space suit extravehicular hazards protection development

8/8/2019 Space Suit Extravehicular Hazards Protection Development

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NASA Tech- Memorandum 100458

Space Suit ExtravehicularHazards Protection Development(NASA-'LEI- l O O U 5 8 ) S P A C E S U I 2 E X ' I B A V E H I C U L A R N 8 8 - 1 2 9 2 7

t A Z A F C S f P C T C T I C E DEVELCECEh3 { N A S A ) 2 9 pCSCL O6K IJnclasG3/54 0 1 1 0 6 7 2

Joseph J: Kosmo

August 1987

N S ANational Aeronautics andSpace Ad rn n s trationLyndonB. Johnson Space CenterHouston, Texas


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NASA Technical Memorandum 100458

Space Suit ExtravehicularHazards Protection Development

JosephJ.Kosmo

August 1987


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CONTENTS

Section

ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .BACKGROUND . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .LUNAR OPERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SHUTT LE MISSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ADVA NCED THERMAL/MICROMETEOROIDGARM ENT (TMG) REQUIREMEPJTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CONCLUDING REMARKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .BIBLIOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TABLES

Table1 GENE RAL REQUIREMEN TS FOR GEMINI G4C

EXTRAVEHICULAR SPACE SUIT ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 PRELIMINARY EVA SP ACE SUIT RADIATION ANALY SIS . . . . . . . . . . . . . . .3 PRELIMINARY MICROMETEOROID TEST R ESULT S . . . . . . . . . . . . . . . . . . . . .

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FIGURES

Figure

1 Astronaut Ed White (Gemini IV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 Gemini G4C extravehicular space suit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 Comparison of Gemini IV and Gemini VI11 extravehicular

coverlayers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 Gemini iron pants ITMG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Apollo ITMG ross section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 Lunar overboots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 Apollo extravehicular glove . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 Lunar extravehicular visor asembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 Astronaut Aldrin (Apollo11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Skylab v s Apollo ITMG cross sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 SkylabEVA . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . .12 Shuttle EV glove . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 Shut tle EVA (ease/access) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Advanced ITMG specialized requirements (Space Station) .....................15 Orbital paths (radiation) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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ABSTRACTThis paper presents a n overview of the development of the integra l thermallmicrometeoroid garment(ITMG) used for protection of a space-suited crewmember from hazards of various extravehicular(EV) nvironments. These hazard conditions can range from thermal extremes, meteoroid and debrisparticles, and radiation conditions in near-earth orbits and free space to sand and dust environmentsencountered on lunar or planetary surfaces. Representative ITMG material s cross-section layups ar eidentified and described fo r various space sui t configurations ranging from the Gemini program toplanned protective requirements and considerations for anticipated Space Station EV perations.

INTRODUCTIONSpace suits provide three basic functions for extravehicular (EV) stronauts. First, in combinationwith a portable life support system, the space sui t main tain s the physiological well-being of the astro-naut . This includes supplying 0 2 or breathing and ventilation,CO2 removal, an d metabolic heatremoval. Secondly, the suit incorporates various mobility joint system features to enable the crew-member to perform useful tasks in the EV environment. Finally, the sui t provides protection againstthe hazards of the par ticular EV nvironment. These hazards range from thermal extremes, meteor-oid and debris partic les, and radia tion conditions in near-earth orbit and free space to sand and dustenvironments encountered on luna r or planetary surfaces. Additional hazards are encountered fromsharp corners and edges of various structura l elements of satell ite or space vehicles as well as gloveabrasion when performing physicalEV asks.As he pressure retention layer of a space suit provides both the physiological protective barr ier andstructura l foundation for the incorporation of various mobility systems, a separate outer coverlayergarment comprising various combinations of mater ial layups constitutes the environmental pro-tective barrier for the EV worker.BACKGROUNDThroughout the Mercury program and until the ini tial feasibility of extravehicular activi ty (EVA)w as established on the Gemini IV mission, space su its were essentially utilized as intravehicularbackup emergency systems in case of loss of cabin pressure. The Gemini program provided the firstexperience for EVA n the United States manned space effort (fig. 1).The original program objectivesincluded the following:

