Departure Phase Aborts for Manned Mars Missions via Lunar and Orbital Safe Havens
- Paper number
IAC-07-B3.I.01
- Author
Mr. Adam Dissel, University of Maryland, United States
- Year
2007
- Abstract
NASA has set its sights on the resumption of human activity on the Moon and the expansion of manned missions to Mars. The paramount design requirement of these space endeavors is the protection of the crew. Contingency plans and abort options are key elements of any system designed to safeguard human lives. Accordingly, stated requirements stipulate the provision of an abort capability throughout the mission. For manned Mars missions, past abort analyses have focused on the interplanetary portion of the transfer. The relatively short departure phase lasting from mission initiation until Earth sphere of influence exit has not received attention. The focus of the present investigation is the formulation and analysis of possible abort modes during this phase. Though of short duration, the departure phase follows one of the mission’s principal propulsion maneuvers, events where manned spacecraft have historically experienced failures, and is also the mission segment where the spacecraft systems are first put into cooperative operation. The high probability of experiencing early failures necessitates inclusion of a spacecraft departure phase abort capability. This study utilized present and supposed habitation and logistics emplacements in Earth orbit and on the lunar surface as possible safe haven destinations for an aborted Mars spacecraft and sought to determine the feasibility of leveraging these assets to provide the desired abort capability. Earth-Mars transit trajectories were determined using an iterated approach to the patched conics approximation. Full transfer trajectories were created for candidate mission classes and solved for every year of opportunity across the fifteen-year Earth-Mars inertial period. Both orbital and Moon abort modes were analyzed for aborts initiated at every point along each of these departure trajectories. Abort results were optimized for minimum propellant cost over a range of constrained abort durations ranging from one to thirty days. Optimization results for the orbit abort mode indicate that, given the inclination and right ascension offsets between target and departure orbits, realistic aborts require dual-leg abort transfers lasting several weeks. Depending on Moon position relative to the departure orbit, the Moon abort mode can enable aborts that are significantly shorter duration with less propellant expenditure. Optimization of the Moon abort mode revealed that acceleration or delayment of the departure date to obtain a beneficial lunar alignment only minimally impacts the interplanetary transfer propulsive requirements. The abort requirements indicate that departure phase abort capability may be achieved by many candidate Mars system architectures.
- Abstract document