Planet Earth’s trash is more than enough for us to deal with, but that doesn’t mean we should forget about the mess we’ve left behind in space.

Space junk presents a potential threat to functioning spacecraft because not only is there plenty of it (tens of thousands of pieces of space trash are in orbit), but at the speed, it’s traveling (upwards of 22,000 miles per hour) even something the size of a pebble can seriously damage a satellite.

To put it in perspective, Jan Wörner, director-general of the European Space Agency, illustrates the problem like this: “Imagine how dangerous sailing the high seas would be if all the ships ever lost in history were still drifting on top of the water… that is the current situation in orbit, and it cannot be allowed to continue.”

Fortunately, there are solutions to the problem of space junk. Here are three of them:

The Space Sustainability Rating

The Space Sustainability Rating (SSR) system was introduced just over a week ago by the European Space Agency (ESA) and World Economic Forum.

This rating system, which will be in full effect early next year, will be available for any future missions into the last frontier so that those developing those expeditions will have information on how/if their work will mitigate the chances of generating even more orbital litter. The SSR requires that each mission undergoes a peer-reviewed assessment based on factors like choice of orbit, measures taken to avoid collisions, and plans to de-orbit satellites on completion of the mission.

Even though the rating system is voluntary, those behind the SSR hope that it will evoke a race to the top between space actors.

ClearSpace-1

While the SSR’s aim is to prevent more space junk from entering orbit, collecting and removing the existing debris is paramount if we are to solve this problem. ClearSpace-1, due to launch in 2025, will be the first space mission whose main goal is to retrieve space junk that is already in orbit. Specifically, a 100 kg payload adaptor that sent the ESA’s Proba-V satellite into space.

ClearSpace-1’s mission is headed by a Swiss startup of the same name: ClearSpace. Hopefully, the ClearSpace-1’s launch will encourage the development of more junk-removal spacecraft and create a market for that service. As Luisa Innocenti, head of the ESA’s Clean Space initiative says, “The only way to stabilize the orbital environment is to actively remove large debris items.”

Wooden satellites

Since there are thousands and thousands of space-junk debris in orbit above us, it’s inevitable that some of them come crashing into the Earth’s atmosphere—and when they do, they burn and create tiny alumina particles that float around in the upper atmosphere for years more.

While there isn’t much we can do about the particles that are already there, a Japanese company, in collaboration with Kyoto University, has come up with a solution for future satellites that are launched into space: making them partially out of wood. The satellites, set to launch in 2023, will be made from timber, which will completely burn up when entering the Earth’s atmosphere, meaning that it won’t shower debris on Earth’s surface either.