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://abcnews.go.com/sections/us/videofiles/Video/030204shuttle_video.ram 10443011539450 ABCNEWS - Launch Trouble lock_icon.gif superpass.gif http://premium.cnn.com/pr/video/meta/us/2003/02/04/mo.shuttle.probe2.affl.r1.smil 10443011539451 CNN - Launch Debris Clues lock_icon.gif lock_icon.gif big_headline