When We Left Earth: The NASA Missions- Episode 5 Clip #2

Astronauts recall the first testing sessions of the 31,000 heat shields used to protect the orbiter's aluminum shell . Don't miss the final two episodes of the Discovery Channel series When We Left Earth airing Sunday June 22, at 9PM! For the first time ever, audiences will have the chance to check out mission and training footage completely restored and digitally remastered in HD. For more info, visit: http://dsc.discovery.com/tv/nasa/nasa.html