My son is 7. I went on Mission Space back in 2009 but went on the "more intense" version and it wasn't really bad for me. But I've never been on the other version. I am thinking it might be too much for him but wanted to see what age your kid(s) have ridden it.
EDIT - To clarify I would not be considering the more intense ride for him.
EDIT - To clarify I would not be considering the more intense ride for him.
Sometimes you never know until you try it....