heart murmur a sound additional to the normal heart sounds, heard on auscultation of the heart. Many murmurs are of no significance (innocent, physiological murmurs), particularly in young children, or due to increased blood flow through the heart during exercise, or in pregnancy.
Columbia Space Shuttle Disaster. On February 1, 2003, the space shuttle Columbia was returning from its 28th mission when, 16 minutes to touchdown, the shuttle incinerated and broke apart over Texas. Communication between the Columbia crew and Mission Control captures the last moments of the flight.
A string of successful missions was broken in 1986 when Challenger disintegrated seconds after liftoff, killing its seven-person crew. The space shuttle program was suspended in the wake of the accident, and no shuttles were launched for nearly three years.