Close Call

For just the second time, astronauts aboard ISS had to retreat to Soyuz capsules as a piece of space debris roughly two inches across threatened to rip a hole in ISS yesterday. That might not sound like a huge problem, but mass that size traveling at 17,500 miles per hour packs quite a punch. Had it hit and caused major damage, the astronauts would have attempted to return to Earth. NASA estimates that, in fact, the piece came within roughly a thousand feet of the station. While NASA generally has a couple days or more warning of such a potential problem, this time it only had fourteen hours.

The incident emphasizes the dangers posed by space debris in low Earth orbit to continuing operations there. Thousands of pieces of stuff that big are zipping around, and that number is only growing as more nations and corporations reach into space; the number of smaller, still dangerous bits is in the tens of thousands.

Space agencies and aerospace corporations are working on the problem by trying to make rocket operations less messy, and by finding ways to de-orbit debris already there. The solutions to the problem are slow in coming, however. There is a small but non-zero chance that we will lose a spacewalking astronaut-- and possibly ISS itself-- to collisions with space debris by 2020.