It's been 40 years since the Challenger space shuttle disaster. This archival footage shows the launch day emotions and the heartbreak that followed. http://www.wcvb.com/article/challenger-40-christa-mcauliffe/70170105 | WCVB Channel 5 Boston

Forty years ago, the Space Shuttle Challenger launched from Kennedy Space Center after nearly a year of repeated delays. Just 73 seconds after takeoff, the shuttle broke apart, killing all seven crew members aboard. The cause of the disaster was the failure of the primary and secondary O-ring seals in one of the rocket boosters, as record-low temperatures on the morning of the launch had stiffened the rubber O-rings, reducing their ability to seal the joints. The boosters were built by Utah-base

The NASA space shuttle Challenger exploded 40 years ago, on January 28, 1986, just 73 seconds after liftoff. The disaster claimed the lives of all seven astronauts aboard, including Christa McAuliffe, a teacher from New Hampshire who would have been the first civilian in space. “The crew of the space shuttle Challenger honored us by the manner in which they lived their lives,” President Regan said in an address to the nation that night. “We will never forget them, nor the last time we saw them,

"It is the worst disaster in the history of the American space program." Forty years ago on January 28, 1986, the space shuttle Challenger exploded 73 seconds after liftoff from Cape Canaveral, killing all seven crew members, including school teacher Christa McAuliffe from New Hampshire, who had won a national competition to become the first teacher in space. Peter Jennings anchored ABC's World News Tonight from Washington, with John Quiñones leading off the broadcast's coverage. | ABC World New