The Top 10 list of the worst breakups in space, those that generated the most debris, consists of two widely condemned anti-satellite tests, five accidental explosions, the catastrophic collision of two objects and one incident whose cause remains unknown.
No. 6 on the list, though, stands out for the pattern it represents: the November 2022 explosion in heavily traveled low Earth orbit (LEO) of a new Chinese Long March 6A rocket. The blast created 794 pieces of trackable debris, according to a catalog at space-track.org that’s kept by U.S. Space Command (USSPACECOM) and uses data from the military’s Space Surveillance Network (SSN).
The Chinese Communist Party (CCP) has called the Long March 6A a milestone in its space program and is relying upon the rocket for a variety of missions, including the deployment of LEO satellite constellations designed to catch up to the ubiquitous Starlink broadband system operated by U.S.-based SpaceX. But in six of its first 14 launches, according to space-track.org, the rocket’s upper stage shed debris on orbit, most recently in May 2025. Two of those six launches generated hundreds of pieces of debris — the November 2022 explosion and a breakup in August 2024 that generated 718 pieces of debris, not counting the main rocket body, according to space-track.org.
China has taken necessary measures and is closely monitoring [the] relevant orbit area and conducting data analysis.” ~ Lin Jian, Foreign Ministry spokesman
These numbers would earn the August 2024 incident a spot on the Top 10 list, compiled by the NASA Orbital Debris Program Office (ODPO). The most recent list published by the ODPO runs through January 31, 2023, and doesn’t include updated space-track.org numbers. Only four of the 10 breakups on the list have occurred since 2008, though space trackers say the danger of another major event grows with time and the number of objects on orbit. The oldest entry is from 1965.
“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,” Manuel Metz, a space debris expert at the German Aerospace Center, told The Wall Street Journal newspaper for a story on the August 2024 Long March 6A breakup. “Ideally, of course, before launching again.”
In statements at the time, the CCP said it was working to avoid a repeat. “China has taken necessary measures and is closely monitoring [the] relevant orbit area and conducting data analysis,” Foreign Ministry spokesman Lin Jian said. As a responsible major country, Lin told the state-run newspaper China Daily, the CCP attaches great importance to space debris mitigation and works to fulfill international obligations. The goal is to “ensure the long-term sustainability of outer space activities,” he said.
These words were welcomed by Darren McKnight, senior technical fellow at U.S. space-tracking company LeoLabs. “The Chinese response is a very good first step,” he told Bloomberg News, “because at least they talked about mitigation and long-term sustainability being important.” McKnight has singled out the CCP among spacefaring nations as lagging global efforts to reduce and track space debris. In a 2024 interview with Apogee, he noted that as most of the world was getting its upper rocket stages safely out of orbit following launch, Beijing was still leaving them there as late as 2020.
History of breakups
The CCP has experienced patterns of breakups before. Long March 4 launches were put on hiatus for nearly a decade after an incident in 1990, then again as soon as they resumed in 1999, according to the Orbital Debris Quarterly News from ODPO. The 1999 event produced more than 300 pieces of trackable debris. In 2005, the CCP began requiring passivation, or depletion of all leftover propellants from orbiting rocket stages. Fragmentation of a Long March 3 upper stage in February 2012 marked the fourth such incident in five years and produced dozens of pieces of trackable debris. The China National Space Administration said at the time that its efforts to design passivation procedures for Long March 3 upper stages, which used fuel different from other rockets, had not yet been completed.
The CCP also holds the No. 1 position on the ODPO’s Top 10 list of debris-causing incidents. Its 2007 anti-satellite test sent a missile into LEO to destroy a defunct weather satellite, creating more than 3,500 pieces of debris. No. 2 on the list is a similar test by Russia in 2021. Both actions drew global condemnation.
What’s more, the Chinese space program has raised global concern with its practice of allowing some Long March upper stages to fall to Earth uncontrolled. The first stage of a rocket typically pushes it out of Earth’s atmosphere and falls back immediately; upper stages can enter outer space for payload deployment and take longer to return. Controlled reentry, where propulsion is used to aim rockets toward a safer descent, has become standard practice worldwide.
The return of two Long March 5B rockets in 2020 and 2021 marked the heaviest uncontrolled reentries in a decade, the European Space Agency (ESA) reported at the time. NASA had harsh words for the practice: “It is clear that China is failing to meet responsible standards regarding their space debris. It is critical that China and all spacefaring nations and commercial entities act responsibly and transparently in space.”
In November 2022, the uncontrolled reentry of a Long March 5B upper stage prompted airspace closures in France and Spain, based on European projections of the path the falling rocket would take. The CCP communicated the spacecraft’s position during the descent but provided no projections. The size of a 10-story building, the rocket landed safely in the south-central Pacific Ocean after orbiting downward for four days. Around that time, on three occasions over two months, the discovery of Chinese rocket debris in the waters of the Philippines’ exclusive economic zone led to tension between the two nations.
