Small-Body Encounters Using Solar Sail Propulsion

摘要

Small-body, high-energy rendezvous and flyby missions have large ΔV requirements, which impose extreme demands on the propellant budget for chemical propulsion. Ion propulsion is a viable alternative, but as the number and difficulty of target objectives increases, it then becomes rapidly unattractive due to increasing launch mass and required thruster life. For solar sails, however, propellant mass is not an issue, and so a large ΔV could be realized without implementing gravitational assists, which prolong mission duration and restrict launch opportunities. High-energy, small-body mission scenarios are analyzed using a parameterized approach to trajectory optimization. Optimal rendezvous trajectories to short-period comets are described. A solar sail mission to comet Wirtanen is presented, which could reduce launch mass by 44% and trip time by 68%, over the previous baseline Rosetta mission. High-performance sails could be used to permit fast flyby intercepts of newly discovered long-period comets. Trajectories to comets during past apparitions have been generated, including comet Hale-Bopp, to demonstrate the feasibility of intercepting a new long-period comet using a solar sail at perihelion or orbit node. Earth return or secondary flybys are also investigated. High ΔV, multiple asteroid surveys of up to four main-belt asteroids are investigated. It is shown that if solar sail propulsion were used for the Dawn mission, a launch mass reduction of up to 33% may be possible.