Space sustainability: Building a safer, more responsible and resilient satellite ecosystem

• Expanding space activity increases the risk of orbital debris and operational issues
• In SES’s view, more stringent disposal strategies should be considered for LEO

Space in low Earth orbit (LEO) is at risk. Competition from new entrants and new satellite-based offerings is increasing in response to significant growth opportunities in our industry. But the rapidly growing number of non-geostationary orbit (NGSO) spacecraft – mostly driven by the exponential growth of LEO constellations with more than 28,000 additional satellites planned for the next decade or so – creates important challenges for a sustainable space environment, such as orbital debris and reducing the risk of collisions.

This rise in the number of spacecrafts increases the risk of orbital debris and operational issues – a risk recognised during the International Telecommunication Union (ITU) Radiocommunications Assembly 2023 held in Dubai. In March 2024, the ITU Radiocommunications Bureau (BR) extended an invitation to Administrations of Member States and Sector Members of the ITU to submit NGSO post-mission, de-orbit and/or disposal strategies being used, or to be used, “to prevent the growth of space debris and to ensure the consequent long-term sustainability of associated spectrum -orbit resources.”

As a company that has been operating satellites safely for over 40 years, space sustainability is woven into the fibre of our operations. While we are regularly assessing our own processes and satellite designs to ensure and improve our safe operations, SES is also committed to working to develop new technologies, partnerships, policies, and solutions that support long-term space sustainability for all spacecraft operators. Therefore, we welcomed the BR’s invitation to collaborate with the industry to ensure the secure and sustainable use of space.

Not all orbits are the same

NGSO and geostationary (GEO) orbits have different intrinsic characteristics and therefore present different space sustainability risks. This means that different best practices and disposal strategies are appropriate for the different orbits.

SES has developed its medium Earth orbit (MEO) post-mission disposal strategy in accordance with our long-standing commitment to space safety. This commitment is reflected in SES’s proven track record of safely operating our spacecraft, successfully disposing of more than 30 satellites and multiple industry-leading initiatives promoting responsible space sustainability policies and practices. This includes founding the Space Data Association, an industry leading platform for orbital data exchange, and joining the Space Safety Coalition, which issued a set of Best Practices for the Sustainability of Space Operations. Also, as a member of the Global Satellite Operators Association, SES supported publication of a Code of Conduct on Space Sustainability.

Given the large number of space objects operating in, planned for and launched through the relatively small volume of space at LEO, as well as the feasibility of disposal via atmospheric re-entry, more stringent disposal strategies should be considered for LEO.

In contrast, there are far fewer objects occupying a much larger volume of space at the GEO and MEO orbits, which suggests that disposal strategies such as passivation in a graveyard orbit away from other active satellites is the most appropriate approach.

Our commitment to space sustainability

Ensuring safe and reliable access to space depends on managing the space environment for all its users. At SES, we believe that high reliability requirements for equipment to be used for disposal, full passivation of stored energy at end of life, and manoeuvrability capabilities during life to reduce risk of in-orbit collisions are vital to ensuring that satellites are disposed of in a safe and sustainable manner.

SES’s NGSO post-mission disposal plan is therefore to retire our MEO satellites into a stable graveyard orbit that is away from the orbits of another operational spacecraft. This is consistent with well-established guidelines and supported by contingency plans, including redundant spacecraft control facilities operating 24/7.

Sustainable space stands as a fundamental pillar within our Horizon Strategy, a purpose-driven Environmental, Social, and Governance (ESG) strategy launched in 2022. In our ongoing pursuit of leadership in space sustainability, we continue our history of incorporating responsible best practices, including space debris mitigation, reducing our environmental impact, end of life plans and a focus on accountability and transparency into our operations.

These principles help to move us to the forefront of space sustainability as we build and contribute to an even safer, more responsible, and resilient satellite ecosystem.