0 Develop the capability for EVA n free space.0 Use EVA o increase the basic capability of the Gemini spacecraft.0 Develop operational techniques and evaluate advanced equipment in support of EVA or future

programs.In order to provide adequate thermal and micrometeoroid protection for the EV environment, the

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init ial EVA protective coverlayer for the Gemini IV mission consisted of an outer protect ive laye r ofhigh temperature res istant (HT-1) nylon, a layer of ballistic fel t for micrometeoroid protection, sevenalte rnating layers of aluminized mylar and unwoven dacron spacer materia l as superinsulation, andtwo innermost layers of 6-ounce uncoated HT-1 for micrometeoroid shock and particle absorpt ion (fig.2). This coverlayer was integrated to and worn over the basic intravehicular Gemini G3C suit. Table1 ists the general requirements for the G4C sui t configuration (EV version of the basic G3C suit) .The bulk of thi s coverlayer (la ter called the integra ted thermallmicrometeoroid gar ment or ITMG) re-stricted astronaut mobility even with the suit in the unpressurized mode inside the vehicle cabin.For the next EV mission (Gemini VIII), the coverlayer ITMG was redesigned to reduce bulk, increasemobility, and maintain or improve thermal and micrometeoroid protection. The micrometeoroid pro-tective layers of the ITMG were modified to utilize two layers of neoprene-coated nylon in lieu of theballistic felt and the two layers of uncoated HT-1 fabric. Overa ll sui t mobility was noticeably im-proved without any loss of environmental protective capabilities by th e introduction of the new ITMGlayup. Figure 3 shows the relative comparison of the Gemini IV and Gemini VI11 ITMG cover layers.Subsequent Gemini EVA missions incorporated additional changes to the ITMG layup primarily inthe lower torso are a of the suit to provide increased thermal protection against t he a stronau t maneu-vering unit (AMU) thruste rs impinging on the suit surface. Temperatures as high as 1300' F werepossible at the AMU thruster impingement areas. A stainless steel fabric w a s used as a n outer fabriccoverlayer along with eleven layers each of aluminized H-film (Kapton) and fiberglass cloth as her-mal insulation for the legs (fig. 4).To complete the G4C EV configuration, a gold-coated sun visor and special overgloves utilizing a si-lastic foam materi al were provided for thermal protection. The total man-hours of EVA experiencegained in the Gemini program amounted to 12 hours and 25 minutes accomplished on 5 of the 10manned Gemini missions.

LUNAR OPERATIONSEVA technology from the Gemini program w as incorporated wherever possible in the design of theApollo extravehicular mobility unit (EMU). The ITMG for the Apollo EMU, however, required de-sign considerations for the more severe lunar surface environment. EV hazards unique to the lunarsurface included potential secondary debris particles ejected by primary meteoroid impacts on the lu-nar surface, abrasive characteristics due to the surface rocks, sand and dust environment, and worst-case thermal conditions due to the combination of lunar-day high-sun angles and the effect of lunarcra ter walls. Figure 5 shows a representa tive ma ter ial s cross section incorporated in the ITMG forthe Apollo EMU assemblies utilized during Apollo 1-unarsurface missions. For protection againstabrasion, a n additional external layer of teflon fabric w as attached to the knee, waist, elbow, andshoulder area s of the ITMG. Special lun ar overboots (fig. 61, worn over the basic Apollo space sui tpressure garment assembly boots, provided thermal and abrasion protection during lunar surface op-erations. Except for the silicone rubber sole area of the boot, the outer layer of the lunar boot was fab-ricated from stain less steel (Chromel-R) woven fabric with the tongue ar ea of th e boot made fromteflon-coated Beta (fiber glass) cloth. A rib-st ructure sole configuration w a s used to increase thermalinsula tion qualities, to provide la teral rigidity, and to provide traction on the lun ar surface. Theinner l ayers of the lun ar boots (from the Chromel-R fabric inward) consisted of two layers of alumi-nized polymid film (Kapton) followed by five layers of aluminized perforated mylar film

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TABLE 1.-GENERAL REQUIREMENTS FOR GEMINI G4CEXTRAVEHICULAR SPACE SUIT ASSEMBLY

WeightBulk

PressureOperating

StructuralMobilityVentilation (EV)

InletOutlet

Spacecraft external (EV)Temperature

Micrometeoroid environment (EV)Initial EV mission exposureProbability of no penetration(Po)f suit bladderExposed suit surface area

