Everything You Need to Know About Scarce Orbital Slots

As the earth's orbit grows more crowded, orbital slots are tge promised answer to the risk of collisions. But how effective are they?

Looking into the vast expanse of space, it seems almost absurd to entertain the idea of running out of room. However, an alarming truth is emerging as the demand for orbital slots reaches unprecedented levels. 

Why Orbital Slots Matter

Satellites have become an integral part of our modern lives, enabling global communication, navigation, weather forecasting, and much more. The advent of technological advancements and the subsequent decrease in launch costs have paved the way for an influx of new players entering the space race. As the barriers to entry lower, we are witnessing a surge in satellite deployments by both established space agencies and emerging private companies. This surge is set to escalate even further with the ambitious plans for mega constellation projects on the horizon. Mega constellations, such as SpaceX’s Starlink and Amazon’s Project Kuiper, are aiming to blanket the Earth with thousands upon thousands of interconnected satellites. These constellations promise improved global connectivity and enhanced internet access for remote areas. However, their proliferation comes at a cost – an exponential increase in the number of satellites orbiting our planet.

According to a McKinsey report, the number of satellites in space is expected to triple to 15,000 by the year 2030. This rapid expansion poses a significant challenge, for the skyrocketing number of satellites is soberly contrasted by the fact that the available space above our planet remains constant. The result? An intensifying scarcity of orbital slots. 

The Idea of Orbital Slots

Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, aptly captures the impending scenario in an overcrowded space with insufficient international governance. He compares it to an interstate highway during rush hour in a snowstorm, with everyone driving at breakneck speeds. “Except that there are multiple interstate highways crossing each other with no stoplights,” he remarks. This vivid analogy highlights the chaotic congestion that awaits our celestial pathways.

As the number of satellites continues to soar, it is becoming increasingly evident that orbital space is a finite and precious resource. The realization of this scarcity is set to transform space into an arena of heated competition and diplomatic wrangling. Nations, private enterprises, and scientific organizations will vie for strategic orbital slots to safeguard their interests and maintain their technological edge in a game whose rules have yet to be fully written. 

In order to fully comprehend the complexities surrounding orbital slots, it is essential to understand their dual nature. An orbital slot consists of both a positional component and a radio frequency component, each playing a crucial role in determining the value and usability of a particular slot.

Appraising Orbital Slots

In order to begin grasping the challenges of orbital real estate, it is essential to understand what makes an orbital slot. An orbital slot consists of both a positional component – how high and above what part of earth the satellite is located –  and a radio frequency component – what frequency it uses to communicate with its operator on the ground Each component plays a crucial role in determining the value and usability of a particular slot.

Orbits Are Not Made Equal

Within the vast expanse of space, certain orbits hold more allure than others. Among them, the Geostationary Orbit (GEO) reigns as the most coveted. Positioned approximately 35,786 kilometers (22,236 miles) above the Earth’s equator, satellites in GEO orbits orbit the earth at the same speed as the earth rotates. They therefore appear to hang stationary in the sky, offering excellent coverage and uninterrupted communication capabilities. It is this unique characteristic that makes GEO the orbit of choice for telecommunications, broadcasting, and weather observation satellites.

Moving closer to Earth, we encounter the Medium Earth Orbit (MEO). This orbit is gaining prominence due to the proliferation of global navigation systems like GPS, Galileo, and GLONASS. MEO satellites, situated at altitudes ranging from 2,000 to 36,000 kilometers (1,243-22,250 miles), provide more accurate positioning data but face the challenge of limited slots as the number of navigation constellations expands.

Further down, we find the Sun-Synchronous Orbit (SSO) and the Low Earth Orbit (LEO). Satellites in SSO whizz approximately 600-800 kilometers (370-500 miles) above us. A satellite in SSO maintains a fixed relationship with the Sun, crossing the equator at the same local solar time during each pass. This synchronized orbit is ideal for Earth observation missions, enabling the capture of consistent lighting conditions for accurate imaging and monitoring purposes.

