Yikes! A commercial Iridium communications satellite and a “presumably-defunct” Russian Cosmos spacecraft smashed into one another on Tuesday, more than 490 miles above northern Siberia. It’s the first ever sat-on-sat collision, SpaceFlightNow.com reports.

“The U.S. space surveillance network detected a large number of debris from both objects,” NASA’s Nicholas Johnson says. For now, the International Space Station appears to be okay. But it’s not yet clear whether that debris “poses a risk to any other military or civilian satellites,” the website adds.

According to NASA, of the 6,000 satellites sent into orbit since 1957, about 3,000 remain in operation.