It was January 27, 1986, the night before the Space Shuttle Challenger was scheduled for launch. The goal was to have a shuttle that could land back on Earth and be reused for future missions; its first-planned priorities were satellite deployment, comet observation, and science education. The last of these would involve students from around the world watching live broadcasts from Christa McAuliffe, the first civilian teacher in space.

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The forecast for the eve of the launch predicted clear and uncharacteristically cold weather for Florida, with temperatures expected to be in the low 20s during the early hours of January 28. Manager Larry Wear, of the Marshall Space Flight Center, asked the manufacturer Morton Thiokol-Wasatch to have its engineers review the possible effects of the cold on the performance of the Solid Rocket Motor (SRM). This was not the first time concerns about SRM performance had been raised between Marshall and Thiokol. On several previous launches, hot combustion gases produced when the propellant ignited at liftoff had charred and sometimes even eroded the surface of the rubberlike Viton O-rings designed to seal the joints between the SRM case segments of the Solid Rocket [...]