O-Rings

The O-Rings

The O-Rings of the Challenger (shown below) were not sealed properly. The fuel began to leak from the ship and touched the flames from the Solid Rocket Boosters, thus, causing the explosion.

Image found at; https://clearthinking.co/the-teleconference-before-the-challenger-disaster-how-the-thinking-shifted/

In the right solid rocket booster, (SRB) of the ship, contained the right side O-Ring. The O-Ring was not sealed properly which caused fuel from the ship to leak into the flames, thus, causing the explosion. After the explosion, the o-rings were investigated by Neil Armstrong, Sally Ride, and Chuck Yeager.