I still need to read The Years of Rice and Salt, I love his historical stuff like Galleleo's Dream and Shaman too.

And the campaign was definitely not a hard sci-fi setting, I just took the concepts of generation ships, self-supporting biomes, and a war on such a ship and used those as my starting point (sprinkled with a bit of Battlestar Galactica and Rendezvous With Rama). I used the Apocalypse World system (my very favorite), and a big part of that game is having the players set up their own corner of the lore and setting; it came out as something quite unique and compelling. We started the story about a hundred years after a failed revolution blew out about half the ship with the survivors scrapping over the remaining resources. Apocalypse World is more narrative focused than simulation directed though (and tends to go PVP in the endgame), so it's not for everyone.