Russian ‘inspector’ satellite falls to Earth

A Russian satellite built to maneuver alongside and inspect other countries’ spacecraft up close fell back to Earth on September 12, but the object that came down may not have been the real satellite, according to Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics who tracks satellite activity.

The satellite, Kosmos-2558, launched from Plesetsk Cosmodrome on August 1, 2022, aboard a Soyuz-2-1v rocket. It belongs to Nivelir, a Russian military program of co-orbital “inspector” satellites, built to fly in close formation with a target spacecraft rather than photograph territory from a distance like a conventional reconnaissance satellite.

Within days of launch, independent satellite trackers found that Kosmos-2558’s orbital plane matched that of USA-326, a classified U.S. National Reconnaissance Office satellite launched earlier that year. Over the following three years, Kosmos-2558 repeatedly adjusted its orbit to stay close to USA-326, at one point passing within about 31 kilometers (19 miles) of the American satellite in April 2023.

Kosmos-2558 stopped performing its regular orbit-maintenance burns around April 2025, and its orbit began decaying naturally, according to space journalist Anatoly Zak. On June 26, 2025, U.S. Space Force trackers cataloged a new object, designated 2022-089C, that appeared to separate from the inactive satellite. That object, referred to by trackers as Object C, has continued making its own engine burns since, including a maneuver in July 2025 that brought it within roughly 81 kilometers (50 miles) of USA-326.

The Kosmos-2558 satellite photographed in orbit. Phoyto by Center for Strategic & International Studies and High Earth Orbit Robotics

McDowell said he still questions whether Object C is actually the original Kosmos-2558 spacecraft, and whether what U.S. trackers had been following as Kosmos-2558 since April 2025 was really a discarded module or a smaller sub-satellite. He pointed to the fact that Russia never registered an additional payload for the mission with the United Nations, as required for new satellites, which he said supports that theory. Russian authorities have not commented on the satellite’s status or on McDowell’s assessment.

This is not the first Nivelir-family satellite to draw scrutiny from U.S. officials. In July 2020, a related satellite, Kosmos-2543, released a high-speed object near another Russian satellite in an incident U.S. Space Command said at the time amounted to a weapons test. “Russia conducted a non-destructive test of a space-based anti-satellite weapon,” the command said in a statement. Russia has described its Nivelir-series satellites as inspection systems meant to monitor the condition of its own spacecraft.

It remains unclear what became of the reentered object’s mission equipment, whether Object C carries any sensors of its own, or whether Russia plans further maneuvers near USA-326. Object C was continuing its periodic orbit-boosting burns as of McDowell’s September 13 update.