IAG09.B6.3.6

21 St CENTURY EXTRAVEHICULAR ACTIVITIES:SYNERGIZING PAST AND PRESENT TRAINING METHODS FOR FUTURE

SPACEWALKING Si"CCESS

Sandra K. Moore, Ph.D.United Space Alliance, LLC

600 Gelrlini, Houston TX ; 77058-2783 ;USAsandra.k.moore@rasa. gov

Matthew A. GastUnited Space Alliance, LLC

600 Gelrlini, Houston TX, 77058-2783; USAlnatthew.gast-1 @nasa.gov

Abstract

Neil Armstrong's understated words, "That's one small step for man, one giant leap for mankind."were spoken from Tranquility Base forty years ago. Even today, those words resonate in the ears ofmillions, including many who had yet to be born when man first landed on the surface of the moon. Bytheir very nature, and in the tnie spirit of exploration, extravehicular activities (EVAs) have generatedmuch excitement throughout the history of manned spaceflight. From Ed White's first space walk in Juneof 1965, to the first steps on the moon in 1969, to the expected completion of the International SpaceStation (ISS), the ability to exist, live and work in the vacuum of space has stood as a beacon of what ispossible. It was NASA's first spacewalk that taught engineers on the ground the valuable lesson thatsuccessful spacewalking requires a unique set of learned skills. That lesson sparked extensive efforts todevelop and define the training requirements necessary to ensure success. As focus shifted from orbitalactivities to lunar surface activities, the required skill-set and subsequently the training methods, changed.The requirements duly changed again when NASA left the moon for the last time in 1972 and havecontinued to evolve through the Skylab, Space Shuttle ; and ISS eras. Yet because the visits to the moonwere so long ago, NASA's expertise in the realm of extra-terrestrial EVAs has diminished. As mannedspaceflight again shifts its focus beyond low earth orbit, EVA success will depend on the ability tosynergize the knowrled^e gained over 40+ years of spacewalking to create a training method that allowrs asingle erewmember toyperfonn equally well, whether perfonnina an EVA on the surface of the Moon,while in the vacuum of space, or heading for a rendezvous with Mars. This paper reviews NASA's past andpresent EVA training methods and extrapolates techniques from both to construct the basis for future EVAastronaut training.. Copyright ©2009 by United Space Alliance, LLC.

Introduction

One of the most exhilarating exercisesconducted during a space flight occurs when ahuman leaves the protective environment of hisor her pressurized spacecraft to work in thehostile vacuum of space. Extravehicularactivities (EVAs), or spacewalks; are a provencapability for meeting mission objectives, bethey lunar sample collection or the constructionof the International Space Station. Additionally,EVAs are an essential element to the futurehuman space programs. Successful EVAsdemand an array of complex technical skills, the

use of advanced technologies, and an acuteability to adapt to changing requirements Asspace-faring nations race to return to the lunarsurface, and future human space endeavors willtake mankind beyond, to Mars and other extra-terrestrial destinations. great care must be takenin plalnling EVAs and in the training of thecrews. An ever-increasing EVA capability hasbeen developed over time, by progressivelycombining lessons leamed from previousmissions with current state-of--the-art technology.As focus shifts outside low earth orbit, the EVAoperations conununity must becomereacquainted with past training philosophies; to

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cull the lessons learned that will be critical toachieve future success and ensure crew safety.

This paper highlights the evolution and lessonslearned from NASA's EVA Task trainingprograms within the overall mission objecti^-•esof Gemini, Apollo, Skylab, Shuttle, and the ISS,and extrapolates effective techniques to constrict

a basis for future EVA astronaut training.

Philosophy on EVA Training

Fonnal EVA training for theInternational Space Station and the space shuttletoday is conducted by the National Aeronauticsand Space Administration (NASA) MissionOperations Directorate (MOD) EVA branch.This branch is responsible for the instruction,plamiing; and execution of any and all activitiesassociated with spacewalks. Current EVAtraining is divided into two major categories:EVA Systems and EVA Tasks. EVA Systemsresponsibilities consist of the extravehicularmobility unit (EMU), or spacesuit, airlockoperations, and the service and maintenanceequipment for this hardware. EVA Task trainingis comprised of generic and flight-specifictraining on the spacewalking activitiescrewmembers will be performing on orbit; aswell as comprehensive training on the tools andhardware that are utilized during EVAs.

The Gemini Program (1965-1966) Beginner'sLuck and the Dangers of EVA

The Genuni Project was designed tobridge the gap of understanding between theMercury and Apollo programs in criticalsituations including precision guidance,navigation; re-entry, and extravehicular activity.The fortunate decision to equip Geminispacecraft with hinged, full-opening ejectionhatches unlocked the door to U.S. EVAcapability (Wilde et. al. 2002).

The first plaimed EVA called for acrewmember to open the spacecraft hatch and"simply stand up" with his shoulders exposedoutside the hatch perimeter. In November of1964, Young & Grissom demonstrated theconcept in a simulated altitude chamber at150,000 ft wearing a prototype EVA pressurizedsuit (GEC). The test wras a success; despite a bitof trouble encountered while attempting to closethe hatch. This accomplishment allowed forserious plaiming of the first U.S. EVA onGemini 4 (Shayler, 2001).

One month earlier, Commander JimMcDivitt and Pilot Ed White began evaluatinginitial EVA suit concepts in preparation for EVAhatch "ingress" training using a Gemini mockupin a low gravity airplane,y NASA's KC-1 ^5(Wilde et. al. 2002). The parabolic flight of theaircraft was employed to achieve 27-^0 secondinter-als of microgravity. With practice, theGemini-Titan III and IV crews became adept atentering the spacecraft and closing the hatch in atimely manner, wearing a spacesuit and chestpack under these microgravity conditions(Weekly Activity Report. Jan. 10-16, 1967, p. 1;Consolidated Activity Report, January 196.5, pp.12, 16.). By December, the crew beganevaluating the first EVA suit prototype (G4C)for mobility in low gray-•ity KC-1 ^_5 tests.Surprisingly, the crew found that the suit was tooheavy and impeded movement. Engineers wereable to remove excess bulk and the crew deemedthe suit satisfactory for EVA use in February(Wilde et. al. 2002).

Altitude chamber tests of the Geminispacecraft IV began in late March of 1965,involving five simulated flights at McDonnell.The first run was unmanned. In the second non,the prime crew flew a simulated mission; but thechamber was not evacuated. The third runrepeated the second with the backup crewreplacing the prime crew. The fourth nui put theprime crew through a flight at simulated altitudeand the fifth did the same for the backup crew.Altitude chamber testing ended March 25 and thespacecraft was prepared for shipment to CapeKennedy (Mission Report for GT-IV, p. 12-22;Weekly Activity Report, Mar. 21-27, 1965, p. 1)

The first stand-up EVA was originallyplamied for December of 1965; however, the LJSEVA coimnunity was spurred to speed up theirtimetable after it was learned that Russiancosmonaut Alexi Leonov performed the firstEVA on March 18 ; 196>. Two weeks later ; thepossibility of doing more than the previouslyplanned stand-up form of extravehicular activityeras introduced at an informal meeting in theoffice of Director Robert R. Gilruth at MannedSpacecraft Center (MSC), now the NASAJolmson Space Center (JSC). Engineers ensuredthe director that the new EVA equipment wouldbe ready in time for the upcoming June launch.When the news reached Washington regardingthe hardware's flight-readiness, it quicklyprompted Headquarters final approval.

