Important Events of the 2000's: The Columbia Disaster

On February 1, 2003, the space shuttle Columbia broke apart over Texas, disintegrating on national television and scattering debris across Texas and Louisiana.  Seven astronauts were on board.  Columbia was the first space shuttle to go into space in 1981 at the beginning of the program.  This flight was its 28th mission. 
The disaster was determined to be caused by a launch-related issue.  Films showed that a piece of insulating foam broke loose from the external propellant tank and struck the leading edge of the left wing shortly after take-off.  While NASA engineers initially believed that the foam pieces would not be able to cause significant damage, post-accident results demonstrated that the foam could carry enough momentum to punch a large hole in the tiles that protect the shuttle from the extreme heat that develops during re-entry. 
As a result of the disaster, NASA grounded the three remaining shuttles until they could develop the means to prevent similar accidents and build repair kits that could be used while in orbit.  Assembly of the International Space Station was also suspended until shuttle flights could resume. 

“Columbia” disaster. [Photograph]. In Encyclopædia Britannica. Retrieved from http://www.britannica.com/EBchecked/media/68870/Streaks-of-burning-debris-from-the-US-space-shuttle-orbiter