As well as the long-running story of E3's dispatching the disk and re-claiming it after it's sortie, is the story of the E3 itself.
It is well known that radiation affects the human body adversely, so the E3 is twin skinned with sheilding in between. (Hence the lack of windows.) This serves 2 purposes. It also allows the inner cabin to rotate, so when it enters an orbit, the inner cabin rotates, within the outer, to allow the floor to stay flat.
As believed by several USAFE members on board a jolly I was on in April 2004 over FYR.