At NASA's Kennedy Space Center in Florida, NASA leaders spoke to social media participants as the Orion spacecraft and its Delta IV Heavy rocket were being prepared for launch. Speakers included NASA astronaut Rex Walheim.

At NASA's Kennedy Space Center in Florida, NASA leaders spoke to social media participants as the Orion spacecraft and its Delta IV Heavy rocket were being prepared for launch. Speakers included NASA Administrator Charlie Bolden, left, and Kennedy Space Center Director Bob Cabana.

At NASA's Kennedy Space Center in Florida, NASA leaders spoke to social media participants as the Orion spacecraft and its Delta IV Heavy rocket were being prepared for launch. Speakers included Kennedy Space Center Director Bob Cabana.

At NASA's Kennedy Space Center in Florida, NASA leaders spoke to social media participants as the Orion spacecraft and its Delta IV Heavy rocket were being prepared for launch. Speakers included, from the left, NASA Associate Administrator Human Exploration and Operations Bill Gerstenmaier, Associate Administrator for the agency's Science Mission Directorate John Grunsfeld, Associate Administrator for the Space Technology Directorate Michael Gazaria, NASA Chief Scientist Ellen Stofan, and Chief Technologist David Miller. Moderator for the panel session was John Yembrick, with the microphone on the far right, who is NASA's social media lead at the agency's Headquarters in Washington.

At NASA's Kennedy Space Center in Florida, NASA leaders spoke to social media participants as the Orion spacecraft and its Delta IV Heavy rocket were being prepared for launch. Speakers included NASA Administrator Charlie Bolden, left, and Kennedy Space Center Director Bob Cabana.

At NASA's Kennedy Space Center in Florida, NASA leaders spoke to social media participants as the Orion spacecraft and its Delta IV Heavy rocket were being prepared for launch. Speakers included Director of Commercial Spaceflight Development Philip McAlister.

At NASA's Kennedy Space Center in Florida, NASA leaders spoke to social media participants as the Orion spacecraft and its Delta IV Heavy rocket were being prepared for launch. Speakers included Kennedy Space Center Director Bob Cabana.