EVA task training continued forcrewmember Ed ^t%hite, and included practicingthe "stand-up EVA" in the altitude chambers, as

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well as training with a Hand-Held Self- --^

Maneuvering Unit (Figure 1) on an air bearingfloor (FigLUe 2) and aboard the KG135 lowgravity aircraft.

Figure t. Hand-Held Self-Maneuvering Unit to be usedduring extravehicular activity (EVA) on Gemini 4 flio-lrt onthe front of the unit. Photo from JSC Digital linageCollection, PHOTO ID 5 65-2 73 3 1. takers 06-02-1965.

EVA in bldg 4 of the Matured Spacecraft Center on the airDearing floor. Photo from JSC Digital Image Collection,PHOTO ID 565-19501. taken 03-29-1965.

NASA's foray into the world of EVAfinally corrtrnenced when Ed White ventured outof the Gemini IV capsule on June 3, 1965 and"floated" at the end of a 25 foot golden umbilicalfor approximately 22 minutes. Although theterm "spacewalk" was coined for the GeminiEVA program, no actual walking took place.The endeavor proved successful when Whiteeffectively demonstrated a small handheld jetcalled the Hand Held Maneuverins Unit(HHMU), which he used to propel himselfthrough space. Figure 3 is an irnaae of AstronautEdward H. White II, pilot for the Gemini-TitanIV space flight, floating in the vacuum of space.

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^yy1 --Figure 3. Astronaut Edward White daring first EVAperformed during Gemini 4 flightwww. starshipmodeler. c orn/real/ed_white_eva . jp g

White's success thrust NASA onto aneven playing field with Russia and paved thewray for eight additional Getnini EVAs. They didnot, however, all ^o as smoothly as the first, andNASA quickly discovered that White's successwas just beginner's luck.

The second U.S. EVA was conductedby crewmember Eugene Cernan on Gemini XIII.Due to the success and ease of White's EVA,Cernan's EVA task training flow wascomparable. Figure 4 shows Astronaut EugeneA. Cernan during tests with the AstronautManeuvering Unit (AMU) conducted inChamber B, Environmental Test Laboratory,Building 32 of the Manned Spacecraft Center inHouston, while Figure 5 illustrates Cernandonning the Astronaut Maneuvering LJnit(AMU) back pack after egressing a Geminimock-up under nucrogravity conditions aboard

the KC-135.The unrealized but inherent difficulties

and dangers of perfornung an extravehicularactivity was first experienced during just thesecond U.S. EVA mission as Eugene Cernandemonstrated the use of ajet-propelled backpackon Gemini IX-A (June 6, 1966). Instead of usingthe HHMU that White had used to control andmaintain his body position, Cernan evaluated theuse of handrails, Velcro patches, and loop footrestraints. Cernan found these crew aidsinadequate for controlling his body position. Ashe flailed, he broke off an experimental antennaon the Gemini IX spacecraft and tore the outerlayer of his suit. Furthermore, Cernan's physicalexertion increased his metabolic rate such thatthe resulting moisture overwhelmed thecapabilities of his AMU, causing his helmetvisor to fog over, effectively blinding him. Atthis point the EVA was ternunated. Upon

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returning to Earth, Cernan repeated the EVA inthe Water hnmersion Facility (WIF), a pool 4m(16 ft) deep, by 8.5 m (28 ft) in diameter, housedat the Johnson Space Center (JSC). He reportedthat the neutral buoyancy simulation was nearlyidentical to actual EVA conditions. Cernan'sexperience laid the groundwork for usin g neutralbuoyancy as an effective EVA training tool(Portree &Trevino; 1997).

^^-.^ ^^^Figure 4. Astronaut Eugene Cerna^r during tests in CharnherB with AMU Photo from JSC Di gital Hnage Collection.PHOTO ID 566-27376, taken 02-19-1966.

Figure 5. Astronaut Eugene Ceman durnrg training withAMU on the KC-135 low gravity aircraft. Photo from JSC:Digital Hnage Collection, PHOTO ID S66-31665, taken 05-03-1966.

During Gemini XI, crewmemberRichard Gordon attempted to perform the U.S.'sfirst "complex" EVA with several planned tasks,including the relocation of the attachment of a30m (100 ft) tether stowed on Agena 11 toGemini XI's nose, the retrieval of an S9 nuclearemulsion scientific package ; and the testing of anumber of EVA tools including the "goldenslipper" foot restraint. an HHMU, and a"torqueless" power tool. GVhile relocating thetether attachment, Gordon found that the G4Cspacesuit's internal pressure forced his legs

together, preventing him from attaching thetether to the nose Of Gemini. This experiencewas counter to his training aboard the zero-gaircraft, and this simple task that he hadperformed during short bLlrStS Of parabolic-flightinduced microgravity took him 30 minutes toaccomplish on orbit in a pressurized suit. LJpuntil this point, neutral buoyancy training hadnot been ^--•iewed as necessary training for EVAtask operations; and thus Gordon had spent littletime training Luldenuater despite thereconnnendation of his colleague. Iu space,however. Gordon had found it very difficult towork in the pressuUized suit, and upon return hepassionately encoLUa^ed Apollo surfaceastronauts to practice any and all required EVAtasks in pressurized, suited training events(Portree &Trevino, 1997).

Hence, before the next attempt of a"complex" EVA on Gemini XII, crewmemberEdwin "Buzz" Aldrin conducted five neutralbuoyancy training sessions in addition to therequired microgravity EVA aircraft training.Aldrin also trained with the near innnobility ofthe stiff G4C suit in the Thermal Vacuumchamber at NASA's MSC. It was this extensivetraining that enabled Aldrin to easily performmany of the tasks Gordon had attempted andseveral additional tasks, including cutting cableand fluid lines, fastening rings and hooks, andtightening bolts. In all, project Genuni missionsinvolved nine EVAs for a total of 12 hours and22 minutes of EVA experience.

The Gemini EVAs, althou gh at timesplagued with problems, demonstrated thefeasibility of employing humans in free space toaccomplish tasks (Newman, 2000). From theseearly EVAs came several key lessons:1. Tasks were found to take loner on orbit

than observed in training. y2. Umbilicals were useful for EVA.i. Loose items must be tethered to prevent

loss.4. Body and foot restraints are important to

maintain body position.5. Underwater simulation training led to higher

success rates on orbit.6. Training in a pressurized suit was important

for situational familiarization and increasedstrength and endurance.

