I was there with my DS 12 last summer, and we must have ridden Mission Space 12 times! There was a single rider line (hopefully there still is), which has a much shorter wait. Last summer we never did Fastpass, we just got in the single riders line, and since there were only 2 of us, we always ended up together. It was great!!
We're going again in a week, this time the whole family!! We will probably try Fastpasses so we can ride together the first time, then do single riders again.
Have Fun!
p.s. - make sure you stop to play the game after you exit the ride. Any kid who likes video games (even their Mom!) has a lot of fun doing this.