NASA researchers are conducting the first research of its kind in decades to ensure that spacecraft landings on the potentially unstable lunar surface proceed safely and reliably.
The work at Huntsville, Alabama’s Marshall Space Flight Center, focuses on how rocket exhaust interacts with the Moon‘s surface dust, called regolith, formed over billions of years as surface impacts pulverized the lunar surface. Understanding exactly how the SpaceX and Blue Origin rockets, which are set to bring NASA‘s next crewed Artemis Campaign missions to the Moon, may disturb the surface will be essential to long-term human habitation with routine comings and goings.
Lunar Regolith
From large asteroids to micrometeoroids, billions of years of space objects impacting the lunar surface didn’t just leave large craters but also produced the dusty regolith covering the surface from what were once large boulders.
Despite how it may appear to the naked eye, regolith is not uniform. Mineral composition varies significantly across the Moon, meaning specific locations feature denser mineral deposits than others. Therefore, identifying the ground stability characteristics of different compositions is essential to supporting secure landings.
“Artemis builds on what we learned from the Apollo missions to the Moon. NASA still has more to learn about how the regolith and surface will be affected when a spacecraft much larger than the Apollo lunar excursion module lands, whether it’s on the Moon for Artemis or Mars for future missions,” said Manish Mehta, Human Landing System Plume & Aero Environments discipline lead engineer.
Recreating the Lunar Landing
The NASA Marshall Space Flight Center scientists are recreating not just the type of exhaust the SpaceX and Blue Origin vehicles create but also the lunar conditions. Utah State University came to the team’s aid with a 14-inch 3D-printed hybrid rocket motor. The small-scale engine produces a powerful exhaust stream by igniting solid fuel and pushing through a torrent of oxygen gas, providing a small-scale replica for laboratory use.
Once the Marshall team possessed the engine, they began their laboratory experiments. The work occupied the space flight center’s Component Development Area, where they could conduct 28 of the 30 test fires under vacuum pressure. Next, the testing will move on to NASA’s Langley Research Center, where research can continue using a 60-foot vacuum sphere at the facility and an imitation regolith called Black Point-1.
“Firing a hybrid rocket motor into a simulated lunar regolith field in a vacuum chamber hasn’t been achieved in decades, Mehta said.
“NASA will be able to take the data from the test and scale it up to correspond to flight conditions to help us better understand the physics, and anchor our data models, and ultimately make landing on the Moon safer for Artemis astronauts,” Mehta added.
NASA Prepares for Next Landings
Continuing tests at Langley Research Center will improve NASA’s understanding of lunar landings. Researchers will fire the 3D-printed motor at varying heights, collecting precise measurements of craters formed by the exhaust and regolith particle dispersal patterns.
“We’re bringing back the capability to characterize the effects of rocket engines interacting with the lunar surface through ground testing in a large vacuum chamber — last done in this facility for the Apollo and Viking programs. The landers going to the Moon through Artemis are much larger and more powerful, so we need new data to understand the complex physics of landing and ascent,” said Ashley Korzun, principal investigator for the plume-surface interaction tests at NASA Langley.
“We’ll use the hybrid motor in the second phase of testing to capture data with conditions closely simulating those from a real rocket engine. Our research will reduce risk to the crew, lander, payloads, and surface assets,” Korzun concluded.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.