The debris heading for the moon is the four-ton upper stage of a SpaceX rocket launched in February 2015 and is expected to make impact on Mar. 4 at 7:25 ET. Bill Gray, an astronomer who runs Project Pluto, which supplies software to astronomers, first spotted the debris’ trajectory last Friday, writing in a blog post, “It is quite certain it’s going to hit, and it will hit within a few minutes of when it was predicted and probably within a few kilometers.”

The trajectory of the debris was later confirmed by Jonathan McDowell, an astrophysicist at the Center for Astrophysics operated by Harvard University and the Smithsonian Institution, on his Twitter account.

This is not the first time space debris owned by Elon Musk is orbiting in places it maybe shouldn’t. The Chinese government filed a complaint last month with the UN after two “close encounters” with Musk’s satellites forced China’s space station to take evasive action to protect its astronauts. And with more than 30,000 Starlink satellites planned for orbit in the next coming years, the chance of a near miss or collision is likely to rise.

The number of new satellites and spacecrafts entering orbit this year, from companies like Boeing, Amazon, and OneWeb, increases the chances of more uncontrolled crashes, experts say.

“We’re at a time of transformative change in the human use of space,” McDowell told Bloomberg, adding, “We are seeing more and more satellites getting damaged by orbital debris hits. Occasionally satellites get destroyed.”

The debris

The debris comes from SpaceX’s first interplanetary mission seven years ago. The rocket was launched on Feb. 11, 2015, carrying a National Oceanic and Atmospheric Administration (NOAA) satellite named Deep Space Climate Observatory. The satellite monitors real-time solar wind to forecast weather events and takes a full-earth photo every two hours.

After launch, the rocket’s second stage, which is now headed for the moon, did not have enough fuel to return to Earth’s atmosphere or escape Earth’s gravitational pull and has since been chaotically orbiting the planet.  

There is a silver lining to the moon crash. Knowing the exact trajectory of the rocket, the site of its impact, and the time it will land, astronomers will get their first glimpse into what is below the surface of the moon in a way they couldn’t with a random comet impact.

And the collision shouldn’t be cause for alarm. Gray, who initially reported the trajectory, writes in his blog, “How much should we worry about this? Short version: from any ‘safety’ viewpoint, not at all.”