Millions of pieces of space junk, big and small, are constantly circling the Earth. This intractable problem has inspired many a grandiose idea, but perhaps none as initially bizarre-sounding as a laser on the International Space Station, a real scheme recently proposed by Japanese scientists.
Now, lasers have been proposed as a space junk solution before, but these lasers were based on on land. And this idea hasn't gained much political traction because, well, you can imagine how they could easily double as weapons. But perhaps a laser on neutral ground, or erh, in more neutral space, might appease those fears?
That's what scientists at Japan's RIKEN institute suggest in a new paper in Acta Astronautica. A high-powered laser can be used to nudge space junk toward the Earth's atmosphere, where it will harmlessly burn up. The researchers say this will work on dangerous and small pieces of space junk. These centimeter-sized pieces might seem harmless, but they can punch right through vehicles and satellites at high velocities.
The researchers arrived at this idea by way of the Extreme Universe Space Observatory (EUSO), a mission that includes a telescope for detecting cosmic rays. The European Space Agency had initiated EUSO but ultimately decided to drop the mission in 2004, before the telescope launched. Now scientists at RIKEN have since taken the project and are aiming to get a telescope up in the ISS's Japanese Experiment Module in a couple of years. The laser system would repurpose EUSO's telescope to track space debris.
The team now suggests a proof-of-concept study with a small telescope (20 centimeters) and small laser (100 fibres) on the ISS. If that happens and it works, the ISS could eventually get a full-sized three-meter telescope and a laser with 10,000 fibres.
Perhaps more so than anyone else, Japan has stepped up to deal with space junk, creating a militarised force to monitor debris and announcing plans to launch a giant collection net. The space laser proposal is still a lot more nebulous than those concrete plans, but hey, it's given us something to ponder.
Picture: An artist's impression of space junk orbiting the Earth. ESA