April 12, 2010 -- With only three missions left to go before NASA's space shuttle program is permanently grounded, the crew members of Discovery STS-131 are some of the last astronauts who will ride one of the winged orbiter into space. The Space Shuttle Program is scheduled to end in September, when Discovery completes its final flight.
With Discovery and its crew currently docked at the International Space Station to deliver supplies, the astronauts are also marking another milestone -- it's the first time that four women have been on board the space station at the same time.
Today, Diane Sawyer spoke with four of Discovery's astronauts, including Commander Alan Poindexter, Pilot Jim Dutton, Mission Specialist Dottie Metcalf-Lindenburger and Mission Specialist Stephanie Wilson. What's it like to be on one of the last shuttle missions, and how does a trip to space change the way they see our world? It's all part of today's Conversation.