Deploying a Practical Solution to Space Debris

At this moment, there are approximately 35,000 tracked human-generated objects in orbit around Earth. Of these, only about one-third are active payloads like science and communications satellites, research experiments, and other beneficial technology deployments. The remaining two-thirds are classified as space debris, which includes defunct satellites, spent rocket bodies, and detritus from hundreds of collisions and explosions over the decades.

The Space Debris Problem

The problem of space debris is well documented, and it is set to grow increasingly severe as launch rates increase and fragmentation events escalate. The vast number of debris—estimated to exceed 1 million objects greater than 1 centimeter—poses serious risks. These risks include:

• Damage to operational satellites
• Need for repositioning of the International Space Station
• Potential catastrophic collisions

Addressing Space Debris: The Space Sustainability Rating

To mitigate the issue of space debris, in 2019 the World Economic Forum selected a team co-led by MIT Associate Professor Danielle Wood's Space Enabled Research Group at the MIT Media Lab. They developed a system for scoring space mission operators based on their launch and de-orbit plans, collision avoidance measures, and other factors. This initiative culminated in what is now known as the Space Sustainability Rating (SSR).

Goals of the SSR

The goals of the Space Sustainability Rating include:

• Enhancing coordination in space operations
• Mitigating the risk of space debris collisions
• Encouraging responsible behaviors among space actors

Implementation of the SSR

The SSR was launched in 2021 as a nonprofit organization, providing ratings based on a tiered scoring system. France-based Eutelsat Group became the first constellation operator to undergo this evaluation.

Eutelsat's Experience

Eutelsat submitted a mission to the SSR for assessment and achieved a platinum rating with a score exceeding 80%. The assessment considered six performance modules, focusing on sustainability in design, operations, and disposal practices.

Recent Developments

As of December 2024, SSR has also provided ratings to operators such as OHB Sweden AB, Stellar, and TU Delft, marking a significant advancement in responsible space operations.

Research and Collaboration

A new open-access paper published in Acta Astronautica discusses the detailed history, motivation, and design of the SSR as an incentive system for satellite operators to reduce space debris. The paper outlines:

• The collaborative effort involving organizations such as the European Space Agency and BryceTech
• The development of a composite indicator to evaluate orbits based on multiple quantifiable factors
• The challenges faced by SSR in adoption and its alignment with international guidelines

Conclusion

Finally, the Space Sustainability Rating stands as a nongovernmental initiative encouraging satellite operators to pursue long-term sustainability in space. Continued research will focus on the benefits of responsible space missions and the intersection of government oversight and private sector actions.

Further Information

Contact Information

For further inquiries, please refer to the contact information provided by the Massachusetts Institute of Technology.

Source: Massachusetts Institute of Technology, 2025