Tethers Unlimited, Inc.
› Phase I Final Report (PDF)
To enable frequent, low-cost opportunities to deliver nanosatellites to destinations beyond Earth orbit, TUI proposes to develop the "Nanosatellite Tethered High-Orbit Release" (NanoTHOR) module. The NanoTHOR module will enable multiple nanosatellites carried as secondary payloads on upper stages launched into GTO to be injected into Earth-escape trajectories by scavenging orbital momentum and propellant from the upper stage. The NanoTHOR module will utilize a lightweight, re-usable tether to transfer momentum from the rocket stage to the nanosatellite. The use of a rotating tether "multiplies" the rocket's delta-V by the mass ratio of the stage to the nanosat, enabling it to provide both very-high specific impulse propulsion competitive with the best EP thrusters AND short transfer times competitive with chemical rockets. The tether also enables the stage's orbital momentum to be converted to tether rotational momentum to increase the nanosat toss velocity. After completing its mission, the tether can be de-orbited within one orbit period to eliminate collision or debris risks. The nanoTHOR module will provide a low-cost, low-mass means to enable nanosatellites to be launched as ride-share payloads on GEO satellite missions and then delivered to deep-space trajectories. It will therefore enable NASA to affordably launch flotillas of low-cost nanosatellites into heliocentric orbits to conduct searches for NEOs, to study potential targets for manned exploration of asteroids, to provide 'nowcasting' of solar weather conditions, and to serve as communications relays for manned and unmanned missions beyond Earth orbit.