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.
Challenger's explosion changed the space shuttle program in several ways. Plans to fly other civilians in space (such as journalists) were shelved for 22 years, until Barbara Morgan, who was McAuliffe's backup, flew aboard Endeavour in 2007. Satellite launches were shifted from the shuttle to reusable rockets.