The upper stage of a Chinese rocket that launched a batch of internet satellites on Tuesday broke up in space, creating a debris field of more than 300 objects in one of the busiest areas of low Earth orbit.
U.S. Space Command, which monitors objects in orbit using a network of radar and optical sensors, confirmed the rocket’s breakup Thursday. Space Command said the event created more than 300 trackable pieces of debris. The military’s ground-based radars can detect objects larger than 10 centimeters (4 inches).
The culprit is the second stage of China’s Long March 6A rocket, which blasted off Tuesday with the first batch of 18 satellites in a Chinese megaconstellation that could eventually number thousands of spacecraft. The second stage of the Long March 6A rocket apparently disintegrated after placing its payload of 18 satellites into a polar orbit at an altitude of about 800 kilometers.
Space Command said in a statement that it had “observed no immediate threats” and that it “continues to conduct routine conjunction assessments to support the security and sustainability of the space domain.”
But it will take decades, if not centuries, for aerodynamic drag to pull the debris back into the atmosphere. As the objects descend lower, their orbits will intersect with those of SpaceX’s Starlink internet satellites, the International Space Station and other manned spacecraft, as well as thousands of other orbital debris, endangering commercial and government satellites.
A new debris field of more than 300 objects is a drop in the bucket of the roughly 46,000 objects that Space Command tracks orbiting Earth. But generating that much debris in a single event is remarkable. According to statistics compiled by Jonathan McDowell, an astrophysicist who tracks global spaceflight and launch activity, the event would rank in the top 20 of all debris-generating events since the dawn of the space age.
This rocket has a history
The Long March 6A medium-class rocket has launched seven times since its debut in March 2022, and military and commercial satellite tracking agencies have reported multiple disintegrations of the rocket’s upper stage. In November 2022, a Long March 6A upper stage disintegrated in orbit, creating a debris field of more than 500 trackable objects, according to NASA’s Orbital Debris Program Office.
Commercial satellite tracking companies have observed smaller debris fields after several other Long March 6A flights this year.
In its Space Environment Statistics report, the European Space Agency says there have been more than 640 “breakups, explosions, collisions or abnormal events leading to fragmentation” in orbit. So these events happen frequently. But it’s unclear what makes Long March 6A, which has a relatively short flight history, particularly vulnerable to debris creation.
Most rockets in service today re-ignite their engines to re-enter the atmosphere after deploying their payloads or, if that is not possible, “passivate” to empty their propellant tanks and drain their batteries to reduce the risk of explosion.
In a report released last year, NASA’s Orbital Debris Program Office said the Long March 6A upper stage had a mass of about 5,800 kilograms (12,800 pounds) without the kerosene and liquid oxygen boosters. It is powered by a single YF-115 engine.
Tuesday’s launch marked the start of the deployment of China’s “Thousand Sails” internet network, which will initially consist of 1,296 satellites, with the potential to expand to more than 14,000 spacecraft. That will require multiple launches, some of which will likely use the Long March 6A.
“If even a fraction of the launches needed to deploy this Chinese megaconstellation generate as much debris as this first launch, the result would be a notable addition to the LEO (low Earth orbit) space debris population,” said Audrey Schaffer, vice president of strategy and policy at Slingshot Aerospace, a commercial satellite tracking and analysis company.
In addition to the recent problems with the Long March 6A rocket, China has been responsible for several incidents involving space debris. In 2007, China destroyed one of its own spacecraft during an anti-satellite missile test. This was the worst case of space debris creation on record, with over 3,000 trackable objects and about 150,000 smaller fragments.
On four occasions between 2020 and 2022, the massive core stage of China’s Long March 5B heavy-lift rocket re-entered the atmosphere uncontrolled, raising concerns that falling debris could endanger people and property on Earth.
China plans to launch new flights with its Long March 5B and Long March 6A rockets. China has continued to fly the Long March 5B rocket despite the risk it poses to people on the ground. Orbital debris fields do not directly threaten people on Earth, but they increase the risk to satellites of all nations, including Chinese spacecraft.
“Events like this underscore the importance of following existing space debris mitigation guidelines to reduce the creation of new space debris and underscore the need for robust space domain awareness capabilities to rapidly detect, track and catalog newly launched space objects so they can be examined for potential conjunctions,” Schaffer said in a statement.
