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 Explosion On January 28, 1986, the tenth mission of the space shuttle Challenger ended in tragic disaster. We remember the seven astronauts who lost their lives that day, including Christa McAuliffe, who was chosen by NASA to pioneer its Teacher in Space program.