I'm stumped now, reached the habitation area and I THINK i'm meant to be looking for a chess piece, as one was used for a similar purpose earlier, but I can't find it. 

I can open the security guy's room, I can open the engineering guy's room, I've found a tape which shows the red matter when inserted into a VCR but I'm stumped for progress. 
Can anyone who has played this game give me a hint please? I don't want to actually look up a guide and spoil it so I figured some of you lot must have played it, the game has been out a while afterall.