They've strapped on their gear, exited the International Space Station, and now astronauts Sunita Williams and Aki Hoshide are doing a spacewalk - with cameras on their helmets, allowing the world to watch their every move.
The two astronauts are working to fix an ammonia leak.
The walk began at 8:29 a.m. ET and is expected to last more than six hours, NASA says.
You can watch live here.
And you can find out why spacewalking is like "giving birth to yourself" here.