Ballistic trajectories for Mercury Orbiter missions using optimal Venus flybys, a systematic search

The considered approach, which has been previously studied by Hollenbeck et al. (1973) makes use of a Venus gravity assist. The search for ideal trajectories for Mercury Orbiter missions involves a determination of trajectories with the lowest possible Mercury approach speed. Ideal Venus-to-Mercury transfers and opportunities are discussed. The second part of the reported investigation is concerned with the determination of suitable trajectories for the trip from earth to Venus. On the basis of the obtained data it appears that the best ten trajectories can deliver spacecraft from a low of 720 kg to a high of 1230 kg to orbits with 500 km periapse and 24 hr periods. The corresponding flight times are 790 days and 1243 days.