A satellite belonging to Russia disintegrated, leaving a cluster of fragments that could remain in the Earth’s atmosphere for a period of time.

On the night of Jan. 3, the 18th Space Defense Squadron (18th SDS) of the US Space Force, the unit responsible for monitoring man-made items in orbit, reported the disintegration of the Kosmos 2499 spacecraft.

On Monday, the 18th SDS reported via Twitter that the breakup event created at least 85 bits of traceable debris orbiting Earth at 726 miles (1,169 kilometers). This large amount of space junk will probably take over a hundred years to descend due to atmospheric drag.

“According to Ostapenko, the satellites were developed in cooperation between Roscosmos and the Russian Academy of Sciences and were used for peaceful purposes, including unspecified research by educational institutions,” Anatoly Zak wrote. “‘They completed their mission,’ Ostapenko said, without elaborating on that mission.”

The 18th SDS did not attempt to guess the reason for the separation of Kosmos 2499, and that is only one of the many unsolved questions related to it.