In recent years, satellites have become smaller, cheaper, and easier to commercialize from shelf parts. Some weigh less than one gram. This means that more people can send them to class. Now, satellite operators have started working together in clusters of hundreds or even thousands of smaller satellites – mega-constellations – around the Earth.
Instead of one large satellite, clusters of smaller satellites can provide coverage of the entire planet simultaneously. Civil, military and private operators are increasingly using constellations to create global and continuous coverage of the Earth. Constellations can provide a variety of functions, including climate monitoring, disaster management or digital connectivity such as satellite broadband.
But small satellites require a lot of them to provide coverage of the entire planet. On top of this, they have to orbit closer to the surface of the Earth to reduce interruption in coverage and communication delays. This means that they call an already busy area of the Earth’s surface, which is 100 to 2,000 km above the Earth’s surface.
From the dangers of space junk to obstructing our view of the night sky, there are several issues associated with orbiting these many satellites. But the shift towards mega-constellations is also a challenge for global space governance.
Today there are about 3,000 active satellites around the Earth, and it is going to touch the sky in the coming years. For example, the European Commission recently announced plans to launch thousands of satellites into Earth orbit, adding to the growing list of planned mega-constellations.
As companies and governments around the world continue to pursue mega-constellations, it is important that the governance framework is able to support an increase in activity. There are several important problems that need to be considered.
Satellites are regulated at the national level and through licensing, guided by the principles of the Outer Space Treaty of 1967. Although mega constellations or mega-constellations are not found in the treaty, they are considered space objects, like all other satellites.
Since procedures and rules differ, the challenge is how to control mega-constellations without causing legal fragmentation. It is necessary that this subject be discussed internationally.
Yet currently, there is no legally binding definition for satellite constellation, nor for the new term mega-constellation. Exactly how many satellites make up a mega-constellation is unknown, and each country can consider the term to be something different. Clarity at the international level can pave the way for creating guidelines specifically for mega-constellations, which can aid in the safe and permanent use of low Earth orbit.
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Most satellites in low Earth orbit are operating at 600 and 800 km above sea level. It is considered a crowded area, as there are already many satellites. Smaller satellites have a shorter lifespan than larger satellites, which usually orbit above low Earth orbit.
However, it can still take up to 150 years for satellites to be removed, re-entering the atmosphere and burning if they are about 750 km above sea level. Some are purposefully removed, through controlled re-entry, and others are designed to fall in an uncontrolled manner. Satellite and mega-constellation operators must consider ways to reduce the debris caused by these satellites over and above normal procedure, to maintain permanent use of low Earth orbit.
Given the number of future mega-constellations currently planned, the space around the Earth can easily be called a limited resource in low Earth orbit.
3. Radio Spectrum
This is true not only when it comes to physical location, but also radio usage. To communicate, satellites use the radio spectrum. With the increase in mega-constellations, operators are at risk of “warehousing” radio frequencies, stocking them before they actually need them.
To prevent this, a United Nations special agency for satellite radio spectrum use has recently updated its regulatory framework, dealing with the problem separately from other space regulation. Mega-constellations will be placed on a flexible timeline, with only the frequencies being used at the time.
4. Collision prevention and tracking
If low Earth orbit is overrun with satellites and mega-constellations, collisions will become more difficult to avoid. In September 2019, the European Space Agency had to fire boosters on one of its satellites to get them out of the way of another satellite, otherwise both would have collided.
As the orbit becomes more crowded, more collision avoidance may require better communication between the maneuvers and satellite operators.
There are national efforts primarily for satellite tracking and collision avoidance maneuvers in the United States. A system alerts satellite operators to possible collision paths and allows for improvements where possible.
It is expected that mega-constellations will be discussed by member states in the UN as soon as they are able to do so. Although work in the committee may be slow and highly political, national licensing procedures as well as international guidelines need to add consideration for mega-constellations.
The benefits of constellations and mega-constellations in low Earth orbit are great for socio-economic and environmental purposes. Because of this, it seems likely that the number of constellations will increase in the near future. The rules and definitions around mega-constellations should be clarified internationally to ensure that we avoid the problems that arise.
This article by Lauren Napier, PhD researcher at Space Law and Policy, Northumbria University, Newcastle, is republished from Conversations under a Creative Commons license. Read the original article.
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