strong leadership will get you through a few weeks but not decades
as for when they landed, there used to be white dudes running the show over there before and there was a prophecy that they would return
Discussion
also, just to point out, you have to scuttle a ship to all die... a spacecraft just needs a big enough hole that doesn't get patched up soon enough, and even then, how long you gonna survive if all your air is a cloud in deep space, spreading outwards at half the speed of sound