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Space debris

Posted April. 03, 2018 07:33,   

Updated April. 03, 2018 07:33


The movie Gravity, released in 2013, depicts the disaster that leave crew members in the outer space as their space shuttle crashes into satellite debris. Space debris that has been created from old satellites and spent rocket stages is orbiting the Earth at a speed faster than a bullet. There are reportedly more than 500,000 space debris that are over 1 centimeters each in diameter and about 19,000 debris that are over 10 centimeters each in diameter.

It is difficult to predict the exact crash site of a piece of debris. The movement of objects falling from space is greatly affected not only by gravity but also by the resistance of the atmosphere. The density of air changes frequently with the flow of air. It is virtually impossible to predict this in real time. It is like throwing a wad of paper from the roof of a high-rise building and predicting where it will land on the ground.

China’s defunct space station Tiangong-1 reentered the Earth’s atmosphere about 9:16 a.m. Monday off the Pacific coast of Chile. Initially, it was expected to crash into the South Atlantic. Until now, most of the space laboratory burned up in the Earth’s atmosphere. Since the first artificial satellite Sputnik 1 was launched in 1957, about 7,900 artificial satellites have been launched into the orbit and approximately 5,400 tons of space debris has fallen to Earth. Luckily, there has not been damage to people although the debris made of stainless steel and titanium survived the heat generated when reentering the atmosphere and fell to the ground.

The bigger problem is space. The space is suffering from garbage just like the Earth. Space debris that is 10 centimeters or bigger in diameter is able to destroy artificial satellites with its fast speed. The Kessler syndrome is a scenario in which collisions between objects could cause a cascade where each collision generates space debris to increase the likelihood of further collisions. If this scenario becomes a reality, we might not be able to launch anything into the space. Although the disaster like the movie Gravity has not happened yet, it will come soon if nothing is being done about space debris.

Jin-Kyun Kil leon@donga.com