Chinese Satellites Complete First High-Altitude Rendezvous for Possible Groundbreaking Refueling

Two Chinese satellites have completed what could be a first for in-space rendezvous and refueling efforts. They came together in a geosynchronous orbit and have since maintained a steady orbit together. Although unconfirmed, this is thought to be the first orbital refueling at such a height—the two satellites are currently over 20,000 miles from Earth.
Orbital refueling is an important component in keeping satellites and space stations in low Earth orbit flying, but any efforts beyond that have been merely speculative until the past few years, when serious efforts from a range of private and national entities have explored its possibilities. China may have gotten ahead of the curve with this latest docking, though, in an impressive world first that raises serious concerns for satellites from nations and entities that align themselves differently from China’s goals and ambitions.
In January, a satellite designated SJ-25 was launched “for the verification of satellite fuel replenishment and life extension service technologies,” according to the Chinese state-owned designer, Shanghai Academy of Spaceflight Technology (via Ars Technica). Sometime last week, it matched orbits with the SJ-21 satellite, which previously conducted space debris manoeuvring tests in 2021 and has remained in a geosynchronous orbit ever since.
Last week, the two satellites matched orbits and seemingly docked together. Analysts believe the newer SJ-25 has likely proven refueling is possible even for geosynchronous satellites without the need for a manned crew to facilitate it. In an effort to prove this, two US Space Force’s inspector satellites have positioned themselves in closer orbits to SJ-25 and SJ-21 for improved optics.
Although this is an impressive use of technology to extend the lifespan of a satellite even so far out as these, it’s raising concerns among the US Space Force that such satellites could also be used to attack their own craft in the vicinity. If spacecraft can autonomously match the orbits of satellites, dock with them, and damage their solar panels or other components without destroying the satellite entirely, they can be incredibly effective without creating large debris clouds which raise problems for all parties operating in that region of space.
The first docking in geosynchronous orbit was accomplished in 2020 when Northrop Grumman used two satellites that were able to extend the mission of aging commercial communications satellites by placing them in a new orbital trajectory. These satellites couldn’t transfer fuel though. If the Chinese satellites have managed that, they have achieved something new, impressive, and to some, concerning.
China continues to suggest these missions are part of a debris clean-up program, though it hasn’t publicly made any statements about the recent alleged docking and refueling to celebrate its successes.
If it doesn’t, the only way we’ll know if a refueling maneuver was successful is if the SJ-21 satellite unshackles from its younger sibling and performs fuel-demanding maneuvers that its previously estimated fuel levels shouldn’t allow for.
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