Breakup of Chinese rocket prompts warnings about space junk

The Long March 6A rocket, launched Aug. 6, was carrying the first batch of satellites that aim to form a rival system to Starlink, the satellite broadband service offered by Elon Musk’s SpaceX. After releasing those satellites, the rocket broke up into hundreds of pieces, for reasons unknown.

The U.S. Space Command, a unit of the Pentagon, said days later it detected more than 300 pieces of debris in low-Earth orbit as a result of the rocket breakup, though it said there was no immediate danger to the International Space Station or its Chinese counterpart.

LeoLabs, a U.S. space-tracking firm, said the event might create at least 700 fragments floating some 500 miles above earth, making it one of the largest rocket breakups in history. Starlink said the debris didn’t pose significant immediate risks to its fleet, but the fragments are “likely to remain in space for decades due to the incident occurring at a high altitude."

China and other countries are pressing ahead with plans to increase rocket launches, raising risks for humans and satellites in orbit. Yet there is little global policing of unsustainable practices.

“Who can enforce anything in space? It’s a bit like the Wild West at times," said Quentin Parker, director of the Laboratory for Space Research at the University of Hong Kong.

Darren McKnight, senior technical fellow at LeoLabs, said China’s recent record on generating debris related to Long March 6 launches was worrisome. “I hope it’s a wake-up call for them, and they’ll be part of the international dialogue," he said.

A Chinese Foreign Ministry spokesman, Lin Jian, said last week that China “attaches great importance to space debris mitigation" and “has taken active efforts to fulfill relevant international obligations." Without giving details, he said China took necessary measures after the recent rocket breakup.

Rockets can generate debris or create other issues as their different so-called stages are used during missions. The main stage of a rocket refers to the booster which powers a vehicle off the ground, while an upper stage is a smaller craft that separates from the booster and is used to deploy payloads into the right orbits.

The U.S. and China, already at loggerheads over trade and regional security, have also had run-ins over space. In 2022, the main stage of a Chinese rocket made an uncontrolled descent from orbit, landing in the Sulu Sea near the Philippines. The National Aeronautics and Space Administration’s leader criticized that re-entry, saying the lack of information made it hard to predict possible damage. China at the time said the risk was extremely low.

A year before, Beijing had complained about what it called two close encounters with Starlink satellites that forced the Chinese space station to alter course to avoid a collision.

China is launching more rockets in pursuit of scientific and military goals. Last year, 66 Chinese launches reached orbit, up from 38 in 2018, according to data compiled by astrophysicist Jonathan McDowell. China is targeting around 100 launches this year, and state media has reported that the country will launch more than 20,000 satellites over the next decade to build out satellite broadband capabilities.

Meanwhile 104 American flights reached orbit in 2023, compared with 31 five years earlier, the data show. Most of the U.S. missions last year were conducted by SpaceX, which frequently launches batches of satellites for the Starlink network. More are expected in the years ahead by operators such as SpaceX and Amazon, which is developing a low-Earth orbit satellite communications system.

Scientists have long worried about space debris causing cascading collisions in what is known as the Kessler syndrome, which would upend everyday life because people depend on satellites for navigation, television, communications and more.

Because of how fast they travel in orbit, debris pieces smaller than 10 centimeters (around 4 inches) in diameter can penetrate the shields of the International Space Station’s crew modules, and anything larger can shatter a spacecraft into pieces, according to the European Space Agency.

When a launcher carrying satellites reaches its designated orbit, it typically releases its payload, then fires its engines a final time in the opposite direction of its orbit to lower its orbit and fall into the atmosphere. The goal is to burn up in the atmosphere without leaving behind space junk.

But some are abandoned in orbit without this “deorbit burn." According to a 2023 paper by LeoLabs, China’s behavior in this regard has more than canceled out improvements by Russia and the U.S. over the past two decades. As a result, China and the U.S. now have roughly the same amount of rocket body mass in low-Earth orbit, while Russia accounts for half of the total mass, down from three-quarters in 2003, LeoLabs said.

The Long March 6A rocket involved in the recent breakup has had a run of problems. In April and July this year, a Swiss company called s2a Systems that specializes in space surveillance detected dozens of debris pieces around the upper stage of a Long March 6A. In November 2022, the same rocket disintegrated in orbit, creating more than 500 pieces of debris.

“If you have a repetition of similar events, you should really look into the design of the system, try and figure out what the issue is and fix it as soon as possible," said Manuel Metz, a space debris expert at the German Aerospace Center. “Ideally, of course, before launching again."

Write to Clarence Leong at clarence.leong@wsj.com and Micah Maidenberg at micah.maidenberg@wsj.com