“For want of a nail, the kingdom was lost,” is the final line of an old proverb that reminds us that seemingly unimportant acts or omissions can have grave consequences. An infamous example of this exists in one of America’s most tragic incidents, the 1986 Challenger shuttle disaster.
The Challenger exploded 73 seconds into its launch, killing all seven crew members. The investigation revealed that the disintegration of the entire vehicle began after an O-ring seal in its right solid rocket booster (SRB) failed at liftoff. The O-ring failure caused a breach in the SRB joint, allowing pressurized hot gas from within the solid rocket motor to reach outside and impinge upon the adjacent SRB attachment hardware and external fuel tank. This led to the separation of the right-hand SRB’s aft attachment and the structural failure of the external tank. Aerodynamic forces promptly broke up the orbiter.