Flight Opportunities from Mars to Earth for Piloted Missions Using Continuous Thrust Propulsion

Abstract

For a piloted Mars mission, the inbound flight (Mars to Earth) is actually the most restricting space-part of the mission – especially if short flight times and short stay times at Mars are required. In this paper, different electric propulsion systems (different thrust levels, specific impulses, and thrust to weight ratios) and different flight strategies for a crewed return from Mars are analyzed and compared to high thrust propulsion systems (chemical and nuclear thermal). This is done with respect to feasibility, flight times, propellant consumption, and influence on the roundtrip problem for launch opportunities within 2016-2031. It is demonstrated that with moderate continuous thrust levels and specific impulses (100N, 3000 s) – even for short stays at Mars – Earth return trips are feasible with moderate propellant needs and within reasonable inbound flight times of 200 to 350 days.