Apollo EVAs (1967-1972)

Two primary objectives for the Apolloprogram were to land safely on the moon and toexplore its surface through a series of

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increasingly complex EVAs. In all, six lunarsurface missions were accomplished with 14successful EVA sorties. Thus the EVA evolvedfrom an experimental activity to a useiiil,functioning exploration mode. During ApolloEVAs, twelve crew members spent a total of 160hours in spacesuits on the moon, covering 100kilometers (60 miles) on foot and aboard thelunar rover; and ultimately collecting 2196 soiland rock samples (Newman. 2000). y

Apollo EVAs differed from GeminiEVAs in four distinct ways. First, Lunar EVAswere remote from the host vehicle. Thisprovided crewmembers a vast exploration area,but the added mobility introduced therequirement of a portable life support system, asthe tethered umbilical was far too restrictive. Italso required the EMU be capable of providing awarning of a pending consumable linutation anda subsequent plan of action to rettun to thevehicle. Second, the lunar EVA environmentwas significantly different than the microgravitymilieu of Gemini. The Lunar surface is dusty,abrasive, and experiences a significantly varyingtemperattue, all of which would playsignificantly into the design of the spacesuit. Inaddition; the reduced gravity (--1/6 g) wouldrequires the crewmembers to bear a fraction ofthe EMU weight. Third, llmar explorationspacewalks involved walking instead of floatingin nucrogravity ; and thus were high-metabolicEVAs. Finally, the aggressive objectives of theApollo program were unprecedented incomplexity, requiring the development of newtechnologies, tools, and extensive 1-G trainingfor the EV crew (Widle et al. 2002).

Due to these vast differences, NASAdesigned a comprehensive program forconducting lunar EVAs. Lunar surfaceastronauts studied geology and took lield trips tosites on Earth thought to possess similartopography as the landing locations on the moon(e. g. Meteor Crater in Arizona). Also, a partialgravity simulator was developed by using an 81°inclined surface on which lunar EVA teamswould walk, utilizing a suspending harness tooffload excess weight. The resultant forceallowed crew to simulate the Moon's 1/6thgravity. KC-135 parabolic flight training wasalso completed for additional practice in a lowgravity, hu^ar simulated environment.

Another training modality used to trainlunar EVA crew was MSc's 5-acre outdoor"rock pile," where suited crewmembers practicedwalking and collecting geological samples.During some training events, a tnick-mortared;

air-actuated weight support system termed"pogo" was employed to simulate lunar gravitylevels. Later, Apollo crews practiced driving thelunar rover over the variety of simulated terrainfoLmd at the "rock pile."

Finally, neutral buoyancy training inJSC's Water Innnersion Facility (WIF) wasexploited for specific task training. These tasksinculded contingency clearing of the hatch andfor egress and ingress of the lunar module(Wilde et a1.2002).

As suggested by Eugene Cernan, asignificant portion of EVA training that wasdeveloped during the Apollo program focused onthe familiarization and use of tools in apressurized glove. The selections of tools usedfor the specific tasks to be perfom7ed werechosen during the planning phase of each

mission and specialized tools were developedwhen existing tools proved insufficient.crewmembers trained tool manipulation in the 1-Genvironment as well as in the pressurized suit.Many of the tools used EVA can be found in atraditional toolbox; however, handholds andtethers present some unique features.

The first lunar surface EVA wasaccomplished by Neil Armstrong and Edwin"Buzz" Aldrin in the Southern Sea of Tranquilityon July 20, 1969. Unlike previous EVAs, thefirst steps of a man on the moon were witnessedby approximately 600 million people watchingthe live television broadcasts. crewmembersArmstrong and Aldrin collected rock and soilsamples; planted a US flag; captured videoimagery, and deployed EASEP (Early ApolloSurface Experiment Package). Similar to thespacewalkers before them, Armstrong and Aldrinfound that even the best EVA training was nosubstitute for actual experience. The crewreported loping as the preferred method ofmovement. and that lunar dust quickly coveredeverything and was quite slippery. Armstronglater reported that the 1/6th partial-gravitytraining back on Earth was actually morestrenuous than the 1/6 g-levels experienced onthe 1LUiar surface. Additionally, like many of theprevious EVA experiences, surface activitiestook longer than expected.

A collection of lessons learned wasgathered from eight of the surviving ApolloEVA crewmember by Conners et al. 1994 toinfluence the planning of future lunar EVAexploration. The results of the sun-ey can besummarized as follows:1. Integration of crew, equipment, and

facilities should be viewed as a total system.

2. In subsystem design, simplicity andreliability are preferred over functionality.

^. In future EVA missions there should be ageneral movement toward increasinglygreater crew autonomy. The on orbit crewshould take a larger role in monitoring theEVAs by assuming primary responsibilityforsome of the activities previouslyperformed by flight controllers back inMission Control.

4. Due to the length of future missions, thecrew timeline should not be tightlyscheduled.

5. A two man team, as used for Apollomissions, is the desired basic unit ofexploration; however larger numbers may beappropriate in some cases.

6. Baseline EVAs should be 7-8 hours induration; however, when and how manyEVAs to be conducted (i.e. one day on oneday off) should not be predetermined.

7. When considering suit design, the majordriver should be suit flexibility and mobility;erewmembers suggested that the suit hug thebody like a second skin.a. Crew placed significant emphasis on

improved glove development8. EVA preparation is necessary. but it should

be concise and productive; combine eventswhenever possible.

9. Lunar dust is ubiquitous; keep EVAequipment separate from living quarters; usedust repelling equipment.

10. Install automation where appropriate (i.e.automatic suit check out).

11. Rovers are useful for translating with tools.12. Equipment should be designed to tit the

task, not vice versa.13. When it comes to training, train the crew

hard.a. The crew should train under realistic

conditions (1/3 or 1/6 g) wheneverpossible.

b. The crew should train to the mission,including contingencies; practice isimportant for performing under adverseconditions. y

c. Sustained mental performance is thetoughest training issue; as well asinterpersonal relations during lengthynussions.

d. The crew should train with tools of thesame wei ght and stiffness as would beused on the hmar or planetary surface.

e. The crew should maintaining their ownequipment during the training process.

£ The crew should train in the pressurizedsuit and for an extended number ofhours.

g. The crew should train for the mission asan integrated whole and not just insegmented parts.

Skylab EVAs (1973-1974)

The Skylab program proved to beinstrumental in demonstrating the power ofextravehicular activity in married spaceflight.Skylab was NASA's first space station. It waslaunched in 1973, six months after the lastApollo Moon landing. In order to have thefunctionality to replace one or all crew at amoment's notice, spaceflight training increasedsignificantly for the Skylab (SL) astronauts.Required EVA training alone was increased toapproximately 156 hours: 1-G events varied bycrew (108 hours for SL (2), 127 hours SL (3);and 119 houus for SL (4)) as did the underwatertraining in the Neutral Buoyancy Simulator(NBS) (48 hours (SL 2), 57 hours for SL(3), and42 hours for SL (4)) (Shayler, 2001 [2]). TheNBS at Marshall Space Flight Center (MSFC), inHuntsville, Alabama, was utilized to trainspecific EVA tasks, including the installationand removal of film ma gazines and the recoveryof samples left outside for experimentation. TheNBS was also used extensively to develop thecomplicated procedures for deploying SkyLab'ssolar sail and sun-shield, and it proved to be avaluable tool for developing and refining genericEVA techniques (Shayler, 2001 [2]). In additionto the NBS, low gravity parabolic flights werestill used to train specific EVA techniquesincluding microgravity maneuvers ; tumble andspin recovery; and the specific EVA task ofexchanging film magazines.

