What caused the flash fire in the Apollo 1 command module during the 1967 test?
Answer
An electrical spark in a pure oxygen environment.
The Apollo 1 crew perished when the cabin, pressurized with pure oxygen, ignited due to an electrical spark during a launch rehearsal test on the pad.

#Videos
Infamous NASA Disasters That Were Worse Than You Realize
Related Questions
How many crew members died in the Space Shuttle *Challenger* disaster?What caused the flash fire in the Apollo 1 command module during the 1967 test?What specific component failure led to the *Challenger* disaster?What unusual environmental condition primarily contributed to the failure of the *Challenger*'s O-rings?When did the critical initiating event occur that led to the *Columbia* disaster?What part of the Space Shuttle *Columbia* was struck by insulating foam?Which commission led the investigation into the *Challenger* disaster?The *Columbia* event demonstrated a failure relating to which design risk category?Approximately how long was spaceflight suspended following the *Challenger* disaster before STS-26 returned?Which disaster resulted in a longer grounding period for the Shuttle program?Where did the *Challenger* vehicle break apart, leading to immediate catastrophe?