The Exploration Office at NASA’s Johnson Space Center is investigating different strategies for the first human Mars missions. The latest results of this work are summarized in the “Design Reference Mission” which is permanently updated as the research continues [1,2]. The mission that is outlined by the design team involves in situ resource utilization not only for the propellant production (ISPP) but also for the production of crew consumables.

In the course of this work, it was the task of the author of this abstract during his work on the Mars Exploration Study Team to make a comparison of all ISRU options that are suited for this task [3,4]. The goal of the six month study was the down selection of the option that is best suited for a human mission out of the countless ISRU options that are proposed. For this purpose, a detailed computer model of 12 different ISRU options was designed, including a number of different fuels (e.g. CH4, CH3OH, C2H4, CO, H2, ...). This model considers not only the features of the core process (e.g. Sabatier) but also the acquisition, filtering, liquefaction, storage and power requirements as well as mission design.

The process data for the computer model thereby is derived more from results of actual systems and less on previous studies. This input to the model is based on the research done by different universities, industry (especially NASA contractors) as well as NASA itself. It is shown that a number of options that look very good on the paper have to be ruled out for practical reasons.

References: [1] S. Hoffmann, D. Kaplan et al.: “Human Exploration of Mars: The Reference Mission of the NASA Mars Exploration Study Team”, NASA Special Publications 6107, July 1997. [2] B. Drake et al.: “Addendum to the Reference Mission of the NASA Mars Exploration Study Team (V3.0)”, NASA-JSC 28208, May 1998. [3] K. Pauly: “Mars ISRU: Comparison of Options”, Interim Report presented to the NASA Mars Exploration Study Team, March 1998. [4] K. Pauly: “Mars Mission Scenarios Involving In-Situ Resource Utilization”, Diploma Thesis, Institute of Astronautics, Technical University Munich, 1998.