Extravehicular activity becamesignificantly important to the Skylab programfrom the moment it launched. One nunute afterlaLUich, SkyLab's micrometeoroid shields rippedaway from its outer surface prematurelydeploying six solar panels. This resulted insevere damage to one and complete loss of solararray 2 due to atmospheric drag. The powergenerated by the remaining panels wasinsufficient to keep thethe station functional, andto add to the concerns ; the station beganoverheating due to the missing shield. Theprogram hinged on the ability of the first threecrewmembers to repair the damage. AstronautPaul Weitz ventured out of Skylab on the firstEVA in a modified, umbilical Apollo EMU to

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try and free the jammed solar array. Using thetools available on orbit, Weitz attempted todislodge the jammed array while Kerwinattempted to stabilize him by holding his feet.To no avail. the crew became concerned that thetask could not be accomplished with toolsaboard.

A plan was quickly developed by EVAtrainers on the ground and uplinked to the crewaboard Skylab. EV crewmembers Joesph P.Ker^^in and Charles "Pete" Conrad fabricatedtools from onboard materials and rehearsed theplan inside the module. Once outside, Kerwinfound Skylab differed from the ground mock uphe had trained on in the water tank in Huntsville.The foot restraints were not in the positions hehad expected, and he was forced to hold on withone hand while attempting to position a "pole-like" cable cutting release tool with the other.During an EVA of 3:25 ; and using all theirstrength and their fabricated tools ; Kerwin andConrad successfillly released the januned solararray, providing much needed power to the

Figure 6. An Artist Concept showing Astronaut CharlesConrad Jr., Skylab lI Commander, attempting to free theSolar Anay System wing on the Orbital Workshop duringExtravehicular Activity (EVA) at the Skylab 1 Rc 2 SpaceStation cluster in Earth orbit. The Astronaut in thebackground is Joseph P. Kerwin. JSC collection: 573-27508.jpg httu://io.isc.nasa.sov/aoU/info.cfur'?pid=308350

The success of the Skylab EVAsconvincingly demonstrated the need for EVAcapability on married spacecraft. Extravehicularactivity literally saved the Skylab program. Inaddition; the Skylab highlighted that humanpresence in space offers many advantages to

ensure mission success including flexibility anddexterous manipulation; human visualinterpretation, cognitive ability, and real-timeapproaches to engineering problems. SkylabEVAs also demonstrated the importance of amanned space crew's ability to:1. Be flexible and trained with a generic set ofEVA skills.

2. Have multiple crewmembers who are EVAqualified.3. Be able to think and innovate solutions whenneeded.4. Have mockup and training modalities be asaccurate as the flight hardware.

In all, Skylab astronauts logged 17.5 hours ofplamied EVA and 6.5 hours of unplanned EVAfor the repair of the station.

Space Shuttle EVAs (1981- Present)

When Apollo XVIII and later missionswere cancelled, the Space Shuttle was still in theconcept phase. In 1969, NASA envisioned theshuttle as a reusable vehicle that would performcrew transfer, cargo delivery, and satellitedeploylnent and capture. Initially, EVA wasviewed only as an option in emergencies;however, as the program evolved, EVA emergedas a major component. As NASA's directionchanged from launching expendable vehicles tousing a reusable orbiter with solid rocketboosters, so did the direction of the EMUdevelopment. Engineers began designing areusable, modular EMU with a stock of standard-sized parts that fit a wide range of crewmemberanthropometrics.

From 1983 through 1985, 13 two-person EVAs were performed during the use ofthe Shuttle Transportation System (STS), ormore commonly called Space Shuttle missions.The first shuttle EVA (and first EVA sinceFebnlary 1974) was a 4 hour and 10 minexpedition to test the new STS (ShuttleTransportation System) EMU and EVAequipment during STS-6 on April 4, 1983(Portree &Trevino, 1997). Astronauts StoryMusgrave and Donald Peterson evaluated theSTS EMU mobility by translating aft along thehandholds inside the payload bay door hinge andassessed the contingency EVA proceduresdeveloped for shuttle (Figure 7). Since the firstshuttle EVA, shuttle crewmembers haveaccomplished many tasks lncludingdemonstration of the Manned Maneuvering LJnit(MMLJ), the Remote Manipulator System,^and aspecialized tool for the capture and berthing ofsatellites and other space structures.

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Figure 7. Story Musgrave translates down the Challenger'spayload bay door hinge line with a bag of latch tools.http://images.jsc.nasa.gov/luceneweb/fiillimage.j sp?photoId=583-3021?.

Many unique challenges are faced by EV crewsduring microgravity spacewalking missions inthe EMU. These challenges include:1. Reduced visibility due to changes inillumination, contrast, and field of view_2. Reduced sense of orientation due to changesin vestibular stimulation.3. Reduced range of motion due to limitation ofthe extravehicular mobility unit (EMU).4. Compromised strength due to fatigue (mostsignificantly hand fatigue), hardware design, andadaptation to weightlessness.(Ricco et. al, 1997)

To combat and overcome these andother challenges faced during shuttle EVAs, thedevelopment of the EMU ; EVA support tools(i.e., foot restraints, handholds, and specializedtools), and EVA training are credited with thereduction in Shuttle mission workloadNeuman,2000). and specialized EVA training facilitieshave been developed and advanced to aid

continued work efficiency.

Special EVA Training Facilities for Shuttle

Special EVA training facilities haveevolved to help develop and nurture the skillsrequired for EVA. An ideal EVA trainingfacility is one that completely and accuratelysimulates all of the conditions that will beencountered during a mission includingtemperature, pressure, lighting, and microgravity(Thuot and Harbaugh, 1995). The microgravitymilieu of low earth-orbit is difficult. if notimpossible, to fully model in a 1-G environment.Textbooks, classes, and numerous speciallydesigned facilities are utilized to replicatemicrogravity; and these training tools are used inconcert to develop a specific skill set employed

by shuttle and International Space Station (ISS)EVA crewmembers. In addition, present trainingfacilities employ high-fidelity hardwaremockups, worksites, and tool locations.

There are a number of major facilities,all housed at JSC, that are utilized during EVAtraining today. They include the Space VehiclesMockup Facility (SVMF), the Sonny CarterTraining Facility, the Neutral BuoyancyLaboratory (NBL), the Virtual Reality (VR)Laboratory; as well as vacuum chambers, aprecision air bearing floor (PABF), and the DC-9low gravity aircraft.

