Managing radio frequency spectrum amid a new space race
When the first artificial satellite, Sputnik-1, was launched into low-Earth orbit in 1957, what came to be known as the “space race” had begun.
Space exploration activities continued for decades, with governments driving increasingly ambitious - and costly - missions to expand our knowledge of the universe.
Since then, the space race has diversified considerably, with 72 countries launching satellites into orbit and an increasing number of private companies joining the newly intensifying competition.
All users of radio frequencies in space, whether by states or private entities, must be notified by an administration with the International Telecommunication Union (ITU) to comply with the Radio Regulations – the binding international treaty that determines how radio frequency spectrum is shared between different users, including space services.
To date, ITU has been notified of more than 1,900 operational satellite systems, each of them containing from one to thousands of spacecraft, and several thousand satellite systems more under coordination to be used in the near future, with the private sector as the main driver in this new, steadily expanding space race.
Partnerships between governments’ space agencies and private space companies aim to establish crewed stations orbiting the Moon and landed on the lunar surface. Other human habitation concepts are in the works to enable people to live in low-Earth orbit or on a crew transport vehicle to Mars or elsewhere.
Once restricted to a few massive government-led programmes, space access is starting to become more open and affordable. Alongside human spaceflight, falling technology and launch costs are reflected in the burgeoning deployment of non-geostationary mega-constellations and small satellites that can be used for low-latency broadband communication, Earth observation, and Internet of Things applications.
“We are entering a new era where space monitoring, space traffic management and spectrum-orbit management are indispensable to assuring a secure, safe and sustainable space sector,” said Jorge Ciccorossi, chairman of the 22nd International Space Radio Monitoring Meeting hosted by ITU earlier this year.
These challenges were also discussed at the International Astronautical Congress 2021, held recently in Dubai (UAE) with the involvement of ITU experts.
While the burgeoning space economy could reach USD 1 trillion by the 2030s, “human-made space debris” – the bulk of the nearly one million objects larger than 1 centimetre now orbiting the Earth – already poses a risk to satellites and spacecraft, notes the World Economic Forum.
Coordinating the space ecosystem
All objects launched into space (except a very small number of passive satellites) require at least one radiofrequency component onboard the spacecraft, capable of transmitting and receiving space operations signals. These components can help control a satellite, in addition to enabling communications or other types of space services as the main payload.
Each such space-bound object is therefore assigned radio frequencies, coordinated under the ITU Radio Regulations to avoid radio signals interfering with each other.
ITU monitors the deployment of all satellite systems, particularly the implementation of large non-geostationary satellite constellation projects to ensure that notifications correspond to the actual satellites orbiting the Earth. Each constellation must be launched within a specified timeframe.
Resolution 35 from the last World Radiocommunication Conference, WRC-19, established a milestone approach requiring that 10 percent of any constellation in the fixed, mobile, and broadcasting satellite services in the traditional Ku and Ka frequency bands, as well as in the higher Q and V bands, must be in orbit within the first two years after the start of deployment, followed by 50 percent in five years and 100 percent in seven years.
Dealing with demand
The growing number of satellite projects has increased the complexity and boosted the volume of new satellite system notifications submitted to ITU. In response, the ITU Radiocommunications Bureau has initiated online processes to facilitate application requests and interference reporting.
The next World Radiocommunication Conference, in 2023, will further refine the space ecosystem to facilitate new applications and frequency bands for space services.
These could include inter-satellite links, sub-orbital vehicles, space weather sensors, Earth exploration satellite services, Earth stations in motion associated with non-geostationary satellite systems, Internet of Things systems connected to small satellites, and more.
Increasingly elaborate space infrastructure and behind-the-scenes coordination support a growing range of day-to-day activities – from using GPS (Global Positioning System) navigation to watching the news while flying or at sea, as well as exploring the ever-more numerous satellite images of our planet and universe.
“Six decades of space innovation have gotten us this far,” said Ciccorossi. “From here, the new space race will take us even further, with ITU safeguarding the invaluable use of space radiocommunications services to make it happen.”
The above image shows SpaceX Crew Dragon Endeavour during its approach to the International Space Station less than one day after launching from Kennedy Space Center in the United States. Image credit: NASA Office of Communications