kT wrote:

That immediately comes to mind. Basically Krafft Ehricke envisioned
entering into the hydrogen tank with a space suit, from the capsule side.

On the Atlas that was the LOX tank.

I'm building a freaking capsule to go onto a five meter tank, so I'm
damn well going to install my hooks on the factory floor. It's a very
clear shot into the top of the hydrogen tank, and it's right there, I
can talk to Mitsubishi directly about the interface modification.

Unless you are going to go down a tunnel into the LH2 tank, you are
going to arrive at the LOX tank before you get to the LH2 tank, as the
LOX is on top on the ET also.
Due to it's higher mass than LH2 per volume, the LOX will end up on top
in pretty much any design you use, for balance purposes during ascent.
You want the CG as far forward as possible.

Pat