Mysterious Russian satellites are now breaking apart in low-Earth orbit

A mysterious Russian satellite whose mission is unknown has come crashing down in Earth’s orbit, creating a dangerous cloud of debris that travels rapidly around the planet and threatens other satellites, according to an announcement from the US Space Force.

The 18th Space Defense Squadron confirmed on Twitter Monday that it had watched a satellite called Kosmos 2499 break into 85 pieces.

Previous collisions and satellite breakups have created debris fields much larger and more dangerous than this.

But the pieces of Kosmos 2499 are orbiting at an altitude of about 1,200 kilometers, so high that they will probably stay there for a century or more before Earth’s atmosphere drags them down and burns them up, according to NASA.

Kosmos 2499 is one of the 3 satellites that Russia secretly launched between 2013 and 2015. Its beginning is even more mysterious than its end.

It seemed like a standard launch, until space trackers noticed that the Rokot had put a fourth object into orbit, according to Anatoly Zak, an English-language reporter who covers Russia’s space program and runs

A few months later, Russia admitted to the United Nations that it had launched a fourth satellite, which became known as Kosmos 2491. Its purpose was unclear.

Russia launched another secret satellite in May 2014, and it soon began maneuvering in orbit, lowering and raising its altitude until it came “suspiciously” close to the rocket stage that had launched it into orbit. The US military recognized the Kosmos 2499 object.

For almost half a year, this mysterious satellite followed the stage of its rocket and maneuvered close to it repeatedly. It then transmitted telemetry data back to Earth in Morse code.

The strange behavior led to the belief that Russia was testing technology to track or destroy other satellites, according to

The head of Roscosmos at the time, Oleg Ostapenko, assured the world at a December 2014 press conference that Kosmos 2491 and Kosmos 2499 were not “killer satellites.”

Ostapenko said the satellites were for peaceful and educational purposes and had “completed their mission.” Zak said that the head of Roscosmos never specified what that mission was.

A similar launch by Rokot put a third unregistered satellite into orbit the following year. The first secret satellite, Kosmos 2491, broke up in 2019. Kosmos 2499 just suffered the same fate.