The large landing vehicles planned for NASA’s upcoming moon missions will throw up large amounts of dust from the lunar surface, posing a possible danger to orbiters.
Planned moon missions with large landers may stir up clouds of dust from the lunar surface, which could be dangerous for orbiters or even space stations.
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| Artist’s depiction of the Blue Moon lander, which NASA has selected for its Artemis V mission Blue Origin |
Later this decade, NASA hopes to return humans to the surface of the moon with its Artemis programme. Two companies, SpaceX and Blue Origin in the US, have been contracted to develop landers that can take humans to the surface by 2025 at the earliest.
However, Philip Metzger at the University of Central Florida says there may be a complication. His analysis shows that large landers on the moon could kick up huge amounts of dust as they touch down. Since the moon doesn’t have a strong magnetic field or an atmosphere like we have on Earth to trap the dust, it could escape into space and damage passing spacecraft.
“As we begin more activity on the moon, the rocket exhaust from landings is going to be spraying more soil off the moon up into these orbital altitudes,” says Metzger. “Within a few decades I think this is going to be a very serious problem.”
Using mathematical models, Metzger studied how much dust would be kicked up by landers weighing over 40 tonnes – eight times the Apollo landers but a mass that NASA has considered for future lunar landers. He found they would kick up millions of pieces of dust that would easily reach the escape velocity of the moon, 2.7 kilometres per second, and escape its gravitational pull.
This small dust could then travel through lunar orbit and hit any orbiters passing overhead, particularly any in low lunar orbit less than 110 kilometers above the surface, with millions of impacts per square metre. “The dust will be impacting at hypervelocity,” says Metzger, meaning thousands of metres per second. While unlikely to completely destroy a spacecraft, this could degrade radiators, solar arrays or scientific instruments, says Metzger.
Also of concern would be NASA’s planned Lunar Gateway space station currently in development, designed to orbit between Earth and the moon but frequently passing near the moon. “NASA’s Gateway is going to be hit by many, many tiny particles,” says Metzger – 10,000 impacts per square metre every time it swoops past the moon. While not causing major damage, this could slightly erode the station’s exterior.
Mihaly Horanyi at the University of Colorado Boulder, who worked on NASA’s LADEE moon orbiter in 2013, isn’t sure how big the problem would be. “It shouldn’t be an issue unless you happen to be flying right over the moment of landing,” he says. “I don’t believe this is a real hazard.”
Ian Christensen from the Secure World Foundation in the US, however, says the study “highlights the need for improved lunar coordination” as lunar activity ramps up, with private companies and other nations such as China also planning upcoming landings. “As the tempo of lunar activity increases, it will be necessary to find ways to mitigate the creation of debris.”
NASA and SpaceX did not respond to a request for comment. Blue Origin declined to comment.
Metzger says a solution might be to have thrusters placed high above the ground, as planned on SpaceX’s Starship lander, which will have its thrusters at the top of the vehicle rather than the bottom. In the longer term, it might be necessary to start building landing pads on the moon that could absorb the thrust of spacecraft touching down, he says.
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