Space Connect: The rise of LEO satellite constellations

The world is witnessing an unprecedented surge in satellite launches, with about 10 times more satellites now active compared to a decade ago, mostly in low Earth orbit (LEO).

The first episode of ITU’s Space Connect examined the fundamentals of LEO satellite constellations, revealing key trends and drivers behind this game-changer in space-based digital communications.

The number of satellites active in 2014 was around 1,000. By last year, that was close to 10,000.

Carissa Christensen, Founder and CEO of BryceTech LLC, attributes the rapid growth to advances in satellite technology and the influx of venture investment in space businesses. More than USD 60 billion has been invested in the past ten years, with nearly USD 50 billion of it in the last five years alone.

Christensen highlighted two key business dynamics in the space ecosystem:

• in-space activities driven by government programmes, and
• the satellite value chain driven by commercial activities.

Smaller, lighter satellites allow for more efficient and cost-effective deployments.

The revolution in low Earth orbit

The boom in small satellites has led to a preference for low Earth orbit.

“These satellites are going to near-Earth orbits,” said Christensen. “And instead of a few satellites with a broad view of the Earth, we have many satellites creating a sort of a mesh that see the majority of the Earth.”

The shift to LEO has unleashed a new wave of remote-sensing and digital communications uses. While investments initially focused on Earth-imaging satellites, constellations supporting various forms of communications now predominate.

Telecommunications – particularly for television and video content – still holds a large share of the market. “But because of changes in the way people view television, it is decreasing, whereas broadband applications are increasing,” said Christensen.

Constellation architecture

Constellation designs vary widely with the evolving mix of services to deliver.

No single architecture is ideal, explained Tim Maclay, CEO of Celestial Insight. Instead, different architectures – from Walker delta and star to tiered, multi-orbit, and ad-hoc configurations – cater to various operational needs. In all cases, satellite operation remains a complex endeavour.

Maclay took the webinar audience back to Kepler’s Laws of Planetary Motion, evoking “a simple world, where all orbits are perfect ellipses.” Real-life LEO satellites, however, must travel imperfect pathways close to “a spinning planet that wobbles on its axis.”

Altitude, inclination, and orbital dynamics all influence service delivery and affect a constellation’s coexistence with other objects in space. Atmospheric drag can serve as a natural cleansing mechanism in low Earth orbits, Maclay added.

Spectrum for the space boom

The space economy is projected to reach USD 1.8 trillion by 2035. The International Telecommunication Union (ITU) supports growth in the space economy while striving to ensure every country can benefit from space and satellite connectivity.

“Not everyone has equal access to these opportunities, making the risk of leaving too many people behind all too real,” said ITU Secretary-General Doreen Bogdan-Martin. “As the UN agency for digital technologies and the custodian of radio spectrum on Earth and space, ITU has a crucial role to play here.”

Global connectivity depends on closely coordinated allocations of the world’s limited radio-frequency spectrum. The Radio Regulations treaty maintained by ITU governs all use of the radio-frequency spectrum, including by satellites in geostationary orbit nearly 36,000 kilometres above sea level and those in lower, non-geostationary-satellite orbits.

LEO satellites and constellations fall into the non-GSO category.

“The growing focus on space is further validated by the remarkable increase in projects submitted to ITU for spectrum and orbit resources,” said Mario Maniewicz, Director of ITU’s Radiocommunication Bureau. “Over the past decade, such requests have grown 5.5 times, showcasing not only the immense promise of the rapidly growing space economy, but also highlighting the complexity and challenges we face.”

Satellite and constellation plans, complete with radio frequencies and spectrum-sharing proposals, must be filed in advance with ITU. National administrations or satellite operators must then agree on how they will avoid harmful interference to each’s other systems, subject to ITU compliance checks.

Coordinated frequency usage lets different constellations share the same limited spectrum resource, said John Pahl, owner of Transfinite Systems, a provider of radiocommunications modelling, interference analysis, and spectrum coordination software.

Replay Space Connect Episode 1: LEO Satellite Constellation Fundamentals

Future episodes

ITU’s webinar series will keep exploring critical topics like space sustainability, advances in launch technologies, and more about non-geostationary constellations.

Don’t miss Space Connect Episode 2, on 27 February: Authorizing LEO services − A global perspective

Other upcoming topics include Earth observation, climate monitoring, and emergency response, as well as direct-to-device (D2D), machine-to-machine (M2M) and cislunar (Earth-Moon) communications.

Tell us your top three areas of interest for future Space Connect sessions

The sessions, hosted at ITU headquarters in Geneva, Switzerland, for participants worldwide, offer insights on how evolving satellite tech will shape future global connectivity and communications.

Learn more about the ITU Radiocommunication Sector (ITU-R) and its Space Services Department

Header image credit: AdobeStock