Space junk is becoming more of a problem on a daily basis. It is not necessarily that a new satellite or part of its launch system is added each day, it's that there is so much junk floating around up there now that collisions between existing components are continually creating new junk. In fact, if you look at the chart to the right that appeared in the April 2012 edition of Scientific American ("Space Age Wasteland: Debris in Orbit Is Here to Stay"), you will see that the multiplication effect will continue to produce more space junk even if all new launches are halted immediately (the lower line). The upper line extrapolates growth of space junk at the current rate of satellite launches. Of course the dots shown are not in scale to the volume of space represented, but we know empirically that collisions occur frequently.
The North American Aerospace Defense Command (NORAD) puts a lot of work into tracking space debris in order to predict reentry hazards, orbital collisions, and to be able to differentiate between benign projectiles and hostile military projectiles. We hear a couple times a year about the need to adjust the orbit of the International Space Station in order to avoid potential collisions with orbiting space junk. Back when the U.S. wasn't a 3rd-world nation from the manned space program perspective, the Shuttle often changed orbit to avoid man-made objects. With an orbital speed of around 18,000 mph, even a small chunk of busted former antenna or attitude control nozzle could rip right through the spacecraft.
Space debris that is just left over from abandoned satellites and their launch systems is bad enough, but a couple years ago the Chinese created thousands of chunks of junk when they tested a space weapon on their own Fengyun-1C satellite. In 2009, a Russian accidently (ostensibly) collided with an Iridium satellite and created a pile of new debris. According to a story by Discover, China is responsible for 40% of all space junk even though they have been relative newcomers to the realm. The U.S. produced 27.5% and Russia produced 25.5%.
To help mitigate the problem, engineers and scientists at the Swiss Space Center at EPFL recently launched the "CleanSpace One" project. The aim is to design and build a satellite that will chase, grab and destroy space debris, primarily one of the first Swiss satellites, Swisscube-1 or TIsat-1. The plan is to hurl the objects into a much lower orbit so that it will quickly degrade and reenter the Earth's atmosphere and burn up. It will be interesting to see what they come up with for a propulsion system that is sufficient to service many objects before having to commit cosmological suicide by intentionally subjecting itself to a fiery end in the sky. We'll know when CleanSpace One is operational by a marked increase the frequency of news stories on Bubbas reporting UFO sightings.
Space Debris Collector Robot
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