Maybe a little too quick now. You should need battleships and bombers to knock one down and it should take a long time. KNF had one battleship with 3 missile launchers take a pirate base from 55% to 0% in less than 2 hours. That's a bit quick. You should need multiple battleships and/or bombers working together.
Its pretty tight timeline for a defensive force to get together. And the base is mpossible to fortify since you're not able to dock with the shield up. Dunno yet.
Anyways... if you want something to be secure, park it next to a stationary battleship in a cul-de-sac.