Fast Mars Free-Returns via Venus Gravity Assist

摘要

Mars free-return trajectories that use a Venus flyby either before or after the Mars encounter are found, and an alternative launch opportunity for the Inspiration Mars mission is identified. Launch dates are searched from 2015 to 2060, and focus is placed on identifying opportunities that have a short total TOF (i.e. that are "fast"), so that they may be used for a human mission to flyby Mars (similar to that proposed for Inspiration Mars). Constraints on Earth launch V_∞ and Earth arrival V_∞ are based on those used for the nominal Inspiration Mars opportunity in 2018. A set of near-term candidate trajectories are found using the gravity-assist path Earth-Venus-Mars-Earth. One such candidate, with launch date on November 22, 2021, has Earth launch and arrival V_∞ of 4.50 km/s and 6.53 km/s, respectively (both lower than the nominal Inspiration Mars trajectory), and with a total flight time of 582 days. Venus free-return opportunities are also found, with promising application for a human flyby mission to Venus.