Two days ago, astronauts on the ISS discovered some little white flakes suspiciously floating away from the station. And now, they're already floating outside in zero gravity to fix it. From planning to go-time, this has been the most impromptu spacewalk in NASA history, and you can tune in below.

When astronauts spacewalk, it looks like they're floating serenely in the vacuum of space. The reality: they're hurtling at 17,220 mph inside bulky pressurized suits. Here's the lowdown on spacewalking, from how it's done to what it costs.

A record number of 13 astronauts were together on the Space Station this week. The Endeavour shuttle crew is leaving this largest-ever space gathering Friday, but one of their final tasks on the station was a five hour spacewalk today.

The astronauts who spent the past week performing space walks outside the International Space Station wore the familiar puffy white jumpsuits that nostalgia buffs innocently refer to as a "space suit." But the spacefaring hardcore know it as an EMU, or "Extravehicular Mobility Unit," and the current ones have been in…