The SVMF consists of full scalemockups of the International Space Station, theShuttle, and other trainers pertinent forspaceflight training. These modules arecoimnonly high-fidelity from a visual standpoint,but are limited in their actLial functionality.From ui EVA task perspective, the SVMF isused to train EVA equipment transfer fromshuttle to station post-docking, in preparation forthe actual spacewalks, fluid quick disconnectoperation for installation of critical equipment onorbit, repair of the Orbiter's thern^al protectionsystem (TPS), and other shuttle contingencytasks that require high fidelity training hardware.EVA skills are also taught at the SVMF, usingthe Partial Gravity Simulator (PGS, aka"POGO") and a precision air bearing floor(PABF). PGS (Figure 8) and PABF areemployed to simulate zero-G and to accentuatethe effects of Newton's Laws of Motion. Similarsystems were originally developed and utilizedduring Apollo and Gemini training, and are stillused for certain EVA skill applications today. Inthe PGS ; a crewmember is suspended from anactive pneumatic system that provides a verticaldegree of weightlessness. The PGS also slidesalong g low-friction rail ; giving a second degreeof freedom in the horizontal direction. PGS ismost often used to teach crewmembers how tostabilize themselves and react the forcesgenerated by the tools they use, such as thetechnique for reacting the torque generated bythe Pistol Grip Too1V (PGT), a "cordless-drill"type tool designed to drive bolts.

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Figure 8. EVAfrom PGS.

Neutral Buoyancy Lab (NBL)

instructor Matthew Gast developing an EVAtimeline for STS-128!'17A in the NBL.

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As previously discussed, NeutralBuoyancy training dates back to the nud 1960'x;after Eugene Ceman had difficulty executingEVA procedures on orbit despite completing therequired low gravity tra1111I1g achieved withparabolic fli^htV in the KC-135 aircraft. Fromthat lesson learned, EVA instructors realized thatastronauts needed longer than the 30 seconds ofweightlessness achieved dllring each parabola toadequately train for Et%As, so they exploredtraining EVA tasks underwater. It was quicklyapparent that neutral buoyancy training reducedpart task training, increased both integratedtraining and the overall training quality, andprovided better timeline fidelity. y

The Sonlly Carter Neutral BuoyancyLaboratory; located at the NASA Johnson SpaceCenter, has become the primary EVA trainingfacility for EVA tasks and skills. Constructionon the gigantic water inunersion facility began inthe mid 1990'x. The NBL pool is 202 ft inlength; 102 ft in width, 40ft in depth, and holds6.2y nullion gallons of water. Since 1995, thelaboratory has been employed for crew trainingand for EVA procedure and hardwaredevelopment. The ilrllnensity of its size isessential; the vastness of the NBL allows anEVA crew to perform valuable end-to-endtimelined runs, mimicking entire spacewalks.Task choreography can be revised repeatedly, sothat when a crew finally performs the timelinefor real on orbit, the spacewalk has beendesigned for maximum efficiency.

The NBL acconunodates both full-sizedShuttle and ISS mockups, multiple controlrooms ; an environmental control system, acolmnunication system, a water treatmentsystem, closed circuit TV's, cranes and aspecialized diving medical treatment facility(Figure 9). Figure 10 shows EVA Task

Figure 9. linage of ISS mockups in the Neutral BuoyancyLab.

Figure 10. EVA Task Instn^ctor Matthew Gast evaluating uiupcoming EVA timeline for STS-128

Virtual EVA

Virtual reality (VR) technology allowscre^t^xrlembers to interact with a computer-simulated exterior environment of the SpaceShuttle and ISS. VR training aids for spacewalkpreparation began in the 1990x. The NASA JSCVR laboratory possesses two VR stationsconsisting of a 3D display headset, EMLJ gloves,and an EMU Display and Control Modulemockup. In this 3-D virtual world ; the crew cantranslate anywhere on the shuttle or ISS bysimplygrabbing from one handrail to the next, orbe virtually translated via the station robotic ann(Space Station Remote Manipulator System orSSRMS). Figure 11 shows Astronauts John"Danny" Olivas and Christer F1lglesang trainingfor EVAs on STS-128;`17A in the `''R lab.

In addition to the visual simulation ofthe space station, robotic arms, or shuttle, the VRhelmet/glove combination can be employed witha robot named Charlotte to accurately simulatethe zero-g Inass handling characteristics of lameorbital replacement units (ORUs). Olivas and

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Fualesang used Charlotte to train the removaland replacement of one of the largest ORU everhandled by EV crewmembers on orbit, theArnlnonia Tank Assembly (---1850 lbs).

Finally, the VR facility is used to trainEV crewmembers in the use and operation of theSimplified Aid For EVA Rescue (SAFER), acrewmember-controlled continency systemused for self-rescue, should the crewmemberbecome disconnected from structure. TheSAFER is aself-contained, gaseous nitrogen,propulsive backpack self-rescue system thatprovides an EV crewmember with self-rescuecapability for any ISS-based EVA. This traininginvokes separating a crewmember fromstricture in the virtual world, and then requiresthe crewmember to use the SAFER to conduct aself-rescue. Due to the limited quantity ofgaseous nitrogent propellant, a crewmembermust become proficient at self-rescue or riskexhausting SAFER propellant before rehtrning tostructure.

Figure 11. Ashonauts Damry Olivas and Christer Fuglesandtrain for their upcoming EVAs on STS-128. Photo front JSCDigital Iutage Collection, PHOTO ID JSC2009e1208^

Computer Based Training (CBT) andImaging Software

In addition to training facilities, stand-alone computer based teaching programs andreview modules have proven to be effective toolsin training, and for review on long durationmissions since the STS program. CD ROMs andother computer based training elements werefound to be very beneficial to aid crews in re-plamiing mission objectives, reviewing EVAtechniques that had not recently trained, andevaluating task-specific body positions. One ofthe lnost effective is Dynamic OnboardUbiquitous Graphics (DOUG). DOUG is 3-Dcomputer imaging package utilized by both theRobotics and EVA training teams to aid inplanning and training spacewalks. Its package

contains ^-D models for the ISS ; Space Shuttle,and several EVA tools. crewmembers oftenutilize DOUG onboard the shuttle and ISSduring procedure review before an upcomingEVA, to visually wralk through the translationpaths and worksites.

Hubble Space Telescope 1Llissions

One accolade of U.S.Space ShuttleEVAs are the Hubble Space Telescope (HST)missions. HST, deployed from the Space Shuttlein 1990, was designed for periodic servicingmissions to enable maintenance, repair, andenllancement. Since its launch, there have beenfive highly successful HST EVA-intensivemissions: STS-61 in December 1993, STS-82 inFebruary 1997, STS-103 in December 1999,STS-109 in March 2002. and the last scheduledservicing mission, STS-125, in May 2009. EVAtasks on these missions ranged from changingout small data recorders to large telephonebooth-sized new instruments. Successfullyoverconung challenges ranging from re-plannedactivities tounscheduled contingencies, returningcrews have creditedthe variety of trainingmethods and the extensiveness of the trainingassome of the most essential elements of success.

HST EVA training flows have been, ingeneral, more rigorous than the training flows forother shuttle missions. Additionally, tHST EVAflows had significantly higher NBL run to flighttraining ratios than current ISS EVAs.

