Assessment of Options for Extending the Life of the Hubble Space Telescope: Final Report Book

Contents

EXECUTIVE SUMMARY....................1
1 INTRODUCTION....................8
Background....................8
Goals of This Study....................9
Report Organization and Development....................10
2 HUBBLE SPACE TELESCOPE....................11
Hubble as a System....................11
Current Status of Hubble....................14
3 THE IMPACT OF HUBBLE: PAST AND FUTURE....................16
Overview....................16
Observing with Hubble....................18
Science Highlights....................19
Ultradeep Images of the Universe-Galaxies in Formation....................19
Measurement of the Hubble Constant, the Distance Scale of the Universe....................19
Giant Black Holes at the Centers of Galaxies....................20
Accelerated Expansion of the Universe-Dark Energy....................20
Protoplanetary Disks-Planetary Systems in Formation....................22
Hubble in the Scientific and Popular Press....................23
Science Impact of Hubble Servicing Missions....................25
Deteriorating Capabilities That Affect Hubble's Science Performance....................27
The Promise of Future Discoveries....................30
Future Science Potential Relative to Past Achievements....................35
Comparison of Hubble with Other Planned Facilities....................35
Coordination with Other Facilities....................38
The Timing of a Servicing Mission....................38
Rehosting....................39
4 HST OBSERVATORY ASSESSMENT AND LIFETIME PROJECTION....................40
Failure Modeling....................40
FailureCategories....................40
Repair Types....................41
Avionics Reliability Model....................42
Components Subject to Wear-out....................45
Battery Assessment....................46
Rate Sensor Unit (Gyroscope) Assessment....................48
Fine-Guidance Sensor Assessment....................49
Other Reliability Considerations....................50
Solar Panel Assessment....................50
Reaction Wheel Assembly Assessment....................51
Thermal Assessment....................51
Radiation Effects Assessment....................52
HST System Lifetime and Mission Timing Considerations....................52
5 HST ROBOTIC SERVICING ASSESSMENT....................56
Program Description....................56
Assessment of the Technical Approach....................57
Mission Description and Risks....................57
Technology Readiness Assessment....................64
Critical Technology Readiness....................64
Program Assessment....................67
Project Team....................67
Program Development Plan....................68
Assessment Summary....................72
Relevance to NASA's Space Exploration Initiative....................72
6 SPACE SHUTTLE SERVICING OF HUBBLE....................74
Requirements Affecting the Viability of a Shuttle Mission to HST While Meeting the CAIB and NASA Return-to-Flight Requirements....................74
CAIB Requirements....................74
Additional NASA Requirements....................75
NASA Administrator's Considerations....................76
Additional Considerations for a Space Shuttle Mission to HST....................76
NASA's Response to Recommendations....................76
The Viability of a Shuttle Mission to HST While Meeting the CAIB and NASA RTF Requirements....................77
On-Orbit Inspection Planning and Flexibility....................77
On-Orbit Repair Capability and Limitations....................78
Safe Haven and Crew Rescue....................79
Micro-Meteoroid Orbital Debris Risks....................81
Public Risk of Overflight....................81
Summary of Viability for Meeting Both the CAIB and NASA Requirements....................81
Additional Operational Considerations....................82
Shuttle Rescue Operations Complexity....................82
HST Manifesting Options....................83
RTF Workload....................83
HST De-orbit Module on a Shuttle Servicing Mission....................84
Time and Resources Needed to Overcome Unique Technical or Safety Issues Associated with HST Servicing....................84
Additional Costs to Reinstate a Shuttle Servicing Mission....................85
HST Versus ISS Crew Safety Risk....................85
Relevant Space Shuttle Mission Successes....................86
Human Response to Unforeseen On-Orbit Contingencies....................86
Space Shuttle Servicing Missions to the Hubble Space Telescope....................87
HST Servicing Mission Risk....................90
7 BENEFIT/RISK ASSESSMENT OF HUBBLE SPACE TELESCOPE SERVICING OPTIONS....................92
Introduction....................92
Assessment of the Risks of Human and Robotic Servicing....................92
Definitions....................94
Risk Tables....................103
Conclusions Regarding Risk for Servicing Options....................104
Benefit/Risk Assessment for Servicing Options....................104
8 CONCLUSIONS AND RECOMMENDATIONS....................106
Recommendations....................107
APPENDIXES A Statement of Task....................111
B Briefings to the Committee....................112
C Interim Report....................116
D State of the Art in Robotics....................126
E Acronyms....................130
F Glossary....................134
G Biographical Information for Committee Members and Staff....................137