The Challenger Explosion

On this day, 29 years ago, the space shuttle Challenger exploded 73 seconds after liftoff from Cape Canaveral, Florida, killing all seven crew members. The explosion was caused by the failure of a pressure seal in the shuttle's right solid rocket booster.

Christa McAuliffe, a teacher from Concord, New Hampshire, was among the crew members who died that day. 

Later investigation would uncover that the defective seal had a calamitous design flaw which had not been adequately addressed for years and that warnings about the danger of launching Challenger that day due to low atmospheric temperatures had been disregarded. 

The launch was a large television event as the crew included Christa McAuliffe (37) - a woman who was to become the first teacher in space. Fully 17 percent of Americans would watch the disaster unfold on their TV screen.

In the aftermath of the tragedy, President Ronald Reagan, postponed his scheduled State of the Union address to deliver one of his most famous speeches in an Oval Office appearance before the nation. At a particularly poignant moment in the speech, Reagan quoted scripture saying.  

We will never forget them, nor the last time we saw them, this morning, as they prepared for their journey and waved goodbye and ‘slipped the surly bonds of Earth’ to ‘touch the face of God.’
— President Ronald Reagan