Multiple NEA Rendezvous Mission: Solar Sailing Options

There may be differences between this version and the published version. You are advised to consult the publisher's version if you wish to cite from it. The scientific interest in near-Earth asteroids (NEAs) and the classification of some of those as potentially hazardous asteroid for the Earth stipulated the interest in NEA exploration. Close-up observations of these objects will increase drastically our knowledge about the overall NEA population. For this reason, a multiple NEA rendezvous mission through solar sailing is investigated, taking advantage of the propellantless nature of this groundbreaking propulsion technology. Considering a spacecraft based on the DLR/ESA Gossamer technology, this work focuses on the search of possible sequences of NEA encounters. The effectiveness of this approach is demonstrated through a number of fully-optimized trajectories. The results show that it is possible to visit five NEAs within 10 years with near-term solar-sail technology. Moreover, a study on a reduced NEA database demonstrates the reliability of the approach used, showing that 58% of the sequences found with an approximated trajectory model can be converted into real solar-sail trajectories. Lastly, this second study shows the effectiveness of the proposed automatic optimization algorithm, which is able to find solutions for a large number of mission scenarios without any input required from the user. Nomenclature A : sail area, 2 m   A x : matrix of the dynamics a : solar-sail acceleration, 2 mm s a : semi-major axis, AU c a : solar-sail characteristic acceleration, 2 mm s   bx : vector of the dynamics e : eccentricity , fg : in-plane modified equinoctial elements H : asteroid absolute magnitudê h : orbital angular momentum unit vector , jk : out-of-plane modified equinoctial elements L : true longitude, rad m : total sailcraft mass, kgˆN : unit vector normal to the sail plane r : acceleration r  : mean Sun-Earth distance, 1 AU t : time, s 0 t : departure date U : quality code x : state vector in modified equinoctial elements  : sail cone angle, deg v  : velocity increment, km s  : longitude of pericenter variation, rad  : sail slew rate, deg s  : sail angular acceleration, 2 deg s  : angle between two angular momenta, rad  : shaping parameter  : gravitational parameter of the Sun, 32 km s  : phasing parameter, rad  : …