By Kurtis Archer | 2025-03-25

The United States and its allies are expressing growing security concerns over China's expanding presence in geostationary orbit (GEO), a region crucial for both military and commercial space operations.

GEO is 35,786km above the equator and allows for satellites to orbit the Earth at a speed that matches the planet's rotation -- meaning spacecraft are in a fixed position in the sky to an observer on the ground.

Lowering or raising a satellite's position in GEO by tens of kilometers allows it to drift east or west, respectively.

As China increasingly deploys satellites in GEO, scientists and officials worry about the potential for surveillance, early missile warnings, signal interception and proximity maneuvers that could destabilize the space domain.

Space scientists and policymakers discussed these risks at the Chatham House Space Security 2025 Conference in London on March 5.

The US Space Force (USSF)'s deputy chief of space operations for intelligence, Chief Master Sgt. Ron Lerch, raised concerns about the behavior of these satellites.

"There are a number of what the Chinese refer to as these experimental communication satellites that are out in GEO, and yet these GEO satellites, they're sliding, or they're moving very frequently across the GEO belt, which is a behavior that is very uncharacteristic of a satellite that's intended to provide satellite communications," he said at the conference.

'Targeted proximity maneuvers'

China on March 10 launched its latest "experimental communication satellite," known as TJS-15 (Tongxin Jishu Shiyan 15). Several Chinese satellites have been observed moving through GEO, approaching and potentially intercepting satellites from other countries.

China is testing a satellite, the Shijian-25, which has the ability to service other satellites in orbit, such as refueling and extending satellite life.

Lerch described this as "the first time that they [China] have publicly disclosed a capability on orbit to do refueling and servicing."

Shijian-25's official purpose is for "satellite fuel replenishment and life extension service technology verification," but China has released few details about its mission.

Juliana Suess of the German Institute for International and Security Affairs highlighted the growing concerns.

"China, at this point, is able to conduct very targeted proximity maneuvers, potentially even doing physical damage or listening to communications, etc.," she said at the conference.

"But they can now also do it, not quite unseen, but they're very good at hiding what they're doing until after the fact," Suess added, stressing how China's precise maneuvers make its activities in GEO difficult to detect.

New technologies, payloads

China's satellite presence has grown significantly over the past 15 years, from about 40 satellites to approximately 1,000 today.

Though Chinese satellite activities have raised alarms, both the United States and Russia too have deployed classified satellites capable of maneuvering in GEO, contributing to the "cat and mouse" interactions observed in this orbital space.

Lerch acknowledged the heightened risk.

"We [the USSF] see great risk right now because of the unprecedented growth, as well as the unmanaged competition," Lerch said of the situation and the space domain at large.

China launched its first TJS satellite in 2015, and the TJS series has continued to grow with over a dozen active satellites in orbit.

These satellites have even maneuvered within 6.2km of US military satellites, raising suspicions that they are testing new technologies and payloads.

The recent launch of TJS-15 marks China's 10th orbital launch attempt in 2025, with further launches planned, including new commercial rockets and crewed missions for the Tiangong space station.