...I think I'm probably drunk right now. First I confuse armour ships with anti-armours, and now it's gravity drills and mass drivers...
Eh, for mass drivers I would just play as if it was not there, save for avoiding the use of starships. Raid starships can be useful because they aren't 1HKO'd by them (I believe), but I generally cap the planet before doing anything with a planet that has a mass driver.