Decluttering Space Debris for Sustainable Space Exploration
- Space Point Staff
- May 9
- 6 min read
Over 75 per cent of tracked objects in Earth’s orbit are debris fragments, which threaten our satellites and space missions. While satellite operators can avoid large, tracked debris, about 100 million fragments of small, untracked debris pose severe risks to Earth’s orbit.
To protect the future of astronomical exploration, it’s necessary to establish a concrete policy in order to maintain a high level of sustainability during space missions in orbit. The 21st century welcomed a new era of research and revolutionized space technology, such as satellites, rocket stages, and other components of spacecraft — and along with them, space debris.
Indeed, the dynamism behind the crowded astronomical workplace allows new opportunities in terms of near-instant global communications. For example, satellite constellations are used for Low Earth Orbit communications, driving autonomously spacecraft, and satellite servicing. Satellites are fundamental in an interconnected world and to explore the global village we live in. They are used for global communications, television broadcasts, navigation services and for day-to-day industries’ operations.
Despite our dependence on satellites, the issue of space debris feels alien in day-to-day life. Yet, it’s necessary to work together to find sustainable solutions for the future of astronomical explorations and the growth of scientific conquests.
NASA agencies take care about sustainability in orbit because the presence of space debris poses threats operating satellites and infrastructure at ISS, the safety of astronauts, the robotic missions in Earth’s orbit and towards other planets in the solar system.
These agencies work together to protect the environment in orbit. For example, the Trajectory Operations Officers prevent NASA’s spacecraft from colliding with tracked space objects and the Office of Technology, Policy, and Strategy analyses the decisions on policies and technology investments for space sustainability. The agencies are managed by the Space Environment Sustainability Advisory Board (SESAB), which focuses on four operational domains:
the Earth surface;
the Low Earth orbit: the area around the Earth where satellites circulate at an altitude of less than 1000 km from Earth;
the Cislunar space: the orbital area around the Moon, which is 384,400 kilometers from Earth, which is reachable by travelling around the entire planet for 9 times;
the Deep Space.
SPACE DEBRIS
According to NASA, orbital debris are defined as human-made objects that don’t function anymore that are present in Earth’s orbit or that are re-entering the atmosphere.
In 2024, NASA published an analysis of the current number of space debris. The report found that about 25 percent of tracked objects are debris from nominal space operations, including unusable spacecraft, rocket bodies and tools released during missions by mistake. About 50 percent of tracked objects were created during fragmentation events, such as anti-satellite tests and self-sabotage, explosion of propulsion systems or batteries, and accidental collisions.
The first official satellite fragmentation happened in 1961, when the Ablestar upper stage, which was one of the first American launch systems, exploded and produced nearly 300 trackable pieces of debris.
The small debris ranges from microscopic dust particles, which are relatively harmless, to objects of 1 cm in diameter (the size of a small button). Debris with a size of 1 to 10 cm is a bigger concern due to their small size and huge quantity; in essence, they cannot be controlled individually, but still could seriously destroy an entire spacecraft during a collision.
Scientists from the European Space Agency (ESA) use modern probabilistic software to understand the risk caused by the debris. The possibility is predicted by analyzing the cross-sectional area of the spacecraft, its orbital altitude, flight path and other factors.
For example, for a satellite with a cross-sectional area of 100 m2 at an altitude of 400 km, the estimated average time between impacts for debris that are 10 cm debris is about 15,000 years. It’s important to notice that even though 15,000 years seems very far to happen now, there are many of these satellites.
The good news is that if you calculate the total surface area of all orbiting satellites, the average time between destructive collisions is about 10 years — meaning that it isn’t as apocalyptic as it may sound. However, a single collision with 10 cm debris, which is the same size as a popsicle stick, could destroy a spacecraft or hit the International Space Station (ISS) and its crew, so the risk of an impact every ten years is more serious than what we could imagine.
According to NASA’s 2024 report, there are already more than 35,000 objects of space debris in orbit, of which about 26,000 are pieces of debris larger than 10 cm, and the number will continue to increase.
