Scientists are considering the possibility of launching a nuclear weapon at an asteroid that could potentially hit the moon in 2032 — but they say more research is needed before taking this forward as an option.
The investigation concerns asteroid 2024 YR4, which reached notoriety shortly after its discovery in December 2024 when scientists (working with limited observations) revealed it had a relatively high chance of impacting Earth in 2032, peaking at 3.1%.
That’s good news for our planet, but the updated tracking also shows the asteroid has a fairly good chance of crashing into the moon — about 4%. A crash of an object that size, and relatively close to Earth, would almost certainly have some effect on us.
Threats to astronauts, spacecraft
If an asteroid the size of 2024 YR4 crashed into the moon, it would produce lunar “ejecta,” kicking up the regolith — the top layer of dust and small rocks on the surface — which would substantially increase micrometeoroid debris in low Earth orbit.
The flux could be up to 1,000 times “above background levels … possibly threatening astronauts and spacecraft” as little space rocks can puncture spacecraft, spacesuits and similar, the researchers wrote in the new study, which was posted Sept. 15 on the preprint server Arxiv and has not yet been peer-reviewed.
While that’s a threat for satellites and the International Space Station (if it does not deorbit in 2031 as planned), any attempt to divert the asteroid could create an even higher risk, the authors warned. There remains great uncertainty about the asteroid’s exact mass, which means any attempt to nudge it off course would also be far from certain. An ill-planned deflection mission could accidentally push the asteroid toward Earth, the researchers wrote.
Scientists do have diverting experience to draw upon: NASA’s DART mission deflected an asteroid moonlet‘s path in 2022. DART sent a kinetic impactor into the moonlet, called Dimorphos, which slightly altered the little space rock’s path around its parent asteroid, Didymos. But the researchers behind the new study concluded that any attempt at deflecting 2024 YR4 would “appear impractical” because of constraints such as not knowing the object’s mass — and having a very limited window to study the object further before its close flyby in 2032.
Just nuke it
The researchers instead consider the idea of breaking up the asteroid. A DART-style spacecraft could be sent to not move the asteroid but to punch it into pieces, they suggest. This is an untested concept, but NASA has several years to think about it given the launch window for such a mission is between April 2030 and April 2032.
Failing that, NASA could send a nuclear mission, detonating a rocket-propelled nuke on or near the asteroid before its approach. This method is also untested but theoretically possible. There would be slightly less time to get that mission ready, but that could launch between late 2029 and late 2031, according to the researchers.
The paper emphasizes that there’s still a 96% chance that the asteroid breezes by the moon with no issues, but the researchers say this situation as an opportunity to further research asteroid-smashing spacecraft.
They call on other researchers to provide estimated build times for spacecraft, and to create more designs — just in case a more serious threat comes by our planetary neighborhood.
