50 years ago today: Tragedy on the Apollo 1 launch pad

[hunter]

9. This had a very direct impact on my family.

My grandfather was one of the many very enthusiastic Apollo engineers. As a World War II Army Air Force Officer my grandfather tried to hide his emotional reaction to the tragedy behind a stoic face but that was always a certain sign he was upset.

The decision to switch to a nitrogen/oxygen atmosphere at launch and gradually transition to a lower pressure pure oxygen atmosphere as the rocket ascended required some intense re-engineering. Previous this accident, mixed gas atmospheres in closed systems were regarded with deep suspicion because they had to be regulated so tightly; any equipment failures or mistakes would either suffocate the astronauts or give them the bends. There had been multiple bad experiences with these sorts of mixed atmospheres in both aviation and diving. That's why the pure oxygen atmosphere had been used in previous spacecraft.

Adding the more complex mixed gas atmospheric systems added mass to spacecraft. The overall mass "budget" of the spacecraft was already fixed, so mass had to be reduced in other systems.

As a wizard with titanium my grandfather was charged with replacing various parts made of heavier metals with titanium. That wasn't a trivial problem. Parts easily made in other metals are not easily reproduced in titanium. Some structural components had to be redesigned entirely. (My grandfather never explained where his skills with titanium came from; it was without a doubt Cold War secret stuff.)

And all of this work had to be done within JFK's deadline.