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

Abstract

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.

Liquefaction and Storage of In-Situ O2on the surface of Mars

“…P roposed human missions to Mars have always relied on launching multiple large cryogenic upper stages into Low Earth Orbit and having them assembled prior to firing into a Martian transfer orbit. 1,2 In order to minimize the number of launches required, the payload mass delivered to the Martian surface must be minimized. On the return stage (often called the ascent stage) between 75% to 80% of the mass is propellant, of which approximately 80% of that is liquid oxygen.…”