0 35 lb (G3C suit w t = 25 lbs)0 Small enough to permit unassistedegress and ingress through Gemini hatch atzero-g

e 3.7 f .2 psia for 5 hrs EVA in hardambient vacuum0 8.0 psig, 15minutes0 Sufficient fo r unassisted hatch egress andingress at zero-g

0

0 3.7psia14-18acfm a t 45 f 3"F

0 -150" to +250" F0 10 minutes (worst shower period)

0 0.99925ft2

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separated by four layers of nonwoven dacron and followed by an inner liner of teflon-coated Betacloth. Two layers of Nomex felt in the sole area provided additional thermal insulation from thelunar surface.The EV glove for the ApolloEMU consisted of a modified intravehicular pressure glove covered by anITMG layup. The EV glove included an integral cuff,or gauntlet, that extended over the wristdisconnect on the space suit arm. The glove ITMG,a multilayer assembly, provided scuff, abrasion,and thermal protection for the pressure glove. The material cross-section layup of the Apollo EVglove is identified in figure 7. A woven stainless steel (Chromel-R) fabric was incorporated over thepalm and fingers to provide abrasion protection. The thumb and fingertip shells were made of highstrength silicone rubber (RTV630) coated nylon tricot for improved tactil ity and strength. A clearsilicone dispersion coating was applied to the palm and palm-side area of the fingers and thumb toprovide increased gripping characteristics.The lunar extravehicular visor assembly (LEVA) shown in figure 8provided visual, thermal, andimpact protection to the astronauts helmet and head. The LEVA was composed of an outer protectiveshell tha t housed two visors and three eyeshades. The outer visor, or sun visor, was made of hightemperature resistant polysulfone plastic and coated on the inside surface with a thin film layer ofvacuum-deposited gold. The sun visor could be manually adjusted in position from full up to fulldown during EV operations. The second visor, or protective visor, fixed in the full down position, wasmade of ultraviolet-stabilized polycarbonate plastic. The outer visor filtered visible light and rejecteda significant amount of ultraviolet and infrared rays. The protective visor filtered ultraviolet rays,rejected infrared rays, and in combination with the sun visor and pressure helmet formed an effectivethermal barrier. The two visors in combination with the pressure helmet protected the astronautfrom micrometeoroid damage and damage that could result from a fall on the lunar surface. Theouter shell housing provided protection for the sun visor during periods of nonuse. Separateeyeshades (left, center, and right) could be adjusted individually by the astronaut toprevent surfaceglare from obscuring vision during EVA. The Apollo 11mission (fig.9)was the first mission on whichthe EM U was exposed to the lunar environment. On July 20,1969,man first set foot on anextraterrestrial surface and collected scientific data while being sustained and protected from ahostile environment. Throughout the Apollo program, the EM U provided a haitable environment formore than 160man-hours of manned lunar surface activities.The Skylab program utilized a modified version of the Apollo EMU ITMG nd successfully accom-plished 82man-hours of EVA over three missions (figs. 10 and 11).

SHUTTLE MISSIONSAs in the Apollo program where the foundation of basic EV environment protective knowledge camefrom the previous Gemini program efforts, the development of the Shuttle space suit ITMG stemmedfrom experience and knowledge gained during the Apollo and Skylab programs. Additionally, effortswere undertaken through advanced technology development activities for improvements to materialsplanned for use in the Shuttle ITMG layup. The most significant outgrowth of this activity was thedevelopment of a high-wear and abrasion-resistant fabric having high tear st rength properties. Thefabric, called Orthofabric, isa woven blend of three different materials. The outer surfaceof the

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fabric isGore-Tex (teflon) backed by Nomex and containinga gridded interlay structureof Kevlar fi-bers. The Orthofabricis currently used as the outer protective layer of the Shuttle ITMG.Due to the low earth orbit (LEO) operations of the Shuttle missions, which are unlike the harsh lunarsurface thermal environment, changes to the numbers of layers of superinsulation were made tha treduced overall ITMG bulk. This resulted in the ITMG being less restrictive to the astronaut's mo-bility while providing adequate thermal and micrometeoroid protection. The Shuttle ITMG incor-porates five layers of aluminized mylar with a reinforcing layer of dacron gridded scrim backing eachlayer as opposed to the fifteen layers of superinsulation and spacer material used in the Apollo ITMG.The Shuttle space suit utilizesan extravehicular visor assembly (EVVA) similar in many regards toearlier Apollo LEVA and Skylab extravehicular visor assembly (SEVA) with the exception that theeyeshades have been deleted. Thermal protection for the Shuttle EV gloves isprovided through a nintegral layup of superinsulation (fig.12). The Shuttle program as ofthisdate has successfullyaccomplished 136man-hours of EVA (fig.13).

