The statistics of flight opportunities to accessible near-Earth asteroids

A statistical study has been carried out of the availability of favourable flight opportunities to near-Earth asteroids with orbits similar to the Earthʹs. Emphasis is given to rendezvous-type mission profiles employing two-burn impulsive transfers. Velocity-optimized Lambert trajectories for a sample of 27 actual objects were calculated and compiled in a database. The velocity and flight time statistics of the resulting 1200 different solutions covering a period of 11 years have been investigated and discussed. Comparison with typical flight profiles to the Moon and near planets has revealed flight opportunities to 5 objects within a decade from the present requiring less ΔV than favourable flight opportunities to Mars or Venus. One of the objects involved, 1999 AO10, can be rendezvoused with using a total velocity increment that is smaller than that required to establish a lunar orbiter. The use of slow flybys for the most scientifically appealing targets is illustrated through an example trajectory involving the C-class binary object 1996 FG3. The challenges and opportunities for doing science in proximity to such small objects are also discussed.