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What is it? -

Space trash, also known as space debris or orbital debris, refers to defunct human-made objects in space. It includes fragments from disintegration, erosion, and collisions of satellites, rockets, and other spacecraft.

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Big or small -

Space trash ranges in size from tiny paint flecks to large defunct satellites and spent rocket stages. In fact, there are currently over 20,000 tracked objects larger than a softball orbiting the Earth.

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Trash composition -

Space debris is made up of a wide range of materials, including metals, plastics, and even organic materials.

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Where it comes from -

Sources of space trash include defunct satellites, spent rocket stages, debris from explosions, and even discarded tools or equipment from space missions. Sometimes, collisions between debris and active satellites or spacecraft can generate even more debris, which exacerbates the problem.

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Low Earth orbit -

The majority of space debris is concentrated in low Earth orbit (LEO), where most satellites and space missions operate.

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Monitor and assess -

Continuous monitoring of space debris populations and collision risk assessments are necessary to understanding how to mitigate this issue and what strategies can be implemented.

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How to track it -

In order to help prevent collisions, space trash is tracked by the United States Space Surveillance Network (SSN). They do this by using radar, telescopes, and other sensors to monitor space.

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Risks -

Since there is no air in space, debris can travel at high velocities without resistance. This poses massive risks to existing satellites, space missions, and even astronauts aboard the International Space Station.

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Longevity -

Some debris objects can remain in orbit for many years or even centuries, depending on their altitude, orbital parameters, and atmospheric drag effects.

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Other planets -

Space debris has also been found scattered on other planets. In particular, Mars was discovered to have many pieces of Perseverance on its surface. This points to a larger issue of space debris and its impact on space travel.

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ClearSpace-1 -

The ClearSpace-1 mission, led by a Swiss start-up company, is one such program, and it aims to demonstrate the feasibility of removing space debris from orbit. They are expecting to launch in the second half of 2026.

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The United Nations -

International cooperation is essential for addressing the global problem of space trash. The United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) plays a key role in coordinating international efforts to address space debris and promote responsible space activities.

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UN Office -

Another department of the United Nations, the Office for Outer Space Affairs (UNOOSA), promotes guidelines and best practices for space exploration and debris mitigation.

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Treaties -

There are also some international treaties and agreements–such as the 1967 Outer Space Treaty–that provide a framework for addressing responsible space activities.

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Crashing satellites -

Some strategies have been suggested to mitigate the creation of debris. These strategies include unique satellite designs that limit trash, and also the deorbiting of satellites at the end of their missions.

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Active removal -

Another solution is active debris removal (ADR), which involves capturing or removing defunct satellites and large debris from orbit. ADR methods include robotic arms, nets, and even harpoons to capture or deorbit debris.

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Lasers -

Ground-based lasers have also been proposed as a solution to nudge debris into lower orbits, where it will eventually reenter and burn up in the Earth's atmosphere.

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Ion thrusters -

Some have suggested using spacecraft equipped with ion thrusters to gradually deorbit space debris by reducing their orbital velocity.

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Computerization -

Simulation studies help assess the effectiveness of different debris removal strategies and their potential impact on space traffic.

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The bigger, the worse -

Regardless of the techniques that have been proposed, many scientists agree that large, high-risk debris objects should be prioritized due to their potential to cause catastrophic collisions.

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No solution yet -

While some companies are developing technologies for capturing and removing space debris, none have been widely implemented yet.

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Collaboration -

Space agencies and organizations worldwide continue to collaborate on tracking, research, and potential solutions. But despite existing mitigation efforts, the amount of space debris continues to increase due to historical debris and ongoing space activities.

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Kessler syndrome -

The Kessler syndrome is a theoretical scenario where the density of objects in low Earth orbit is high enough that collisions could cause a cascade, leading to further collisions and a significant increase in space debris.

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Prevention -

Preventing the Kessler syndrome requires proactive measures to limit the generation of new debris and remove existing debris from orbit. This has proven difficult to achieve, due to the substantial costs involved with space travel.

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Raising awareness -

There are many education and public awareness campaigns that attempt to raise awareness about the issue of space debris and the importance of responsible space activities. These programs also endeavor to engage the next generation of space professionals in solving this global challenge.

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Sustainability -

Sustainable space practices, including responsible satellite disposal and spacecraft design, are essential for preventing the further accumulation of space debris.

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Expansion -

As space exploration and commercial activities expand, addressing the challenge of space debris becomes increasingly urgent.

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Limitations -

Limited funding, technological constraints, and the continued buildup of satellites continue to present obstacles to achieving long-term space sustainability. But scientists are hopeful that continued efforts will yield positive results.

Sources: (NASA) (Natural History Museum) (McKinsey & Company) (National Geographic)

See also: Things movies get wrong about space

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