ADVANCED THERMALIMICRQMETEOROID GARMENT (TMG) REQUIREMENTSWith the advent of the Space Station program and the anticipation of routine EVA'Sbeing conductedon a weekly basis over longperiods of time, design requirements regarding protection against poten-tially new EVA hazards have become apparent. As shown in figure 14,along with the basicprotectiveaspectsof the typical Shuttle-type ITMG (such as thermayabrasion and micrometeoroidprotection), specialized provisions for chemical protection, enhanced radiation shielding, electrostaticcharge control, increased impact protection due to orbital debris, possible material considerations foratomic oxygen degradation, and improved long-term wear characteristics are either necessary ordesirable for advanced space suit ITMG's.Proximity to satellite or spacecraft propellants and other chemicals during future EVA refuelingoperationsrequires the incorporation of a chemical contaminant control barrier on the exterior of thespace suit. The propellant contaminants (ifthey persist as a liquid in space) would be capable of dis-solving the mylar film in the TMG multiple layer superinsulation. Tests of the chemicals of concern,such as monornethylhydrazine (N2H3CH31, ydrazine (N2H4),itrogen tetroxide (N204). nd ammon-ia (NHQ) ,ndicate tha t a thin film (2 mil) of floral ethylene propylene(FEP)eflon, laminated to theinside surface of the exterior Orthofabric layer of the typical Shuttle ITMG, will provide thenecessary barrier function. Similarprotective measures can be utilized in the EV glove ITMG layups.Protection for the (Lexan) pressure helmet from chemical degradation can be provided by the additionofa thin polysulfone laminated layer over the polycarbonate surface.In space, ionizing radiation hazardsareproduced by solar flare events, deep spa- galactic cosmicsources, and trapped solar electrons and protons from the Van Allen belts. Radiation in LEO dependsupon the orbital altitude and inclination of the space vehicle (fig. 15). Of the three radiation sourcesmentioned, the trapped particles cause the most concern during planned routine Space Station EVAoperations. For 28.5 degree orbits, typical of the Space Station flight path, radiation exposure fromtrapped protons isconfined to the South Atlantic Anomaly (SAA) region of the inner Van Allen beltwhich isonly encountered for approximately 15 minutes of each of five or six consecutive orbits perday. For polar orbit, exposure from trapped protons is confined to the SAA; however, most of the

