Dust from Asteroid Mining Could Turn Into Another Space Junk Hazard

By Sarah Zhang on at

There is gold out there on asteroids. Silver and platinum and titanium, too. And if we’re seriously going to mine asteroids, it might be easier to tow them closer to Earth. But that could be serious trouble for satellites, according to new calculations by astrophysicists.

NASA was recently considering an Asteroid Redirect Mission, where it would tow a bus-sized asteroid into orbit around the moon for. (It ended up choosing a plan to pluck a boulder off an asteroid and place it in lunar orbit, instead.) But relocating an asteroid closer to Earth to better mine its resources is a not unrealistic plan that deserves some serious thought. And in the case of astrophysicists, some serious maths.

New Scientist reports on a paper recently uploaded to ArXiv that talks about the danger of dust coming from asteroids being drilled and hammered for precious metals. Of special concern is satellites in geosynchronous orbit. These satellites are in an orbit that takes them to the same place in the sky at the same time everyday, making them especially important for communications and defence. Here’s what might happen:

According to Casey Handmer of the California Institute of Technology in Pasadena and Javier Roa of the Technical University of Madrid in Spain, 5 per cent of the escaped debris will end up in regions traversed by satellites. Over 10 years, it would cross geosynchronous orbit 63 times on average. A satellite in the wrong spot at the wrong time will suffer a damaging high-speed collision with that dust.

The study also looks at the “catastrophic disruption” of an asteroid 5 metres across or bigger. Its total break-up into a pile of rubble would increase the risk to satellites by more than 30 per cent.

There’s not much danger from NASA’s planned mission, but larger-scale asteroid mining could add real risks. And there’s a lesson we should have learned from mining on Earth: There is no mining without waste.

[New Scientist, ArXiv]

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