Also a +1 sector bonus seems very small... and doesnt make it worth the effort. And it doesnt make sense to build it on a planet... at least not a planet with an atmosphere.
Maybe. But consider the advantages:
You can launch instant (one-turn) attacks against targets +1 square away.
You'd also get +1 movement in combat while defending the planet.
And you can always increase the ability amount to whatever value you feel is fair.
True enough.. all in all I think this could be incorperated to a new but minor tech tree.. maybe working around system-scale activities.. from asteroid mining, resource moving, etc... I dunno.. I will give it more thought over the next few days.