Trajectories to Jupiter via gravity assists from Venus, Earth, and Mars

Gravity-assist trajectories to Jupiter, launching between 1999 and 2031, ar e identified using patched-conic techniques. The classical trajectories, su ch as the Venus-Earth-Earth gravity assist, and many less conventional path s, such as Venus-Mars-Venus-Earth, are examined. Flight times of up to abou t seven years are considered. The DeltaV-optimized results confirm that Ven us-Earth-Earth is the most effective gravity-assist trajectory type, with l aunch opportunities occurring almost every year and launch vis viva for bal listic trajectories as low as 9 km(2)/s(2). If the Earth is excluded as a f lyby body, Venus-Venus-Venus gravity assists are typically the best option, with launch vis viva for ballistic trajectories as low as 30 km(2)/s(2), a lthough in some years nonconventional paths are better, such as a ballistic Venus-Mars-Venus-Venus trajectory in 2012, with a launch vis viva of 16 km (2)/s(2). NonconventionaI paths, such as Venus-Mars-Venus-Earth with a 3.7- year flight-time trajectory in 2021, can occasionally decrease the time of flight significantly, at very minor DeltaV cost, when compared with the cla ssical types.