字幕表 動画を再生する 英語字幕をプリント Our planet is surrounded by a hazardous shell of space trash that is threatening any chance at future exploration beyond Earth. NASA defines orbital debris as any man-made object in Earth orbit which is no longer in use. This junk includes objects as small as screws and paint flecks to as large as spent rockets and satellites. There are so many abandoned objects that the U.S. military issues over 20 warnings each day for potential space collisions. So now, scientists are starting to deploy sci-fi inspired spacecraft to clean up our mess, but it's not gonna be easy. Since humanity's first satellite lifted off, we've launched thousands of satellites and spacecrafts, of which, only a fraction are still active. Many of the retired satellites are wasting away in low-Earth orbit, breaking apart into millions of smaller pieces that make up the artificial junk cocoon surrounding our planet. This is a huge problem because these tiny pieces of trash are traveling ten times as fast as a bullet, and a collision between a ten centimeter sphere of aluminum and a spacecraft would have the same outcome as the detonation of seven kilograms of TNT. And the potential for collisions is highly likely. In 2013, Ecuador's first satellite collided with a cloud of particles from an old Soviet rocket. And in 2018, the CryoSat-2 spacecraft was on a crash course with a rogue object so the European Space Agency had to shift the spacecraft out of its normal orbit. The International Space Station has also been hit by debris and has the scars to prove it. To protect the ISS and future spacecraft, European scientists developed RemoveDEBRIS - a satellite built to combat space junk. And in mid-2018, the first of its kind cosmic custodian was on the clock in space. RemoveDEBRIS is testing out several different ways to dispose of space junk launched from the satellite. One of which is the net - a spider web of sorts made of super strong material designed to capture junk. Six small motors act as weights to spread the net to 5 meters across. The motors are then used to close the net around the debris. After a successful capture, the weight of the net drags the junk into Earth's atmosphere, where it'll burn up. RemoveDEBRIS will also test out a harpoon to snare rogue objects. The harpoon projectile is about the size of a pen, and has a set of barbs near the tip, which will latch onto the target. These scientists aren't the only ones taking on the role of space clean up. Russian engineers are attempting to use a process called laser ablation, in which a beam would irradiate an object like a lost screw, removing layers until it is entirely vaporized. While we're finally making progress on the clean up, potential solutions like RemoveDEBRIS, are still just being tested so they aren't yet being used at their full potential. And even if the experiments prove to be successful, legal hurdles are preventing a start to the clean up. Until we perfect one of these concepts, scientists are focusing on monitoring debris using technology like NASA's Space Debris Sensor, which helps zone in on objects too small to detect from Earth. But just like pollution here at home, if we don't find a solution, the consequences will be catastrophic and will certainly hinder any plans of future spacecraft, and humans venturing beyond Earth. If you want to see more Space Crafts, check out this playlist here. And be sure to let us know in the comments what astronomical phenomena you want to learn more about. Thanks for watching Seeker! Don't forget to subscribe.