There are more than 1300 satellites currently orbiting the Earth, providing us with communication and navigation signals, studying the world, and taking pictures. Since the launch of the first satellite over 50 years ago, our communication has increased as a result of these satellites. The trouble is these satellites rarely last more than a decade, needing to constantly be replaced by new ones, crowding the vital orbit surrounding the Earth. Old satellites, combined with discarded rocket parts, crowd this orbit and have create a layer of “space junk” around the Earth. Currently there are more than 500,000 pieces of debris orbiting the Earth. Space debris poses a danger to all space vehicles, but particularly to spacecraft with humans aboard. With the threat of collisions rising, NASA and other international space agencies agree there is a problem. But whose job is it to clean it up and how it should be done? Although many suggestions about potential solutions have been posed, none have yet been implemented.
Orbital debris is any man-made object in orbit around the Earth that no longer serves a useful function. Debris includes spacecraft that is no longer in use, pieces of rockets, and out-of-use satellites. Currently there are more than 500,000 pieces of debris larger than a marble, while around 20,000 are the size of a softball. On average, pieces of debris travel at a speed of 17,500 mph—meaning even the smallest piece can cause damage. In fact, a number of space shuttle windows have had to be replaced because of material that was as small as a paint fleck. Surprisingly, with so much debris, there have been few disastrous collisions.
The Department of Defense, along with NASA, maintains a highly accurate record of objects in Earth’s orbit that are larger than a softball. The total number of tracked objects is greater than 21,000. By tracking this debris, satellites and spaceships can track and avoid the larger pieces. The problem comes from the debris too small to be tracked and avoided.
FOCUS ON THE BIG STUFF
Since it is impossible for NASA and the other space agencies to track every piece of space junk, they are looking for ways to reduce the number of larger pieces. Many smaller pieces of space debris are a result of explosions or collisions between the larger pieces. If the larger pieces are removed before they explode into smaller pieces, it will help clean up a significant amount of the space debris. Some NASA scientists are advocating for cleanup to begin by 2020 with the hope that 10 pieces of junk per year will be removed. Scientists believe that will help keep the debris at manageable levels. While relatively few ideas are ready to launch and begin, there are some that planned for the next few years.
Set to launch in 2018, the Swiss CleanSpace One is like a space vacuum. Set to launch in 2018, its first target will be the now defunct Swiss Satellite. Once it comes within range of the satellite, the CleanSpace One will extend its net and capture the Satellite.
In the 1990s, the US Air Force began experimenting with the idea of a laser broom. Rather than targeting a large piece of debris, the laser broom would vaporize a small piece of debris, creating a cloud. This cloud would slow down a targeted piece of larger debris that could then be dragged into the Earth’s atmosphere where it would burn up.
Another solution being explored is the Electrodynamic Debris Eliminator (EDDE, created by Star Inc.), which uses a large net to capture space junk. Different from other proposed ideas, the EDDE does not run on liquid fuel, but instead a wire generates electricity as it moves through the Earth’s magnetic field, meaning it will never run out of fuel. The EDDE could capture a large piece of debris in its net, deliver the piece to the Earth’s atmosphere, and then turn around and repeat the process again and again.
While many ideas are being explored and designed, it is agreed that the best solution is to ensure that newly launched spacecraft include a safe way for it to come back down when no longer in use. This means including a way for the craft to slow itself down and reenter the Earth’s atmosphere. The small pieces would burn up upon re-entry while the larger pieces would have to be brought down to a safe place, such as the middle of the Pacific Ocean.
Removing space debris is an expensive endeavor and as of now, no one has fully agreed to step up and fund the mission. “Everybody recognizes that this is a problem, and that the problem is getting worse, but it’s not clear exactly whose job it is to clean it up,” says Jet Propulsion Laboratory robotics researcher Aaron Parness.