Analysis of Launch and Earth Departure Architectures for Near-Term Human Mars

This paper presents a comparative analysis of launch and Earth departure strategies for human Mars missions. A variety of Earth departure architectures are analyzed with regard to their trans-Mars injection capabilities (performance surrogate metric) and equipment and operational requirements (cost surrogate metric); it is assumed that aerocapture and chemical propulsion are used for all maneuvers in Mars vicinity for all architectures. The architectures are based on chemical propulsion (custom stages or Ares V Earth Departure Stage) as well as nuclear thermal propulsion. Consideration is also given to the impact of different Earth departure options on Mars aerocapture and Mars entry, descent and landing. The comparative aspect of the analysis consists of an iso-TMI mass analysis for the different options. Results of the set of architectures indicate that while chemical Earth departure strategies results in a 30 – 50 % increase in the number if Ares V launches required per mission, the associated additional marginal cost may be outweighed by the cost of developing and maintaining a nuclear thermal propulsion capability, as well as the increased marginal cost of nuclear thermal propulsion stages. In addition, chemical Earth departure strategies side-step the sensitive issue of space nuclear applications that would be associated with nuclear thermal propulsion. I