Non-geostationary orbit (NGSO) satellite constellations are reshaping the landscape of satellite communications. Unlike traditional geostationary (GSO) satellites that orbit at a fixed position approximately 36,000 km above the Earth’s equator, NGSO satellites orbit at much lower altitudes, typically between 500 km and 2,000 km. This unique characteristic allows NGSO constellations to provide ubiquitous coverage across the globe, even in remote and underserved regions, making them increasingly important for bridging the digital divide and enabling new applications like real-time communications, Internet of Things (IoT) connectivity, and more.
The key advantages of NGSO constellations compared to GSO satellites and terrestrial networks are numerous. Firstly, the lower altitude of NGSO satellites results in significantly reduced latency and higher data speeds, which are critical for real-time applications such as video conferencing, online gaming, and telemedicine. Secondly, NGSO constellations have the ability to provide broadband access in rural and remote areas at lower costs compared to traditional terrestrial infrastructure, as they do not require extensive ground-based networks. Thirdly, the global coverage offered by NGSO systems makes them ideal for supporting IoT and machine-to-machine communications, enabling connectivity for devices and sensors in even the most remote locations. Finally, the distributed nature of NGSO constellations provides inherent resiliency and redundancy when integrated with terrestrial 5G networks, ensuring reliable connectivity even in the event of localized failures or disasters.
Major companies like SpaceX (Starlink), OneWeb, Amazon (Project Kuiper), and others are actively deploying or planning massive NGSO constellations consisting of hundreds or even thousands of satellites to provide global broadband internet and other services. SpaceX’s Starlink constellation, for example, aims to deploy nearly 12,000 satellites in multiple orbital shells, with plans for expansion to 42,000 satellites in the future. OneWeb, despite facing initial setbacks, has resumed launches and aims to provide global coverage with a constellation of 648 satellites. Amazon’s Project Kuiper has received approval for a constellation of 3,236 satellites, with plans to offer broadband services to underserved communities worldwide.
This rapid increase in NGSO systems is driving innovation and expanding connectivity options but also creates new policy and regulatory challenges that need to be addressed by national administrations, international bodies like the International Telecommunication Union (ITU), and the industry as a whole. These challenges include ensuring efficient and equitable spectrum sharing, mitigating the risk of orbital debris and collisions, addressing concerns raised by the astronomy community, and fostering a level playing field for market access and competition.
Characteristics of NGSO Systems
NGSO satellite systems operate in various orbits, including low Earth orbit (LEO), medium Earth orbit (MEO), and highly elliptical orbits (HEO), at altitudes ranging from a few hundred kilometers to around 10,000 km. This is in stark contrast to the 36,000 km altitude of GSO satellites. The shorter distance between NGSO satellites and the Earth’s surface results in several advantages, such as reduced latency, lower signal loss, and the ability to provide coverage in polar regions that are difficult to serve with GSO satellites.
However, to provide continuous global coverage, NGSO systems require constellations of many satellites, often referred to as “megaconstellations,” that hand off communications seamlessly as they orbit around the Earth. The number of satellites in a constellation can vary greatly depending on the intended application and orbital configuration, ranging from a few dozen to several thousand.
Some key characteristics of NGSO constellations include:
- Use of multiple orbital planes: NGSO constellations often employ multiple orbital planes, with specific positioning of satellites within and between planes to ensure optimal coverage and minimize interference. This allows for efficient use of spectrum and enables the constellation to provide consistent service across different regions.
- Ability to reconfigure and scale capacity: NGSO constellations can be flexibly reconfigured and scaled by adding or removing satellites as needed to meet changing demand or to replace aging spacecraft. This adaptability allows operators to respond quickly to market needs and ensures the long-term sustainability of the constellation.
- Utilization of inter-satellite links (ISLs): Many NGSO systems employ ISLs, which enable satellites to communicate and route traffic directly with each other in space, without the need for ground stations. This improves network efficiency, reduces latency, and enhances privacy by minimizing the need for ground-based infrastructure.
- Support for spectrum sharing and small, low-cost user terminals: NGSO constellations are designed to share spectrum efficiently with other satellite and terrestrial systems, using techniques like frequency hopping and dynamic beam forming. They also enable the use of small, low-cost user terminals, making it easier and more affordable for consumers to access satellite broadband services.
