Debris from the space shuttle Columbia streaks across the sky over Tyler, Texas, Saturday, Feb. 1, 2003. (AP Photo/Tyler Morning Telegraph, Dr. Scott Lieberman)
Astronaut Mark Kelly, right, carries a piece of debris from the space shuttle Columbia as he and fellow astronaut Greg Johnson
Debris from the space shuttle Columbia streaks across the sky over Tyler, Texas, Saturday, Feb. 1, 2003. (AP Photo/Tyler Morning Telegraph, Dr. Scott Lieberman)