Space, particularly near-Earth space, is becoming increasingly cluttered with man-made debris. This debris, often called “space junk,” consists of everything from spent rocket stages and defunct satellites to paint flecks and ice particles. While most of it is very small— microscopic even—a few large pieces pose a serious threat to both manned and unmanned spacecraft. The problem has gotten so bad that some experts have suggested declaring a moratorium on new satellite launches until the situation can be brought under control.
There are two ways to remove space junk: active removal and passive removal. Active removal involves going out and physically capturing or destroying the debris. Passive removal simply involves waiting for the debris to fall back into Earth’s atmosphere where it will burn up upon reentry.
Both methods have their pros and cons. Active removal is more expensive and requires more manpower, but it can be targeted specifically at the most dangerous pieces of debris. Passive removal is cheaper and doesn’t require as much planning, but it takes longer and there’s no guarantee that the most dangerous pieces will be removed first.
The best solution is probably a combination of both methods. In the short term, we need to start actively removing the most dangerous pieces of debris before they have a chance to do any damage. In the long term, we need to put more effort into developing better methods of passive removal so that we can slowly clean up all of the smaller pieces of space junk over time.