National Aeronautics and NASA/CP—2000–210429 Space Administration AD33 George C. Marshall Space Flight Center Marshall Space Flight Center, Alabama 35812 Space Elevators An Advanced Earth-Space Infrastructure for the New Millennium Compiled by D.V. Smitherman, Jr. Marshall Space Flight Center, Huntsville, Alabama This publication is based on the findings from the Advanced Space Infrastructure Workshop on Geostationary Orbiting Tether “Space Elevator” Concepts, NASA Marshall Space Flight Center, June 8–10, 1999. August 2000 The NASA STI Program Office…in Profile Since its founding, NASA has been dedicated to • CONFERENCE PUBLICATION. Collected the advancement of aeronautics and space papers from scientific and technical conferences, science. The NASA Scientific and Technical symposia, seminars, or other meetings sponsored Information (STI) Program Office plays a key or cosponsored by NASA. part in helping NASA maintain this important role. • SPECIAL PUBLICATION. 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Smitherman, Jr. Marshall Space Flight Center, Huntsville, Alabama This publication is based on the findings from the Advanced Space Infrastructure Workshop on Geostationary Orbiting Tether “Space Elevator” Concepts, NASA Marshall Space Flight Center, June 8–10, 1999. National Aeronautics and Space Administration Marshall Space Flight Center • Huntsville, Alabama 35812 August 2000 i Acknowledgments Sponsors: This publication is based on the findings from the Advanced Space Infrastructure Workshop on Geostationary Orbiting Tether “Space Elevator” Concepts, managed by David V. Smitherman, Jr., Architect, Technical Manager in the Advanced Projects Office, Flight Projects Directorate, NASA Marshall Space Flight Center, Huntsville, Alabama. The workshop was conducted June 8–10, 1999, by the Flight Projects Directorate in cooperation with the Advanced Projects Office, Office of Space Flight, NASA Headquarters, Washington, DC, and the Advanced Space Transportation Program, NASA Marshall Space Flight Center, Huntsville, Alabama. Cover Artwork: NASA artwork of the space elevator was created by Pat Rawlings, Science Applications International Corporation. This illustration for a space elevator concept is taken from the geostationary transfer station looking down the length of the elevator structure toward Earth. Electromagnetic vehicles travel the length of the elevator to transfer passengers and cargo between Earth and space. Six vehicular tracks surround a high-strength tubular core structure fabricated from advanced carbon nanotube materials. Three tracks carry passengers and cargo vehicles, while the other three tracks provide for service vehicles that maintain the elevator systems. Large reels with high-strength cables work back and forth to provide small adjustments to the position of the geostation and an asteroid counterweight above (not shown) to maintain the center of mass for the entire structure at a geostationary point above the Earth. Inflatable spheres and space station modules provide habitable volumes for the transfer of passengers and cargo through the station to outbound orbital transfer vehicles. Available from: NASA Center for AeroSpace Information National Technical Information Service 7121 Standard Drive 5285 Port Royal Road Hanover, MD 21076–1320 Springfield, VA 22161 (301) 621–0390 (703) 487–4650 ii TABLE OF CONTENTS 1. SUMMARY ............................................................................................................................................ 1 1.1 Introduction: What is a Space Elevator? .......................................................................................... 1 1.2 Key Findings From the Workshop .................................................................................................... 1 1.3 Future Directions .............................................................................................................................. 2 1.4 Technology Demonstrations ............................................................................................................. 2 2. SPACE ELEVATOR CONCEPTS .......................................................................................................... 2 2.1 Brief History ..................................................................................................................................... 2 2.2 A Space Elevator Concept ................................................................................................................ 3 2.3 Space Elevator Basics ....................................................................................................................... 4 3. TECHNOLOGY DEVELOPMENT PATHS ......................................................................................... 6 3.1 Materials ........................................................................................................................................... 6 3.2 Tension Structures ............................................................................................................................ 7 3.3 Compression Structures .................................................................................................................... 12 3.4 Electromagnetic Propulsion ............................................................................................................. 14 3.5 Supporting Infrastructure ................................................................................................................. 18 4. ISSUES ................................................................................................................................................... 23 4.1 Environmental Issues ........................................................................................................................ 23 4.2 Safety Issues ..................................................................................................................................... 25 5. CONCLUSIONS AND RECOMMENDATIONS .................................................................................. 29 5.1 Pros for Building Space Elevators .................................................................................................... 29 5.2 Cons Against Building Space Elevators ........................................................................................... 30 5.3 Concerns and Possible Solutions ...................................................................................................... 31 5.4 Recommendations ............................................................................................................................ 31 APPENDIX A—WORKSHOP PARTICIPANTS AND CONTRIBUTORS ................................................ 33 A.1 Workshop Participants ...................................................................................................................... 33 A.2 Additional Contributors and Virtual Research Center Participants .................................................. 33 REFERENCES .............................................................................................................................................. 34 BIBLIOGRAPHY