Astronomers have observed two Russian military satellites passing within 3 metres (10 feet) of each other in an unexplained manoeuvre. The COSMOS 2581 and COSMOS 2583 satellites, launched by Russia ’s space agency Roscosmos in February 2025, performed the operation last week while orbiting at an altitude of around 585 kilometres. The incident. which was tracked by US-based space situational awareness firm COMSPOC. has raised concerns about space-based surveillance and orbital collisions . “This week we observed a complex proximity event involving Russian satellites,” COMSPOC wrote in a post to X, alongside a simulation of the event. “This wasn’t a coincidental pass – COSMOS 2583 performed several fine manoeuvres to maintain this tight configuration... Whatever Russia is testing, it’s sophisticated.” Russia has not disclosed the specific purpose of the satellites, though space analysts noted that one of them released a “sub-satellite” referred to as Object F.…