I Contents Executive Summary........................................................................................ 1 Principal Observations ..................................................................................... 3 Principal Recommendations ............................................................................. 3 1. Introduction..................................................................................................... 5 Charter/Scope ................................................................................................... 5 Approach........................................................................................................... 5 Report Organization ......................................................................................... 5 2. The International Space Station Program.................................................... 7 International Space Station Characteristics..................................................... 8 3. International Space Station Crosscutting Management Functions............ 12 Robust On-Orbit Systems.................................................................................. 12 The Design ........................................................................................................ 12 Verification Requirements ................................................................................ 12 Physical (Fit) Verification ................................................................................ 13 Multi-element Integrated Test........................................................................... 13 Stage Verification Reviews ............................................................................... 13 Critical Items and Hazard Analyses ................................................................. 14 International Space Station Mission Management Team ................................. 15 Safety and Mission Assurance .......................................................................... 15 International Space Station Safety Review Panels ........................................... 16 Anomaly Resolution .......................................................................................... 16 Fleet Leader Program....................................................................................... 16 Program Risk Advisory Board.......................................................................... 17 International Space Station Certification of Flight Readiness Process ........... 18 NASA Engineering and Safety Center............................................................... 19 NASA Engineering Technical Authority ........................................................... 19 NASA Advisory Council .................................................................................... 20 Aerospace Safety Advisory Council.................................................................. 20 Office of the Inspector General......................................................................... 20 Summary ........................................................................................................... 21 4. Threats to and Vulnerabilities of the International Space Station............. 22 4.1 Loss of Crew and/or ISS Destruction ............................................................... 22 4.1.1 Micrometeoroid and orbital debris damage/penetration ................................... 22 4.1.2. Collision with visiting vehicles or Remote Manipulator System ..................... 22 Visiting Vehicle Background............................................................................. 23 Risk Mitigation for Visiting Vehicle Collision.................................................. 23 Mobile Servicing System Description ............................................................... 24 Space Station Remote Manipulator System Collision Avoidance..................... 24 Space Station Remote Manipulator System Modifications for Free-Flyer Capture and Berthing..................................................................... 26 Shuttle Remote Manipulator System ................................................................. 26 Japanese Experiment Module Remote Manipulator System............................. 26 4.1.3 Fire .................................................................................................................... 26 iii 4.1.4 Toxic spills........................................................................................................ 27 4.1.5 Catastrophic system failures ............................................................................. 27 Summary ........................................................................................................... 27 International Space Station Safety Analysis ..................................................... 27 Post-Columbia Noncompliance Report Review................................................ 28 Post-Columbia Failure Mode and Effects Analysis/ Critical Items List Review................................................................................. 29 Post-Columbia International Space Station Enhancements Review ................ 29 Conclusion ........................................................................................................ 29 4.1.6 Critical hardware and software design flaws.................................................... 29 Summary ........................................................................................................... 29 Design Specification Methodology ................................................................... 29 Testing and Verification Methodology.............................................................. 30 Hardware and Software Acceptance Process................................................... 31 On-Orbit System Monitoring ............................................................................ 31 4.1.7 Extravehicular activity...................................................................................... 31 Summary ........................................................................................................... 31 Extravehicular Mobility Unit Background ....................................................... 32 Inadvertent Separation from the Vehicle .......................................................... 32 Extravehicular Activity Micrometeoroid and Orbital Debris Risk................... 32 Contaminant Exposure...................................................................................... 33 System Failure .................................................................................................. 33 4.1.8 Security compromise of the ground system...................................................... 34 4.1.9 Errant critical command from the crew or ground controllers ......................... 34 4.2 Premature Abandonment .................................................................................. 35 4.2.1 Maintaining a pressurized cabin environment .................................................. 35 Summary ........................................................................................................... 35 Design and Testing ........................................................................................... 35 Pressure Monitoring and Control..................................................................... 36 On-Orbit Leak Isolation and Repair Hardware ............................................... 36 Leak Response................................................................................................... 36 4.2.2 Providing a habitable atmosphere..................................................................... 36 Summary ........................................................................................................... 36 Contaminant Release or Toxic Spill ................................................................. 37 Microbial Overgrowth ...................................................................................... 37 On-board Fire................................................................................................... 37 Life Support....................................................................................................... 38 4.2.3 Ensuring critical systems functionality............................................................. 39 Summary ........................................................................................................... 39 Assembly Sequence Planning............................................................................ 39 System Resiliency.............................................................................................. 40 Anomaly Detection and Resolution................................................................... 40 Ongoing Improvements..................................................................................... 40 4.2.4 Sufficient consumables availability .................................................................. 41 Summary ........................................................................................................... 41 Transportation for Consumables ...................................................................... 41 Consumables Baseline ...................................................................................... 41 International Space Station Consumables Team .............................................