- Need for autonomous operations: Given the large number of satellites in NGSO constellations and their constant motion, continuous ground-based control and monitoring is not feasible. Instead, these systems rely on autonomous operations, with satellites capable of performing tasks like station-keeping, collision avoidance, and fault detection independently, with minimal human intervention.
The optimal design of an NGSO constellation depends on the target applications and must balance factors like coverage, capacity, latency, and cost. For example, sun-synchronous LEO orbits are often preferred for Earth observation applications, as they allow satellites to pass over a given location at the same local time each day, ensuring consistent lighting conditions for imaging. On the other hand, overlapping LEO planes with satellites at different altitudes and inclinations are better suited for providing global broadband connectivity, as they ensure continuous coverage and minimize the impact of signal blockage by terrain or buildings.
Regulatory Landscape
The dramatic rise in NGSO systems is creating new regulatory challenges for national administrations and international bodies like the ITU. These challenges span a range of issues, from spectrum allocation and orbital debris mitigation to the protection of astronomical observations and ensuring fair competition in the satellite broadband market.
Spectrum Sharing and Interference
One of the most pressing issues facing NGSO constellations is the need for access to sufficient radio spectrum to operate their services. However, radio spectrum is an increasingly scarce resource, with competing demands from a wide range of terrestrial and satellite services. In many frequency bands, existing GSO satellite networks have priority rights, which means that NGSO systems must find ways to share spectrum without causing harmful interference to incumbent users.
To facilitate spectrum sharing between NGSO and GSO systems and protect GSO services from interference, the ITU Radio Regulations have established coordination procedures and technical limits on power flux density (PFD) and equivalent power flux density (EPFD) from NGSO systems. These regulations are designed to ensure that NGSO constellations can coexist with GSO networks while minimizing the risk of interference.
The ITU’s World Radiocommunication Conference in 2019 (WRC-19) updated these rules, introducing new requirements for NGSO fixed-satellite service (FSS) systems. For example, NGSO FSS operators must now provide a commitment to meet specific EPFD limits and coordinate with potentially affected GSO networks before deploying their constellations. These changes aim to strike a balance between facilitating the growth of NGSO systems and protecting the rights of existing GSO operators.
National administrations are also grappling with spectrum sharing challenges as they allocate frequencies for NGSO constellations. In the United States, the Federal Communications Commission (FCC) has established a regulatory framework for NGSO systems in various frequency bands, including the Ku, Ka, and V bands. This framework includes rules for sharing spectrum with GSO networks, as well as provisions for protecting terrestrial wireless services operating in adjacent bands.
Orbital Debris and Collision Risks
Another major concern associated with the proliferation of NGSO constellations is the increased risk of orbital debris and collisions in low Earth orbit. With tens of thousands of satellites planned for deployment in the coming years, the potential for collisions between active satellites, as well as between satellites and existing debris, is significant. Such collisions could generate additional debris, leading to a cascading effect known as the Kessler syndrome, which could render certain orbital regions unusable for decades or even centuries.
To mitigate these risks, NGSO constellation operators are expected to adopt a range of measures, including:
- Collision avoidance: Satellites should be equipped with sensors and propulsion systems that allow them to detect and avoid potential collisions with other objects in orbit.
- End-of-life disposal: Operators must have plans in place for safely deorbiting their satellites at the end of their operational lives, either by using on-board propulsion to lower their orbits and burn up in the atmosphere or by boosting them to higher “graveyard” orbits.
- Use of materials that minimize debris generation: Satellites should be designed with materials that are less likely to generate debris in the event of a collision or breakup, such as using non-explosive battery technologies and avoiding the use of paint or other coatings that can flake off over time.
- Adherence to international guidelines and best practices: Operators should follow the UN Committee on the Peaceful Uses of Outer Space (COPUOS) Long-Term Sustainability Guidelines and ITU Recommendations, which provide voluntary guidance on debris mitigation and sustainable space operations.
Some national administrations are considering additional requirements for NGSO constellations to ensure the long-term sustainability of space activities. For example, the FCC has proposed rules that would require NGSO operators to submit detailed orbital debris mitigation plans as part of their license applications, and to provide regular updates on the status of their constellations and debris mitigation efforts.
