[imglorp]

The challenge with the "suits stay outside" model is that you basically need some kind of airlock between the suit hatch and the ship hatch. You might imagine both hatches get contaminated when the suit is detached. Then when you dock, that whole between-hatch space needs to be decontaminated before you can open the two hatches, because the outside of the suit hatch brought that stuff into the airlock.

Someone else linked to this: https://en.wikipedia.org/wiki/Space_Exploration_Vehicle#Spec...

edit: in that context^ search for "SEV suitport design" find NASA has written some docs on the matter, eg https://ntrs.nasa.gov/api/citations/20130013652/downloads/20...

[nomel]

It looks like that requires a panel to move out of the way. I was thinking more like "zipper" (probably more of a contiguous interface), so closer to zero volume when attaching, then it "unzips"/splits and pulls the back of the suit open, into the cabin.

    |
    |     /\ 
    | to |  |  
    |     \/

I don't see why an intermediate airlock would be required, except maybe for redundancy/safety reasons if the "unzip" process went wrong.

Since the inside of the suit is already at pressure, you could just pop it open and step out.

The near-zero volume of the coupling would make things much easier to clean/isolate.