- A secretive Russian satellite broke apart in Earth's orbit, the US Space Force said on Monday.
- Kosmos 2499 launched secretly and made "suspicious" maneuvers to complete a mysterious mission.
- The satellite's possible explosion-induced debris field could last a century, according to NASA.
A mysterious Russian satellite with a shady mission has broken apart in Earth's orbit, creating a hazardous cloud of debris zipping around the planet and menacing other satellites, US Space Force announced.
The 18th Space Defense Squadron said on Twitter Monday that it had confirmed a satellite called Kosmos 2499 had broken apart into 85 pieces.
—18th Space Defense Squadron (@18thSDS) February 7, 2023
Previous collisions and satellite break-ups have created far larger and more hazardous debris fields than this.
But the pieces of Kosmos 2499 are orbiting at an altitude of about 745 miles — so high that they'll probably be there for a century or longer before Earth's atmosphere drags them down and burns them up, according to NASA.
Kosmos 2499 is one of three satellites that Russia launched secretly from 2013 to 2015. Its beginning is even more mysterious than its end.
NASA and the US Department of Defense did not immediately respond to Insider's requests for comment.
The satellite was launched secretly and made 'suspicious' maneuvers in orbit
On Christmas Day 2013, Russia launched a small Rokot rocket into the skies above Plesetsk, carrying three military communications satellites into orbit.
It seemed like a standard launch, until space trackers noticed that the Rokot had released a fourth object into orbit, according to Anatoly Zak, an English-language reporter who covers Russia's space program and runs Russianspaceweb.com.
A few months later, Russia admitted to the United Nations that it had launched a fourth satellite, which came to be known as Kosmos 2491. Its purpose was unclear.
Russia launched another secret satellite in May 2014, and it soon began maneuvering itself in orbit, dropping and raising its altitude until it brought itself "suspiciously close" to the rocket stage that had delivered it to orbit, according to Zak. The US military designated the object Kosmos 2499.
For nearly half a year, this mystery satellite trailed its rocket stage and maneuvered up close to it repeatedly. Then it transmitted telemtry data back to Earth in Morse code, according to Zak.
The bizarre behavior led to speculation that Russia was testing technology to follow or wreck other satellites, according to Space.com.
The head of Roscosmos at the time, Oleg Ostapenko, assured the world in a December 2014 press conference that Kosmos-2491 and Kosmos-2499 were not "killer satellites," Zak reported. Ostapenko said the satellites had peaceful, educational purposes and that "they completed their mission." Zak said the Roscosmos chief never specified what that mission was.
A similar Rokot launch sent a third unregistered satellite into orbit the next year.
The first secret satellite, Kosmos 2491, broke apart in 2019. Kosmos 2499 just met the same fate.
The satellite may have exploded, rather than crashing
The cause of the satellite's disintegration is not yet clear.
Brian Weeden, a space-debris expert at the Secure World Foundation, told ArsTechnica that he doesn't think a collision caused it, since two of the secretive satellites have gone out like this.
"This suggests to me that perhaps these events are the result of a design error in the fuel tanks or other systems that are rupturing after several years in space rather than something like a collision with a piece of debris," Weeden told ArsTechnica.
That aligns with a preliminary analysis by LeoLabs, a company that tracks objects in Earth's orbit. The company tweeted that its early data "points toward a low intensity explosion," likely from the satellite's propulsion system.
LeoLabs said its models had "moderate confidence" in this finding.
"As more of the fragments get cataloged and included in the analysis we will be able to provide a more definitive cause of the event," the company wrote, adding that "understanding why these types of events occur is key to preventing them in the future."