Early HST missions were trained atMSFC in the Neutral Buoyancy Simulator (NBS)since MSFC managed the design anddevelopment of the telescope. The NBS itselfwas designed by the U.S. Army in 1955 at theRed Stone Arsenal to provide azero-gravitysimulator for research, testing, and development.The heart of the NBS is a 40ft deep, 7> ftdiameter 5.3 million gallon, temperaturecontrolled water tank. Figure 12 illustrates oneof 32 separate training sessions conducted byfour of the STS-(1 crew members in June 1993.The HST mockup wras separated into twro piecesbecause the water tank depth could not supportthe entire structure in one piece. The three-weektraining process allowed mission trainers torefine the timelines for the five separatespacewalks conducted during the December1993 f7i^ht. y

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Figure 12. A mockup of the Hubble Space Telescope (HST)in the MSFC NBS for one of 32 separate trainuig sessionsconducted by four of the STS-61 crew members in June forthe 1993 HST servicing mission. JSC collection:S9340315.jpg

Later HST missions were managed byGoddard Space Flight Center (GSFC), EVAtraining transpired both in the JSC NBL and onreal flight hardware at GSFC. Not only werethese EVA flows Given significantly higher NBLrun to flight training ratios than are currentlyused for ISS EVAs, but the HST crews weregiven more developmental NBL water runs aswell. These additional water events were viewedas necessary, due to the sheer complexity of theassigned EVA tasks. STS-109 (HST SM3B) hada ratio of approxitnately 10:1 to 13:1 and earlierflights often had even more. Ironically, the last —and probably most complex —HST flight, STS-125, ranged only between 7:1 and 9:1,considerably less than previous HST missions.The difference can be attributed to a few factors_including NBL availability and new super highfidelity 1 G trainers (Hansen, 2009). The PGS,aka POGO, modality was used along with thehigh fidelity HST 1-G trainers built by GoddardSpace Flight Center to provide HST crewmember with an accurate feel for inserting andremoving hardware from the telescope. Hi-fitrainers were also built to overcome issuesran^in^ from those encountered on previousmissions to the sensitivity and difficulty ofreplacing hardware that was not originallydesigned or intended to be replaced by an EVAcrewlnember.

Philosophy on EVA Training: ShuttleFlight Specific 1^^Tission Training vs.Long Duration Flight Generic EVATraining (1998-present)

The philosophy of EVA task trainingshifted significantly with the ambition of theInternational Space Station (ISS) assembly andmaintenance requirements. In addition to themajority of EVA tasks becoming more complex,the training programs have become moreinternational, with crewmembers from countriesacross the world including America, Canada,Europe, Russia, and Japan requiring training.Special EVA cadres were formed within theastronaut core and programs were developed toselect and qualify crewmembers for EVA. EVAcadres were then further dig-•ided into crew rhowould train for EVA shuttle flight-specificmissions and those who would train as longduration ISS residents.

EVA task training is essential forsuccess in both flight specific EVA missions andlong duration flight. The training methodology,however, for these two types of flights, is quitedifferent. As would be expected, preflighttraining places a strong focus on erewmembersafety in both cases. For short duration missions,however, specific repetitive task choreography isessential, ^t-bile long duration flights rely moreheavily on basic skills, in sitr.^, just in time, andproficiency training.

ASCAN EVA Task Training

The development of a Generic skills setbegins with the Astronaut candidate (ASCAN)EVA training flow. This flow was designed tofamiliarize crewmembers with the fundamentalsof performing an EVA. ASCANs begin withhands-on classes covering EVA tools and theintricacies of the Extravehicular Mobility LJnit(EMU) or space suit. Such classes introducecre^t^xrlembers to the nomenclature andconstraints of approximately (8 of the primarytools, tethers, restraints, translation aids, andbags used dLUing EVA in a t-shirt environment.An emphasis is placed on nomenclature, sincecolmnunication between crewmembers and withthe ground require clarity. The fundamental 1-Gclasses are followed by a set of four differentwater runs in the Neutral Buoyancy Lab (NBL).These runs are progressive (each builds upon theskills learned in the previous run), and arededicated to introducing the ASCAN tooperating the EMLJ in a neutrally buoyant

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environment, learning basic EVA skills.practicing fundamental EVA operations, andinstilling good EVA habits such as situationalawareness, verbalizing actions, optimal bodyposition selection, and proper tether (life-line)protocol (EVA SOP, 2009).

Due to the sheer cost and preparation ofEVA, it is necessary to have crewmembersdevelop and maintain physical conditioning thatallows for the maximum EVA time possible. Onorbit EVA tasks demand high levels of muscularexertion, stamina, physical and mentalendurance, and psychomotor skills such as hand-eye coordination. The attributes that best suit anEVA crew member are those possessed by a"young; energetic, vigorous, well-conditionedathlete" (Abeles &Schaefer, 1986). Hence, indeveloping an EVA skills set ; EVA trainingfocuses on the manipulation of mechanicalobjects in a simulated EVA environment and anintensive physical conditioning program. Theobjective of the EVA instructor is to provide arich and varied framework from tuhich thestudent can research and determine his or heroven preferred method for efficiently perfornngEVA tasks.

EVA Task Skills Program

If adequate achievement and aptitude isdemonstrated in ASCAN EVA trainine.astronauts become eligible for the EVA SkillsProgrurl. This is a more thorough and rigorousseries of training runs that work to improve theastronaut's ability to operate effectively andefficiently in the EMU. The program consists ofa series of 1-G "table-top" discussion sessions, anumber of SCUBA sessions to becomeacquainted firsthand with the translatlon pathsand worksites, and up to ten NBL water suitedevents. Early Skills nuls focus on basic EVAtraining and mission timeline deg-•elopment.These early runs allow crewmembers to discoverand improve areas of weakness, and learn thenuances of developing a spacewalk. As trainingprogresses; the tasks become more difficult andEVA instructors demand a greater contributionfrom the crevv^Inember (EVA SOP, 2009).

To ensure the crewmembers becomemore involved as the training progresses; each ofthese later nuts begins by providing the EVAcrewmember with a set of tasks that need to beaccomplished for either ISS maintenance orinuninent ISS repair along with a set ofconstraints. To evaluate the EVA student'ssituational awareness, the crevvrnember is asked

to develop a timeline and provide a list of toolsand tethers needed to accomplish the tasksrequired. Students are provided a 1-G class withthe evaluating EVA instructor, to discussconcerns, constraints, and to become familiarwith hardware and mockups. Many students alsoSCUBA their timelines to examine the worksite,evaluate proposed body positions ; and assess thedeveloped plan.

Upon the completion of each NBL nul,the EVA instructor conducts a debrief with thecrewmembers, to identify and discuss areas ofimprovement. Instructor astronauts (IA), a groupof experienced EVA crewmembers, also work tocoach and evaluate EVA Skills students, anddllring each NBL water nIn and debrief, an IA ispresent to critique and provide insight andadvice.

Upon successful completion of theSkills program, qualified astronauts are theneligible for a flight assignment as an EVAerev^^Inember.

