In Brief
Scientists would use the laser in combination with a telescope that could track down debris just one centimeter in size. 
  • There are about 25,000 human-made objects larger than your fist flying around in orbit, and about half a million pieces bigger than a dime. If you include millimeter-scale shrapnel, the number of rogue bits reaches deep into the millions. Typical speeds in low-Earth orbit are about 30,000 kilometers per hour (18,000 miles per hour), ten times the velocity of a rifle bullet. 
  • Once a piece of junk is identified, the laser would blast it out of orbit and into Earth’s atmosphere, where it would burn up and never hit the ground.
  • The researchers behind the project announced in April that they plan to deploy a small-scale proof of concept on the International Space Station, and if that’s successful, they’ll build a bigger system that would be able to zap trash within a roughly 65-mile radius.