Chinese researchers appear to have revealed a previously unknown satellite-to-satellite refuelling operation in high Earth orbit, putting the country at the forefront of a technology that could reshape the space race.

In a paper undergoing peer review for the Journal of Deep Space Exploration, the team said China had “successfully provided room-temperature propellant refuelling for a high-orbit BeiDou satellite for the first time”.

The researchers from the state-funded Deep Space Exploration Laboratory gave no details about the operation. They said it had given China valuable experience but emphasised the need to develop technologies for transferring extremely low-temperature propellants, which offered better performance for large spacecraft and deep-space missions.

BeiDou is China’s answer to the US Global Positioning System or GPS, a globe-spanning satellite network that provides positioning, navigation and timing services. It underpins everything from smartphone maps and financial transactions to military drone swarms and hypersonic missile guidance.

BeiDou is China’s answer to the US Global Positioning System or GPS, a globe-spanning satellite network that provides positioning, navigation and timing services. It underpins everything from smartphone maps and financial transactions to military drone swarms and hypersonic missile guidance.

Launching a replacement when a satellite runs low on propellant is an expensive and time-consuming process, while in-orbit refuelling could extend a satellite’s life by years.

For the BeiDou constellation, that would mean a more resilient, continuously available navigation service capable of outlasting and outmanoeuvring rival systems in a crisis.

Scientists from the Chinese Academy of Sciences (CAS) went further, naming the two spacecraft involved and even the amount of fuel supplied in a separate study published by the International Journal of Aerospace Engineering in April.

According to the CAS researchers, the servicing satellite was Shijian-25, which was launched in January 2025 to refuel, repair and remove space debris from other spacecraft in orbit.

“In February 2025, Shijian-25 successfully refuelled the BeiDou-2 G7 satellite with 142kg (313lbs) of propellant, extending its lifespan by eight years,” they wrote. After presenting the case as a real event, the team simulated a rendezvous between the same two satellites, starting on August 31, with Shijian-25 manoeuvring towards BeiDou-2 G7 over two days.

If confirmed, this would be only the second known case of satellite refuelling in high orbit. The first took place in July 2025, when Shijian-25 docked with and reportedly supplied fuel to Shijian-21 in geostationary orbit. That operation was closely watched around the world, including by US spy satellites that flew in for a closer look.

The first took place in July 2025, when Shijian-25 docked with and reportedly supplied fuel to Shijian-21 in geostationary orbit. That operation was closely watched around the world, including by US spy satellites that flew in for a closer look.

So far, China is the only country known to have carried out satellite-to-satellite refuelling in orbit. The technology’s military implications have raised concerns in Washington.

In January, US Space Command chief General Stephen Whiting warned that China’s ability to refuel satellites could give it an advantage in a future conflict in orbit. “Dogfighting in space takes fuel. And if the Chinese are refuelling their effectors, what happens when we run out of manoeuvre in a fight,” he asked at the Space Mobility Conference in Florida.

The technology could also play a critical role in the new “moon race”, allowing spacecraft to make repeated journeys between Earth and the moon to build and supply lunar bases – or potentially fight in a future conflict in cislunar space.

Neither paper cited a source for the claimed refuelling. Both Shijian-25 and BeiDou-2 G7 have been closely tracked by the US Space Force and their orbital records show they never came close enough to dock in February last year – or at any point in the first half of 2025.

According to Jonathan McDowell, a former Harvard astrophysicist and expert in satellite tracking, BeiDou-2 G7 remained in geostationary orbit at around 110.5 degrees east from January to July 2025.

Shijian-25 was tracked in a transfer orbit after its January 7 launch before disappearing from US tracking for six days. When it was picked up again on January 13, it was drifting near 120 degrees east and by the following day had settled there, where it remained until June before moving to 127 degrees east.

“Could it have visited 110E during the six days it was out of sight? Not at the rate it was drifting on January 13,” McDowell said. “And I don’t think a rendezvous and refuelling is plausible on that timescale.” Unless the US Space Force had been tracking the wrong objects, “the rendezvous postulated in early 2025 could not have happened”, he added. The South China Morning Post has contacted the Chinese teams for comment.

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