ArsTechnica has a great story about NASA's early space program and how the tragic fire during Apollo 1's testing was a turning point for the program.
As Gus Grissom said, "The conquest of space is worth the risk of life." He was one of the astronauts who died in the Apollo 1 fire.
(Score: 3, Informative) by MichaelDavidCrawford on Saturday December 09 2017, @08:45AM
not only was the capsule filled with pure oxygen, but it was pressured so as to simulate the pressure differential that would occur when the capsule was in a vacuum.
The three astronauts had a photographer take a photo of them praying around a model of the capsule. Let's see if I can find it:
http://cdn.history.com/sites/2/2017/01/hith-apollo-1-disaster-prayer.jpg [history.com]
Yes I Have No Bananas. [gofundme.com]