What do you know about Sally Ride? For American citizens of a certain age, science wonks, space geeks, and feminist historians, the easiest answer is the most obvious one: she was the first American woman astronaut to visit outer space.

National Geographic premiered "SALLY," Cristina Costantini's new documentary about the first U.S. woman in space and her untold love, at the Sundance Film Festival in Utah on Tuesday (Jan. 28).

When Sally Ride arrived at NASA's Lyndon B. Johnson Space Center in 1978, there were approximately 4,000 technical employees working there. Want to guess how many were men? If you said 3,996, you're already aware that Ride faced considerable challenges as the first American woman chosen to go into space.