NEWS ALERT Shuttle Columbia breaks up over Texas as it headed towards landing in Florida. No word on fate of astronauts. news_spaceshuttle_columbia_flames_abc.jpg 187x47 l lock_icon.gif superpass.gif http://abcnews.go.com/sections/us/videofiles/Video/streamer6_video_r1.ram 10437068481010 LIVE- Shuttle Disaster lock_icon.gif webpage.gif http://abcnews.go.com/ 10437068481011 More ABCNEWS lock_icon.gif superpass.gif lock_icon.gif headline