To buy the docking module, you have to go into "misc" equipment in the purchase screens. Docking module doesn't ever show up on the R&D screen - you have to run unmanned docking missions then manned docking missions to get the percentage up. I usually do about 6-8 unmanned with gemini before trying manned.
And yea, I killed a lot of astronauts sometimes. It was worst in the floppy version but even recently in the CD version I killed 15 yesterday - and still barely won landing in 1974
