Humanity's trash problem doesn't end on Earth—it's followed us to outer space. Thousands of tons of derelict satellites, spent rocket parts, and stray garbage fragments now whiz about our planet at breakneck speeds, and the volume of space junk is growing every year.
All that marauding trash poses a threat to the ISS and future space development, as anyone who's seen the movie Gravity will be viscerally aware. Now, an international team of scientists is proposing that we strap a giant laser to a space telescope, and start blasting junk out of orbit once and for all.
"We may finally have a way to stop the headache of rapidly growing space debris that endangers space activities," said Toshikazu Ebisuzaki, the UC Irvine-based researcher leading the effort, in a statement. "We believe that this dedicated system could remove most of the centimeter-sized debris within five years of operation."
In more than 50 years of spaceflight, we've sent thousands of tons of satellites and rockets into space. More than 500 thousand pieces of debris, many smaller than a centimeter, now circle our planet at speeds of up to 10 kilometers per second, or 22,000 miles per hour. At these speeds, a collision with even a small particle can pack the punch of a hand grenade, according to ESA.
To eliminate this orbital minefield, a proposal outlined in a forthcoming Acta Astronautica paper would take advantage of the Extreme Universe Space Observatory, or EUSO, a new Japanese space telescope that's slated to join the ISS in 2017. The EUSO wasn't intended for garbage duty—in fact, its primary aim is to detect UV light emitted from high-energy cosmic ray showers entering Earth's atmosphere at night. But the telescope's powerful optics and wide field of view also make it the perfect tool for spotting small, high velocity debris as it hurtles about the ISS.
And when combined with a high-energy laser, the EUSO becomes a junk-buster worthy of a spot in any shoot 'em up game. Ebisuzaki and his colleagues are proposing to outfit the telescope with CAN, a laser system that was designed to be the driving force behind a new generation of particle accelerators. CAN lasers use an array of thousands of optical fibers that act in concert to produce a powerful plasma pulse that Ebisuzaki believes iis capable of slowing a piece of debris until it falls out of orbit and burns up in Earth's atmosphere.
With the EUSO's eyes and CAN's punch, Ebisuzaki says we'll be able to stop renegade particles in their tracks and punt the suckers back into Earth's atmosphere. The researchers are now gearing up to deploy a small proof-of-concept experiment on the ISS, using a 20-centimeter version of the EUSO and a mini-CAN laser with 100 optical fibers.
"If that goes well," Ebisuzaki, said, "we plan to install a full-scale version on the ISS, incorporating a three-meter telescope and a laser with 10,000 fibers, giving it the ability to deorbit debris with a range of approximately 100 kilometers. Looking further to the future, we could create a free-flyer mission and put it into a polar orbit at an altitude near 800 kilometers, where the greatest concentration of debris is found."
Between this high-tech trash-removal system and another effort to deploy a giant garbage-collecting fishing net into space, it seems fair to hope that the skies will soon be much cleaner. Next up, let's put some of that creative energy to work mopping up trash on Earth.