^Oh god please, not that stupid "build the Enterprise" crap again. That guy's a loon.
Where did you read about building "space docks on the moon"? Not gonna happen in any near future time frame if at all. Why build them in a gravity field when you can put them in orbit?
Don't current satellites have impulse thrusters? Low power ones I think.
Hall effect ion thrusters have been used on some satellites in recent years for station keeping. They're not the same as fictional "impulse engines".