Which female astronaut has the most cumulative spacewalk time? (Hint: today is her birthday.)

It's Sunita Williams, who has 50 hours and 40 minutes of extravehicular activity from 7 spacewalks on two tours of duty on the International Space Station. With 322 days in space she has also spent the second most time in space for a female astronaut and is sixth on the U.S. all time endurance list. In 2012 she served as commander of Expedition 33 on the ISS.

Images from here and here