It's time to deal with it Traffic jam in outer space.

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It's time to deal with it Traffic jam in outer space.

Original: Lauren Napier

Translation: Huang

Proofreading: Chen Jie

Review: Mu Fu Astronomy Proofreading Group.

Arranged by wang pu

Backstage: Courtlia, Li, Xu Jiukun, Hu Yongqiao.

Original link:

Space traffic jam

Source: Shutterstock/osoriotart

In recent years, with the smaller and smaller satellites, lower manufacturing costs and more standardized components, launching satellites into space is no longer a high threshold, and more people can afford satellite launch. Now, satellite operators have begun to launch giant constellations into Earth orbit, that is, satellite networks consisting of hundreds or even thousands of small satellites.

Civil, military and private satellite operators are increasingly using satellite constellations to create a continuous global network. These satellite constellations have many functions, including climate monitoring, disaster management, satellite broadband and so on.

However, covering the whole earth requires a large number of small satellites. In addition, they must run in orbit near the earth's surface to reduce coverage interruption and communication delay. This means that they must run in an already busy area of space-low earth orbit, that is, from 100 to 2000 kilometers from the earth's surface.

Putting so many satellites into orbit will cause many problems, from affecting us to watch the night sky to creating dangerous space junk. At the same time, giant constellations also bring challenges to global space governance.

At present, there are nearly 3,000 active Earth-orbiting satellites. More satellites will be launched in the next few years. For example, Council of Europe recently announced plans to put thousands of satellites into Earth orbit.

As companies and governments around the world continue to launch giant constellations, the framework of space governance becomes crucial. There are many important issues to consider.

definition

At present, under the guidance of the Outer Space Treaty issued by 1967, countries all over the world issue licenses to manage satellites at the national level. Although the word "constellation" or "giant constellation" does not appear in the treaty, they are regarded as space objects like all other satellites.

However, due to the different procedures and regulations in different countries, it is extremely difficult to coordinate and manage the huge satellite constellation system only at the national level. Therefore, it is imperative to solve this problem from the international level.

However, there is no legally binding definition of satellite constellation or "giant constellation" at present. There is no standard for how many satellites a giant constellation consists of. Every country may think that the word has different meanings. Defining the "giant constellation" from the international level is the first step to manage the huge satellite system, and it is also helpful for human beings to use the near-earth orbit safely and sustainably.

be stuck in a traffic jam

Most low Earth orbit satellites operate between 600 and 800 kilometers above sea level. This is a crowded area because it is already crowded with satellites.

Star chain is by far the largest giant constellation.

Source: Star Chain Mission

However, it takes time to remove the satellite. For example, it takes about 150 years to re-enter the earth's atmosphere and remove it by burning. Some satellites were intentionally removed by controlled re-entry, while others crashed in an uncontrolled manner. Operators of satellites and giant constellations must find ways to reduce the debris caused by these satellites in order to maintain the sustainable use of near-earth orbit.

Considering the number of giant constellations in the future, low earth orbit will become a scarce resource.

radio spectrum

Spatial congestion is not only the congestion in physical space, but also the congestion in radio use. Satellites use the radio spectrum for communication. With the increase of the number of giant constellations, there is a danger that operators "store" radio frequencies and store them before actual needs, thus causing radio spectrum congestion.

In order to prevent this situation, a United Nations agency specializing in the management of satellite radio spectrum recently updated its management framework, separating this issue from other space management issues. This organization stipulates that giant constellations can only use the radio frequencies needed at that time.

Collision avoidance and tracking

If the near-earth orbit is crowded with satellites and giant constellations, collision avoidance will be more difficult. September 20 19, the European space agency had to ignite the booster of one satellite to avoid the other, otherwise the two satellites would collide.

As the orbit becomes more and more crowded, more anti-collision mechanisms and better communication between satellite operators may be needed to maintain space traffic.

Some countries (especially the United States) have formulated satellite tracking and collision avoidance rules. They have an alarm system to warn the satellite operator of the potential collision path and correct the satellite's route if necessary.

prospect

I hope that UN member states can discuss the regulation of giant constellations as soon as possible. Although the Committee's work may be slow and highly politicized, giant constellations do need international norms and national licensing procedures.

Low-earth orbit constellations and giant constellations have brought great benefits to social economy and environment. Because of this, there will be more and more constellations in the future. In order to avoid problems, we should make clear the rules and definitions of giant constellations internationally.

Mu Fu Xin media editorial department

"Astronomical Wet Engraving" produced in Mu Fu.

The picture comes from the internet.