Trajectory Options to Pluto via Gravity Assists from Venus, Mars, and Jupiter

Analytic and numeric techniques are used to assess trajectory options for the Pluto Express sciencecraft for a launch early in the next decade. The constraints placed on the Pluto Express trajectory for this study are severe—total  ight time to Pluto of 12 years or less using a Delta-class launch vehicle. In addition, no  ybys of Earth are permitted. Suitable trajectories are found with launch windows before, near, and after the date of the baseline launch. All of these trajectories take advantage of a gravity assist with Jupiter, and all use two or three gravity assists with Venus before arriving at Jupiter. In two cases, a Mars gravity assist is used in conjunction with three Venus gravity assists. Several asteroid  yby opportunities are presented for the baseline mission and for a backup trajectory, which launch in March 2001 and July 2002, respectively. For example, a  yby of the asteroid Seraphina (which has a radius of 32 km) can be accommodated in the baseline mission for an additional deterministic delta-velocity of 0.12 km/s, well within the capability of the system.