No. 155 / Dec 6, 2021
What surrounds the Earth? Scientists would answer the atmosphere, ozone layers, magnetic fields, and other things. However, although not created by the Earth but by humans, things that are harmful to humans also surround the Earth. Currently, their number is estimated to be approximately 100 million and growing. They are called space junk.
What is space junk? Space junk refers to any artificial object, generally orbiting the Earth, that is not currently in use. In 1957, the first satellite, Sputnik 1, was launched by the Soviet Union, and since then satellites have been continually launched. Korea has also launched several satellites, starting with Star No.1 in 1992. When a new satellite begins to orbit the Earth, it is necessary to ensure that it will not collide with existing satellites, which are difficult to collect, so sometimes it is necessary to wait until they naturally fall to Earth. Thus, the number of satellites orbiting the Earth continues to increase and junks is generated, such as parts, debris, and accessories that fall off when a spacecraft leaves the Earth. With so much space junks, there are also traffic accidents in space, like the collision of the United States (U.S.) communication satellite Iridium 33 and Russian military satellite Cosmos 2251. So far, there have been four such traffic accidents.
Why is space junk dangerous? The more space junk there is around the Earth, the more dangerous it is for spacecraft or satellites leaving the Earth. Hundreds of thousands of pieces of debris are travelling in space at great speeds, where even minor parts can lead to fatal damage. A small piece of space moving at 100km/h has an impact equivalent to that of hundreds of kilograms on Earth. Currently, 90% of artificial space objects orbiting the Earth are space junk, and as their number increases, various treatment methods are being proposed to collect them. The European Space Administration (ESA) plans to launch a space junk collection robot by 2025 that will extend four arms to collect space junks and re-enter the atmosphere, where it will burn up on re-entry. The second method is to collect garbage using harpoons and nets. British researchers have successfully experimented with collecting space junks using nets, but this method has many costs and risks. Many other methods are being studied, such as removing garbage with lasers and pulling garbage to the Earth with magnets so that they burn up in the atmosphere. Space junks is constantly increasing, and if scientists do not find a way to dispose of it, people may not be able to go into space.
By Kim Jae-hyun, AG Reporter
zxc2337@ajou.ac.kr
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