One way to learn about U.S. spy satellites? China

For years, U.S. military officials have been circumspect about a family of spy satellites first launched in 2014 and aimed at providing close-up looks at spacecraft in geosynchronous orbits.

The satellites are known as GSSAP, the Geosynchronous Space Situational Awareness Program. A decade ago, Defense Department leaders declassified the program as a way to show the world the U.S. military had eyes on what was happening in orbit.

But U.S. officials have rarely discussed the work of the six GSSAP satellites. Nor do they include the standard information about the satellites’ location in public U.S. space catalogs aimed at avoiding collisions.

Now, a new paper from the U.S. Air Force’s China Aerospace Studies Institute offers a perspective on what GSSAP has been doing from an unlikely source: China.

“GSSAP’s mission and the orbital elements of its current location are not classified; U.S. government and Western experts just don’t often talk about it,” wrote Kristin Burke, the senior space and counterspace researcher for China Aerospace Studies Institute. “Consequently, the Chinese and others are filling the vacuum.”

U.S. military space leaders have said the GSSAP satellites perform rendezvous and proximity maneuvers to allow close-up looks at spacecraft in geosynchronous orbits, some 36,000 kilometers above Earth’s surface. They’ve described the mission as a kind of “neighborhood watch.”

In a Sept. 7 paper titled “China Can Track GSSAP,” Burke said while U.S. officials may not want to discuss GSSAP, Chinese astronomers are carefully parsing data about where it flies and assembling a dossier on the GSSAP satellites’ patterns. That means they know where to look and what to expect from the satellite.

It also means, she wrote, that China is likely building software that allow its satellites “to autonomously detect and command the satellite to maneuver when its sensors notice anything similar to GSSAP’s historical approaches.” In other words, the Chinese satellites can scatter before the U.S. gets a closer look at them.

“We have seen Chinese satellites maneuvering and very clearly demonstrating that they know what the GSSAP is, what it's doing, changing their orbital trajectories, either to put them into position to keep an eye on them, or to make it harder for us to keep an eye on [a Chinese satellite],” said Brendan Mulvaney, the director of the China Aerospace Studies Institute. “China is out there developing the techniques, tactics, the procedures to be able to do orbital warfare. They're practicing.”

All of this creates a game of cat-and-mouse. 

In the paper, Burke points to an instance in February 2022 when two Chinese satellites predicted the third GSSAP satellite was approaching. As a result, one of the Chinese satellites repositioned itself and likely took a picture of the U.S. satellite in more favorable lighting conditions.

In addition, Burke wrote that by using data from the International Scientific Optical Network, research organizations associated with the Chinese Academy of Sciences and the China Academy of Space Technology had determined which satellites GSSAP was scouting. The list included a 2017 approach of Russia’s Luch satellite, which had frustrated commercial and government leaders with its own close approaches.

Burke, who speaks and reads Mandarin, also offers further details about GSSAP’s movements in the paper. For example, she explained that a Chinese military report in 2021 showed that a year earlier a GSSAP-2 satellite moved within 8.71 kilometers of another satellite. For perspective, a CSIS study found that the median distance between satellites in geosynchronous orbit is 207 kilometers.

“There's not a whole lot of reason to get that close other than to demonstrate, ‘I'm going to get this close and you're not going to do anything about it,’” Mulvaney said.