Orbital slots and space congestion

For this new article on Space Legal Issues, let’s have a look at orbital slots and space congestion. The use of telecommunication satellites have continued to increase since they were first launched in the 1960s. Their applications are now very much a part of day-to-day living. Satellite spacing has become vital in gaining the most from assets in the sky. New Space entrepreneurs propose constellations that number in the thousands of satellites, and in the rapidly evolving space industry, they may very well succeed. But constellations of this size bring greater risk for collisions and the creation of debris, and no organisation is responsible for assessing how they may impact the broader space community. In a future world of mega constellations, is the unregulated status quo for orbit selection a sustainable path?

Geosynchronous Earth Orbit (GEO) has long been recognised as prime, and scarce, real estate. Starting as a measure for spectrum management, the international community agreed in the 1960s to regulate the assignment of slots in the GEO belt through the International Telecommunications Union (ITU). Today, any company or nation planning to launch a satellite to GEO must apply to the ITU for an orbital slot, and popular regions over North America, Europe, and eastern Asia have become so congested that few or no slots are left for new entrants to the market. With most of the so-called hot orbital slots taken, what opportunities remain for satellite operators to develop new positions or make better use of the existing slots?

Orbital slots and space congestion

This is a multi-faceted debate with no easy answer as to what can be done to create additional room for more spacecraft. Most industry experts agree, however, that more can be done to free up slots and developing existing locations more effectively. The question as to whether there are still hot orbital slots out there is a hard one to define. Issues such as frequency bands and separation of satellites has to be taken into account. “The simple answer is that no, there are not any orbital slots currently unused or unspoken for (as in allocated to satellites already under construction and expected to launch in the near future) that provide access to what might be considered significant markets”.

Some regions such as the North American and European arcs are more heavily utilised than others, particularly in the C- and Ku-band frequencies. Growth opportunities continue to exist in other regions such as Latin America, Africa and the Asia-Pacific. Satellite operators have been innovative in deploying higher-powered satellites with greater throughput and co-locating multiple spacecraft and using more advanced coding schemes to maximise the efficiency at each orbital slot. Other frequency bands, such as Ka-band, hold marked promise for continued growth.

Another factor in this debate are the advances in satellite technology, which make it possible for satellites to be operated more closely together. When satellites were first launched in the 1960s and 1970s, it was believed that satellites needed separation of a number of degrees in space to avoid interference problems. Over time, the nominal standards for separation informally evolved first towards 3-degree separation and later and more formally to 2-degree spacing. The difference between 3-degree spacing (which in a geosynchronous plane would limit the possible number of satellites in a particular frequency band to one hundred and twenty orbital slots) as contrasted with 2-degree orbital spacing (which would limit the possible number of satellites to one hundred and eighty) is considerable.

In addition, advances in ground station technology can help expand the utilisation of spectrum to the same effect. So it is not just a matter of opening up new orbital slots but also how the satellite networks operate in the naturally limited number of orbital slots available. There also are other factors on the technology side having an impact on the issue. Use of hybrid satellites is another factor that may contribute to the relative inefficiency in use of orbital resources, since satellites with transponders operating in both frequency bands are less likely to employ maximum frequency reuse techniques in either band, although use of hybrid satellites may nonetheless offer certain countervailing flexibility advantages.

What is important is the amount of allocated spectrum; a company can have as many satellites in a slot as it has spectrum to use. It is not how much space there is, but how much spectrum there is: “you can share a slot between satellites and even operators if you have spectrum; depending on the nature of the spectrum, you can put more or less satellites in a given arc”. Regulations have tightened up in terms of the management of orbital slots.

The filing mechanism for orbital slots also has come under the microscope in recent years, as some countries are pushing the ITU to crackdown on the use of so-called “paper satellites” or spacecraft that most likely will not be manufactured or launched but instead are used to hold the slot for a given country. The phenomenon of paper filings is a real, continuing problem, although the ITU has taken certain measures to try to discourage it. One of the measures previously taken was to reduce the time period by which a satellite must be placed in orbit from nine to seven years. This, however, has not completely remedied the situation. Even so-called good citizens can be guilty of what in effect are paper filings, the clearest example being the United States of America at Ka-band, where the United States of America filed for a large number of orbital slots based on the filings of a number of U.S. companies, but where there would have been obvious bases for doubting that many of those systems would in fact actually be launched. The ITU believes it has stronger measures in place to make sure slots are being filled within a more agreeable time frame.

The role of ITU is even more important than before, because the situation is becoming more and more complex with the appearance of new services and new users and the more complicated sharing situation on the orbit. Today, some satellites use the same spectrum, separated by one or two degrees: “it means you are obliged to accept more constraints for your operations; there are more interference probabilities”.

The ITU planned bands are a good example of orbital slots that are set aside but are consistently under-utilised. This ultimately adds unnecessary costs and complications to new satellite development throughout the design and manufacturing stages. The ITU’s efforts to recover costs for satellite filings have had a positive downstream effect by reducing the time that paper filings in the non-planned bands sit in the queue.

The International Telecommunication Union (ITU)

The nature of activities undertaken in space is such that cooperation is essential: satellites can’t be launched without different ground stations following the trajectory of the launcher, the continuous observation of the Sun can’t be realised (considering the rotation of Earth) without a cooperation between multiple operators, and telecommunications can be exchanged audibly only if there is an agreement on the distribution of frequencies; space technology therefore necessarily passes through a fairly elaborated cooperation. In telecommunications, it’s the International Telecommunication Union or IUT which deals with inter-state cooperation. Telecommunication includes any transmission or reception of signs, signals, images, images, sounds or intelligence of any kind, by wire, radio, optical or other electromagnetic systems.

