Good ways to limit space travel?

[Calvin]

I think I'm probably going to use the jump drive option.

The trouble with the constant 1g is that if something is out of range for the sup to constantly burn during the trip, then all it needs to do is not constantly burn. Do it for half/one quarter/etc the time and you still arrive just fine.

The radiation idea is good, both the lethality and the interference with communications, it was actually what I was imagining. The jump drive option just happens to solve the second issue of in-system travel without the 1g drive. It also has less of a "footprint" than the radiation thing, which might raise other issues.

These don't exist in a binary system with more-or-less equal masses. You need the smaller mass to be less than ~1/25 of the larger mass for the equilateral points (L4-L5) to be stable. The co-linear Lagrange points (L1-L3) do exist, but stable orbits around them (halo or Lissajous) will be extremely difficult to find and maintain.

Don't exist at all? Or do they have the same instability that the L1 through L3 normally have? The plan is for two 1.2 solar mass stars and one 0.6 solar mass star. I don't suppose there's some other set of gravitationally stable points to use?

I would assume that both systems were colonized from somewhere else at nearly the same time, not one from the other. That gives you a space race to drive development, even if it isn't strictly economical. If your default drive is space sails (photon or magnetic), your "breakthrough" could be the fielding of laser/maser or particle beam boosters.

The plan is actually to have the larger of the two systems (It kinda just happened during system generation, I ended up with several more orbits to fill on the first of the two 1.2 solar mass stars) be home to this campaign's "Earth". During TL8 a colony ship was sent to the second star where a second habitable planet was found. In the vein of the British colonization of Canada the colony continued to get more or less reliable support to help it grow. It also achieved independence in the same way Canada did around late TL8, early TL9. The difference is that now the mother government is sort of regretting letting go so easily. The first star is home to a Representative Democracy with heavy corporate influence. It's in-system (in-star?) outposts and colonies each with a corporate government. The second star is home to an Athenian Democracy, transitioning more and more towards a Cybercracy, limited only by how powerful they can build their computers. The idea is that the mother government has a much better developed industrial base, with a lot more natural resources. The cybercracy on the other hand has fewer resources (though not a massive shortage), but have gotten better at using them effectively and are somewhat more advanced.

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As a total aside, the Space book is really great. I got pretty much all of the inspiration from the setting as I was rolling up the three star's planetary systems. I got one large system with a bunch of good resource rolls, that later in generation got a lot of Standard or Delayed rolls for TL. The second system had fewer bodies, but got very good rolls during TL generation. No Delayed and most of the Advanced. Finally I got a third star that has a gas giant in the habitable zone (Using eccentric gas giant layout) with a whole bunch of habitable moons.