Extravehicular Activity EVA Operations as a System Design Driver

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Extravehicular Activity (EVA) Operations as a
System Design Driver

• Gerald E. Miller
• Edward R. Rubio
• June 19, 2006

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There is no reason to send people to the surface
of another celestial body, other than to perform
EVA.
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Past Programs Approach to EVA

• The impact of EVA has not been a primary
  consideration in the design of past space
  missions
• Apollo came closest to correcting this, but was
  limited by lack of experience
• EVA was relegated to a secondary consideration in
  all subsequent program designs
• Skylab
• Mir
• Shuttle
• Shuttle/Mir
• ISS

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Necessary Approach to Future EVA

• Systems design must be driven by operational
  needs and lessons learned
• EVA is a major design driver
• Proven fact across years of Soyuz, Gemini,
  Apollo, Shuttle, Mir, Shuttle-Mir and ISS EVA
  experience
• Experience repeatedly demonstrates criticality of
  operations-driven design philosophy
• Palapa/Westar
• Solar Max
• Intelsat
• Bringing EVA to the forefront of systems design
  will be accomplished in stages

• Hubble
• Mir
• ISS Assembly Maintenance

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Defining the Path from Past to Future

• Short-Term Era (2-9 years in the future)
• Mid-Term era (10-20 years in the future)
• Long-Term Era (20 years in the future)

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Short-Term Era Design Drivers

• Automated Component Tracking (ground on-orbit)
• Demonstrated ops problem during Skylab, Mir,
  Shuttle-Mir and ISS
• EVA currently tracks over 500,000 active items

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Short-Term Era Design Drivers (cont.)

• Spares Management
• EVA items or vehicle ORUs
• Limited life tracking system
• Remote (In-Situ) Training Capability
• Skills-Based Training
• Concept in use, but no technologies explored to
  enhance it
• Contamination Control (Crew Environment)
• Improved detection technologies
• Decompression Sickness Treatment (Intravehicular)

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Mid-Term Era Design Drivers

• Zero-Prebreathe Suit
• Significant impact for EVA planning and
  operations
• EVA responsiveness
• Vehicle impacts
• Avionics
• Crew isolation
• Remote (In-Situ) Consumables Generation
• Significant program impact for supply-chain
  logistics
• Remote (In-Situ) Repair/Maintenance Capability
• ISS demonstrating impact on overall program

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Mid-Term Era Design Drivers (cont.)

• Component Interoperability
• EMU/EVA components should be exchangeable with
  other systems
• i.e., batteries
• EVA/Robotic
• Interaction
• Training
• Current training
• limited to
• SRMS/SSRMS
• interaction
• Future EVA/Robotic interaction more complex

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Mid-Term Era Design Drivers (cont.)

• Large Field/Cross-Country Terrain Training
• Current experience confined to Shuttle PLB and
  zero-g vehicle exteriors (HST, ISS, Mir, etc.)
• Develop technologies training for EVA
  crewmember navigation, location, transportation,
  communication, rescue/retrieval, malfunction
  response, etc. in surface terrain
• Surface Tracking and Non-Line-of-Sight
  Communication
• Extraterrestrial surfaces less prone to zero-g
  disorientation, but more prone to featureless
  navigation
• Technologies to overcome communications
  obstructions

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Mid-Term Era Design Drivers (cont.)

• External Overhead Reduction
• Definition of EVA Overhead
• Automated/assisted worksite setup, tools
  acquisition, transportation, etc. required
• Contamination Control (Suit Components)
• Differs from contamination
• of crew environment
• discussed above
• Apollo 17 crew cites it
• as single, most significant
• issue needing addressed
• for surface EVA

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Mid-Term Era Design Drivers (cont.)

• Contamination Control (Worksite/Sample)
• Turns normal contamination concerns inside out
• Not dealing with environments impact on suit or
  crew, rather EVAs impact on indigenous
  environment
• Precedence exists with Hubble servicing
• Future examples include water vapor on surface
  samples
• Smart Return Capability
• Progress in artificial intelligence (AI) required
• Brings EVA/Robotic interaction to bear
• Smart return technology for both nominal and
  off-nominal operations

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Mid-Term Era Design Drivers (cont.)

• In-Suit Medical Treatment
• Currently limited to DCS treatment
• Future needs include
• Triage/diagnosis
• Medication ingestion/injection
• Physical manipulation
• Temporary splinting
• Wound compression
• Overnight Campout Capability
• Accommodates overnight stays at remote worksites
• Addresses consumables transportation, waste
  management, shelter provision, etc.

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Mid-Term Era Design Drivers (cncl.)

• Remote Worksite Power Generation
• Crosses Mid-Range and expands across Long-Range
• EVA on continuous upward trend in task complexity
• Exploration EVAs demand technologies for
• Geological exploration/sampling
• Assembly
• Excavation
• Maintenance
• etc.

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Long-Term Era Design Drivers

• Virtual Re-Size Capability
• Current technology encumbers mission operations
• Significant impact to supply logistics
• Time consuming when required
• Technology to eliminate Internal Overhead of
  resize

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Long-Term Era Design Drivers (cont.)

• Variable-G Ground Based Training
• Ability to train for EVAs that may occur in
  varying gravity conditions
• Moon, Mars, asteroids, outer planet moons, zero-g
• Suited Crew Access/Extraction/Retrieval
• Physical challenges of surface EVA
• Crevasse traversing/ bridging
• Inclination/slope translation

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Long-Term Era Design Drivers (cont.)

• Path/Road Clearing or Construction
• Technologies to clear regularly used paths
• Eventual capability to strengthen and maintain
  rudimentary roadways

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Conclusion

• EVA will be central to future human space
  programs
• It is the only reason to send humans to alien
  surfaces
• Future EVAs will require new capabilities
• Technologies needed are diverse, requiring
  integration over time
• Systems designs must enable these capabilities
• Lessons learned prove the operational impacts of
  failing to do so
• EVA operations must drive future systems designs
• Failure to consider EVA a primary driver leads to
  negative programmatic impacts
• EVA cannot be relegated to a secondary
  consideration