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.
Later this decade, NASA hopes to return humans to the surface of the moon with its Artemis programme. Two companies in the US, SpaceX and , have been contracted to develop landers that could take humans to the lunar surface by 2025 at the earliest.
However, 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鈥檛 have a strong magnetic field or an atmosphere to trap the dust, like we have on Earth, it could escape into space and damage passing spacecraft.
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鈥淎s 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,鈥� says Metzger. 鈥淲ithin a few decades, I think this is going to be a very serious problem.鈥�
Using mathematical models, Metzger studied how much dust would be kicked up by landers weighing over 40 tonnes 鈥� eight times the mass of the Apollo landers 鈥� such as the SpaceX and Blue Origin lunar vehicles. He found they would kick up millions of pieces of dust that would easily reach the escape velocity of the moon, 2.4 kilometres per second, and escape its gravitational pull.
This dust could then travel through lunar orbit and hit any orbiters passing overhead, particularly any in low lunar orbit less than 110 kilometres above the surface, with millions of impacts per square metre. 鈥淭he dust will be impacting at hypervelocity,鈥� says Metzger, meaning thousands of metres per second. While unlikely to completely destroy a spacecraft, this could degrade radiators, solar arrays or scientific instruments, he says.
Also of concern would be NASA鈥檚 planned Lunar Gateway space station, currently in development, which is designed to orbit between Earth and the moon, and will frequently pass near the moon. 鈥淣ASA鈥檚 Gateway is going to be hit by many, many tiny particles,鈥� says Metzger, around 10,000 impacts per square metre every time it swoops past the moon. While not causing major damage, this could slightly erode the station鈥檚 exterior.
at the University of Colorado Boulder, who worked on NASA鈥檚 LADEE moon orbiter in 2013, isn鈥檛 sure how big the problem would be. 鈥淚t shouldn鈥檛 be an issue unless you happen to be flying right over [at] the moment of landing,鈥� he says. 鈥淚 don鈥檛 believe this is a real hazard.鈥�
at the Secure World Foundation in the US, however, says the study 鈥渉ighlights the need for improved lunar coordination鈥� as lunar activity ramps up, with private companies and other nations such as China also planning upcoming landings. 鈥淎s the tempo of lunar activity increases, it will be necessary to find ways to mitigate the creation of debris,鈥� he says.
NASA and SpaceX didn鈥檛 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鈥檚 Starship lander, which will have its thrusters at the top of the vehicle. In the longer term, it might be necessary to build landing pads on the moon to absorb the thrust of spacecraft touching down, he says.
arXiv
