A Russian military satellite maneuvered in “extreme proximity” of a commercial Earth-imaging satellite in recent days in the first known example an unsanctioned rendezvous in low-Earth orbit, according to the orbital intelligence company LeoLabs.

The Russian spacecraft, Kosmos 2612, “conducted a deliberate series of maneuvers toward ICEYE-X36, a US-operated commercial imaging satellite,” LeoLabs said. “Kosmos 2612 closed from hundreds of kilometers away to extreme proximity to ICEYE-X36. It then maneuvered around ICEYE-X36, remained nearby for an extended period, and then began moving away.”

US military officials and independent analysts have tracked Kosmos 2612 since its April launch on a Soyuz rocket from a spaceport in northern Russia. Within weeks, it became apparent that at least four of the six satellites from that launch were stalking ICEYE-X36 after they adjusted orbits to line up with the orbit of the ICEYE spacecraft.

Russia’s modus operandi

The situation remained stable until last week, when Kosmos 2612 began rapidly moving toward ICEYE-X36. By Friday, Kosmos 2612 was holding station 2 to 3 kilometers away before shifting positions ahead of and behind the ICEYE satellite, LeoLabs said. The satellites were within 500 meters (1,640 feet) of one another over the weekend, and “likely quite a bit closer than that,” said Adam Marsh, LeoLabs’ vice president of technical solutions.

LeoLabs operates a global network of radars to track objects as small as 2 centimeters, about the size of a marble, in low-Earth orbit. The proximity of Kosmos 2612 and ICEYE-X36 “occasionally made it difficult to distinguish the two spacecraft independently,” LeoLabs said.

“This was not a routine conjunction or ‘fly by,’” LeoLabs said. “The sequence included a controlled approach, changes in relative position, close-proximity loitering, additional small maneuvers, and a controlled departure. The behavior is consistent with sophisticated rendezvous and proximity operations (RPO).”