Dastardly

I see, I was indeed paying more attention to the volume than the mass, thanks eveyone for your help!

I'm curious about the balancing of the nerva engines- I have been trying to use them in various configurations, but I am consistently finding I will get almost half the delta-v as I would from a hydrogen or hypergolic design of similar mass. Am I overestimating the nervas abilities, or is this something that needs to be worked out yet? Sorry for the topic change, the centrifuges are looking great!

Has the hab-D been removed in the new update? Sorry if its a stupid question, but I can't seem to find it, and I was planning on using a couple of them on my maned Duna mission, lol. I am also having trouble finding the airlocks... Did I install it wrong or am I just being an idiot? (or both? That's also possible...)