LEO, on the other hand, refers to other orbits located between 160 and 2,000 kilometers above Earth’s surface. LEO satellites, with their proximity to the planet, offer advantages such as reduced signal latency, enabling applications like real-time communication and remote sensing. Companies like SpaceX’s Starlink and OneWeb are actively deploying large constellations of LEO satellites to provide global broadband internet coverage. Other orbits, such as Polar Orbits, tend to be less crowded. 

Frequencies are Not Equally Desirable

In addition to the positional component, radio frequencies play a pivotal role in determining the effectiveness and efficiency of satellite communications. Different frequency bands serve various applications, each with its own advantages and limitations.

A graphic detailing the different frequency bands used by satellites, delineating the radiowave component of orbital slots
A graphic detailing the different frequency bands used by satellites. They delineate the radiowave component of orbital slots [Credits, ESA]
Finding the sweet Spot

The frequency bands between 1 and 30 GHz encompass a range of bands marked with letters.  Higher frequencies offer wider bandwidths, enabling the transmission of large amounts of data. Moreover, higher frequencies require smaller antenna sizes, making them suitable for compact satellite designs. However, they are more susceptible to atmospheric attenuation, commonly known as rain fade, which can degrade the quality of the signal. The “sweet spot” will depend on use: satellites handling relatively light telephone data or pings can operate at the lower end of the spectrum, while television or internet data satellites will need higher bandwidth – just like how your phone performs better with 5 bars of Wi-Fi than spotty signal. Most satellites’ sweet spot lies in the C,X, and Ku bands. 

Nevertheless, radio interference poses a natural limit on the number of satellites that can operate within a frequency band. Interference arises when signals from multiple satellites in close proximity interfere with each other, degrading the overall performance. This interference issue has led to overcrowding in certain frequency bands, particularly those C, X, and Ku bands, making them highly contested resources among satellite operators.

To mitigate interference, spatial separation rules have been established, dictating the minimum distance between satellites operating in the same frequency band. Over time, these rules have evolved from six degrees to the current standard of two degrees. This reduction in separation requirements has enabled more satellites to operate within the same band, exacerbating the congestion and intensifying the competition for limited orbital slots. Nevertheless, 2-degree separation limits the number of satellites using the same frequency to 180.

Governance in Orbital Slots

The responsibility of determining those separation rules and maintaining order on this increasingly heated scene falls on the International Telecommunication Union (ITU), a specialized agency of the United Nations entrusted with managing global radio frequency spectrum and satellite orbits.

The ITU serves as the governing body for satellite communications and ensures fair and equitable access to orbital slots. It establishes regulations, coordinates frequency assignments, and resolves conflicts arising from the limited availability of slots. This international cooperation is vital to maintain order and prevent chaotic congestion in space.

How to Acquire a Slot

The process of acquiring a GEO slot – the most valued ones – begins with individual countries submitting their satellite plans to the ITU. These plans outline the technical specifications, frequencies, and desired orbital positions for their satellites. The ITU carefully reviews these proposals on a “first come, first served” basis to ensure they comply with international regulations and do not interfere with existing satellite operations.

To avoid states hoarding onto orbital slots without using them, the ITU gives filers a seven-year deadline to bring their satellite into the assigned slot.  This approach promotes a dynamic and competitive environment in space, encouraging innovation and reducing the risk of resource hoarding. Some actors, particularly developing countries, have criticized the rule for advantaging developed economies that have the immediate capacity to build and launch satellites while putting countries with smaller industries at a disadvantage. 

The ITU’s role in managing orbital slots ensures a fair and transparent system for satellite operators worldwide. However, as the demand for slots continues to rise, the ITU faces the challenge of balancing the interests of various stakeholders while maintaining order and avoiding potential conflicts. The delicate task of managing this limited resource requires ongoing coordination, collaboration, and adaptability in the face of rapidly evolving technologies and increasing competition.

