test it by placing the "astronaut's" arminto the suit arm.They will then evaluate thearm by repeating the range of movement testsdone before and by asking the astronaut howcomfortable the arm is to wear. If the fit is notcomfortable or the range of movements are7 8 • 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
Page 26 and 27: 17.Communications Carrier Assembly
Page 28 and 29: settings to be read. Setting number
Page 30 and 31: 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: InvestigationInsulating LayersIn th
Page 79 and 80: Arm Range of Movement Data SheetSub
Page 81 and 82: Body Size Range MeasurementsBased o
Page 83 and 84: ProcedureStep 1. Obtain the materia
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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