Given the recent launch of Artemis II on April 1, 2026 on the first crewed US mission to the moon in decades (more about the mission here) and its return to earth today, April 10, 2026, this posting about space junk seems à propos.

December 3 and 4, 2025 were banner days for space debris (or space junk) stories. I have three.

What is the space debris problem and just how bad is it?

Ian Whittaker (Senior Lecturer in Physics, Nottingham Trent University) and Lesley Masters (Senior Lecturer in International Relations, Nottingham Trent University) wrote a December 4, 2025 essay for The Conversation that introduces the problem and provides updates on what is happening internationally, Note: Links have been removed,

China routinely sends astronauts to and from its space station Tiangong. A crew capsule is about to undock from the station and return to Earth, but there’s nothing routine about its journey home.

The Shenzhou-20 capsule will carry no crew, because one of its windows has been struck by space debris. Astronauts noticed an apparent crack on November 5 [2025], during pre-return checks.

Space journalist Andrew Jones explained how experts on the ground had studied images of the damage and concluded that a piece of debris smaller than 1mm (roughly 1/25th of an inch) had penetrated from the outer to inner layers of the glass.

Simulations and tests confirmed a low probability that the window could fail during the high-temperature re-entry through Earth’s atmosphere. Although a worst-case scenario, it was one that officials deemed unacceptable. A rescue mission – Shenzhou-22 – was launched to bring the astronauts back from the station.

Experts have been warning about the threat posed by space debris for years. The ever-growing number of space programmes by states and private entities is now contributing to an increasingly congested environment in orbit.

The European Space Agency estimates that there are more than 15,100 tonnes of material in space that has been launched from Earth. There are 1.2 million debris objects between 1cm and 10cm, and 140 million debris objects between 1mm and 1cm.

In low orbit they will be travelling around 7.6 km/s (roughly 17,000 miles per hour), damaging anything they hit. This is how a piece less than 1mm in size was able to penetrate the thick glass of Shenzhou-20’s capsule.

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A number of countries are able to track what’s in space, but given that these may include classified satellites, there is a reluctance by states to share details. China’s space programme is overseen by its military, in line with a view that space is inherently linked to national security. This only adds to the geopolitical tensions between states around the use of space.

Treaties and responsibilities

The outer space treaty from 1967 sought to outline how space should be governed. But it is outdated and does not account for the increased presence of debris or the proliferation of private space launches. Nor does it address responsibilities when it comes to the sustainable use of space.

A total of 117 states are parties to the treaty, yet while efforts are ongoing to develop new norms around space governance, including the creation of the Inter-Agency Space Debris Coordination Committee, the organisation may offer a platform for cooperation and research but does not result in binding decisions for state action. The lack of any global agreement on space debris, and more importantly repercussions, makes tackling the problem of space debris even harder.

Technology is being developed to address space debris – but this generally appears as concept mission plans with only a few trial tests being launched anywhere globally. Examples include the idea of a harpoon to collect large pieces – although the recoil of such an instrument means the spacecraft that deploys it could become a new piece of debris.

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A solution for cleaning up the space debris

This December 3, 2025 news item on ScienceDaily (also available with some embedded images in a December 1, 2025 news item on SciTechDaily) offers a technology fix based on the notion of a circular economy,

Earth’s orbit is getting crowded with broken satellites and leftover rocket parts. Researchers say the solution is to build spacecraft that can be repaired, reused, or recycled instead of abandoned. They also want new tools to collect old debris and new data systems that help prevent collisions. The goal is to make space exploration cleaner and more sustainable.

Each rocket launch sends valuable materials into the sky that cannot be recovered, while also releasing large amounts of greenhouse gases and chemicals that damage the ozone layer. A new paper published December 1 [2025] in the Cell Press journal Chem Circularity examines how familiar ideas like reducing, reusing, and recycling could be built into the way satellites and spacecraft are designed, repaired in orbit, and handled at the end of their service lives.

“As space activity accelerates, from mega-constellations of satellites to future lunar and Mars missions, we must make sure exploration doesn’t repeat the mistakes made on Earth,” says senior author and chemical engineer Jin Xuan of the University of Surrey. “A truly sustainable space future starts with technologies, materials and systems working together.”

