The rise of LEO mega-constellations: Shaping the future of SatCom and global connectivity

With the number of satellites on the rise – particularly in Low Earth Orbit – there are various technical and operational challenges that satellite operators are facing.

Network providers like Starlink are considering eventually having up to 42 000 satellites in their Non-Geostationary Orbit (NGSO) constellations. Some estimates suggest that the overall number of active satellites in orbit could reach 100 000 by 2030.

This growth of LEO satellite constellations is reshaping the future of SatCom by enabling global, low-latency connectivity. However, this also demands advanced system design.

Thanks to Magister’s simulation tools, the performance and potential of these mega-constellations can be analyzed and evaluated.

Satellite numbers on the rise: The space race for global connectivity

The number of satellites in orbit has more than doubled in the last five years. According to Jonathan McDowell, Astronomer and Astrophysicist at the Center for Astrophysics (Harvard & Smithsonian), the total number of active satellites in orbit as of May 2025 is around 11 700. Over 7500 of them are Starlink satellites, accounting for more than 60% of the total.

The difference to just five years ago is significant. By the end of 2020, the number of active satellites in orbit was 3371, with around 900 of them belonging to Starlink.

SpaceX’s Starlink is currently dominating the satellite internet market. However, competitors are also arising, such as Project Kuiper by Amazon, the Shanghai-based Spacesail, as well as Eutelsat OneWeb.

While this recent surge in satellite deployments is already substantial, Starlink is considering eventually having as many as 42 000 satellites in their NGSO constellations. 

When factoring in all current and emerging satellite operators, some estimates suggest that the number of active satellites in orbit could reach 100 000 by 2030.

Optimizing LEO mega-constellations – System simulators make it easier to study routings in space

Traditionally, satellite communication – or SatCom – has relied on Geostationary Orbit (GEO) satellites. However, Non-Geostationary Orbit (NGSO) satellites have been becoming increasingly common over the past decade. NGSO includes satellites in Low Earth Orbit (LEO) and Medium Earth Orbit (MEO).

This growing popularity is especially prevalent in LEO satellites. There are various reasons for this. As the name suggests, LEO satellites orbit closer to the Earth’s surface than those in higher orbits. This proximity enables lower communication latency and faster data transmission, leading to high-speed internet connectivity. Additionally, LEO satellites are smaller and more cost-effective to build and launch than other types of satellites.

In comparison to GEO satellites, the coverage of a single LEO satellite is relatively small. LEO satellites are also moving constantly, whereas GEO satellites match the Earth’s rotation and therefore appear stationary. This is why achieving continuous global coverage with LEO satellites requires deploying large constellations.

While these constellations bring significant societal benefits – such as improved internet access – they also introduce greater operational complexity in terms of system management and optimization.

Challenges of LEO satellite constellations: Gateway locations, sustainability and interference

LEO satellite constellations present several technological challenges. Managing the cost of the constellation and ensuring service quality are essential for satellite operators to justify their business cases.

One major challenge for these LEO mega-constellations is finding sufficient gateway locations. There must either be a huge number of gateways all over the world, or satellites must be equipped with Inter-Satellite Links (ISLs) and routing capabilities. 

ISLs enable satellites to form networks in space, being able to relay data directly with one another. This means shorter delays and a more consistent global coverage.

Looking ahead, ISL routing algorithms appear to be a key part of future satellite constellation design, with operators like Telesat and Viasat already moving in this direction.

Other challenges for LEO satellite constellations include sustainability concerns – for example, the increased risk of collisions and growing amount of space debris. As more satellites are launched, the likelihood of collisions rises. This can lead to a growing number of non-functional or dead satellites in orbit. The debris poses a threat to current operational satellites, as well as future launches.

Another issue is the coexistence of terrestrial networks and non-terrestrial networks. It’s essential to ensure that new satellite systems don’t cause harmful interference with existing terrestrial systems, particularly in neighboring frequency bands. Without careful coordination, interference can lead to performance loss for both satellite and ground-based systems.

Simulators for satellite constellation design

At Magister, we are always on the lookout for new and better uses of technology for optimizing LEO mega-constellations. Through our collaborations with the European Space Agency and our internal work, we have developed advanced satellite simulation software for exploring these systems in detail.

For example, in the SCNE project, we developed a system-level simulator that enables our customers to study advanced ISL routing algorithms, mobility management, higher layer and end-to-end performance.

Our C-DReAM simulator is an ideal tool for satellite constellation design. It supports a wide range of capabilities – from determining the optimal number of satellites to analyzing constellation coverage, capacity, and more. We’re constantly enhancing C-DReAM to address emerging challenges and evolving use cases of the satellite industry, including the capability for analyzing ISLs.

We’re currently working on the Nova simulator, which will make it possible to evaluate 5G control plane procedures with flexible NGSO constellations. Nova will support 3GPP specified NTN system architectures, as well as modeling of simple Inter-Satellite Links.

C-DReAM helps you simulate various sized NGSO and GSO constellations 

The time is right for future SatCom systems using NGSO satellite constellations

NGSO satellite constellations are not a new invention. The earliest attempts at something similar were made in the 1990s. However, most of them failed due to financial, technical, and other difficulties.

Today, the idea of using NGSO constellations in the development of SatCom systems has become a reality. This time, the prospects for success are much stronger for a number of reasons:

• Rising demand for bandwidth and low latency communication, including rural and hard-to-reach areas such as seas, mountains, and deserts.
• Technology involved in the mass production of satellites, frequency resources and usage, antennas, and launching satellites has become more available and affordable.
• More capital is now available from investors, for example. SatCom is a CAPEX-intensive industry.
• New Space players have entered the field with fresh, innovative ideas.
• New business cases, including the digital divide, the seamless connectivity of handheld devices, and the Internet of Things (IoT).
• 3GPP 5G Non-Terrestrial Network (NTN) standardization as a global connectivity standard – attracting new vendors, increasing competition and lowering production costs.

In many ways, the future is already here, with innovation moving faster than ever.