As far as apocalypses go, being trapped on Earth might not seem too intimidating. However, the rapidly growing problem of space debris could make anything outside our atmosphere untraversable. Before the launch of the first satellite, the space surrounding our planet was relatively clear of pollution. Now, after decades of space launches, low earth orbit is a minefield of debris, where the debris is moving at up to 30,000 miles per hour.
Space debris, or more aptly named, space junk, can refer to any piece of machinery or equipment left behind in space from our thousands of rocket and satellite missions. These can be as big as dead satellites (which have either had mechanical failure or were simply left in orbit after their mission), or they could be as small as bits of metal that came off a rocket as it launched. The scope of this problem is astounding. There are nearly 3,000 dead satellites floating in Earth’s orbit, about 34,000 pieces of junk larger than 10 centimeters, and perhaps up to 128 million pieces between 1mm and 1cm long, according to the European Space Agency. Although the latter may seem insignificant, they are still extremely dangerous. Debris in space moves at speeds up to seven or eight kilometers per second (About five times as fast as a bullet). At these speeds, even the smallest piece of orbiting junk could wreak havoc on the complex hardware of satellites.
All of these problems, although substantial, pale in comparison to the largest danger of space junk, known as the Kessler Syndrome. The Kessler Syndrome is named after the scientist Donald J. Kessler. It refers to the scenario where the amount of space debris in orbit reaches a critical level. At this point, collisions between pieces of junk would cause a cascade, where each collision generates more debris, which in turn collides, causing an exponential increase in the total amount of debris. Within a short period of time, this effect could make it too dangerous and expensive to launch anything into space at all, bringing our space missions to a grinding halt.
But why does this even matter, unless you’re an astronaut? Space debris pose a second danger, with more far reaching effects. Already, satellites in space make hundreds of maneuvers per year to avoid debris. If the amount of junk continues increasing at this rate, it could possibly destroy our satellite system. Satellites serve extremely important purposes on Earth, from GPS systems to cell phone communication to the internet. The loss of the satellite grid could send human technology back to the 1970s.
So, with all of these impending dangers, how can we stop this problem? Space agencies have already begun searching for strategies to prevent future debris, such as more efficient de-orbiting systems. These would reduce the velocity of the satellite or rocket component via a sail or other friction-creating device, which would cause the satellite to sink into Earth’s atmosphere and burn up. Other solutions proposed include an orbital use fee on satellites in Earth’s orbit, to prevent operators from excessively launching satellites. These solutions all regard preventing future space debris. The solutions for removing current space debris are a bit more far fetched, suggesting using nets, harpoons, or lasers to capture or destroy space junk. NASA has already tested an autonomous satellite which was capable of deploying a net to capture a simulation of debris.
On the bright side, looking into the future, more and more satellites are beginning to follow debris guidelines, peaking at 35 percent in 2018. Between 40 to 80 percent of rockets also complied with debris guidelines in the last decade. Since rockets are some of the largest bodies we send into space, preventing them from causing more debris is important. More satellites are also being placed in lower Earth orbits where they burn up on their own, and in geostationary orbit (where many important satellites are used for GPS systems on Earth), between 60 percent to 90 percent of satellites successfully followed debris mitigation systems.
Although space debris is an obscure problem, it’s one that needs to be addressed before it leaves obscurity. It has far reaching effects, and if left unattended, could cause catastrophic damage. Thankfully, most major space operators such as NASA and the European Space Agency are taking this problem seriously, and solutions are being developed by governments and private organizations. However, despite these efforts, we still have a long way to go before Earth’s orbit is secure for future generations.