There exist crucial gaps in the understanding of engine plume physics that make it impossible to develop reliable, high-fidelity modeling for lunar blast effects. Research has shown that deep cratering will occur on Mars for human-class landers and that it might occur on the Moon for the very large landers planned by NASA for human missions from the Lunar Gateway, and for large landers on the soft rims of young craters or in permanently shadowed craters where the data indicate the soil is much less densified than at the Apollo sites. It is vital to make progress observing, describing, and understanding the physics of erosion and scouring under a supersonic jet, and deep jet-induced fluidization cratering. The physics of deep cratering are very complex and almost no progress has been made by prior researchers since this is a unique area of physics that occurs only for larger rockets landing on planetary bodies. Experimental work, proposed in this effort, is needed using actual rocket thrusters and regolith with adequate instrumentation, in addition to laboratory and low gravity experiments. These results will drive plume modeling leading to development of mitigation requirements for landing larger vehicles on the Moon and Mars while protecting the surrounding hardware.
Accurate modeling of rocket plume effects addresses key knowledge barriers that presently exist in NASA’s Moon-to-Mars exploration strategy. NASA’s technology roadmap calls for increasingly heavy spacecraft to perform lunar surface transportation over the coming decade, as transportation vehicles and their corresponding propulsion systems become larger, adverse effects associated with surface ejecta and cratering will become more severe particularly if extreme ejecta blasts hit the lander or the surrounding lunar region.
The Joint Chiefs of Staff, the Department of State, National Space Council and NOAA, the FAA, and the Department of Defense (Air Force, Intelligence Community) all are looking to understand how plume impingement from lunar landings may disturb the surface and any US assets or territories located there.