The Challenger was a NASA space shuttle that tragically broke apart 73 seconds after launch on January 28, 1986. It was carrying seven crew members, including teacher Christa McAuliffe, who was set to be the first civilian in space. The disaster was caused by the failure of an O-ring seal in one of the solid rocket boosters, which allowed hot gases to escape and damage the external fuel tank. Following the accident, NASA conducted an extensive investigation, leading to significant changes in safety protocols and shuttle design. The Challenger disaster highlighted the importance of communication and risk management in space exploration, ultimately shaping future missions and policies.