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When it comes to space debris, what goes up is coming down more often – and not safely.
When spacecraft launch, some components, including nonreusable rocket boosters, are jettisoned to decrease weight, leaving them to intentionally burn up as they reenter the atmosphere. Satellites also enter the atmosphere at the end of their life, supposedly burning up. But in many cases, they are .
Debris from partially burned-up spacecraft components and satellites reentering Earth’s atmosphere can . The surge in launches, driven largely by , is turning a once-remote risk into a growing threat.
Our materials research group at the University of Wisconsin-Stout is studying the materials that allow reentry debris to survive. We look for ways to safely modify their exceptional heat-resistant qualities to make them safer for atmospheric reentry.
Debris landing on Earth
Reentry debris both private and public property around the world since 2021. Some of the most notable events involve pieces from SpaceX Dragon’s carbon fiber trunk, which stays attached to the crewed capsule until just hours before its reentry. These trunks are larger than a 15-passenger van and used for storage.
Trunk debris from the Crew 7 mission to the International Space Station has , and fragments from the Crew 1 mission . Similarly, debris from the Axiom 3 mission .
In addition to trunk debris, carbon fiber components that hold pressurized gases to adjust a spacecraft’s orientation also make up a lot of recovered reentry debris. Some of these most recent recoveries have been in .
Most of the debris that reenters the atmosphere burns up, so why are these pieces making it down to Earth’s surface?
Atmospheric reentry
Satellites such as , typically between 190 and 1,240 miles (300 and 2000 kilometers) above the Earth’s surface. To stay there, they need to move really fast, at about . To reach this speed, a rocket with a million pounds of fuel had to accelerate it, and part of this energy is still contained within the satellite’s momentum.
As an object in orbit drifts down, closer to Earth’s upper atmosphere, it starts to collide with air molecules, . The amount of heat generated from this interaction , melting metal at over 3,000 degrees Fahrenheit (1,600 degrees Celsius).
More launches
Countries around the world have been launching items into space since the 1950s, so why is reentry a concern now?
Starting in the 1960s, about – or at least that was the case until 2016. Since then, the number has been increasing exponentially. In 2016, 200 objects launched. But in 2025, 20% of since the 1950s were launched last year.
Most of these launches came from companies in the United States, and . Companies like these, along with those outside of the U.S., have composed of hundreds of thousands to a million satellites.
The more objects and payloads launched, the more reentry events occur. Satellite operators are decommissioned satellites from orbit after 25 years to comply with regulations set in place by international committees. Groups across the world, including the Federal Communications Commission in the U.S., have pushed to shorten the deorbit window . Because of these guidelines, the full influx of reentry debris events from these recent launches will not be felt for another 10 or more years.
The objects launched and policy decisions made today will have a lasting effect on future safety.
Carbon fiber
As the world has progressed technologically, efficiency for launching items into space has too.
Satellites and spacecraft are becoming lighter, stronger and more heat resistant because of materials such as and new metals. These strong materials are sought after because they’re lightweight, but they can also cause deorbiting debris to withstand reentry temperatures.
Carbon fiber, once used exclusively in space technology, is now found in common . It is still the gold standard for fabricating high-strength, low-weight materials for such as rocket fuselages, interstaging – the protective housing found between the rocket stages – and pressure vessels that experience extreme temperatures and high mechanical stress and strain.
Simple metals such as aluminum and steel melt and burn away, while complex materials such as carbon fiber, which is manufactured at up to , , changing the way jettisoned components break up upon reentry.
Since the early 2000s, a either carbon fiber-reinforced plastic sections or metal components wrapped with carbon fiber. The carbon fiber can act as an unintentional heat shield for heavier, more harmful debris.
Design for demise
Design for demise is a major area of research focused on mitigating the risk of reentry debris. Instead of relying on that send components that survive reentry into the ocean at the end of their lives, spacecraft components are engineered to ensure they completely disintegrate while deorbiting through the atmosphere.
Design for demise can take many forms. changing to more heat-susceptible materials to relocating harder-to-burn components to areas of the spacecraft that will be hotter during reentry, or using linkages that break apart at high temperatures to separate structures into smaller components to help them burn up.
With so much focus historically on spacecraft being made from the lightest, strongest and most heat-resistant materials available, it may seem counterintuitive to intentionally make some materials weaker. The key is making materials smarter, so they maintain their strength during their mission but weaken under the heat of reentry.
