on Investigators focus on dislodged debris at launch that may have damaged Columbia's tiles. news_spaceshuttle_columbia_launchcrew_0201_rts.jpg home Disaster Clues superpass.gif http://premium.cnn.com/pr/video/meta/us/2003/02/04/mo.shuttle.probe2.affl.r1.smil 10443031255200 CNN Video (Members) lock_icon.gif audio.gif rtsp://audio.npr.org/me/20030204_me_01.rm?rpurl=http://www.npr.org/news/specials/shuttle/investigation.html 10443031255201 NPR Morning Edition lock_icon.gif lock_icon.gif big_headline