I am Tom Marshburn, U.S. astronaut and the most recent spacewalker to return to Earth. AMA!
I'll be on this AMA for the next hour answering your questions about living and working on the International Space Station. I'm an M.D. and astronaut — and recently completed my own 5+ hour spacewalk to fix an ammonia leak outside the space station in May, marking more than 24 total hours I've spent outside walking in space (It's a pretty good office view!). I returned to Earth in May after 144-days on the space station where I conducted microgravity scientific research on orbit. Ask me anything!
Update: My time is up for today. Thanks for all of your wonderful questions. I hope to do this again soon! For now, you can follow me on Twitter @AstroMarshburn. I'll also be sure to tell my colleagues in the astronaut corps you're interested in hearing from them too! As always, get the latest on life and work in space at www.nasa.gov/station.