Challenger: Seventy-Three Seconds

The morning of January twenty-eighth, nineteen eighty-six was cold for Florida. The temperature at Kennedy Space Center had dropped below freezing overnight, and ice had formed on the launch structure. Engineers at Morton Thiokol, the contractor that built the solid rocket boosters, had been on the phone with NASA managers the night before. They were worried about the O-rings, the rubber seals that prevented hot gas from escaping between the booster segments. Cold made the O-rings stiff. Stiff O-rings did not seat properly. The engineers wanted to delay the launch.

NASA management overruled them and launched anyway.

Seventy-three seconds after liftoff, Space Shuttle Challenger broke apart over the Atlantic Ocean. All seven crew members died: Gregory Jarvis, Christa McAuliffe, Ronald McNair, Ellison Onizuka, Judith Resnik, Michael Smith, and Francis Scobee.

Christa McAuliffe was a thirty-seven-year-old high school teacher from Concord, New Hampshire, selected from more than eleven thousand applicants for NASA's Teacher in Space program. Schools across the country had brought their students together to watch the launch live. The television footage of the explosion ran continuously for days.

The presidential commission investigating the disaster was led by former Secretary of State William Rogers, and it included physicist Richard Feynman, who used a glass of ice water and a small rubber ring to demonstrate the O-ring failure mechanism in a televised hearing. The compressed rubber emerged from the water stiff and deformed. The demonstration was simple. The point was devastating: NASA engineers had documented concerns about O-ring performance in cold temperatures for months before the launch. The launch schedule pressure that overrode those concerns was, the commission found, a management failure, not an engineering one.

The seven names are on a memorial at Kennedy Space Center. They are also on a plaque at the South Pole, placed there by a crew who wanted to mark where explorers go when no one is waiting to bring them back.