If you've ever driven through a cloud of dust that temporarily obscured your view, congratulations: you now have a partial understanding of a problem NASA's Artemis landers will face when they touch down on the Moon. Daniel Stubbs, an aerospace engineer with the Plume and Aero Environments team at NASA's Marshall Space Flight Center in Huntsville, Alabama, spends his days studying how rocket exhaust interacts with lunar regolith - because nothing ruins a historic moon landing like not being able to see the ground.
Stubbs, a native of Trussville, Alabama, who earned a bachelor's, master's, and doctoral degree in aerospace engineering from Auburn University, decided early in his college career he wanted to work for NASA, though the path wasn't immediately clear. In graduate school, he got the chance to work on plume-surface interaction modeling as part of a NASA Early Stage Innovations grant. Now, he's continuing that work - proving that sometimes grad school projects do pay off.
NASA's Apollo missions revealed that lunar regolith - essentially razor-sharp, abrasive particles formed by meteoroids grinding up the Moon's surface over millennia - is a menace to astronauts, spacecraft, spacesuits, and anything else that gets near it. Future lunar explorers will face the same problem, except worse: the new landers are larger, heavier, and have more rocket engines than the Apollo Lunar Module. And unlike those Apollo landers, which left their descent stages behind, these new ones will take off directly from the surface using the same engines and thrusters. Accurately predicting how the rocket plumes interact with the regolith is key to ensuring the lander hardware survives and can actually lift off to meet Orion and bring astronauts home.
"The dust and regolith plume can make it difficult for instruments on the landers to see the surface of the Moon," Stubbs said. "If these instruments don't report correct readings to the guidance computers, it could affect a lunar landing." Also, when a lander takes off, the regolith blasted away could damage scientific instruments or other assets deployed on the surface - because nothing says "giant leap for mankind" like accidentally sandblasting your own equipment.
NASA's Human Landing System program is conducting a ground-based study of rocket engine exhaust plumes and lunar dust in the 60-foot space simulator chamber at NASA's Langley Research Center in Hampton, Virginia. The tests will replicate the conditions lunar landers may experience - and create - when landing on the Moon. The research will help engineers understand aerodynamic forces during descent and ascent, heating at the lander's base, and the potential for a large lunar lander to tip over due to crater formation or surface instability.
When the dust settles - literally - and NASA lands American astronauts on the Moon in 2028, Stubbs will be able to reflect on his work modeling the very plumes he helped predict. Through the Artemis program, NASA aims to send astronauts to explore the Moon for scientific discovery, economic benefits, and to build the foundation for crewed missions to Mars - for the benefit of all, and with hopefully fewer dust-related mishaps.