Ever had to do a surprise bit of work on your car? Now imagine doing it in space. From Fox News:
Astronauts making a rare, hastily planned spacewalk replaced a pump outside the International Space Station on Saturday in hopes of plugging a serious ammonia leak.
The prospects of success grew as the minutes, then hours passed and no frozen flecks of ammonia appeared. Mission Control said it appeared as though the leak may have been plugged, although additional monitoring over the coming weeks will be needed before declaring a victory.
Can you think of anything more stressful than that?