Humanity started exploring the solar system only 60 years ago and have already made a very expensive mess. More than 500,000 pieces of debris larger than a marble litter the bands of space where geosynchronous and low-Earth orbiting satellites cluster around the planet. Earth’s front porch needs a cleanup.
You may not be able to tell by looking, but quite a few products of human design are cluttering up the night sky. Not just active satellites — which total 4,857 according to the United Nations Office of Outer Space Affairs — but also a massive number of dead or smashed satellites, fragments of rocket stages, and other pieces of debris orbit the planet at speeds of thousands of miles per hour. There’s also a Tesla Roadster out there.
There’s plenty of incentive to clear up the space junk: It’s valuable. We’re surrounded by $300 billion worth of abandoned satellites. Also, debris can pose serious risks to future missions into space — whether we’re sending up new satellites or launching ships with payloads of people or materials off-world in the future. The presence of debris is a pressing problem that many scientists are working to solve.
Blowing Up Our Space Trash?
Some ideas about cleaning up space debris have been more destructive than constructive. One of the earliest ideas for the disposal of space debris was, “Let’s blow it up.” Both the United States and Russia tested this method decades ago. Both countries abandoned this solution, since it just created more space debris. China, unfortunately, missed this memo and still takes the blow-stuff-up approach to space junk.
In 2007, during a test of the country’s anti-satellite systems, China launched a missile at one of their own broken satellites. On the one hand, the satellite was destroyed, which likely made the Chinese military very happy about their program’s success. On the other hand, approximately 2,000 new pieces of large space debris and countless small-scale fragments of the resulting shrapnel were now hurtling around the planet, putting spaceships and other satellites at risk of collision. No one was happy about this. Particularly the Russians, when a chunk of the exploded weather satellite hit a satellite of their own, five years later.
Less destructive tests have been conducted, however. In 1996, a test was conducted on the Mir space station where panels of gel were set up on the outside of the ship to see what space junk was caught on them. While microscopic debris was captured — small fragments of paint, electronics, fluid droplets, and the like — it was nowhere near an efficient method of cleaning up the massive amount of microscopic debris that orbits the planet. So, alternative methods have been proposed for both large and small space debris.
Harvesting Space Junk
The RemoveDebris experiment, a program launched by the University of Surrey in the U.K., is making steady progress towards a simple design that may just work: a fleet of space whaler craft. By using both nets and harpoons to capture space debris, RemoveDebris slows the speed of the objects until they drop out of orbit: a simple, yet effective approach to reducing large chunks of debris.
The project is also experimenting with Radio Frequency Identification Devices (RFID) systems that will be used by “chaser ships” to mark debris for removal. After tagging, a space junk harvester will be deployed to harpoon and return the debris to Earth.
The RemoveDebris team has worked to test their system on Earth, and last month, the first test was carried out in space. Space.com hosted the following video from the project showing the test of their net system, which caught a piece of space debris without causing it to break up.
The United States decided to go its own way, focusing on tracking the objects in the valuable geosynchronous orbit region where communications and spy satellites operate.
Cataloging Orbiting Debris
The U.S. Defense Advanced Research Project Agency (DARPA) introduced its space cleanup plan in 2011. The agency will improve the way we place objects in geosynchronous Earth orbit to support recovery at the end of the satellite’s life. The DARPA Phoenix program seeks to create new, less bulky designs for satellites, increase the versatility of their use and their longevity, and find safe ways to deliver payloads into space more effectively. Other proposed uses include harvesting materials and reusing components from outdated, non-functioning, or retired satellites in geosynchronous orbit, essentially recycling materials in space without bringing them back to the planet. In short, the U.S. intends to pioneer space recycling and reuse.
The value of space debris is a significant economic issue. Cleaning up large chunks of satellite, or even intact satellites, must be prioritized based on the value of materials recovered and the risk that leaving debris in place creates for new satellites.
Sure, we could feasibly shove most of the space debris back down to the planet. But most large satellites in orbit around Earth are privately owned and considered proprietary or vital to national security — one can’t just grab anything in space without creating potential political conflicts. While this question is important to ponder, at the current stage of our space cleanup initiatives, we don’t have the means to go up and bring back everything intact.
And there is a smaller, just as dangerous issue present that should be dealt with as quickly as possible: shrapnel.
The Smallest Debris Carry Huge Risks
In August 2018, the International Space Station sprung a leak. A tiny hole punctured the Soyuz capsule docked to the station, apparently due to passing space debris.
The challenge with small fragments of debris in orbit around the planet isn’t size but speed. A small, fast-moving object can do tremendous damage to a satellite or space station. An astronaut hit by one of these shards could be killed. As popularly depicted in the film Gravity — or in reality, by the damage done to the space shuttle by fragments of paint or the damage to the Russian satellite caused by a chunk of the exploded Chinese satellite from five years prior — a chunk of material the size of a bolt must maintain speeds faster than a bullet in order to stay in orbit around the planet.
There is no current practical solution to cleaning up space micro-debris. It’s a problem similar to finding and capturing microplastics in the sea. The particles are too small and the area to patrol too vast and changing. Both China and Russia are pushing the development of Earth-based laser systems to remove small debris from orbit. Such systems would work by reducing the momentum of these objects, causing them to spiral into Earth’s atmosphere and burn away
A good way to think of the need to clean up space junk is to picture low-Earth and geosynchronous orbit as our planet’s front porch. If we want to come and go from the planet, we have to clean the porch. The last thing we need is for the outbound path to the stars to be filled with chunks of sharp metal. It is in the best interest of our future in space to make sure we have a clear path to the stars.