Near-Earth Asteroid Missions Using Tether Sling Shot Assist

A new space exploration technique, called tether sling shot assist, is examined for near-Earth asteroid sample return missions. A spacecraft eying near an asteroid can attach itself to the asteroid using a space tether and an anchor device. After attachment, thevelocity vector ofthespacecraft relative totheasteroid canberotated, thereby modifying its heliocentric velocity. The link to the anchoring device can then be severed, and the spacecraft can reel the tether back for reuse. A simplieed analysis is presented of the problem, and the technical issues related to this maneuver are discussed. A trajectory analysis software is also developed and implemented to determine the possible trajectories of near-Earth asteroid sampling missions. For each trajectory, the strengths and weaknesses of different mission scenarios are highlighted. When combined with chemical propulsion, tether sling shot assist leads to very signiecant payload mass gains over conventional all-chemical propulsion systems.