When did the critical initiating event occur that led to the *Columbia* disaster?

Answer

81 seconds into the flight during liftoff.

The root cause originated during launch when a piece of insulating foam broke off the External Tank and struck the shuttle.

When did the critical initiating event occur that led to the *Columbia* disaster?

#Videos

Infamous NASA Disasters That Were Worse Than You Realize

HistorySpaceNASAdisaster