Columbia crew catches a mysterious TIGER in the Indian Ocean
WASHINGTON -- An unprecedented flash observed by the space shuttle Columbia crew in 2003 over the Indian Ocean may be a new type of transient luminous event, like lightning sprites, but one that is not necessarily caused by a thunderstorm. The discharge was observed less than two weeks before the shuttle was lost during its Earth reentry.

The authors describe the discharge as a Transient Ionospheric Glow Emission in Red, or TIGER, event. It was recorded by a video camera in the near-infrared spectrum in the nighttime sky just south of Madagascar on 20 January 2003. The authors analyzed the video several months later and found what visually looks like a bright flash. They report that the emission did not resemble any known class of luminous events, which typically appear in conjunction with thunderstorm activity. [continued]