Challenger's shocking explosion devastates the families of the crew as well as millions watching live, and an investigation puts NASA on the defensive.

After several delays, the crew prepares for launch as engineers and NASA officials tensely discuss concerns about the O-rings and a cold weather launch.

The new Space Shuttle program captivates America and draws a diverse, determined crop of astronauts. But safety issues arise out of public view.

To revive public interest, NASA chooses teacher Christa McAuliffe to be the first civilian on the Shuttle. Issues with the solid rocket boosters linger.