tbeard, if I may ask here, you mentioned in another thread that you don't use contra-grav vehicles like the air/raft, instead favouring vectored thrust, which I like.
What powers your spacecraft? What kind of maneuver drive do you use. Don't you see a disparity between having grav plates but not contr-grav....? Wouldn't any grav manipulation lead quickly to unviversal grav manipulation ... maybe I don't see the fine details here...
Originally, I assumed a highly efficiency Nuclear Thermal Rocket, using (ideally) hydrogen as the reaction mass. However, unrefined fuel often contained methane, which had the delightful effect of contaminating the fuel rods with carbon, reducing power. So when the coolant/cleanser plumbing malfunctioned (or was damaged in an attack), a crewman had to periodically don a rad suit and scrub the carbon off the fuel rods with a brillo pad.
As an aside, power plants in my campaign were originally assumed to be fission, not fusion. Jump fuel was
reaction mass (IMTU a ship had to maintain a very modest amount of thrust in hyperspace to get anywhere, hence the reaction mass). The labels changed, the design rules and systems did not.
Subsequent research led me to discover that solid NTR drives would leave a radioactively contaminated residue behind, which would make planetary landings problematic. I also decided that having fusion power widely available would make my colonial military forces plausible. So, with a stroke of the backspace key, I decided that the drives were fusion and that the maneuver drive was a fusion drive, probably an "intertial confinement fusion drive" (i.e., a pellet of fusion fuel is bombarded on all sides by strong pulses from laser or particle accelerators. The inertia of the fuel holds it together long enough for most of it to undergo fusion.). <sigh> I really liked those brillo pads...
In any case, my objection to widely available grav tech is that it is a dramatic buzz kill. I get tired of having to come up with clever ways to deprive players of their air rafts, grav belts, etc. Plus, I *like* things like helicopters, tiltrotors, ornithopters and dirigibles. All would be obsolete with Traveller style contragrav.
Finally, I like the military aspects of having no grav tech. Unlike Traveller militaries, which can mount everything in grav vehicles and zip all over the planet, militaries in my campaign have to make harder choices -- highly mobile light infantry vs slower heavy armor? How much air transport (or sealift) will you need? Etc.
EDIT: I *do* have artificial gravity, primarily so that I can make use of the numerous free deckplans available on the interweb. I haven't bothered to come up with a rationale for why it works (or why you can have artificial gravity but not contragrav propulsion).
