For almost 70 years, humanity has been launching rockets, satellites, people and animals into space. While most people and some animals came back, much less of the equipment comes back. For most satellites there are no plans to return them to sender. When their lifetimes run out, they simply stay orbiting Earth. This build up of space junk and debris is a growing problem that requires constant surveillance. The US department of defence even has a global space surveillance network whose sensors have to constantly monitor more than 27,000 pieces of space junk. However, the estimated number of dangerous debris is much higher considering that a lot of it is too small to be detected, even though with the speed it travels at orbiting the earth it is still a big source of danger. Functioning satellites’ orbits are carefully monitored along with the international space station. If it is calculated that a collision may occur between the space station and some orbital debris an emergency manoeuvre may have to take place. However, even with this surveillance and tracking costly accidents can still occur. So, what can be done to prevent this from continuing to be a growing problem.
The one saving grace we have so far is that some spaced junk drops down low enough into the Earth’s atmosphere and begin to feel its presence in the form of atmospheric drag. This causes the debris to burn up and disintegrate. This will eventually occur for all of the Earth’s orbital debris, however it may take decades and the rate at which the amount of debris is increasing vastly outdoes the amount that is getting burnt up.
The first planned mission to remove orbital debris is slated to occur in 2025, with the European space agency funding a company to send an experimental 4-armed robot into space to collect a large payload adapter and drag it into the Earth’s atmosphere where it and the robot will burn up. While this is a positive step, it is only one piece of large debris being removed at quite a high cost. A better, more economic solution is required.
A new idea is to possibly add drag sails to future satellites. Rather than a light sail which is used to propel spacecraft further from the sun using the force of the photons radiating from the sun, these will act more like parachutes. They will be very thin, and extremely sensitive to any force, so even just slightly grazing the top of the earths atmosphere and barely encountering any air, the satellite will be slowed and force down towards earths atmosphere, causing a much quicker burn up.
So hopefully with more creative ideas and solutions, the amount of junk in Earth’s orbit will soon begin to decrease.