I was a 7 year old who was in love with the space program. Watched every launch from John Glenn through the shuttle.
The weird thing about that whole mess, and the ironic nature was what happened to Grissom's Mercury flight.
Up until the Apollo missions, the hatch opened OUTWARD. On Mercury, there was a button that the user would
punch with his fist, that would activate explosive bolts to blow the hatch. Grissom's flight splashed down, and the
hatch "just blew". Speculation was that Grissom wiggled around, got scared or something an hit the button, causing
the capsule to take on water & sink. After that, they figured it would be better to have an INWARD opening hatch.
Also, to simulate the take off, the "plugs out" test, the cabin pressure was tanked up to around 22psi of PURE O2.
The used pure O2 back then, because they were worried about them getting the bends & they didn't want the added
weight of a nitrogen tank. Also, since everything floats, they had YARDS of Velcro all over the place. I remember
watching a test. Normal air, pressurized and igniting velcro. Nothing happened. Then the pure O2 pressurized,
and the spark caused the whole thing to catch fire. Pure pressurized O2, LOVE flames along with the flammable
Velcro. With the dual hatch design, the inner hatch pressurized outward, once the fire started, the hatch sealed
tighter & tighter, making it impossible to open, until the safety valves popped open. By that time, they had been
overcome by smoke, lack of breathable air, and had been asphyxiated.
I remember the days after, and the funerals. Sad...
A few years ago, they found the Mercury capsule of Grissom's, and took it to the Kansas Cosmodrome in Hutchison, Ks.
After cleaning it up, they found out that the hatch "just blew" as Grissom had claimed all along. The switch was still in
the off mode (it was a one way switch). Also, every Mercury astronaut had a distinctive red spot/bruise on their wrist, where they
smacked that button (it required a LOT of force). Grissom had NONE.
Had that hatch not "just blew", who knows...that fire might have allowed them to blow the hatch and escape.
One positive outcome was it changed the mindset at NASA. They had "go fever" and finally put on the brakes, took a look
at what they were doing and had a change of attitude. Gene Kranz, after the fire wrote two words on a blackboard, to NEVER
be erased..."tough & competent". He & Kris Craft redid how mission control was run, and they never had an issue. Even when
Apollo 12 was hit by lightning, or when the Apollo 13 explosion happened, they did what he always dictated, WORK THE PROBLEM.
A lot of good came out of that tragedy