Cape Canaveral, Florida

At the heart of the John F. Kennedy Space Center’s visitor center stands a striking monument that’s made of 90 panels of reflective polished black granite: the Space Mirror Memorial. Carved into a handful of individual squares are the names of 24 astronauts who have given their lives for space exploration. Seven of these names stand apart, as they are forever linked to a tragic disaster that played out in front of the nation.

What was the terrible tragedy that doomed these brave explorers?

On the morning of January 28, 1986, 7 astronauts smile for the cameras as they make their way towards NASA’s launch pad. It’s the 25th flight of the shuttle program, but this trip is getting more attention than usual, almost entirely due to the presence of the first-ever civilian crew member, teacher Christa McAuliffe. NASA will be broadcasting a live feed of the launch to schools nationwide and even more people are watching on CNN. The name of the Space Shuttle is The Challenger.

But as the ship rockets towards space, something goes horribly wrong. Just 73 seconds into the flight, a huge fireball explodes in the sky. In that one chaotic moment, The Challenger and all 7 astronauts are lost.

What caused this horrific tragedy? And could anything have been done to prevent it?

Review of the launch footage shows that the problems began before the shuttle was even off the launch pad. Puffs of black smoke indicate there was a problem with the shuttle’s O-rings, the rubbery seals on the 2 rocket boosters that flank the spacecraft.

A defective O-ring allowed hot gases and flames to seep out, effectively creating a giant blowtorch. The flames then burned a hole in the shuttle’s external fuel tank, causing liquid hydrogen and oxygen to combine and create the giant fireball seen from the ground. Although it appeared to explode, The Challenger, in fact, did not blow up. Instead, when the external fuel tank exploded, the shuttle was knocked off course and sent flying into a Mach 2 airstream. There, aerodynamic forces wrenched the orbiter apart in an instant.

But why did the O-ring fail this time when it had held for all previous missions?

The culprit proves to be a force engineers couldn’t control: the weather. The morning of the launch was unseasonably cold, and the O-rings had never been tested at such low temperatures. In fact, an engineer was so concerned that the integrity of the O-rings would be compromised by the temperature that he refused to sign the launch recommendation the night before the fateful lift-off. But NASA, under pressure to stick to their launch schedule, dismissed these concerns.

Today, the Space Mirror Memorial at Kennedy Space Center in Florida serves as a reminder of the 7 brave astronauts who lost their lives that terrible January day, and the importance of vigilance in space exploration.