Quonset Point submarine sections and Soviet satellite reconnaissance

Submarine hull sections fabricated indoors or under tarps at Quonset Point because Soviet satellites could measure wall thickness from space, revealing classified diving depth. Used as an aside about how hull thickness encodes operational capability.

If you go down to Quonset Point when they're building the sections, which are just vertical tubes, they do it indoors. If they have it outdoors they put a big tarp over it. Because the Soviets have satellites that can measure the wall thickness from space. They want to know if it's three inches thick or a quarter of an inch thick of the outer hull, because then they know the diving capability, which is classified. I know but I'm not supposed to know, because I didn't get a security clearance to learn it — but I can't tell you, which you probably already know anyway. Right? Approximately. So it is more than half an inch thick and less than four inches thick, but they do have foundations in there that are four inches thick. That's typically for about a 30-foot-diameter submarine.