In 1961, at Baikonur(sp?), a manned rocket began the launch sequence. It was a three stage launch system, and when the count hit zero, the main engines failed to fire. Perplexed, engineers cautiously approached the rocket after verifying the the connections were correct, but knowing that the second stage seperation sequence had continued unimpeded.The seperation engines fired on the pad in a spectacular explosion killing hundreds of folks in an around the cosmodrome.
Around 1967, an incident in the Soviet Union would have a direct impact on our program occured when a young cosmonaut was brought to a hospital with horrific burns over 90% of his body. He had been training in a O2 saturated environment and was using a hot plate in there. It ignited some cotton on the cosmonauts clothes, literally lighting the air on fire. Had the Russians bothered to share this hard won info, we could saved Grissom and his crew..
And then there was the woman cosmonaut’s voice heard in the blind on shortwave as she burned up on on re-entry..
More Soviet space disasters here..
More Soviet space disasters here..
It's been known since long before the space programs that things burn quite well in a high-oxygen atmosphere.