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electron exposure comes from the outer belts which are encountered at high latitudes (50 to 80degrees) on each orbit. At geosynchronous earth orbit (GEO) altitude, the nominal radiation expo-sure comes from trapped electrons and is continuous. Results of preliminary analysis concerningallowable radiation dose limits based on radiation attenuation characteristics of representative spacesuit material layups indicate that the nominal EVA environment in LEO, ncluding polar orbit, doesnot present a s i d i c a n t radiation hazard (table2).Since the principal dose of harmful radiation from protons is experienced during transits in LEOthrough the SAA region, and since the duration of those periods of high proton flux represents a smalland readily predictable portion of the Space Station orbit, the best strategy fo r protection againstover-exposure appears to be avoidance of EVAs while the station is passing through this region. It istherefore recommended that EVA mission planners should avoid times that encounter the SAA in or-der to comply with the as low as reasonably achievable (AEARA) guidelines. This would allow ap-proximately 16 consecutive hours out of a 24-hour period free of the SAA during which mannedEVAs could be conducted safe from high proton flux.In response to the philosophy of keeping radiation dosageAEARA, additional attenuation character-istics can be incorporated into the ITMG ayup. Nuclear particle transport through any material isprimarily governed by the electron density of the material . Energy losses due to ionization duringparticle transport are greater for low density materials, whereas secondary X-radiation (bremsstrah-lung) protection isprovided by high density materials; for example, teflon is approximately 35% moreeffective than aluminum in slowing down or stopping protons, whereas lead or tungsten is more effec-tive in providing protection against X-ray production in electron transport. The material layup,therefore, most effective in terms of efficiently arresting both incident protodelectron flux and secon-dary X-radiation would be a composite material layup containing low atomic number material in theouter layers which are backed by a layer or layers of high atomic number materials.The addition ofa layer of tungsten-loaded silicone rubber as the innermost layer of the ITMG mayprovide a n effective radiation attenuation media. Efforts are underway to fabricate and evaluatesample layers having thickness of0.035 nches (0.089cm) and containing about 75 percent tungstenby weight, as well as a layer 0.082 nches (0.21 m) thick. The 0.089 cm layer provides an additionalmass per unit area of 0.36 gm/cm2; the 0.21 cm layer provides 0.86gm/cm2. It is planned that thethinner layer would be used in the ITMG layup covering the mobility joint elements of the SpaceSta-tion space suit and the thicker layer material would be used in the nonflexing portions of the suitITMG, covering such areas as the upper torsoand briefelements. This approach would add approxi-mately 28pounds (13kg) to the overall weight of the space suit.A double benefit can be realized from this addition to the ITMG. Coupled with the potential for en-hancing radiation shielding, the heavier layers incorporated into the multilayer composition of theITMG will provide increased penetration resistance to micrometeoroid and debris particles. Severaltests of these layups have been conducted with a hypervelocity gun facility a t NASA-JSC. Based onthese tests and preliminary analysis of the projected exposed EMU area, the proposed enhancedITMG cross section should provide a probability of no lethal penetration from micrometeoroids or deb-ris that meets the NASA Space Station goal of 0.9995. This is for one EMU having an EVA exposuretime of 936 ours over a l-year period (table 3).In some orbits primarily associated with high inclination or polar orbit operations, static electricalcharges from the auroras can build up on the surface of an EVA object such as the EMU. he concern

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TABLE 2.- PRELIMINARY EVA SPACE SUIT RADIATION ANALYSIS[Analysis - Equivalent AL Thicknesses, AP8 and AE8 Solar Minimum (LGRF 65/640),NRL GCR Model, Modes Man]

Total Trapped and GCR Dose (Mill iredDay) and Percent of Limits*

Shuttle space suit (SSA)Eye (sunvisor up)Eye (sunvisor down)Skin(torso)Skin (arms & legs)Depth

NASA-JSC8.0psiZero-prebreathe suit

Eye (sun ieor up)Eye (sun visor down)Skin(torso)Skin (arms& legs)DepthNASA-ARCAX-5 hard suit

(Without rad. prot.)Eye (sunvisor up )Eye (sunvisor down)Skin (torso)Skin(arms& legs)Depth

(With rad. prot.)Eye (sunvisor up)Eye (sun isor down)Skin(torso)Skin (arms& legs)Depth

400km %x28.5" limit92.1 0.0588.1 0.04101.8 0.03141.5 0.0548.1

Total400 km %x28.5" limit84.1 0.0482.1 0.0498.7 0.0388.2 0.0348.1 0.10Total400 km %~28.5" limit

84.1 0.0482.1 0.0494.4 0.03102.1 0.0347.4 0.09

84.1 0.0482.1 0.0476.1 0.0377.1 0.0343.1 0.09

500km %x28.5" limit353.8 0.18334.4 0.17403.6 0.13579.0 0.19165.1 0.33Total500km %x28.5" limit317.1 0.16305.1 0.15387.5 0.13339.2 0.11164.1 0.33Total500km 8x28.5" limit

317.1 0.16305.1 0.15371.0 0.12405.1 0.14163.1 0.33

317.1 0.16306.1 0.15282.1 0.09284.1 0.09149.1 0.30

250km %x 90" limit24.4 0.0117.9 0.0175.7 0.03362.0 0.1211.4 0.02

Total500km %x28.5" limit16.2 0.0114.1 0.0158.2 0.0224.0 0.0111.4 0.02

rota1250 km 8X 90" limit

15.2 0.0114.1 0.0149.1 0.0280.2 0.0311.4 0.02

15.2 0.0114.1 0.0113.5 0.00513.6 0.00511.2 0.02GCR (galactic cosmic ray) doses included are 4 milliredday at 400 km x 28.5"

