Re Asteroid strikes, I once got hit by an asteroid whilst experimenting with a 1-sq base separation ICS strategy. It wasn't pretty afterwards. I guess I could've recovered but I was playing momentum style on a large map and this just removed all my momentum. I was far ahead at the time....
Moral of the story: if you really wanna go for rapid 1-sq ICS, bear in mind that an asteroid will dust nine cities straght off...