Astronomy and Dark Skies
The astronomical community has raised concerns about the potential impact of NGSO megaconstellations on both optical and radio astronomy. The large number of satellites in these constellations, combined with their reflective surfaces and low orbits, can create significant challenges for ground-based telescopes.
In the optical domain, sunlight reflections from the satellites can appear as bright streaks in telescope images, interfering with observations and potentially obscuring faint celestial objects. This problem is particularly acute during twilight hours, when satellites are still illuminated by the sun but the sky is dark enough for astronomical observations.
In the radio domain, out-of-band emissions from satellite transmitters can interfere with sensitive radio telescopes operating in adjacent frequency bands. This is a concern for radio astronomers studying distant galaxies, quasars, and other objects that emit faint radio signals.
To address these concerns, satellite operators are working with the astronomy community to develop mitigation strategies and best practices. These include:
- Reducing satellite reflectivity: Operators can apply less reflective coatings or surface treatments to their satellites to minimize sunlight reflections. SpaceX, for example, has experimented with “darksat” coatings and visors to reduce the brightness of its Starlink satellites.
- Orienting satellites to minimize reflections: By adjusting the orientation of satellites relative to the sun and Earth, operators can reduce the amount of sunlight reflected toward the ground. This can be achieved through careful mission planning and the use of on-board attitude control systems.
- Avoiding certain orbits and frequency bands: Constellation designers can choose orbits that minimize the impact on astronomical observations, such as avoiding the use of certain altitudes or inclinations. They can also work with the ITU and national regulators to ensure that their frequency assignments do not interfere with radio astronomy bands.
- Sharing data and collaborating on observations: Satellite operators can provide detailed information about the orbits and transmission characteristics of their spacecraft to the astronomy community, allowing astronomers to plan their observations around potential interference. In some cases, operators may even be able to adjust the orbits or operations of individual satellites to accommodate specific astronomical campaigns.
Continued collaboration between the satellite industry and the astronomy community will be essential to develop standards and best practices that balance the benefits of NGSO constellations with the need to protect the dark skies and the science that depends on them.
Market Access and Level Playing Field
As NGSO broadband constellations begin to enter the market and offer services to consumers, regulators must ensure a level playing field between these new entrants and established satellite and terrestrial broadband providers. This involves addressing a range of issues, including spectrum access, infrastructure sharing, universal service policies, and network resilience requirements.
One key challenge is ensuring that NGSO constellations have fair access to the radio spectrum they need to operate, while also protecting the rights of incumbent users. This may require the development of new spectrum sharing frameworks and the establishment of clear rules for coordination and interference management.
Another important consideration is the integration of NGSO systems into existing broadband markets and universal service programs. Regulators must ensure that NGSO operators are subject to the same obligations and requirements as other broadband providers, such as contributing to universal service funds, meeting network reliability and resilience standards, and providing transparent pricing and service terms to consumers.
At the same time, regulators should also recognize the unique capabilities and benefits of NGSO systems, particularly in terms of their ability to serve remote and underserved areas. This may require the development of targeted policies and incentives to encourage NGSO deployment in these regions, such as subsidies, tax breaks, or regulatory flexibility.
National administrations are updating their satellite licensing rules and procedures to facilitate the entry of NGSO constellations into the market while also protecting competition and consumer interests. In the United States, the FCC has approved several NGSO constellations, including those proposed by SpaceX, OneWeb, and Amazon, subject to certain conditions related to spectrum sharing, orbital debris mitigation, and other factors.
At the international level, the ITU is studying how to integrate NGSO systems into the existing regulatory framework for satellite communications. This includes examining issues related to spectrum allocation, coordination procedures, and the application of existing ITU Recommendations and Regulations to NGSO constellations.
Opportunities for 5G and Digital Inclusion
Despite the regulatory challenges associated with NGSO constellations, these systems offer significant opportunities to expand broadband access and support the deployment of 5G networks worldwide. By providing global coverage, high capacity, and low latency connectivity, NGSO systems can help meet the growing demand for broadband services in areas that are currently underserved or unserved by terrestrial networks.
