Here are a few direct quotes from a lucky passenger who has ridden Mission Space.
"The official press release talks of "pulse-racing lift-off." This is not merely marketing spin. "Lift-off" is "pulse-racing," that's for sure."
"It's not all about the physical experience. Much of what makes Mission: Space brilliant is the psychological aspect. In this way the ride really does "push the envelope." There really is nothing else even close to this experience in a theme park. Many people who ride this attraction are going have sore cheek muscles from smiling so much before the ride portion of the attraction has even started. I've never been to a Space Camp, but I can't imagine a more thrilling experience for someone who wishes to be an astronaut than the Mission: Space ride at EPCOT"