High-Power Solar Electric Propulsion for Human Mars Transportation
- Paper number
IAC-05-D3.2.03
- Author
Mr. Gordon R. Woodcock, Space America Inc., United States
- Year
2005
- Abstract
Earlier IAC papers by Morgenthaler and Woodcock have advocated reusable in-space transportation for lunar and Mars human exploration. These papers referenced the use of solar electric propulsion (SEP) for transportation from Earth vicinity to Mars and return; specifically operating from the Earth-Moon L1 point to a high Mars orbit and back. The proposed paper describes SEP transport vehicle design concepts and concepts of operations. A SEP vehicle lends itself to re-use better than the alternatives. Chemical propulsion has marginal performance even in an expendable mode. Nuclear thermal propulsion, because of reactor life issues, is probably not reusable, and in the usual architectures, employs staging which would yield a partially reusable system at best. Nuclear electric propulsion is the only other candidate offering potential re-use. Here, also, reactor life issues and the difficulty of performing maintenance on a highly radioactive propulsion system, may preclude re-use. The power level for electric propulsion for human Mars transportation, 5 to 10 megawatts, is quite beyond flight experience for SEP, which has flown at power levels 1 to 5 kWe. SEP, however, is nearer technology readiness for high power than may be apparent. Technology advancement activities for 6 kWe ion thrusters have been underway for a couple of years, and Hall thrusters up to 100 kWe have been tested in the laboratory. Experimental lithium MPD thrusters have been tested for short duration at 500 kWe. The main solar panel for ISS is 65 kWe, and when ISS is complete, the solar panel output will be a couple hundred kWe. Two design concepts are presented in the paper. The first uses near-term technology; flat panel (planar) multiple band gap cells on arrays at about 300 W/kg, deployed by simple extenders, all panels attached to a central spine structure, and 100 kWe Hall thrusters with direct drive. The second concept uses advanced deployable concentrator cells at estimated 600 W/kg, with MPD thrusters, and 3-phase AC power distribution. Concepts of operations for construction of the SEP and recurring transportation operations are presented. Unlike the alternative systems, the SEP is compatible with delivery to Earth orbit (or direct to L1) on modest launch vehicles of the general capacity of EELV-heavies and Ariane V, although a rather large number of launches is needed. This lends itself to reduction in transportation costs by enabling frequent launches by reusable or partially reusable launch vehicles such as described in a paper by the present author at IAC Bremen, 2003.
- Abstract document
- Manuscript document
IAC-05-D3.2.03.pdf (🔒 authorized access only).
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