Space Shuttle

He piloted Apollo 16 and commanded the shuttle. But he may be best known for the mission he didn't fly: the ill-fated Apollo 13. And he worried late in life about the high cost of human space flight.

On June 18, 1983, she made history aboard the space shuttle. America's first woman in space had joined NASA after responding to a newspaper ad. "I knew that's what I wanted to do," she said.

Seven astronauts died when the Space Shuttle Columbia disintegrated upon reentry on Feb. 1, 2003. NASA Deputy Administrator Pam Melroy looks back on the tragedy and how it shaped the agency.

A documentary crew with the History Channel initially made the discovery during a dive looking for World War II-era wreckage.