Momentum-Exchange/Electrodynamic-Reboost (MXER) tether systems can provide propellantless propulsion for a wide range of missions, including: orbital maneuvering and stationkeeping within Low Earth Orbit (LEO); orbital transfer of payloads from LEO to GEO, the Moon, and Mars; and eventually even Earth-to-Orbit (ETO) launch assist. By eliminating the need for propellant for in-space propulsion, MXER tethers can enable payloads to be launched on much smaller launch vehicles, resulting in order-of-magnitude reductions in launch costs. In order for MXER tethers to achieve their potential in real-world application, several key technologies must be developed and demonstrated, including space-survivable tethers incorporating both high-strength and conducting materials, technologies for rendezvous with and grappling of payloads, and techniques for predicting and controlling tether rotation and dynamics.
