posted 06-27-2021 07:28 AM
As a former US nuclear sub officer it is interesting to me to think about the evolution of the diameter of the hatch.The older nuke subs I served on had a hatch about 30 inches or so in diameter (the "people hatch," not talking torpedo/missile hatches). I believe Apollo's lunar module/command module hatch diameters were also somewhere in this range (29"?).
But I've read that the shuttle hatch was 42" in diameter and — at least in this photo — looks like it takes a couple of people to "hoist and heave." 
And of course the hatches on the space station can be quite large too compared to our older hatches from decades ago.
The logistics advantage of a large hatch is obvious — of course in the old submarines you'd have to make hull cuts to change out turbines and other large pieces etc. so the safety vs. convenience aspects were/are always in play.
posted 06-25-2021 09:41 AM
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