Taking off from the Kennedy Space Center in Cape Canaveral, Florida, the cold weather conditions that morning
combined with a design flaw led to a rocket booster failure and caused a structural collapse.
The external fuel tank collapsed due to a leak in the shuttle's right solid rocket booster joint, which released liquid hydrogen and liquid oxygen propellants and ignited to create a giant fireball, which made it appear as if the Challenger had exploded.
Allan McDonald, director of the Space Shuttle Solid Rocket Motor Project for the engineering contractor Morton Thiokol, refused to sign a launch recommendation for the Challenger
the night before over safety concerns.
The Challenger broke apart 73 seconds after launch
at approximately 11:40 a.m. ET on January 28, 1986.
The launch and subsequent explosion was aired live on CNN
and was watched in classrooms across the US that morning. NASA had a special satellite broadcast set up for schools across the nation to watch what was supposed to be a historic moment.
, a high school teacher from New Hampshire, was supposed to be the first civilian and American teacher in space. She was selected as part of the Teachers in Space program.