Space Shuttle Columbia disaster marks 15th anniversary

(CNN) - Thursday, Feb. 1, marks the 15th anniversary of the Space Shuttle Columbia disaster.

The craft was the oldest shuttle in NASA's fleet and had completed 27 previous missions. Investigators say Columbia broke up during re-entry.

The board determined that a piece of foam broke shortly after lift-off and formed a hole in the shuttle's left wing.

A report said engineers noticed the break and thought it could lead to a problem, however, management didn't think the incident was a serious enough issue.

All seven crew members, including Payload Commander Michael Anderson, died in the accident.