Scientists are keeping a close watch on a roughly 60-meter-wide space rock known as 2024 YR4, which now carries an approximate 4 % chance of colliding with the Moon on 22 December 2032. While it no longer poses a meaningful threat to Earth, the potential lunar impact has serious implications—especially for satellites, spacecraft, and the International Space Station.
What we know so far
The asteroid was discovered on 27 December 2024. Its estimated diameter is about 50-70 m (or about as tall as the Leaning Tower of Pisa). Early in its observation, there was a brief concern that it might hit Earth; at one point the chance for Earth impact peaked around 3 %. However, subsequent observations refined the orbit and ruled out any meaningful risk of Earth impact. What remains is the ~4 % possibility of a Moon strike. The European Space Agency refers to this as “approximately 4 %”.
Why the Moon collision matters
If the asteroid does strike the Moon, the impact would eject a significant amount of lunar material into space. One study estimates up to 10⁸ kg of debris might escape the lunar surface and some of that could reach Earth or Earth orbit. The risk is not to human life on the surface of Earth, but rather to satellites, spacecraft, and any astronauts in orbit. A debris cloud or increased micrometeoroid flux could damage sensitive space assets. Additionally, a visible blast on the Moon could present a spectacular observation opportunity from Earth.
What about defence options?
Space agencies are already discussing mitigation strategies should the risk rise further. One preferred option is deflection—nudging the asteroid off course sufficiently early so it misses the Moon. But knowing the exact mass, structure and composition of the asteroid is critical to modelling a deflection. Without that, deflecting could itself be risky. As a last-resort, more aggressive methods are on the table: smashing the asteroid with a heavy impactor or even using a nuclear device to break it into smaller pieces. Though no nuclear device has ever been detonated for asteroid-defence purposes, the physics suggest a sufficiently powerful blast—on the order of one megaton—could fragment the rock and reduce the threat. (This is purely precautionary at this stage.)
What to expect and what to watch
We won’t know for sure whether impact will occur until the asteroid returns into view again in 2028, giving a much better chance to refine its orbit and impact probability.
If the asteroid does hit the Moon, expect several days of elevated meteoroid activity around Earth orbit—possibly up to 1,000 × normal background levels for satellites.
Even if the Moon is impacted, Earth’s surface is safe—our planet is not at risk of direct strike by this asteroid under current data. The fault zone is lunar, not terrestrial.
For space-operators and astronaut-mission planners, this is a reminder: impacts and debris are not just Earth-surface issues; cis-lunar space and near-Earth orbit are part of the risk environment.
Why this is still worth noting
Even though a 4 % chance might sound small, in the context of large asteroid impacts those odds are significant. Impacts of this size on the Moon are rare—and this may be one of the few times we’re tracking one ahead of time. As noted by the Guardian, “if 2024 YR4 strikes the Moon in 2032, it will (statistically speaking) be the largest impact in approximately 5,000 years.”
Moreover, the fact that scientists are already considering deflection and disruption options illustrates how planetary defence is evolving: from reacting after a strike to preparing in advance.
While dear reader, you can rest assured that your city is safe—this asteroid poses no meaningful risk to Earth for now—the possibility of a lunar impact by 2032 is a scenario worth following. For anyone interested in satellites, lunar science, or planetary defence, this story is a reminder that our space-environment is dynamic, and even the Moon isn’t immune from surprises.
I’ll follow up with updates as new observations come in (especially around 2028) and let you know if the risk changes, or if a mission is announced to intercept or alter the asteroid’s course.