Today’s Highlight in History:
On Jan. 28, 1986, the space shuttle Challenger exploded 73 seconds after liftoff from Cape Canaveral, killing all seven crew members, including schoolteacher Christa McAuliffe.
The mission, known as STS-51-L, was the 10th flight of the Challenger space shuttle and the 25th flight of the Space Shuttle program.
The launch ended in a catastrophic failure of the shuttle’s rockets. McAuliffe, a teacher, would have been the first-ever American civilian to fly in space.
The mission, known as STS-51-L, was the 10th flight of the Challenger space shuttle and the 25th flight of the Space Shuttle program.
The launch ended in a catastrophic failure of the shuttle’s rockets 73 seconds after liftoff, killing all seven crew members, including Christa McAuliffe, a teacher who would have been the first-ever American civilian to fly in space.
Visual evidence of the failure of an O-ring was observed on video less than 1 second after ignition.
“Just after liftoff at .678 seconds into the flight, photographic data shows a strong puff of gray smoke was spurting from the vicinity of the aft field joint on the right solid rocket booster,” NASA explained on its website.
More puffs of smoke were observed shortly after the seal failed, allowing hot gas to escape. Later in the flight, this escaping gas caught on fire and ultimately led to the failure of the larger external fuel tank and an explosion that caused Challenger to break apart over the Atlantic Ocean.
Wreckage recovered following the incident also suggested a major failure in the O-ring was the primary cause of the explosion.
The weather conditions leading up to the launch were likely the primary reason why the O-ring failed after ignition.
A record-setting chill descended across the Florida Peninsula with temperatures bottoming out in the 20s F near the launch pad just hours before liftoff on Jan. 28, 1986.
This is significantly lower than the typical low temperature of around 50 F along Florida’s Space Coast in late January and was the lowest temperature ever for a launch of a space shuttle.
“O-ring hardness is a function of temperature and may have been another factor in joint performance,” the report stated.
In addition to affecting the resiliency of the O-rings, the freezing conditions could have allowed ice to form in the joints, further compromising the joint’s ability to perform properly.
Analysis after the disaster revealed that the O-rings were destroyed shortly after ignition.
Not only did the freezing weather affect the O-rings, but it also caused ice to form around the launch pad. This included the only evacuation route that astronauts could take in the event of an emergency prior to launch.
“Had the crew been required to evacuate the Orbiter on the launch pad, they would have been running on an icy surface,” the report said.