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Applying the 3 Rs to spacecraft, satellites, and space stations

According to the team, the foundation of a circular space economy lies in the 3 Rs: reduce, reuse, and recycle. Reducing waste would begin with building satellites and spacecraft that last longer and can be fixed more easily in space. They also suggest turning space stations into multifunctional centers where spacecraft can refuel, undergo repairs, or even have new components manufactured, which could cut down on the number of launches required.

The authors add that bringing spacecraft and space stations safely back to Earth for reuse would require better recovery systems, including technologies such as parachutes and airbags. They point out that equipment in space experiences significant wear because of extreme temperatures and radiation, so any part intended for reuse would need to pass strict safety checks.

Recovering orbital debris and using advanced technology for safer space operations

The researchers also recommend new efforts to gather orbital debris, such as using robotic arms or nets to collect fragments so the materials can be recycled. This would also help prevent collisions that create even more debris.

Data-driven tools will play an important role in this transition, the authors say. Information gathered from spacecraft could guide improvements in design and help limit waste, while simulation tools may reduce the need for expensive physical testing. They add that AI systems could help spacecraft and satellites avoid dangerous debris in real time.

Transforming the entire space system through innovation and global cooperation

The authors emphasize that a circular space economy represents a major shift in how the space sector works. Instead of focusing on single pieces of hardware, the entire system needs to be considered at once, from the materials used to how spacecraft are operated and retired.

“We need innovation at every level, from materials that can be reused or recycled in orbit and modular spacecraft that can be upgraded instead of discarded, to data systems that track how hardware ages in space,” says Xuan.

“But just as importantly, we need international collaboration and policy frameworks to encourage reuse and recovery beyond Earth. The next phase is about connecting chemistry, design, and governance to turn sustainability into the default model for space.”

This research received support from the UK Engineering and Physical Sciences Research Council, the Leverhulme Trust, and the Surrey-Adelaide Partnership Fund.

Here’s a link to and a citation for the paper,

Resource and material efficiency in the circular space economy by Zhilin Yang, Lirong Liu, Lei Xing, Adam Amara, Jin Xuan. Chem Circularity, 2025; 100001 DOI: 10.1016/j.checir.2025.100001

This paper is open access.

Commercializing space debris cleanup

This December 4, 2025 Stevens Institute of Technology news release (also on EurekAlert) theorizes that commercializing the cleanup will lead to clearer skies, Note: Links have been removed,

High up in the earth’s orbit, millions of human-made objects large and small are flying at speeds of over 15,000 miles per hour. The objects, which range from inactive satellites to fragments of equipment resulting from explosions or collisions of previously launched rockets, are space debris, colloquially referred to as space junk. Sometimes the objects collide with each other, breaking into even smaller pieces. 

No matter the size, all of this debris poses a problem. Flying at high speeds caused by prior launches or explosions, they create danger for operational satellites and spacecraft, which are vital for the efficacy of modern technologies like GPS, digital communication and weather forecasting. At orbital speeds, even tiny fragments can cause significant damage to operational equipment, endangering future space missions and the people who would participate in them. 

“Even if a tiny, five-millimeter object hits a solar panel or a solar array of a satellite, it could break it,” says Assistant Professor Hao Chen, whose research involves space systems design. “And we have over 100 million objects smaller than one centimeter in orbit. So if you want to avoid a collision, you have to maneuver your spacecraft, which takes up fuel and is costly. Additionally, we have humans on the International Space Station who sometimes must go outside the spacecraft where the space debris can hit them too. It’s really dangerous.”

Cleaning up space junk is technologically challenging and expensive. Furthermore, there are currently no incentives for countries or private companies to do so. Without binding international regulations or an enforceable “polluter pays” principle with consequences for non-compliance, the circumstances have led to a “cosmic free-for-all.” So in his latest study, Space Logistics Analysis and Incentive Design for Commercialization of Orbital Debris Remediation published in Journal of Spacecraft and Rockets on October 5, 2025, Chen and his collaborators investigated ways to create commercial opportunities for space operators and debris remediators to clean up the dangerous junk. “We wanted to see whether there’s any potential to have commercial players interested in removing the debris,” Chen says. 

