A Discussion on the Making of an EVA: What It Really Takes to Walk in Space

1
A Discussion on the Making of an EVAWhat It
Really Takesto Walk in Space

• Ernie Bell
• United Space Alliance
• NASA Johnson Space Center, Houston, Texas
• June 19, 2006

2
Agenda

• Introduction
• EVA Training
• Ground Servicing
• Planning Process
• On-orbit Preparation
• Mission Control Center Activities
• Required Personnel
• Conclusion
• Potential Evolutions

3
Introduction

• Extravehicular Activities (EVA) ? Spacewalks
• Essential capability for human spaceflight
• Appearance
• Relatively easy to conduct
• Reality
• Requires significant training, planning,
  coordination, specialized personnel
• Major Operational areas
• Personnel with specialized skills
• Steps personnel involved prior to hatch open

4
Facilities Utilized

• Spacesuit EVA hardware processing labs
• Space Vehicles Mockup Facility (SVMF)
• Vacuum chambers
• Classroom/part task trainers

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Facilities Utilized (continued)

• Neutral Buoyancy Laboratory (NBL)
• Virtual Reality (VR) Laboratory
• Space Station Space Shuttle
  Simulators
• Mission Control Center (MCC)

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EVA Training EVA Systems

• Conducted by EVA flight controllers/instructors
• Operation of Extravehicular Mobility Units (EMUs
  or spacesuits), airlocks, support equipment
• Single session training
• Decompression sickness, airlock maintenance,
  EMU component change outs

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EVA Training EVA Systems (continued)

• Repetitive training events
• Caution warning, SAFER, Prep Post
• Vacuum chamber session

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EVA Training EVA Task

• Conducted by EVA flight controllers/instructors
• Preparation on use of tools conducting tasks
• Classroom sessions
• Pistol Grip Tool (PGT) EVA tools
• Part task trainers
• Fluid quick disconnect, mass handling, two
  degree of freedom, mockups

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EVA Training EVA Task (continued)

• NBL training
• Generic training flight specific training
• Develop familiarity with tasks and environment
• Procedure and timeline development

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EVA Training Instructor Flight Controller

• Conducted by EVA flight controllers/instructors
• Similar to crew training
• Requires additional level of knowledge
• Training flow
• Facilities
• Same as used for crew training
• SSTF MCC

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Ground Servicing EMU Servicing

• Portable Life Support System (PLSS)
• Servicing maintenance on all systems
• Component level system level checkouts
• Space Suit Assembly (SSA)
• Pressure testing and cycling of each component
• Track usage of each item
• Common servicing
• seals, bearings, lubrication, bladders,
  restraints, TMG
• Integrated EMU/orbiter checkout prior to launch

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Ground Servicing Tools Equipment

• Types of processing
• Thermal cycling
• Consumables replenishment
• Component cycling
• Operational verification
• Major items serviced
• Ancillary equipment (helmet lights, SAFER,
  cameras)
• Servicing equipment (battery chargers, equipment
  kits)
• Tools (PGT, tethers, mini-workstation)

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The Planning Process

• Generic Ground Rules and Constraints (GGRC)
• Shuttle Crew Scheduling Constraints (SCSC)
• Task determination
• Analysis (structural, thermal, etc.)
• Training timeline development
• International coordination
• Coordination with other disciplines
• Space to ground tagups

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On-orbit Preparation

• Battery charging
• Four types of batteries (EMU, REBA, helmet light,
  PGT)
• Two methods of charging (ISS charger or battery
  specific)
• Charge times vary from 4 to 22 hours
• Spacesuit resizing
• Size suit to properly fit crewmembers
• Various component sizes (HUT, arms, legs,
  waist)
• Adjustment of relative lengths of
  restraint straps

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On-orbit Preparation (continued)

• Spacesuit checkout
• Shuttle vs. International Space Station (ISS)
• Confirm proper function of spacesuit systems
• Systems included communication, pressurization,
  ventilation, cooling, electrical, caution
  warning
• Dry run (ISS crew only EVA)
• Additional checkouts
• SAFER verifies operation and
  sufficient consumables
• PGT verifies operation, calibration,
  battery capacity, settings

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On-orbit Preparation (continued)

• Tool gather
• Locate, configure, pre-position tools
• Procedure review
• Familiarization with task procedures
• Familiarization with translation paths (DOUG)
• EVA day prep activities
• Configure vehicle systems
• oxygen, power, communications, cooling
• Prebreathe activities
• Suit donning
• Airlock depressurization

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Mission Control Center

• On-console activities
• Coordinate activities
• Realtime changes
• Monitor execution
• Provide progress to flight control team
• EVA day MCC activities
• Planning shift monitors preparation prebreathe
• Execute shift monitors depress through repress

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Personnel Required

• Crewmembers
• Positions Extravehicular, Intravehicular,
  Capcom, Ground IV
• Help develop plan timeline, execute procedures,
  report progress
• EVA Flight Controllers/Instructors
• Team assigned to each mission (Lead, Systems,
  Task)
• Coordinate conduct EVA training events
• Develop plan timeline
• Fill role of execute shift in MCC

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Personnel Required (continued)

• EVA Program Office
• Interface for operational programmatic elements
• Engineers technicians
• Facilities
• General facilities
• EVA specific facilities
• Spacesuits
• Life support system
• Space suit assembly
• EVA tools hardware
• Includes design, development, validation
• Structures mechanics engineers

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Personnel Required (continued)

• Mission Planning Support Personnel
• Define program requirements
• Coordinate logistics
• Biomedical Personnel
• Flight surgeons biomedical engineers
• Develop prebreathe protocols
• Monitor health throughout training during EVAs
• Technicians
• Found in all facilities hardware processing
• Assist with training
• Suit PLSS technicians, divers, facility
  operators

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Conclusions

• Substantial time and manpower required to prepare
  crew and hardware for an EVA
• Spacesuits are very difficult to work in
• Spacesuit systems are unique
• EVA hardware is unique
• Significant training required
• Limited crew servicing maintenance capability

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Potential Evolutions

• Development of next generation of spacesuit
  spacecraft should include
• Systems commonality (suit ancillary equipment)
• Reduces EVA specific systems training
• Reduces on-orbit prep time
• Reduces logistics
• More user-friendly suit
• Increased work envelope
• Increased mobility
• Increased availability
• On-location servicing maintenance
• Commonality provides for reduced maintenance
  training
• Reduced, or no, ground processing time
• Generic task training verses task specific

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A Discussion on the Making of an EVAWhat It
Really Takesto Walk in Space QUESTIONS?

• Ernie Bell
• United Space Alliance
• NASA Johnson Space Center, Houston, Texas
• June 19, 2006