Engineering Robust and Autocatalytic Architectures for Human Missions to Mars

Abstract

For decades, Mars architectures had been constrained to up to 6 crew members for surface endurances up to 600 days because the increased mass for larger missions implied significantly higher costs. More recently, reusable rockets and mass manufacturing approaches are starting to transform the human spaceflight landscape, offering increased mass to orbit capabilities, dramatically reduced unit costs and a falling cost of access to space. In view of the above, the approach in this work is to turn crew size from a constraint to the primary design variable and explore the design space for larger architectures that could offer increased value, robustness and a potential for growth. This requires more elaborate and flexible approaches to modeling the supply and demand for crew time, going beyond the state-of-the-art. The crew time model in this work is based on the parametric modeling of 533 activities and considers economies of scale and productivity effects from specialization, task focus and learning to estimate time demanded for logistics, utilization, thriving and growth. An architecture screening model integrates the high-resolution crew time model with low-fidelity sub-models for mission aspects like food production and habitat construction, all driven by crew size and surface endurance. Mars architectures from 4-63 crew members in up to 3 nearby sites for up to 10 years were evaluated using new metrics such as the Lifecycle Cost per Non-Logistics Full Time Equivalent person on Mars per year and the Robustness Composite Indicator (ROCI), finding that dual-site designs with 30 to 42 crew strike a balance between affordability to NASA, mission value, high robustness with a self-rescue capability, and potential for autocatalytic growth. A case study proposes a NASA-led, 36-crew, 10-year Mars mission, with broad participation from Artemis Accords member countries. The 27-year program, with an average annual cost of $3.1b peaking at $7b in the mid-2030's, fits within NASA's current deep space exploration budget. This work shifts the focal point for human spaceflight from mass to crew time, supports the study of larger, hitherto unexplored Mars architectures, and finds that larger, multi-site Mars missions could be more cost-effective, robust and sustainable than traditional concepts. The research also supports future work towards new, larger-scale Mars analog missions which could improve our understanding of crew productivity and other factors which vary with mission scale.