One of the key benefits of NGSO constellations is their ability to complement and extend the reach of terrestrial 5G networks. By integrating satellite and terrestrial networks, operators can provide seamless connectivity to users across a wide range of environments, from dense urban areas to remote rural regions. This integration can take several forms, including:
- Backhaul and trunking: NGSO satellites can provide high-capacity backhaul links for 5G base stations, particularly in areas where fiber or microwave infrastructure is unavailable or impractical. This can help reduce the cost and complexity of deploying 5G networks in rural and remote regions.
- Edge computing and caching: NGSO satellites equipped with on-board processing capabilities can serve as edge computing nodes, bringing cloud services and content closer to end-users. This can reduce latency and improve the performance of applications like video streaming, online gaming, and virtual reality.
- Mobility support: NGSO constellations can provide continuous connectivity to mobile users, such as those on aircraft, ships, trains, and vehicles. This can enable a range of new applications and services, from in-flight entertainment to autonomous vehicle communication.
- Internet of Things (IoT) connectivity: The global coverage and low latency of NGSO systems make them well-suited for supporting IoT applications, particularly in industries like agriculture, maritime, and logistics. By providing reliable and affordable connectivity to remote sensors and devices, NGSO constellations can help unlock the full potential of the IoT.
In addition to supporting 5G deployment, NGSO constellations can also play a crucial role in bridging the digital divide and promoting digital inclusion. By providing affordable and reliable broadband access to underserved communities, these systems can help close the gap between those who have access to the benefits of the digital economy and those who do not.
Governments and policymakers should consider how to leverage NGSO constellations as part of their broader strategies for expanding broadband access and promoting digital inclusion. This may involve incorporating NGSO systems into national broadband plans, universal service programs, and other initiatives aimed at improving connectivity in rural and remote areas.
For example, governments could provide subsidies or tax incentives to encourage NGSO operators to deploy services in underserved regions, or they could establish public-private partnerships to fund the deployment of ground infrastructure and user terminals. Policymakers could also work with NGSO operators to develop targeted programs and services for specific user groups, such as schools, healthcare facilities, and small businesses.
Another important consideration is ensuring that NGSO services are affordable and accessible to all users, regardless of their income or location. This may require the development of flexible pricing models, such as prepaid or pay-as-you-go plans, as well as the provision of subsidies or discounts for low-income households and other vulnerable populations.
Governments and regulators should also work to ensure that NGSO services are integrated into existing digital inclusion programs and initiatives, such as digital literacy training, device subsidies, and public access facilities. By providing a comprehensive suite of connectivity, devices, and skills training, these programs can help ensure that all individuals and communities can fully participate in the digital economy.
Summary
The rapid emergence of NGSO satellite constellations represents a major shift in the landscape of global connectivity, offering new opportunities to expand broadband access, support 5G deployment, and bridge the digital divide. However, realizing the full potential of these systems will require a proactive and collaborative approach to regulation, one that balances the need for innovation and investment with the protection of public interests and the sustainability of the space environment.
Regulators and policymakers at the national and international levels must work together to develop a flexible and adaptive regulatory framework that can accommodate the unique characteristics and requirements of NGSO constellations while also ensuring a level playing field for all market participants. This will involve addressing a range of complex issues, from spectrum allocation and orbital debris mitigation to the protection of astronomical observations and the promotion of fair competition.
At the same time, the industry must continue to engage in good-faith efforts to address the concerns of stakeholders and to develop best practices and technical solutions that can mitigate the potential negative impacts of NGSO constellations. This will require ongoing collaboration and dialogue between satellite operators, equipment manufacturers, astronomers, and other interested parties.
Ultimately, the success of NGSO constellations will depend on the ability of all stakeholders to work together in pursuit of a shared vision of a more connected, inclusive, and sustainable world. By embracing the opportunities and challenges presented by these systems, we can unlock new possibilities for innovation, growth, and social progress, while also ensuring that the benefits of the digital revolution are shared by all.
As we look to the future, it is clear that NGSO satellite constellations will play an increasingly important role in shaping the global connectivity landscape. With the right policies, investments, and partnerships in place, these systems have the potential to transform the way we live, work, and communicate, bringing the power of the digital economy to every corner of the globe. The work of realizing this potential is just beginning, but the stakes could not be higher – for the industry, for governments, and for the billions of individuals who stand to benefit from a more connected and inclusive world.
