Lasers Could Solve the Space Junk Problem
If you gaze up at the night sky, you expect to see stars, meteors, and maybe a couple of satellites. What you can’t see with the naked eye is the tons and tons of space junk currently orbiting our planet. It’s estimated that there are more than 20,000 pieces of debris larger than a softball currently in orbit, and half a million pieces so small they can’t be tracked. Even flecks of paint can be dangerous when moving at high speeds. A number of plans have been floated over the past few decades for cleaning up space junk, and China has just come up with a new one.
What Makes Up Space Junk?
First, what is actually classified as ‘space junk’?
This term is a broad descriptor for pieces of both natural and man-made debris that are trapped in orbit around the planet. Space junk includes old satellites that have since expended their fuel source, empty rocket boosters and other refuse we’ve left behind during our forays into outer space. Many of these pieces of junk have been broken into smaller pieces due to natural erosion or collisions, making them too small to track and thus potentially even more dangerous than their larger counterparts.
Natural debris also orbits the planet. Small meteoroids, space dust, and other naturally occurring materials are also classified as space junk and they create the same sort of risk that man-made space junk does.
Space junk is a growing problem, so the world’s space agencies have come up with a variety of ideas to combat it— from giant magnets to nets and harpoons deployed via satellite. China is taking a different approach to the problem. Their plan is to deploy a network of satellite-based lasers in a high enough orbit that they could take care of the debris.
The project isn’t going to destroy large pieces of debris with lasers — that would just break targets up into smaller and more dangerous pieces of space junk. China found this out first hand in 2007 when they tried to destroy one of their own defunct satellites — it broke up into small pieces, creating a dangerous debris field.
Instead, the plan is to make a laser that is capable of tracking and targeting smaller pieces of debris less than 4 inches across and zapping them. This would ideally have one of two outcomes — either the debris will be pushed out of the way to prevent a collision or it will cause the small pieces of debris to burn up in the atmosphere.
The idea might not make it off the ground though. Many fear that this space debris laser could potentially be used as a weapon against targets on Earth. If that is the case, it could mean that the laser violates the Outer Space Treaty of 1966 that was put in place to ensure that space could not be weaponized.
Reclaiming Spent Rockets
Much of the large space junk is made up of spent rockets and fuel canisters that were (and still are) required to get astronauts and payloads up into orbit. SpaceX, the brainchild of tech giant Elon Musk, is looking for a way to curb our space waste by creating fully reusable rockets. The company has already made great strides — the 1st stage of their Falcon 9 rockets are already fully reusable and many of the rockets that are currently being used have been on one or more missions to date. They’ve also had luck with recovering the payload fairing — the section of the ship that protects the payload during launch — thanks to small thrusters and parachutes.
The last thing that they need to reclaim and reuse is the second stage Merlin engine that carries the payload into orbit once the Falcon 9’s main rocket has expended its fuel.
This trend toward reclamation even extends to the newly christened Falcon Heavy, which had its maiden voyage on February 6th, 2018. The goal was to successfully land all three engines, the two side boosters (which were actually reused Falcon 9 boosters that had been on more than one flight) and the center core, as well as recover the fairing. While it wasn’t a total success — the center core was lost when its engines failed to relight for the final landing burn, the fact that SpaceX was able to recover both of the side booster engines is phenomenal.
Everyone in the Sandbox
SpaceX's efforts aren't controversial, but China's lasers are. The worry that cleanup lasers could be used as a weapon might be alleviated if the project became a joint effort between all the space agencies in the world. It’s a global problem, after all — space junk threatens satellites, ships, and even the International Space Station.
In the long run, it’s going to take everyone’s cooperation to help manage the growing ring of space junk that surrounds our planet — that includes efforts to create less waste as well as efforts to destroy the waste that is already there.