Flight Specific EVA Training

Once an astronaut is assigned to ashuttle mission, he or she follows a flightspecific training plan developed by an EVAinstructor vuho also works as the mission'sspacewalk designer. This EVA instructor worksclosely with assigned crew to foster a timelinethat works effectively for the individualcrevL^Inember performing each specific task,while incorporating requirements from the entireEVA colmnunity (safety; engineering; EVAtools etc.). For example ; if the task involvesremoving and replacing an on-orbit battery, theinstructor and the crewmembers will togetherevaluate translation paths, body position, toolstowage, and battery removal steps for thespecific battery being replaced. Hence, theamount of training required for each EVA varies.NBL water nlns nominally range from 4:1 to 7:1depending on the "complexity of the EVA, priorcrew experience, number of EVAs in a mission,and the interactions with other disciplines" (EVASOP, 2009). The instructors and cre^^^Inembersmay also SCUBA dig-•e to develop preliminarytimelines and examine translation pathways,body positions, and techniques. SCUBAprovides access to shuttle and ISS mockupswithout being encumbered by the EMU, whileminimizing the cost of de g-•eloping an EVA. Inmost cases; initial EVA plans evolve through

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crew training and are flight-ready within 12 to 16months. On orbit; EVA instructors pro p-•ide theEVA crewmembers with real-time technicalinsight and guidance and respond to crewquestions on EVA-related issues thatunexpectedly arise.

In addition to flight specific tasks, EVAcrewanembers are also trained for any number ofspecific contingency EVA scenarios that couldarise on shuttle or station during that particularflight. Such tasks depend heavily on the payloadsetup in the shuttle payload bay and, if dockingwith ISS, the configuration of the space stationbefore launch. Many of these tasks are heavilytrained during the ASCAN and Skills flows andare typically only reviewed once or twice duringflight specific NBL training events.

As the station grew in size andcomplexity, it became virtually impossible forastronauts to train for every possiblemaintainence and contingency EVA. Hence, thephilosophy of EVA training for long durationcrew members required a different trainingapproach_

ISS Increment Crew EVA Training

Once an EVA-qualified astronaut isassigned a prime crewmember to a long durationISS Increment mission, he or she follows ageneric ISS Increment EVA flow. Developed bythe EVA TASK and safety conumznity, this flowensures an EVA crewmember is prepared for onorbit operations. The generic increment flowbegins with a review of the critical informationEVA crewmembers first encountered duringASCAN training. The flow continues with threeNBL maintenance pool runs and at least oneSCUBA session to ensure the crewmember isfamiliar with 14 of the critical orbitalreplacement units (ORUs) that might need to beremoved and replaced (R&R) during their longterm stay on station and a generic set of taskrequired to be mastered by all EVAcrewmembers. During the ISS increment floweach crewmember is evaluated by EVAinstructors; instructor astronauts, EVA safety,engineering, and the tools commLUiity in anEVAAT (EVA Assessment Team) run. TheEVAAT run is a mock sta ge EVA run in theNBL. Procedures are provided to the crew in afashion similar to how they would be uplinked tothe ISS EVA crew aboard the ISS during a longduration mission. The EVAAT run provides themission training team with a comprehensive

evaluation of the crewmember's current EVAaptitude and identifies any deficiencies. By theirnature ; EVAAT runs develop and maintain anEVA standard ofpractice.

Training for Future Space R'alks: Synergy ofPast and Future Training Programs

Over the past 40 years, microgravityEVAs have been marvelously demonstrated; thetechniques have been advanced and thecomplexity has grown exponentially,culminating in an orbital laboratory whereNASA and international space agency partnerscan perform research in an attempt to improveour ability to explore the universe. Butastronauts have not stepped foot on the lunarsurface or performed a surface EVA sinceDecember of 1972. As inamied spaceflight plansto return to the moon to establish a lunar base inpreparation for Martian exploration, EVAtraining must evolve to meet these challenges.

Successful EVAs are a testament to theadaptability and skill of the EVA crew. TheGemini and Apollo programs established earlythat adequate EVA task training in flight-likemodalities is necessary for success. SkylabEVAs demonstrated that adequate skills trainingand real-tune approaches to engineeringproblems can lead to success even under adverseconditions. A conservative estimate fromShuttle flight-specific EVAs indicates that thereare "at least ten hours of flight-specific ground-based EVA training for every hour of on-orbit[complex] EVA performed" (Ricco et. al, 1997).This training does not include estimates forcontingency training. Significant advancementshave also been made in training programs tofacilitate long-term space station EVA. Thehiuidamental nature of planetary EVAs willrequire a similar effort.

Early spacewalks and planetary baseconstruction will most likely demand high levelsof choreography similar to that of a flightspecific mission to construct the ISS or repairHST. Although some tasks. like the constanttethering of hardware and tools, becomes lesscritical due to the presence of a gravity field,other potentially more difficult issues arise.EVA task training must evoh-•e to account forthese differences. Probably the most challengingdifference is that the crew must learn to bear aliaction of the wei ght of the EMU they will bewearing and the hardware they will bemanipulating. Pressurized EMU characteristics

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will also play a significant role in determiningoverall mobility of both locomotion and handdexterity. Monitoring and controlling metabolicrate to maximize EVA time will be essential forEVA optimization. Specialized tools will needto be designed or modified, including roboticequipment; which may be necessary to aid inconstruction.

One of the critical EVA task trainingmodalities for planetary EVAs is thedevelopment of an accurate partial gravitysimulator. In the past, as documented earlier;much of the training has been accomplished withthree primary techniques, including underwaterinunersion, low gravity aircraft flying Kepleriantrajectories, and suspension systems. Parabolicflight is the only way to achieve b^uemicrogravity here on earth; however it is costprohibitive on a grand scale; and only providesat most 30 seconds of partial gravity. A cablesuspension method typically employs verticalcables to suspend a suited subject, relieving aportion of the weight exerted by the subject onthe ground, thus simulating partial gravity.Suspension systems are the most economicalpartial gravity simulation technique, but limit thedegrees of freedom for movement. Waterinnnersion offers a suited crewmember unlimitedduration and freedom of movement. buthydrodynamic drag dampens movement andbuoyancy issues can interfere with flight-liketraining (Newman & Barratt, 1997). Research isLuiderway at several universities to develop anaccurate lunar gravity simulator to prepare lunarsurface astronauts for surface EVAs. If possible,evaluation by lunar astronauts would bebeneficial in the early stages of modalityassessment and selection: as was seen duringApollo; techniques developed on the ground forsomething as simple as walking ilnlnediatelyevolved to a loping boLlnd by crewmembers onceon the surface of the moon.

Lunar dust is another S1gI11f1C3Ilt issuethat will arise during early EVA Inissions.Apollo crews reported that lunar dust quicklycovered everything and eras quite slippery. Thismay have significant impacts on tool operationand crew footing. In addition, orbitalreplacement mechanisms must be designed toprotect and handle its inexhaustible presence.

