I find Hard Science games to be hard to sell becasue most players don't want to worry about gravity, air pressure, etc when they game.
They want drama, romance, gun fights, etc.
Now, how in the past have you as GMs taken elements of Hard Science into your game but not overwhelmed your players with it? How do you sell this idea to your players? What is the upper limit on real life vs. game life you can use?
Thanks.