What is space debris?

The Inter-Agency Space Debris Coordination Committee defines space debris as “all man-made objects, including fragments thereof, in Earth or re-entering the atmosphere that are non-functional"¹. These man-made pieces of debris can range from specks of paint and missing screws to broken pieces of the International Space Station and inactive satellites. The European Space Agency (ESA) estimates that there are more than 30,000 individual pieces of space debris larger than 10cm, with millions of smaller pieces of debris also littering earth’s orbits², many of which are currently unknown and untracked.

Why is space debris a problem?

The creation of space debris not only pollutes space, but it also threatens assets in orbit. Satellites form part of our critical national infrastructure – enabling navigation, telecommunications, geo-observation, weather monitoring and more. In addition, manufacturing, launching and managing these assets is expensive, putting a high price tag on the value of satellites in space. For satellites, a collision with a piece of space debris could cause significant damage if not destruction, resulting in financial loss and jeopardising critical operations on earth.

With the number of objects being launched into space, and the number of conjunction events³ both growing², the risks posed by space debris are only increasing. It is estimated that 70% of objects in LEO (low Earth orbit) are pieces of debris⁴ that satellite operators must avoid collision with. The UKSA’s tool “Monitor Space Hazards” (formerly known as ‘Monitor Your Satellites’), shows that there have been ~425,000 conjunction events for UK satellite operators in the last 6 months, and 64% of these have involved a piece of space debris⁵. The time spent by satellite operators monitoring the skies, calculating risk and potentially executing manoeuvres means that navigating around debris in space is costly.

What is the solution? 

There is no quick fix to prevent this crisis, but there are plenty of ways we can take action. Below we outline five ways of mitigating and managing the problem of space debris.

1) Improved SST capabilities

Accurate space-surveillance and tracking tools (SST) enable satellite operators to make in-orbit manoeuvres to avoid collisions with debris. These tools help operators to protect their satellites from damage. The PSC has proudly supported the UKSA in the design and management of their SST tool “Monitor Space Hazards” which has monitored ~5000 CDMs (Conjunction Data Messages⁶) involving UK satellites alone since 2021. We are continuing to develop new features and services to help UK licensed operators navigate space responsibly and to support the UKSA as they maintain defence, safety and security in space.

2) New technologies to better understand debris

There are significant gaps in our understanding of space debris, particularly the millions of pieces of space debris that are under 10cm². For the debris we do know about, our understanding is limited, particularly around the shape, size, and tumbling trajectories of objects. This limits our understanding of how debris behaves over time and therefore its potential future impacts. However, new technologies are being developed to improve our understanding of debris. For example, UK start up ODIN Space have developed in-orbit sensors to track the size, speed and trajectory of debris between 1cm and 0.1mm. They completed their first successful test in orbit onboard of Space X’s Transporter-8 mission in June 2024⁷.

3) Active debris removal

Active debris removal (ADR) aims to tackle the problem of space debris by targeting, capturing and de-orbiting pieces of debris in space. Governments, academics and private companies are coming together to identify suitable targets for removal, and to test the technology to do so. For example, the UK’s COSMIC (Cleaning Outer Space Mission through Innovative Capture) mission, led by ADR leading company Astroscale⁸, will use robotic devices to remove two defunct British satellites, it is due to launch in 2026⁹ following the success of its demonstration mission, ELSA-D.

Whilst ADR technology is currently nascent and expensive, it provides an exciting opportunity to reverse, rather than prevent, the problem of space debris, particularly if solutions can be scaled up in the near future. However, until the ADR market matures and the technologies reduce in price, it is unclear what role ADR will play in tackling space debris¹⁰. 

4) International regulation and coordination

To regulate space and curb the exponential increase in space objects that we have seen over the last decade³, international coordination and regulation is critical. At an international level the UN Office for Outer Space Affairs (UNOOSA) and Inter-Agency Space Debris Coordination Committee are bringing countries and space agencies together to consider the problem of space debris. Similarly, at a regional level the European Space Agency’s recent ‘Zero Debris Charter’ sets ambitious debris mitigation and remediation targets for 2030 across Europe¹¹. At a national level, the UK’s National Space Strategy sets out the aim to “lead the effort to make space mores sustainable”¹², and it is key that all parts of the UK space industry come together to do this.

5) Increased public awareness and education

Finally, whilst many in the industry recognise the danger of space debris, there is a need for widespread education and awareness around space debris to garner public support and pressure decision-makers into driving space sustainability forward. Aligning space debris to wider narratives around sustainability, and clearly outlining the potential consequences of space debris, such as damage to critical national assets, will help drive change. The UK has an opportunity to encourage more people to enter the space sector, foster private sector innovation to develop space sustainability solutions, and lobby decision makers about space debris where possible. 

I was privileged to interview 50+ stakeholders, on behalf of the UKSA, across government, academia and industry about the issue of space debris. Whilst stakeholders referenced the new technologies and international coordination that is emerging in this field, they also noted that there is an urgent need to convince the whole space industry, public and government decision makers of the importance of tackling space debris.

The PSC is proud to be continuing to support the UKSA in their work to promote a responsible and safe use of space and we are excited to see how the space debris landscape evolves over the next few years. 

Author: Izzy Montgomery

1. IADC (2007), “IADC Space Debris Mitigation Guidelines”
2. ESA (2023), “ESA’s Space Environment Report 2023”
3. A conjunction event refers to an event whereby two objects in space make a close approach
4. LeoLabs (2023), “What’s up in LEO? Insights and analysis from 2022”
5. Monitor Space Hazards (2024), data captured 31/07/2024
6. CDMs (Conjunction Data Messages) are generated when there is a close encounter between two objects, it will include information such as miss distances and probability of collision
7. Space.com (2024), “The UK’s ODIN Space Just aced its 1st space junk tracking system test in orbit”
8. Odin Space (2024), “Odin Space”
9. Astroscale (2024), “COSMIC”
10. Space.com (2023), “Taking out the trash: Here's how private companies could be vital for space debris removal”
11. ESA (2024), “The Zero Debris Charter”
12. HM Government (2021), “National Space Strategy”