Space debris is a big problem, but we can solve it

Humans fill the space surrounding Earth with garbage. Most of this waste comes from abandoned satellites, discarded jet engines, and other mission-related debris. When these objects inadvertently collide, they explode into thousands of debris fragments that can seriously damage operational spacecraft. And with a booming commercial space industry that has put an unprecedented number of new satellites into space in just the past few years, our space debris problem is only getting worse.

Scientists are concerned about a condition called Kessler Syndrome, which was coined in the 1970s, in which a runaway chain reaction of collisions and fragmentation creates a cloud of debris around Earth so dense that it threatens future space missions.

But there are a few options to start clearing up the debris surrounding us, most of which coalesce into the strategy of slowing objects enough to knock them out of their orbit, forcing them back into Earth's atmosphere to be destroyed. For the largest class of debris, fragments longer than 10 centimetres, one solution is to send a small spacecraft into orbit, where it will rendezvous with the large piece of debris and slow its orbit by either pushing or pulling it.

For the smallest category of debris, which ranges in size from 1 millimeter to 1 centimeter, there are two main ideas. One is to put a physical sweeper into orbit to capture or slow down these tiny, untraceable fragments. The other method is to introduce a cloud of metallic dust into orbit to weigh it down and pull it into the Earth's atmosphere.

For the category of space debris in the middle, between 1 and 10 centimeters in size, the idea of ​​using ground-based and space-based lasers as a cleanup method has been bandied about for years. In this approach, a laser uses radar to track a piece of debris as it flies over the horizon and then fires a pulse of energy at it. The goal is to push the debris enough to disrupt its orbit, and ideally enough to slow it down.

Currently, NASA considers this the most cost-effective way to deal with most space debris, but it will take commitment from the international space community to implement any removal strategies.