The International Telecommunication Union, which manages space telecommunications (equitable and rational distribution of terrestrial frequencies and the specific application for geostationary orbit), is a specialised agency of the United Nations (UN) that is responsible for issues that concern information and communication technologies; it is the oldest among all the fifteen specialised agencies of UN. The ITU coordinates the shared global use of the radio spectrum, promotes international cooperation in assigning satellite orbits, works to improve telecommunication infrastructure in the developing world, and assists in the development and coordination of worldwide technical standards. ITU’s mission is to harmonise the development of telecommunications resources so as to make the best use of the technologies they offer, particularly in space; it recognises the sovereign right of each State to regulate its telecommunications.

Space Legal Issues and orbital slots

Telecommunication operators are increasingly struggling to find “parking spots” for their satellites in outer space. Telecom operators are limited in their choice of parking spots because there are only one thousand and eight hundred available spaces in the Geostationary Earth Orbit (GEO), which is located approximately 35,786 kilometres above the Earth’s equator and revolves at the same rate as the Earth’s rotation. There are other space orbits, closer to Earth, which satellites are launched into, but they have unique advantages and disadvantages and are appropriate for different satellite uses.

Telecommunication satellites are mostly parked in the geostationary orbit because the speed of orbit allows them to appear in a fixed position in the sky. They are therefore stable for ground stations, allowing them to ensure a continuous service. Spots are limited to one thousand and eight hundred because the satellites have to be safely distanced two degrees or one thousand kilometres apart in order to avoid collisions and interference. Consequently, there is an ongoing fight amongst telecom operators over this limited geostationary space, particularly over parking spots where the coverage area on Earth that the satellite can “see” covers market hotpots.

Orbital slots – the “parking spots” of outer space – are allocated to telecom operators via national administrations by the International Telecommunications Union (ITU). There is no cost for an orbital slot, but allocation is on a first-come, first-served basis. If an operator’s competitor files by just a day before them, then they have priority. Although the allocation of a slot does not come with an ownership right to the areas of outer space, it does grant an operator exclusive rights to the resource for the lifetime of its satellite (usually fifteen years). Typically, the operators then keep refiling for the slot and replace old satellites with new ones. So, for all practical purposes, they keep the orbital slot indefinitely.

An orbit is the curved path through which objects in space move around a planet or a star. The 1967 Treaty’s regime and customary law enshrine the principle of non-appropriation and freedom of access to orbital positions. Space Law and International Telecommunication Laws combined to protect this use against any interference. The majority of space-launched objects are satellites that are launched in Earth’s orbit (a very small part of space objects – scientific objects for space exploration – are launched into outer space beyond terrestrial orbits). It is important to precise that an orbit does not exist: satellites describe orbits by obeying the general laws of universal attraction. Depending on the launching techniques and parameters, the orbital trajectory of a satellite may vary. Sun-synchronous satellites fly over a given location constantly at the same time in local civil time: they are used for remote sensing, meteorology or the study of the atmosphere. Geostationary satellites are placed in a very high orbit; they give an impression of immobility because they remain permanently at the same vertical point of a terrestrial point (they are mainly used for telecommunications and television broadcasting).

Geosynchronous orbit (GSO) and geostationary orbit (GEO) are orbits around Earth at an altitude of 35 786 kilometres matching Earth’s sidereal rotation period. All geosynchronous and geostationary orbits have a semi-major axis of 42 164 kilometres. A geostationary orbit stays exactly above the equator, whereas a geosynchronous orbit may swing north and south to cover more of the Earth’s surface. Communications satellites and weather satellites are often placed in geostationary orbits, so that the satellite antennae (located on Earth) that communicate with them do not have to rotate to track them, but can be pointed permanently at the position in the sky where the satellites are located.

Near-Earth space is formed of different orbital layers. Terrestrial orbits are limited common resources and inherently repugnant to any appropriation: they are not property in the sense of law. Orbits and frequencies are res communis (a Latin term derived from Roman law that preceded today’s concepts of the commons and common heritage of mankind; it has relevance in international law and common law). It’s the first-come, first-served principle that applies to orbital positioning, which without any formal acquisition of sovereignty, records a promptness behaviour to which it grants an exclusive grabbing effect of the space concerned. Geostationary orbit is a limited but permanent resource: this de facto appropriation by the first-comers – the developed countries – of the orbit and the frequencies is protected by Space Law and the International Telecommunications Law. The challenge by developing countries of grabbing these resources is therefore unjustified on the basis of existing law. Denying new entrants geostationary-access or making access more difficult does not constitute appropriation; it simply results from the traditional system of distribution of access rights. The practice of developed States is based on free access and priority given to the first satellites placed in geostationary orbit.

The geostationary orbit is part of outer space and, as such, the customary principle of non-appropriation and the 1967 Space Treaty apply to it. The equatorial countries have claimed sovereignty, then preferential rights over this space. These claims are contrary to the 1967 Treaty and customary law. However, they testify to the concern of the equatorial countries, shared by developing countries, in the face of saturation and seizure of geostationary positions by developed countries. The regime of res communis of outer space in Space Law (free access and non-appropriation) does not meet the demand of the developing countries that their possibilities of future access to the geostationary orbit and associated radio frequencies are guaranteed. New rules appear necessary and have been envisaged to ensure the access of all States to these positions and frequencies.

Concluding remarks

Space has become congested. There is not an inexhaustible supply of attractive orbital slots for satellite operators, and as the economy becomes more global, access to this real estate becomes even more important. However, other frequency bands remain widely under-used, so plenty of opportunities exist for satellite operators to find ways to meet the needs of their customers. The challenge is to work within these new parameters.