Apollo crewmembers acknowledged theimportance of understanding hnar geographyand geophysics. Textbooks and applied Geologyinstruction are critical to studying the planetarysurface and recognizing new findings. Analogsites here on Earth have been and will continue

to be critical in developing, testing, and trainingfor surface EVAs. These can be either created tobe representative of a particular site or naturallyoccurring on the Earth's surface withrepresentative characteristics (Hoffinan, 2004).Of those sites constructed during the Apollo eraonly the site at USGS at Cinder Lake, Arizonastill exists. This site has been utilized mostrecently for the Desert Rats program where thenext generation of IIIIIar and Martianexperimental hardware/sottw rare and missionoperational techniques are being evaluated by agroup of NASA scientists and engineers as partof the new Constellation program. Figure 13shows Astronaut Eugene A. Cernan (left),commander; and Scientist-Astronaut Harrison H.Schnutt, lunar module pilot, collecting lunarsamples during EVA training at the KennedySpace Center (KSC). Figure 14 is an image ofexperimental hardware from a Desert Ratsexcursion in Arizona.

Figure 13. Apollo 17 crewmen during EVA training. Photofrom JSC Digital hnage Collection, PHOTO ID 572-48888taken 09-13-1972.

^. -,^-^.

_ _ .. _

^ '--i ^ti' ^^ ^__ ^ ^^,,^

Figa ►• e 14. hnage frotn a Desert Rats trial iu the desert ofArizolta.

Thurot and Harbaugh (1995) describethe ideal EVA task training facility as one thatcompletely and accurately simulates all theconditions that will be encountered during amission. Due to the complexities of planetaryEVAs, creating just one EVA training modality

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to completely mimic all nuances would beimpossible. From the successful construction ofthe International Space Station, current EVAcrews have demonstrated that multiplemodalities are adequate for training: however itis significantly important thaty when themodalities overlap, they are identical. Inaddition, it is vital that crews understand theways in which each trainin g facility is flight-likeand the ways in which it is deficient.

Once the lunar base is constructed andmanned, much more autonomy must be grantedto the crew. Apollo crews recotmnended thatthere should be a general movement towardincreasingly greater crew autonomy. Hardwareand software must be developed to allow the in-situ erewtnembers to take a larger role inmonitoring and modifying each EVA'sparameters, both with respect to EMU hardwareparameters and the re-planning of tasks. Thismovement should be carefully planned anddesigned with highly experienced NASA EVAMOD flight instructors/controllers. Theseindividuals have great insight into what level ofautonomy could be achieved without putting thecrew in danger (Hansen, 2009).

Training for these later missions shouldfocus on an evolving skills set, much like longduration crew are trained today for ISSincrements. Most importantly, crew must beable to demonstrate the ability to be flexible,innovative ; and responsive to real-time changesthat must be handled autonomously. This criticalskill is not an easy concept to train or to develop.Research should be conducted to investigate themost efficient and effective methods fordeveloping this skill in long duration crew. Thisskill is a combination of psychology, ilmovativethinking, and perseverance. Overlappingmissions by a few weeks may provide on-comin^ crews with mentor iprotege on orbitexperience that could never be replicated here onEarth.

Conclusion

EVA is no r an established method formeeting human space mission objectives rangingfrom planned routine tasks to unexpected,tuitrained contingencies. Significant lessonslearned from past NASA EVA programs havebeen collected, evaluated, and incorporated tohelp EVA training curriculum evolve into aprogram that will be successful for future

exploration endeavors. The successful design offuture planetary spacewalks depends onproviding crew with the necessary skills set thatwill allow them to react appropriately in bothexpected and unexpected circumstances.

Figure 15. Astronaut Eugene Centan salutes deployed U.S.flag on lunar surface. Photo from JSC Digital hnageCollection, PHOTO ID AS17-134-20380, taken 12-13-1972.

Acknowledgements

The authors would like to thank United SpaceAlliance for their sponsorship to the 2009 IACconference. Dr. Moore would like to also thankMr. Matthew Gast for working with her as a co-author and presenting this paper at theconference and Mr. Brian E. Moore and Mrs.Claire Halphen for their proofreading andsuggestions.

References

1. Abeles, F.J. & Schaefer, R.H.,1986,"Advanced EVA Operation On-Orbit Tasksand Services." Space Systems TechnologyConference, San Diego, CA, June 9-12, 1986,Tecluiical Papers (A86-40576 19-12). NewYork. American Instituteof Aeronautics andAstronautics, p. 60-68.

2. Connors, M., Eppley, D., and Morrow, D.;Interviews with the Apollo Lunar SurfaceAstronauts in Support of Plamiing for EVASystems Design, NASA Technical Metnorandutn108846, NASA Ames Research Center, MoffetField, CA, September, 1994.

3. Extravehicular Activity Standard OperatingProcedures (SOP); Revision B. NASA-JSC:MOD CB-QMS-004 Revision B, June 2009.

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4. Hansen; Christy. Personal Interview. 21August 2009.

5. Mission Report for GT-IV, p. 12-22; WeeklyActivity Report, Mar. 21-27, 1965, p. 1)

6. Newman. D. J., 2000; "Life in ExtremeEnvironments' How Will Humans Perform onMars?" Gravitational and Space Biologti^Br^lletin, li(2),pp 35-48.

7. Newman, D & Barrat, M. (1997) Life Supportand Perfornlance Issues for ExtravehicularActivity (EVA). In: Chtuchill, S and Heinz, O.eds. Fundamentals of Space Life Sciences;Chapter 22, Krieger Publishing Company.

8. Pogue ; VV., &Carr, G. 1990, "AdvancedExtravehicle Activity Requirements in Supportof the Manned Mars Mission." AIAA 90-3801.

9. Portree, D.S.F. ; and Trevion, R. i^'alkng toOlympus: An EVA Chronologti^, Monographs inAerospace Histon^ Series #7, Washington, D.C..National Aeronautics and Space Administration„History Office, Office of Policy and Plans, 1997.

10. Riccio, G.E., McDonald, V., Peters, B.T.,Layne, C.S. ; and Bloomberg; J.J.;"Understanding Skill in EVA Mass Handling,Vol. I: Theoretical &Operational Foundations."NASA Technical Paper X684; June, 2007.

11. Shayler, D.J, Gemini' Steps to the Moon.Springer-Praxis, 2001 [1].

12. Shayler, D.J. Skylab^ America's SpaceStation. Springer-Praxis, 2001 [2].

13. Shayler, D.J, Walking in Space. Springer-Praxis, 2004.

14. Thuot, P.J., and Harbaugh, G.J.,"Extravehicular Activity and Training andHardware Design Consideration." ActaAsironautica Vo1.36, No. 1, pp 13-26, 1995.

15. Weekly Activity Report, Jan. 10-16, 1965, p.1; Consolidated Activity Report, January 1965,pp. 12, 16.

16. Wilde. R.C., McBarron II, J.W. ; Manatt;S.A. ; Fullerton, R.K., 2002, "One Hundred USEVAs: A Perspective on Spacewalks." ActaAstronazrtca Vol. Sl, No. 1-9. pp 579-590.

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