4 milliredday at 50 0 km x 28.5"10milliredday at 250km x 90'20milliredday at GEO+Annualdose limits (86NCRP tentative): Depth 50 remEye 200remSkin 300rem

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TABLE .-PRELIMINARY MICROMETEOROID TEST RESULTS

Suit Effective'"' Particle'b' Individualelement area (m? energy (x io7 rgs) P pArmdegs(flex) 1.09 94.2 test) 0.9997788Torso, briefsEVVA shell(nonflex) 0.72 98 calc.) 0.9998597Helmet/visodd' 0.084 31 (test& calc.) 0.9999452

Combined Po = 0.9995838

Conditions:000 OneEMU

500km altitude; 28.5 egree inclination orbit936hours EVA per year (18 ours EVA per week per crewmember)

Notes:(a) Assumes 60percent of exposed EMU area, due to shielding effect of SpaceStation structural elements, workstation, satellites, etc.(b) Energy of particle required for penetration (94.2 lo7 rgs energy is near

upper capability of NASA-JSC gun)(c) Probability (Po) of no lethal hit , i.e., no leak exceeding 0 2 makeup parameters(assumes nonlethal hole size of 0.26 cm; purge flow can maintain suit pressureapproximately30minutes with hole size of 0.39 cm)(d) Visor and helmet thicknesses three times Shuttle helmet thickness (Shuttlehelmet plus protective visor and solar visor combined thickness = 0.5an)

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is that these charges might find their way into electronic circuits of the EMU causing subsequent arcdischarges and disrupting normal operation or possibly disabling them. To provide a conductive sur-face and path for static charges toWeed ob' the EMU, conductive fibers can be woven into the outer-most layer of the ITMG. This should result in a more uniform charge over the ITMG exterior and alsoprovide a safepath for charged particles if the EM U contactsa body of unlike charges (e.g., vehicle orsatellite).

CONCLUDING REMARKSApproximately400 man-hours ofEVA xperience have been accumulated over the past 20 years inspace environments ranging fron near-earth orbit to lunar surface excursions. In al l cases, the pri-mary space sui t environmental protective barrier, the ITMG, has been specifically designed for theunique environmental conditions encountered. Further material and design changes to the ITMGlayup will be required for the various environmental conditions anticipated during forthcomingSpace StationEVA operations.As future space mission plans are developed that encompass longer stay times and diversified types ofEVA perations, including lunar base activities and Mars surface exploration, new environmentalhazards and material requirements will be established for the subsequent development of the nextgeneration of BTMG assemblies.

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BIBLIOGRAPHY1. Fina l Report Ge min i Space Su it Program, David Clark Company, Inc., Worcester, MA, Jun e

1967.2. NASA SP-149;Summary of Gem ini Extravehicu lar Activity, Edited by Regina ld M.

Machell, 1967.3. NASA TN D-8093;Apollo Experience Report - Developmentof the E xtravehicular Mobility

Un it, Charles C. Lutz, Harley L. tutesman , Maurice A. Carson, and Jame s W . McBarron 11,November 1975.

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Figure 1.- Astronaut Ed White (GeminiIV).11


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Figure 2.-Gemini G4C extravehicular space suit .

ORIGINAL PAGE IS12 OF POOR QUALITY


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Gemini Y IU E V A coverlayere min i IY EV A coverlayerconstruction construction

Coated ny lon inne rstopper layers

2Total weight = 33.9 ozlydTotal thicknes s 0.200 in .

Total weight = 26.3 oz/yd2Total thickn ess - 0.037 in.

Figure 3.- Comparison ofGem ini IV and G emin i VI11 extraveh icular coverlayers.

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Figure4.-Gemini ironpantsITMG.

