Differences from Comet / Real World

The speed of light is a lot faster. Radio communication across a solar system isn't quite as ungodly slow.
This is space opera, not science fiction. Don't think about the physics too hard.

You fall down when you take damage > hp. Make a death check to see if you're unconscious or unconscious-and-dying, and the death check is x5 instead of x3.
Speed is adapted from Seventh Sea, not Comet.
There's no base concept cost for shticks.
(but big shticks have to have disads, and little shticks can be "out of concept", and when you're buying a new shtick all your old ones count, not just the ones bought with eps).
Psi shticks are somewhere between magic and priest shticks; psi talents are more general than spells (and more expensive), but are required to use the shticks.
Toughness starts at zero, and comes only from items and abilities.
Normal people have stats of 3 instead of 5.
There aren't any mooks, except as special cases.
No splitting dice more than two ways without a shtick
Things you don't have skill in aren't necessarily for 9s.