Russian military satellite stalks U.S. radar satellite in orbit

Russia and Ukraine are at war on the ground — and two satellites around 550 km above have come to the centre of a similar confrontation. The Russian Cosmos-2612 satellite has changed its orbit repeatedly to approach ICEYE-X36, a commercial radar-imaging satellite registered in the U.S. and whose operator currently supplies radar data to Ukraine.

While no attack of any kind had been established as of 10 am IST on October 18, astronomer and TU Delft lecturer Marco Langbroek had estimated late on the previous day that the two satellites were only 1-2 km apart — considered a very small distance in earth orbit — and expected them to get within metres of each other if their existing trajectories continued.

These manoeuvres, in which one satellite adjusts its path to approach another, are called rendezvous and proximity operations (RPO). Usually, RPOs allow operators to conduct inspections or repairs. In the present instance, however, there is no indication that ICEYE-X36’s operators invited the approach by Cosmos-2612, making it a non-consensual RPO.

Satellite profiles

Cosmos-2612 is one of six military satellites Russia launched on April 16 this year. Moscow has not disclosed its mission or instruments onboard, nor its fuel capacity, which determines what kind of manoeuvres the satellite can undertake in orbit and for how long. ICEYE-X36 was launched in March 2024 and weighs roughly 90 kg. Built by a Finnish company, it has a synthetic aperture radar capable of imaging military deployments and infrastructure.

One ICEYE satellite has supplied data to Ukraine since 2022 as part of an agreement funded by the Serhiy Prytula Charity Foundation. A new agreement in January this year expanded Kyiv’s access to images from the wider ICEYE fleet, consisting of around six dozen satellites. There is at present no public confirmation that Ukraine leases or uses ICEYE-X36. However, the ICEYE fleet counts Finland, Germany, Greece, Poland, Portugal, the Netherlands, and Sweden among its defence partners, and all of them are part of NATO.

In May, five of the six military satellites Russia had launched expended a considerable amount of fuel to change their orbital inclination — the tilt of their orbits with respect to the equator — from 97° to 97.8°, which is closer to the inclination of ICEYE-X36. By August, they were orbiting the earth 600 m to 5.2 km above ICEYE-X36. Then their orbital planes drifted apart, leaving observers less alarmed.

But then Cosmos-2612 began a new programme: its altitude climbed by around 46 km on September 30, and it changed its orbital plane and aligned itself more with ICEYE-X36. On October 12, it descended to get closer to the satellite, leaving it some 475 km behind by October 13. More manoeuvres on October 15 and 16 finally brought the two satellites much closer. All these changes together in the orbit of Cosmos-2612 are difficult to explain away as coincidental.

Possible outcomes

In 2020 as well, the Russian Cosmos-2542 satellite manoeuvred itself to get within 50 km of the U.S. reconnaissance satellite USA 245. What could be unprecedented today is the non-consensual RPO involving a foreign commercial satellite associated with a war.

That said, without knowing more about what Cosmos-2612 is capable of, it remains hard to say what it ultimately plans to do. One possibility is Russia wants to demonstrate that Cosmos-2612 is capable of such an RPO, and intimidate the U.S. into moving ICEYE-X36 away, expending fuel and disrupting its imaging operations. A second possibility, in case Cosmos-2612 is equipped with the corresponding electronics, is it could jam transmissions or otherwise temporarily disable ICEYE-X36.

Third, and perhaps most dangerously, Cosmos-2612 could physically attack ICEYE-X36 and attempt to end its mission. Such an interaction could also produce debris that threatens other spacecraft. Conversely, its Russian operators could miscalculate the parameters of the close approach and unintentionally collide with ICEYE-X36. In 2020, the Cosmos-2543 satellite had released a fast-moving object during what Russia said was a test.

What the law says

Currently, no international law or rule specifies a universal minimum distance between two satellites in earth orbit; the Outer Space Treaty (OST) of 1967 only requires states to have “due regard” for other states’ activities and provides for consultations in the event of a potentially harmful interference. For ICEYE-X36, the U.S. retains legal jurisdiction — but Cosmos-2612 damaging it would not directly imply an armed attack on U.S. territory. NATO has previously said attacks in space could trigger its collective defence provisions as well as that it will decide on a case-by-case basis.

Under the terms of war, an object can become a military objective only if its location, purpose, nature or use contributes to military action and attacking it confers a definitive military advantage. The military use of ICEYE-X36 is not currently publicly established. Other possible outcomes include Russia halting the RPO and explaining the purpose of the manoeuvres. Ukraine can ask ICEYE operators to protect ICEYE-X36 and/or transfer its imaging needs to other satellites in the fleet.

The U.S. has the strongest options, however, including warning Russia, having ICEYE operators plan avoidance manoeuvres, seeking consultations under the OST, seeking compensation under the 1972 Liability Convention should Cosmos-2612 physically damage ICEYE-X36, and imposing sanctions and other lawful countermeasures.