Mission: Space is a motion base ride in Future World - Mission: Space at Epcot. While it's not a "must do," it is also recommended. The minimum height to ride is 44 inches.
Blast off to Mars in this elaborately-decorated pavilion
Do note that this is a centrifuge-type attraction, based on the spinning machines used to train astronauts to handle high G-forces and weightlessness. On this ride, you will experience 2.5 Gs of force over a sustained period, followed by simulated weightlessness. If you have high blood pressure, are significantly overweight, or have any history of heart problems, you should not ride the spinning “orange team” version of the ride. Choose instead the “green team” option, where your ride vehicle does not spin and you’ll experience none of the extreme G-force or simulated weightlessness. The capsules are a tight fit either way, so anyone with claustrophobia should just skip the whole thing.