Starlink launch Vandenberg
SpaceX started launching a new group of Starlink satellites to sun-synchronous orbits in July, putting them in the path of debris created by a Russian ASAT test last year. Credit: SpaceX

LOGAN, Utah — Debris from a Russian antisatellite weapon demonstration that caused “squalls” of close approaches to satellites earlier this year is now affecting a new series of Starlink satellites.

During a presentation at a Secure World Foundation event during the Small Satellite Conference here Aug. 8, Dan Oltrogge, chief scientist at COMSPOC, said his company found a “conjunction squall” affecting Starlink satellites Aug. 6, with a spike in the number of close approaches of debris from the former Cosmos 1408 satellite.

That debris, created when a Russian direct-ascent ASAT destroyed Cosmos 1408 in a November 2021 test, is in an orbit that lines up with satellites in sun-synchronous orbit. COMSPOC found earlier this year that this created surges of close approaches, or conjunctions, as the satellites run head-on into the debris.

In the Aug. 6 event, Oltrogge said there were more than 6,000 close approaches, defined as being within 10 kilometers, involving 841 Starlink satellites, about 30% of the constellation. It’s unclear how many, if any, of the satellites had to maneuver to avoid collisions.

This conjunction squall was exacerbated by a new group of Starlink satellites. SpaceX launched the first set of “Group 3” Starlink satellites July 10 from Vandenberg Space Force Base into polar orbit, followed by a second set July 22. A third batch of Group 3 satellites is scheduled to launch Aug. 12.

Those satellites are in similar orbits to the remote sensing satellites in sun-synchronous orbit whose orbits lined up earlier this year with the ASAT debris, causing conjunction squalls. “It’s the very orbit that’s put at risk by the ASAT,” Oltrogge said.

SpaceX has long emphasized the ability of its Starlink satellites to autonomously maneuver to avoid conjunctions. The company said that, between December 2021 and May 2022, Starlink satellites performed nearly 7,000 collision avoidance maneuvers, of which 1,700 were linked to Russian ASAT debris.

While SpaceX may be able to manage those conjunctions with its technology, it may be more difficult for other operators of satellite constellations. “If you didn’t have that automated system taking care of a spike like this, it could be really challenging to work it though,” he said.

Those conjunction squalls will subside over time as the debris decays. However, Oltrogge said that may only shift the risk to other orbits, notably the International Space Station. “It’s going to put ISS and others at risk.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...