Space sustainability: Balancing exploration with responsible resource use

As humanity’s ambitions stretch beyond Earth’s boundaries, the need to keep space sustainable becomes increasingly evident.

At the turn of the 21st century, only 14 nations had authorized satellite operators. Since then, satellites from 91 countries have reached orbit, and the number of companies with space-related activities continues growing.

Moreover, exploring and utilizing outer space is no longer the exclusive domain of national space agencies. Private companies, international space ventures, and even space tourism are on the rise – making responsible management more urgent than ever before.

Amid the industry’s staggering expansion, long-term space sustainability has become a key consideration for national and international agencies, emerging small satellite operators, established private and public-sector space ventures, and practically every other space stakeholder.

The International Telecommunication Union (ITU) – as the regulatory custodian of the world’s radio spectrum – has an important role in keeping space sustainable. Managing spectrum use by satellites – both geostationary (GSO) and non-geostationary (non-GSO) – remains one of the organization’s most significant contributions.

Space-based technologies provide connectivity. They support vital communication services for agriculture, banking, transportation, and other sectors globally. Space services, therefore, are central to modern digital economic and social interactions.

Crucially, they save people’s lives during emergencies, as well as offering long-term environmental and climate insights.

As the key international regulatory agency for satellite-based communications, ITU allocates radio frequencies to different space services and develops global standards that help ensure long-term space sustainability.

Radio spectrum management

Satellites rely on specific frequency bands to communicate with their associated earth stations or with other satellites, and these bands are a limited resource. ITU manages the assignment of frequencies to all authorized satellite systems, preventing harmful interference to, from and between satellites and ensuring efficient spectrum use in the interest of all countries worldwide.

Through the ITU Radiocommunication Sector (ITU-R), member states agree on how to share the radio spectrum among various terrestrial and space-based radio services. This coordination is essential to avoid signal interference, which otherwise degrades communication services.

One of the most pressing issues in space sustainability is the management of orbital debris – meaning any human-made object in orbit around the Earth that no longer serves any useful purpose. 

These range from objects smaller than 1 millimetre in diameter (such as tiny flecks of paint released by thermal stress or small particle impacts) to those of 10 centimetres or much more (like defunct satellites or spent rocket boosters).

Steadily accumulating orbital debris threatens the operational viability of future satellite missions.

Ensuring spectrum sustainability

Orbital debris management falls outside ITU’s mandate. ITU does, however, help promote compliance with agreed guidelines from the UN Office for Outer Space Affairs (UNOOSA) for the long-term sustainability of outer space activities.

The recent ITU Radiocommunication Assembly (RA-23) held in Dubai, UAE, produced Resolution ITU-R 74, focusing on the sustainable use of radio-frequency spectrum and associated satellite-orbit resources by space services.

The resolution noted the rise in satellite filings for non-GSO systems, as well as the rising frequency of satellite launches.

Tracking de-orbit and disposal

A recent communication regarding Resolution ITU-R 74 describes the process for informing ITU of spacecraft deorbit and disposal strategies. This data collection aims to inform space actors about methods to prevent the accumulation of debris in outer space.

The dedicated ‘Space Sustainability Gateway’ website will feature the collected information, continually updated by the ITU Radiocommunication Bureau.

Clarity about de-orbit and disposal will help to prevent the growth of orbital debris and ensure the long-term sustainability of satellite orbits around Earth that serve innumerable communications purposes.

ITU’s work on the sustainable use of radio frequencies in space supports the Space2030 Agenda of the United Nations. Along with improving access to space for all, Space2030 aims to raise awareness about space science and technology to help achieve the UN’s Sustainable Development Goals.

Recording and resolving radio interference

The rapid growth and expansion of satellite connectivity also mean increased risks of radio interference. Continuous monitoring and international coordination are crucial to ensure the highest reliability in space services and satellite communications.

ITU’s Satellite Interference Reporting and Resolution System (SIRRS) enables governments and other space stakeholders – such as satellite operators, space agencies, and other participating entities – to report, through their respective national administrations, any harmful interference affecting space services.

SIRRS records contain reports of incidences of interference over successive years, making ongoing and new cases easier to track, analyse, and resolve.

Constant monitoring is essential to identify and mitigate harmful radio interference to space systems. To maintain the necessary vigilance, several Earth stations observe how satellite systems in different orbits utilize the radio spectrum.

Unresolved cases of harmful interference are eventually referred to the Radio Regulations Board – the key ITU body that is empowered to act between World Radiocommunication Conferences to support the practical and effective application of the Radio Regulations.

Through collaboration and information-sharing among space stakeholders, ITU seeks to promote a collective culture of spectrum and space stewardship.

A global mindset of space responsibility is essential to ensure sustainable use of the radio-frequency spectrum both in space and on Earth.

Anticipating challenges

Keeping space sustainable involves not only managing current space activities but also anticipating new developments and challenges.

UN agencies and space stakeholders worldwide are striving to ensure that outer space remains a safe and sustainable environment for future generations.

Through UN-Space, an inter-agency coordination mechanism on outer space activities, ITU liaises actively with UNOOSA and other UN organizations on current and future activities, emergent technologies of interest, and other related matters.

With growing space use comes great responsibility.

The future of space hinges on humanity’s ability to balance exploration and technological advancement with the preservation of the space environment, ensuring that space remains accessible for future generations.

Space Sustainability Forum 2024

ITU’s first Space Sustainability Forum took place in Geneva, Switzerland, on 10-11 September.

Watch highlights video