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ORIGINAL PAGE ISOF POOR QUALITY

Entrance cbsure Material function1 Function2 Junction3PLSS abrasion palches Rubkr-cmlrd nybn Inner linerlripslopl

micromeboroidcross vct inI4 Iaprs) laytr section prokclionAluminized Kwbn ThermalfilmlBela radiation

(2 laytrs)Tefbn-waW Nonflammbk andfilament Beta cbth abrasion protectionTeflon cblh Nonflammlk

laytrabrasionpatches

Pressureg q t merTorso djustmenl slrw merEnlrance cbrure

'Alternaling laytrsof inrulalion an d spacer.

pockel

(a) Lunar integrated therm al/ (b) Material cross section for ITMGmicrometeoroid garm ent. (Apollo 11 to 14 missions).Figure 5.-Apollo ITMG cross section.

Liner and insulation assembly7

Right boot

Figure 6.- Lunar overboots.

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ORIGINAL PAG-E ISOF POOR QUALITY;

Figure9.-Astronaut Aldrin (Apollo 11).

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SIZED BETA MARQ.L K R I W L E D K A P TO N FILM

NEOPRENE COATEDNYLON R I P S T O P

1/ 2 MIL ALUMINIZE0 CRIDDE

A718 - APOLLO

T l b 2 TEFLON FABRIC4484 BE TA CLOTH

SIZED BETA MARQ.ISCHRIMI1/2 MIL AL .GRIDDED K A P T D N FlLU

SIZED BETA MAW.lL? MIL AL.GRIDDED N A P T O M FILMI

N O W W E N DACRONNEOPRELE COATEONY LW RI PS TOP

N O W W E N D AC RO Y

114 MIL AL.

N O W W E N D A C RO N

Figure 10.-Skylab vs. Apollo ITMG crosssections.

19ORIGINAL PACZ IS.OE POOR QUALI TY


24/29

.P

dc

20


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,ORIGINAL PAGE IS.OF POOR QUALITY

Figure12.- huttleEV glove.

21


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n

Figure 13.-ShuttleEV A (ease/access).22


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THERMAL/ABRASION0 THERMAL RADIATION0 THERMAL CONDUCTIVITY0 SHARP CORNERS

1 I CRO-METEOR0 I(a) Basic protective features.

CHEMICAL PROTECT ON0 PROPELLANT HAWDLING

RADIATION PROTECTION0 PROTONS 8 ELECTRONS

ELECTRO-STAT I C CHARGEPROTECTI N

EXTENDED SERVICE LIFE

DEBR IS IMPACT PROTECTI N

ATOMIC OXYGEN (?I

(b) Specialized protective/construction features.Figure 14.-AdvancedITMG pecialized requirements (Space Station).

23


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ORIGINAL PACE TSOE:POOR QUALITY

.-

RADIATION IN LE O DEP ENDS O N ORBIT TRACK

Figure 15.- Orbital paths (radiation).

24 U.S. GOVERNMENT PKINTING OFFICE 1987-761-013 /60428


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1 Report NoNASA TM 100458Space Suit Extravehicular Hazards Protection Development

2 Government Accession No. 3 Recipient's Catalog No

August 19876. Performing Organization Code

4 Title and Subtitle 5 Report Date

I 11. Contract or Grant NoLyndon B. Johnson Space Center

7 Author(s)Joseph J . Kosmo

9 Performing Organization Name and Address

481-89-00-00-728 Performing Organization Report No

S-56510 Work Unit No.

I

National Aeronautics and Space AdministrationWashington, D.C. 20546

Houston, Texas 7705812 Sponsoring Agency Name and Address

14. Sponsoring Agency Code

NA13 Type of Report and Period Covered

Technical Memorandum

15 . Supplementary Notes

19 Security Classif (of this repo rt) 20 . Security Classif (of this page) 21 No of pages

16. AbstractThis paper presents an overview of the development of the integral thermal/micrometeoroid garment (ITMG) used forprotection of a space-suited crewmember from hazards of various extravehicular (EV) environments. These hazardconditons can range from thermal extremes, meteoroid and debris particles, and radiation conditions in near-earth orbiand free space to sand and dust environments encountered on lunar or planetary surfaces. Representative ITMGmaterials cross-section layups are identified and described for various space suit configurations ranging from the Gemiprogram to planned protective requirements and considerations for anticipated Space Station EV operations.

2 2 Price'

17 . Key Words (Suggested by Author(s))0 Spacesuits0 Extravehicular Activity0 Integral Thermal/Micrometeoroid Garment

18. Distribution StatementUnclassified - Unlimited

Subject category: 54

space suit extravehicular hazards protection development

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