Challenger Disaster: Seven Astronauts Lost on Launch

Space Shuttle Challenger explodes shortly after take-off on Jan. 28, 1986. (NASA photo via Wikimedia Commons)

Thirty years ago today, the space shuttle Challenger exploded shortly after liftoff, killing the seven crewmembers aboard.

Here are some things you may not have known about the disaster.

The mission was originally scheduled to launch on January 22, but was delayed by the previous space shuttle mission which landed on January 18. Weather delays at landing sites and at Kennedy Space Center pushed the launch back to January 27. The scheduled launch that day was delayed by hatch problems and a stripped bolt. The weather forecast for January 28 was for unusually cold weather. The night before launch, the overnight low temperature was 18 degrees fahrenheit. The temperature warmed slightly on the morning of the launch, but was still below freezing. Up to that point, the coldest temperature for a space shuttle launch was 53 degrees fahrenheit.

Engineers from the contractors who built the shuttle and the solid rocket boosters were initially unsure whether the launch should proceed. Both groups reversed themselves for reasons that are unclear and gave the go-ahead for launch.

Onboard the Challenger that day was a crew of seven: commander Dick Scobee, pilot Michael J. Smith, mission specialists Ellison Onizuna, Judith Resnick and Ronald McNair and payload specialists Gregory Jarvis and Christa McAuliffe. McAuliffe was a social studies teacher from Concord, New Hampshire, selected to the crew as part of the Teacher in Space Project. Because of the increased interest in the mission brought by having a teacher onboard, thousands of schoolchildren across the country watched the launch live in their classrooms.

With 6.6 seconds remaining in the countdown the main engines of the shuttle ignited as planned. As the countdown hit zero, the solid rocket boosters fired lifting the shuttle and its massive fuel tank from the launch pad at Cape Canaveral. A little more than a half-second after liftoff, several puffs of dark gray smoke came from the right solid rocket booster. The last puff came about two seconds later. The smoke was later determined to be from the opening and closing of a joint in the booster rocket caused by failed O-ring gaskets. In a bit of good luck, aluminum oxides from the burned rocket fuel helped seal the joint temporarily.

The good luck ended there however. Wind shear caused the oxide seal to shatter allowing flame to pass through the failed joint. About 58 seconds after launch, a plume could be seen forming on the booster rocket. Two seconds later, flames could be seen. Four seconds later, the liquid hydrogen tank was breached by flame. At 72 seconds after liftoff, the external fuel tank failed creating a massive fireball. The shuttle itself began breaking up shortly afterward. The crew cabin, which was reinforced, survived the breakup and could be seen exiting the gas cloud.

It is likely that at least some of the crew survived the initial blast, as the unused air supply was consistent with the amount expected to have been consumed during the 2 minute, 45 second free fall to the Atlantic Ocean. It was also discovered that several switches had been moved from their usual launch positions, likely by pilot Michael J. Smith after the explosion.

An investigation following the disaster could not determine the cause of death of the crew, however it found that the forces during the “breakup were probably not enough to cause death or serious injury and that the crew possibly, but not certainly, lost consciousness due to a loss of cabin pressure.”

The cabin was found on the floor of the Atlantic Ocean on March 8, 1986.

The space shuttle program was grounded for almost three years following the disaster. The shuttle Discovery returned to space on September 29, 1988.

Shuttle missions continued regularly until the 2003 loss of the Columbia on reentry to the earth’s atmosphere.

After 135 missions, the space shuttle program ended when the Atlantis landed on July 21, 2011.

Our question, besides the Challenger, Columbia, Discovery and Atlantis, which have already been mentioned, name the only other American shuttle to be launched into space.