Overall, the CCP follows international norms in space more closely than it does in many other arenas, said Brian Weeden, who at the time was working for nonprofit Secure World Foundation, during testimony before a congressional advisory committee in May 2023. “China does generally abide by the obligations and prohibitions established by international space law, voluntary guidelines such as orbital debris mitigation, and the broader set of norms of international behavior for space,” Weeden said. The uncontrolled reentry of rocket stages is an exception that creates “significant risk,” he added, while noting existing voluntary guidelines are not legally binding on China or any other state and that “China is not the only country to violate them, although its recent transgressions are among the most serious.”
Too small to count
Depending on its altitude in LEO, space debris can continue circling from weeks to centuries as gravity pulls it toward Earth’s atmosphere. An ESA space debris fact sheet estimates the total number of orbital breakups, explosions, collisions or anomalous events resulting in fragmentation at more than 650. Space-track.org puts the number of trackable space objects at nearly 50,000.
An ODPO report on the first Long March 6A explosion points to a more expansive problem: “Data from past observations and experiments has shown that there is more small debris than large. Fragments large enough to be detected and cataloged by the SSN only represent the tip of the iceberg. Hundreds of thousands of fragments as small as one millimeter in size were likely generated from this breakup.”
No immediate threat to space assets was detected from debris in the latest breakup, USSPACECOM reported. But the incident increased the risk of future collisions. “The added danger from such events is that the resulting debris cloud can often span a far wider orbital band than the main rocket body itself,” Belinda Marchand, chief science officer at space tracking firm Slingshot Aerospace, told Apogee. The debris from the August 2024 breakup currently occupies a wide band, Marchand said — from lower segments of LEO to altitudes twice as high as the main rocket body.
The numbers describe the hazard. As of August 2025, the Satellite Orbital Conjunction Reports Assessing Threatening Encounters in Space (SOCRATES) from nonprofit space tracker CelesTrak projected 97,151 conjunctions, or incidents where two or more man-made objects on orbit will pass close to each other. Of that number, 29,947 involved orbital debris — and nearly 10% of these, or 2,693, were associated with debris from the August 2024 Long March 6A fragmentation. Drilling down further, more than half that number, or 1,482 forecast conjunctions, would pass close by Starlink satellites — at a lower altitude than the main rocket body — and seven involve satellites in the OneWeb constellation, orbiting much higher than the main rocket body. Marchand provided the SOCRATES numbers at Apogee’s request.
“Operating complexity will be further compounded over time by growing levels of satellite maneuvering agility and operational autonomy, making it progressively difficult for operators to keep up with the evolving risks to their satellites,” she said.
Reports from the ESA and a Dutch space observer say the August 2024 breakup was presumed to be propulsion related, perhaps from a failure to dump fuel before moving to reentry orbits. Most spent rockets today either reignite their engines and deplete fuel while reentering the atmosphere for incineration or passivate to reduce the risk of explosion.
Before its breakup, the August 2024 Long March 6A mission succeeded in deploying the first parts of the Chinese SpaceSail broadband network, designed eventually to include more than 14,000 satellites. Among the other five Long March 6A rockets that produced debris, the November 2022 explosion came after the deployment of a satellite in the Yunhai-3 weather constellation, and two others drew attention in news reports and social media — a fragmentation in March 2024 over South America that produced nearly 60 pieces of debris by initial counts, and a July 2024 incident resulting in debris too small to catalog at the time.
In updates at space-track.org, the March and July 2024 incidents — as well as two others in September and October 2023 — were reduced to a single piece of debris. “In general, it is not uncommon for launch vehicles to generate some small measure of debris — sometimes not all trackable,” Marchand said.
Establishing networks
The backbone of Chinese launches, the Long March family of 18 rockets — known as Chang Zheng within the CCP and named for the Red Army’s retreat during the nation’s 1934-1935 civil war — first entered service in 1970. The medium-lift Long March 6A is the first Chinese rocket that uses both liquid- and solid-propellant engines as its main propulsion. It was developed by the Shanghai Academy of Spaceflight Technology, or SAST — a subsidiary of the state-owned China Aerospace Science and Technology Corp., or CASC. The first Long March 6A was the initial rocket launched from a new complex at the Taiyuan Satellite Launch Center in March 2022.
“The Long March 6A is suitable for sending large groups of satellites to low Earth orbit to establish networks,” Fu Zhiheng, president of the CASC trade arm China Great Wall Industry, told China Daily during the June 2025 Paris Air Show. “We are ready to put it on the international market if there are demands for the type.”
On its website, SAST showcased the Long March 6A and a July 2025 mission to deploy more satellites for the SpaceSail constellation. “It can meet diverse and intensive launch requirements, including tandem, parallel, stacked, wall-mounted, and piggyback configurations for both single and multiple satellites,” the website said. The rocket can carry 6.5 metric tons into a 500-kilometer low Earth orbit. “Currently,” the website said, “the Long March 6A is in a phase of intensive launches.”