Since space debris travels at around 15,700 mph (25,266 km/h) in low Earth orbit and the impact of even a tiny fragment of orbital debris with a spacecraft could create major problems. This worrying scenario is called the "Kessler effect”, named after consultant and NASA researcher, Donald J. Kessler, who designed the problem in 1978.
Today, the volume of space debris in low Earth is becoming increasingly massive, because when the orbiting objects collide with each other they create a chain reaction, increasing the volume of debris with the risk of further impacts.
The smallest objects are the most dangerous because they cannot be tracked and carry more kinetic energy than bullets, so they move ten times faster.
To remove space debris, it has been theorized that astronauts would need to be close to the objects, maintain the same speed as each object and then somehow move it into a lower orbit or re-enter it directly into the ocean. However, if the object is a rocket stage with propellants still on-board, there is a possibility of an explosion. As well, most of the debris orbit at high speeds, so it would pose critical dangers for astronauts. In addition, another issue of property rights since it is illegal to grab a satellite or rocket that belongs to another country without their permission.
An unmanageable number of satellites is not only a physical risk to satellites in Earth’s orbit, but also to the ozone hole, which could be reduced by the chemicals produced during the combustion of satellite pieces that burn up as they re-enter the atmosphere.
Lastly, an orbit cluttered with space debris could become inaccessible for national security purposes, ground observation, telecommunications, scientific exploration and economic development.
SPACE TRAFFIC MANAGEMENT
Space Traffic Management refers to the ability of international and national authorities to track spacecraft and space debris, in order to regulate where space operators position their spacecraft and to control debris mitigation.
Although we have some international space law guidelines like the Inter-Agency Space Debris Coordination Committee (IADC) and other national frameworks, we currently lack binding global enforcement on these regulations. Every nation is responsible for their operating satellites and they have the obligation to share information with the rest of the world about any kind of risks. In addition, some private-sector organizations like Astroscale and LeoLabs manage the economics of space debris and maintain sustainability in space.
According to the Atlantic council, more than 4,800 active satellites currently orbit Earth, representing over 40 nations, and nearly 25 thousand satellites are projected to join by 2030.
Nowadays, it’s necessary to go beyond national agreements because it cannot allow a centralized collaboration. The limits of the space situational awareness were demonstrated in September 2019, when an ESA satellite veered off-path to avoid a Starlink satellite whose operator missed an email notification signaling a high probability of collision.
The ESA is working on the world’s first-ever active debris removal system, called ClearSpace, with the aim to clear the low Earth orbit from the ESA's 95kg PROBA-1 satellite, launched in 2001.
The ClearSpace-1 mission will remove the PROBA-1 satellite from orbit as the first-ever mission to remove an unprepared and uncooperative object from orbit through highly precise, complex, close proximity operations, all in the name of cleaning up space.
CONCLUSION
Recognizing the dangers of neglected space debris, supporting initiatives to curb orbital clutter ensures a brighter future for sustainable operations in space.
A first step towards a more eco-friendly atmosphere is through the use of reusable rockets, which can be reflown once recovered, avoiding more debris and reducing launch costs definitely. The first reusable launch vehicle was created in the 1970s, called the Space shuttle, but its concrete development started in the 2000s — at the same time of the rise of private spaceflight companies. For example, SpaceX launched Falcon 9 in 2010, which is a reusable, two-stage orbital rocket designed for the reliable and safe transport of people and payloads into Earth orbit and beyond.
As well, there are other such efforts to address orbital pollution. Some other frameworks that have been conceptualized include active debris removal methods — by using robotic capture, for instance - AI-based monitoring, and drag sails, alongside other passive debris mitigation strategies. These approaches provide viable, comprehensive frameworks for solutions, with ideas and options that can be engineered and implemented. With financial support and a growing urgency from policymakers, steady improvements are underway.
As Luisa Innocenti, ESA's Clean Space Manager, said: "If you love space, you have to love to clean space." Truly loving our planet and treating it with respect and responsibility secures a future that will allow for more sustainable opportunities.
Yours truly,
Alice Coppini
Writer, Writers Team
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