Design Considerations for Space Elevator Tether Climbers

The 2013 ISEC study addresses a critical aspect of the space elevator infrastructure: the tether climber. The tether climber will leverage 60 years of spacecraft design while incorporating aspects of traditional terrestrial transportation infrastructure. The following conclusions were refined from discussions during the year and the assessment of relevant research:

  • The study used a constant power model as a baseline, rather than constant speed or acceleration, because the constant power model simplifies design requirements and reduces the mass of the tether climber.

  • A mass of 6 metric tons (MT) for a climber and 14 MT for customer payloads seems feasible. We estimate that with a travel time of one week to Geosynchronous Earth Orbit (GEO), seven tether climbers can be on a 31 MT tether simultaneously.

  • A conceptual operating plan should be developed to assist in the refinement of requirements.

  • The communication architecture should be integrated into the space elevator infrastructure and nodal layout. This will enable the tether climber to be in constant contact with operators and customers.

  • It appears possible to operate the tether system exclusively on solar power, eliminating the need for ground-level power sources.

  • Exclusive use of ground-based laser power transmission also seems practical.

  • A hybrid of solar power and laser power transmission is an option.

  • Detailed designs of the climber, tether attachment apparatus, and drive mechanisms will be accomplished later when the characteristics of the tether are better defined, but it is clear that terrestrial motor designs can be leveraged for climber development.

The study report makes the following recommendations related to space elevator development:

  • Conduct further studies to lower technological risk in several specific areas.

  • Continue to support technical competitions in areas such as tether design and tether climber design.

  • Develop more international connections during ISEC studies, especially with Japanese Space Elevator Association, EuroSpaceward, and the International Academy of Astronautics.