The study analyzed three possible scenarios of debris cleanup — controlled reentry back to earth, uncontrolled reentry back to earth, and recycling in space. All three methods would require a space debris remediation satellite — a vehicle designed to capture and remove space junk from orbit.

In the uncontrolled reentry scenario, the remediation service vehicle would grab the debris from the orbit path it flies in and bring it down to about 350 kilometers away from earth. The piece of debris would continue orbiting around our planet until it enters the atmosphere and either burns or lands someplace. “It will either burn or drop somewhere on earth, but we don’t know where because it depends on the atmospheric drag it receives,” Chen explains. This uncontrolled reentry method is the cheapest as the remediation vehicle doesn’t have to fly long distances. 

In the controlled reentry scenario, the remediation service vehicle would bring the debris much closer to earth, down to about 50 kilometers. “Controlled reentry is more expensive because the servicer needs to bring the debris down closer to earth and then fly up again to get the next piece of debris,” Chen says. “That consumes more energy and more fuel than an uncontrolled reentry.”

In the recycling scenario, the debris would be transported from its original orbit to a recycling center up in space. The transportation would require fuel adding to the cost, but a lot of energy will also be saved by reusing aluminum, the metal commonly used in spacecraft, up in orbit rather than having to bring it up from earth. “It takes about $1500 per kilogram to launch anything from earth to space,” explains Chen. “So if you don’t have to launch from earth, it’s a benefit.”

Next Chen and collaborators analyzed ways to incentivize companies into space debris removal. They used Game Theory and Nash Bargaining Theory, developed by mathematician John Nash, to figure out the fairest deal for the two entities involved — in this case space operators, companies that own and run satellites, and debris remediators, entities that remove the space junk. 

“The debris remediators pay for the missions, the technology, and the actual work. Without some kind of financial incentive, they don’t really gain anything from it — they bear all the costs while others reap the benefits,” says Chen. Meanwhile space operators stand a lot to gain from debris removal. Their satellites can operate more safely and efficiently, so they save money on fuel and operations, since they don’t have to make extra maneuvers to avoid collisions. “However, they don’t actually do anything to remove the debris themselves — they just enjoy the cleaner, safer environment,” Chen points out. 

To solve this problem, Chen’s team proposes creating fees that space operators would have to pay. “We will need some agency to create an incentive for the debris remediators,” says Chen. “The money should come from the people who enjoy all those benefits. Our analysis shows that there is a surplus to be generated from the remediation of orbital debris, and that surplus can be optimally shared by space operators and debris remediators.”

Without such a solution, the space debris dangers will only continue growing, generated by the current and future objects left in orbit, Chen notes. “That is what’s needed to move us closer to a space industry that is safer, more sustainable, and still profitable.”

Chen’s research was funded by the NASA Office of Technology, Policy, and Strategy. The team will present their research at NASA headquarters on December 10, 2025.

About Stevens Institute of Technology

Stevens is a premier, private research university situated in Hoboken, New Jersey. Since our founding in 1870, technological innovation has been the hallmark of Stevens’ education and research. Within the university’s three schools and one college, more than 8,000 undergraduate and graduate students collaborate closely with faculty in an interdisciplinary, student-centric, entrepreneurial environment. Academic and research programs spanning business, computing, engineering, the arts and other disciplines actively advance the frontiers of science and leverage technology to confront our most pressing global challenges. The university continues to be consistently ranked among the nation’s leaders in career services, post-graduation salaries of alumni and return on tuition investment.

Here’s a link to and a citation for the paper,

Space Logistics Analysis and Incentive Design for Commercialization of Orbital Debris Remediation by Asaad Abdul-Hamid, Brycen D. Pearl, Hang Woon Lee and Hao Chen. Journal of Spacecraft and Rockets Volume 63, Number 1Bimonthly January 2026 DOI: https://doi.org/10.2514/1.A36465 Published Online:5 Oct 2025

This paper is behind a paywall.

Good luck to the Artemis II astronauts.

For anyone interested in more space debris stories, here are four from this blog,

• August 5, 2010 posting: Nano art and a solution for space junk from New Zealand
• November 30, 2011 posting: NanoSail-D cleans up space junk
• January 21, 2020 posting: Space debris, water, and DIY biology, science events in Canada (Jan. 22 – 23, 2020)
• June 26, 2020: Space junk clogs up low-Earth orbit