This. If you look sit up front and look carefully you should be able to see the track for most of the ride.
@SpiffyScribbles , you sound just like me before I rode it. I rode (and loved) rides like Thunder, Splash, and Test Track many times, but avoided Space Mountain because of all the fear I built up around it.
One night I finally plucked up the courage and rode it... and realized it was just Thunder Mountain in the dark. I've since ridden it many times and have never had any problems or feelings queasiness afterward. Even the "big" (?) drop isn't what it used to be with the brakes that slow the vehicles down. Ride Thunder Mountain with your eyes shut and you will have a VERY similar experience to Space Mountain.
I'm sure you'll be fine.
P.S. I'm also of the opinion that the front seats are tamer than the back, so that may be another incentive to ask for the front.