The upper stage from a commercial Chinese rocket that launched last week has broken apart in space, spreading debris in a heavily trafficked part of low-Earth orbit home to the International Space Station and a significant portion of SpaceX’s Starlink broadband network.

The breakup occurred shortly after the Zhuque-2E rocket reached orbit on June 9 with two satellites providing direct-to-cell communications, perhaps around the time the upper stage was expected to perform a disposal burn. The US Space Force confirmed the breakup event in a post on space-track.org, a website used by the military to distribute orbit data to the public.

“The tracked pieces are being incorporated into routine conjunction assessment to support spaceflight safety,” the Space Force wrote in an advisory. “There are currently no threats to human spaceflight. Analysis is ongoing.”

Counting the pieces

So far, the Space Force has not added any of the debris fragments to the official catalog of human-made space objects. Darren McKnight, a senior technical fellow at the orbital intelligence company LeoLabs, told Ars the fragmentation event likely generated 100 to 150 pieces of debris.

In one piece, the second stage of the Zhuque-2E rocket, made by a Chinese company called LandSpace, measured between 25 and 30 feet (about 8 meters) long and 11 feet (3.35 meters) in diameter. The main body of the rocket’s upper stage is now orbiting between 208 miles and 263 miles (335-by-424 kilometers) at an inclination of 54.5 degrees to the equator.

The uppermost part of this orbit crosses the orbit of the International Space Station, but aerodynamic drag will quickly pull all the debris fragments below the ISS. The debris could pose a greater threat to hundreds of Starlink satellites, particularly those providing direct-to-device connectivity and newly launched satellites, which fly at lower altitudes than the bulk of the Starlink constellation.