Who’s Who: Navigating Diplomacy and Emerging Players in Orbital Slots

The pursuit of orbital slots not only involves technological advancements and economic interests but also carries significant diplomatic implications. Looming scarcity shed light on the ridge between established and emerging powers, as well as the challenges faced by smaller states in the race for orbital real estate.

While the 5+2 year rule implemented by the International Telecommunication Union (ITU) aims to ensure efficient use of orbital slots, there are concerns about its impact on smaller states. For countries with limited resources, designing, building, and launching a satellite under these strict timelines can be a significant challenge. As a result, smaller states may face difficulties in capitalizing on their allocated slots, potentially hindering their participation and competitiveness in the space industry. 

Smaller States and Slot Governance

Many of these smaller space powers are located in Africa, which has been historically underrepresented in space. Recognizing the potential of space technologies for development and connectivity, African countries are now actively asserting their presence, with an increasing number of African states launching satellites of their own. However, the most valuable GEO slots are growing rare, especially when considering sub saharan African operators’ heightened need for C-band frequencies, among the rarest, due to increased rainfall in the region. In this context, the African Telecommunications Union (ATU) organized a workshop in 2019 focused on orbital slots and spectrum management, highlighting the interests and aspirations of African nations in maximizing the benefits of space-based applications. It is however unclear if African states will succeed in maintaining a position of collective bargaining, especially as gaps in advancement will continue growing between countries on the continent. 

Another noteworthy example that sent ripples through the established order of orbital slot allocation is that of Tonga, in an unlikely story involving a princess, bribery, and the Chinese Government that deserves an article of its own. Tonga’s commodification of slots raised questions regarding transparency, accountability, and the potential exploitation of orbital slots. Tonga’s case illustrates the debates around fairness, sovereignty, colonialism, international influence, diplomacy  and market forces that are will grow louder as the issue of orbital slots becomes more pressing. 

Potential Solutions: Optimizing Slot Usage and the Role of Public and Private Sector Actors

As the demand for orbital slots continues to grow, exploring potential solutions becomes imperative to address the scarcity and challenges associated with their allocation. Several strategies and considerations can help optimize slot usage and pave the way for a more efficient and equitable distribution.

One potential solution lies in the deployment of smaller satellites. The miniaturization of satellite technology could allow for a more optimized use of orbital slots. This approach not only maximizes the utilization of limited space but also enables improved connectivity and data gathering across various applications.

The Future Role of Governance

In addition to technological advancements, public sector actors play a crucial role in shaping the future of orbital slots. Governments and regulatory bodies can implement measures to ensure responsible and sustainable usage of orbital resources. This may involve setting limits on the number of satellites that can be deployed within a specific region or orbit, considering environmental impact assessments, and establishing regulations to mitigate potential conflicts and interference between satellite operators.

The possibility of regulatory mechanisms to prevent an overcrowding of satellites in space raises an important question about the balance between innovation and regulation. Striking the right balance is essential to foster a competitive and vibrant space industry while safeguarding the long-term sustainability and stability of orbital resources.

An intriguing alternative to the current allocation process is the idea of trading orbital slots on a market, akin to the trading of landing slots at airports. This market-based approach would introduce a dynamic and flexible mechanism for slot allocation, potentially enabling more efficient utilization of resources. However, such a system raises ethical and practical considerations. Would a market-driven approach to orbital slots be fair, equitable, and in the best interest of humanity as a whole? Balancing the pursuit of commercial interests with the needs of scientific exploration, national security, and global cooperation is a critical aspect to be considered in any potential market-based system.

Conclusion

In anticipation of evolving dynamics and potential changes in the allocation of orbital slots, private sector actors need to be prepared. Satellite operators and companies involved in space exploration should proactively adapt their strategies and technologies to ensure compliance with evolving regulations, efficient use of resources, and responsible stewardship of orbital slots. This includes considering the use of innovative satellite designs, implementing advanced frequency management techniques, and actively engaging in international discussions and collaborations to shape the future policies and frameworks surrounding orbital resources.