ISS might get a laser cannon to zap space junk

One of the biggest dangers to a spacecraft in orbit isn’t meteorites, the atmosphere or radioactivity – it’s man-made space junk. Worryingly, the International Space Station (ISS) has had to divert its course several times to avoid orbiting trash, but soon it might not have to. Scientists from Japan’s RIKEN Computational Astrophysics Laboratory have proposed a new system that will allow the ISS to vaporise junk in its path.

Space junk poses one of the biggest dangers to spacecraft today. Made from useless pieces from previous missions such as decoupling rings, nuts, bolts and bits of satellite, it’s now a very real problem. In 2009, NASA calculated there were more than 500,000 pieces of space junk floating around the Earth – and with each mission that number only gets bigger.

The laser

To protect itself from the growing threat of space debris, Japan wants to give ISS the EUSO or Extreme Universe Space Observatory module by 2017. EUSO’s main job would be to monitor cosmic rays, but lead researcher Toshikazu Ebisuzaki believes it could also be used to track and eliminate nearby space junk.

The best bit? After identifying threats to the station, the EUSO will use a laser to fire debris out the way. Using a 100,000W Coherent Amplification Network beam, the laser will have a range of 60 miles and the ability to fire 10,000 pulses per second – more than enough firepower to move any debris. Rather than blowing up junk, the system will be used to carefully zap it down to the atmosphere, where it will burn up thanks to intense friction. 

Space junk

In part due to a lack of forward thinking during the heyday of the space race, space junk has come to haunt modern spaceflight. There have already been two impacts involving satellites, and the possibility of “Kessler syndrome” is now a very real threat. Put forward in 1978 and more recently depicted in the film Gravity, the theory suggests that with so much junk in low Earth orbit (LEO), one collision could cause a chain reaction, with the resultant debris wiping out satellites and making the atmosphere impenetrable for spacecraft.

What’s more, the high speed of orbit also increases the amount of energy involved, turning harmless, small objects into bullet-like projectiles. The ISS orbits at around 17,000mph, so even an impact with a tiny object could have a huge effect.

What are space agencies doing to curb space junk?

The laser is the most proactive way of removing debris, but spacecraft already use more passive defensive methods. When the ISS encounters debris, it shifts its course as much as possible, while the crew take shelter in an escape pod and hope. Spacecraft, including the ISS, also use Whipple shields to protect themselves against stray orbital debris. Comprised of several thin layers sometimes stuffed with Kevlar or other hard materials, they’re designed to soak up and disperse the high-energy impacts of debris.

However, prevention is better than cure, and what’s needed are regulations that will reduce the amount of junk put in space by missions – as well as finding ways to remove what’s already there. If we do nothing, we run the risk of the catastrophes seen in films such as Gravity becoming a reality.