1. Satellites in geostationary orbit appear to stay in the same spot in the sky
Above the equator, at a height of about 36,000 kilometers (about 22,400 miles), there is an orbit where satellites take the same time to orbit Earth as Earth takes to rotate once. When a satellite travels in this path, it looks like it is staying still in one place in the sky when viewed from the ground [1]. Because of this, antennas for television and communication do not need to move once they are pointed in the right direction.
2. There is a limit to how many satellites can fit in geostationary orbit
This special orbit forms a ring around the equator. If satellites are too close to each other, their radio signals mix and interfere. Therefore, they must be spaced out by a certain amount of longitude [2]. In the past, a rule of thumb was to place one satellite every 2 to 3 degrees of longitude. A simple calculation shows that this leaves room for only about 180 spots in the entire ring [2]. It is like a crowded, limited parking lot. However, technology has advanced, and sometimes multiple satellites can operate in the same location now.
3. Countries on the equator once claimed the geostationary orbit as their territory
In 1976, eight countries located on the equator—Brazil, Colombia, Congo, Ecuador, Indonesia, Kenya, Uganda, and Zaire (at the time)—gathered in Bogotá, the capital of Colombia. They issued a declaration stating that the special orbit directly above their countries was part of their national territory [3]. However, this claim was considered a violation of the 1967 Outer Space Treaty, which states that space cannot belong to any specific country. Other nations in the world did not accept this claim, and it eventually faded away [3].
4. An international agency assigns orbits using a first-come, first-served rule
Ultimately, the International Telecommunication Union (ITU), a United Nations agency, manages the coordination of radio wave usage for this special orbit. The rule is based on a queue: countries that apply earlier get priority in this coordination process [4]. This system often favors countries with more money and technology. To help, the ITU rules also include ideas to save space for developing countries that do not yet have satellites [4].
5. The small island nation of Tonga applied for 16 orbit slots
In 1990, Tonga, a small island nation in the Pacific, used this rule to apply for 16 orbit slots at the ITU. Tonga did not have a single satellite of its own [5]. The person who planned this strategy was Matt Nilsson, an American consultant hired by Tonga [5]. Many countries reacted with anger, saying it was wrong to apply for so many spots without using them. After discussions, Tonga was first granted 6 slots in 1991 and eventually secured 9 slots [5]. Tonga then lent these slots to companies that wanted to launch actual satellites, charging them fees [5].
6. New rules were created to check for real plans
After Tonga’s actions, applications that reserved space without actually using it increased. These are called "paper satellites" [6]. So, the ITU created rules requiring proof that a company has a contract to build a satellite and that a launch rocket is already decided. If this information is not shown, the application is cancelled [6].
7. Look at where parabolic antennas are pointing
If you look at the round dish antennas on houses or nearby buildings, you might notice they are aligned in similar directions. This is because they are all aiming at the same special place in the sky where these satellites stay [1].