Ok i dont know if this was mentioned here already but i just accidently found out where the Fallout 3 devs took their inspiration for the design of the Valiant 11 lunar lander from.
Nope, its not a completely imaginary design.

It seems that they used the proposed soviet lunar lander LK (Lunniy Korabl - russian for Lunar Craft) as design inspiration.
They just changed a bit here and there by combining it with parts of other proposed soviet moon lander designs. There were several proposed design for landers but the LK lander was the only one that was built and tested in space.

It never went to the moon as the soviets did not managed to make their equivalent to the Saturn 5 , the N1 rocket work.

In the Museum of Technology, you may have wondered how three men were supposed to fit into that small thing. (Captain Richard Wade, Captain Mark Garris, and Captain Michael Hagen of the USSA)
Well, thats because the F3 devs did not changed the real size of the LK lander for their Fallout universe Valiant 11 lander.
Maybe they should had.

The real LK lander was so small as it was designed to take just one soviet kosmonaut to the surface of the moon and not two people like with Apollo 11 or even three like with Valiant 11.

Here is a sketch of the LK lander in size comparison to the "Eagle" of Apollo 11

http://upload.wikimedia.org/wikipedia/commons/9/92/Manned_Moon_landers_LK_vs_LM_-_to_scale_drawing.png

Nice find. It's interesting they would use a russian design for an american space craft. I guess they wanted to use something besides the Apollo 11 lander, and the LK was from around the same time.

Wow I never new that. Nice find man!

Nice I too wondered how so many people could fit into that thing.