Humans have sprinkled hundreds of thousands of pieces of debris into space, and a few times a year, the crew of the International Space Station must change its course to avoid a piece of broken-off rocket or out-of-service satellite. But most of the debris is so tiny that the ISS can’t see it—and when a piece just a few centimeters in size, hurtling at extremely high speed around the earth, can disable a huge satellite, not being able to see debris becomes a real danger.
The government can currently see less than five percent of the estimated 500,000 pieces of debris that are circling the planet, according to Ilima Loomis in the latest issue of Science. In fact, the U.S. Air Force currently only tracks about 20,000 pieces of space debris that are at least the size of a basketball, according to an infographic by Lockheed Martin. But starting this month, the U.S. Air Force is building a new radar—the Space Fence—in the Marshall Islands. This new system will permit outer space look-outs to see up to ten times as many pieces—including those as small as a marble.
This video by Lockheed Martin, which is installing the system, explains how it will work:
With all the new data that the Space Fence will generate, part of the challenge will be in separating serious threats from the not-so-serious ones. As Loomis reports, ISS receives about 12 to 15 warnings a month from the ground about debris that could possibly inflict damage, but only a handful of those are serious enough to cause the crew to take action each year. With the new system, Loomis says, ISS could receive up to ten times as many warnings.
Astronauts will have to sit tight, though, because the radar will not be operational until 2019.