I am 40-something and rode Mission:Space five times over two days without any ill effects. I previewed the ride for my otherwise fearless DD11, who had read too much about M:S beforehand and was afraid of feeling closed in. After I reported back, she went on it and loved it. Let me add that I don't like small enclosed spaces myself, but I did fine on this ride. The screen is *not* six inches from your face as you might have read, but more like a foot. And the continuously blowing air, and visuals, and audio keep your mind occupied.
This was my first trip to WDW since 1972, and M:S was definitely one of my favorite attractions.
This was my first trip to WDW since 1972, and M:S was definitely one of my favorite attractions.