China has a growing issue with space debris, particularly from its upper rocket stages, which are frequently abandoned in orbit. Over the last 21 months, China has launched 21 out of 26 new hazardous rocket bodies, each weighing an average of more than 4 metric tons (8,800 pounds). Additional contributions to this concern come from the United States, Russia, India, and Iran, each of which has launched one rocket body during the same period.
The trend of increasing debris is expected to persist as China advances the deployment of two significant megaconstellations, known as Guowang and Thousand Sails. Both constellations consist of thousands of communications satellites positioned in low-Earth orbit, with launches for these satellites commencing last year. While the Guowang and Thousand Sails satellites are smaller and likely equipped to avoid collisions with space debris, the specific capabilities of these satellites have not been publicly revealed.
However, the rockets utilized for the Guowang and Thousand Sails deployments have often left their upper stages in orbit. According to expert analysis by McKnight, nine upper stages abandoned after launching these satellites will linger in orbit for over 25 years, in violation of established international guidelines that recommend deorbiting waste.
It is anticipated that hundreds of rockets will be needed to fully establish China’s two major megaconstellations. McKnight expresses concern about the potential for increased space debris. He noted, “If they continue the same trend, they’re going to leave well over 100 rocket bodies over the 25-year rule if they continue to deploy these constellations.” This ongoing trend raises alarms for the future of space sustainability.
There are multiple technical and practical reasons why Chinese rockets do not always deorbit their upper stages at the end of missions. Some older Chinese rocket models lack the ability to restart their engines in space, rendering them essentially useless after delivering their payloads. Even in cases where rockets are equipped with restartable engines, a launch provider must maintain sufficient fuel for a deorbit maneuver. This requirement reduces the rocket’s overall payload capacity and limits the number of satellites that can be launched.
“We know the Chinese have the capability to not leave rocket bodies,” stated McKnight, referencing the Long March 5 rocket, which has successfully launched Guowang satellite batches three times. This rocket features the YZ-2 upper stage, which is capable of deorbiting at the conclusion of its mission. In contrast, the performance of other rocket types remains less promising.
“With the other ones, they always leave a rocket body,” McKnight explained. “While they have the potential for sustainable practices, on average, they do not utilize them.”
A Japanese H-IIA upper stage imaged by Astroscale’s ADRAS-J spacecraft last year.
Credit: Astroscale
Since the year 2000, China’s accumulation of non-functional rocket debris in long-lived orbits has surpassed the total from the rest of the world combined, as noted by McKnight. “We are now at a stage where the deployment of these constellations has accelerated the issue,” he emphasized.
