Speakers
Description
Background of the study
The potential for laser-thermal propulsion has recently been proposed to realize near-term rapid transit to Mars missions (Duplay et al., Acta Astro., 2022, DOI: 10.1016/j.actaastro.2021.11.032). The ability to reach Mars in 45 days would largely eliminate the long-term risk from GCR exposure and greatly facilitate human exploration and potential settlement of Mars. A rapid return mission is more challenging, since laser thermal propulsion requires a large, high-power (GW-class) laser at the location of the impulsive maneuver. Traditionally, it has been assumed that a directed-energy infrastructure for solar system transportation would have to await industrialization of the other planets. In this talk, we will explore concepts that would enable laser thermal propulsion to be used on both ends of a humans-to-Mars mission in the near term, possibly even immediately following the first few crewed Martian missions.
Methodology
Astrodynamics solutions done through patched conics and Lambert’s algorithm confirm the viability of a six-month round-trip mission to Mars, consisting of a two-month outbound flight, a one-month stay at Mars and a three-month return to Earth. The one-month surface stay could alternatively be swapped out for a synodic period surface stay (2.1 years). These solutions do not require a delta-V beyond the expected capabilities of a laser-thermal system. A summary of ongoing experimental work at McGill University to support theoretical predictions for the performance of laser-thermal propulsion is provided, with expected testing of a laboratory-scale, 3-kW-class prototype thruster to commence in 2023. The potential of transporting a GW-class laser array to Mars and then powering it via in-situ resource utilization is examined.
Results
The energy that would need to be produced on Mars to power the laser-thermal burn back to Earth is found to be feasibly provided via solar photovoltaics, leaving energy storage and power delivery as the main challenge. Several options are explored, including lithium-ion battery storage, chemical energy storage in propellant form to be released on demand, and other in-situ options. The notional capability of the proposed SpaceX Starship vehicle is used as the baseline for the infrastructure that will be available. A tentative solution that could be enabled with a small number of missions would be to use MHD power generation via the exhaust of a Starship Raptor engine fueled by in-situ propellant production.
Conclusion
The early deployment of robust infrastructure that can safely and quickly deliver humans to and from Mars would greatly increase the attractiveness and of realizing long-term Mars settlement in the coming decades.
