Rode it....
I was very skeptical of the ride summaries and the opening times, but it was all true! We rode Mission: Space last Thursday, July 17. We stayed at the Hilton Grand Vacations and I posted some messages in the off-site hotels. This may or may not confirm to some people that I was in Orlando, FL.
Reading some of the summaries I figured I wanted to get to Mission: Space around 2-3pm. We went to Magic Kingdom first. In MK, I asked a Cast Member and he told me only about 10-15 people are allowed in at a time. This scared me, so off we went to Epcot.
Riding the monorail in gives you a great view of MS. It is right next to Test Track and from the monorail I could see that people were being allowed in to MS. I yelled it in the monorail. I was so freaked that by the time me and my wife got there it would be closed.
Nope, we made it in. Wow, what an awesome spectacle. I wish I could have enjoyed it more, but I wanted to make sure we got in. I asked a Cast Member what time they opened and they said 1pm, but that the ride can close at any time.
The Gravity Wheel is interesting, but doesn't stand out. The murals of astronauts was pretty cool, but than it got fake with the futurisitic people in space (e.g., first family in space).
The ride is definitely not for everyone. It is an awesome experience, but for me a one timer only. The rocket blast off, thruster burns, and landing are all similar to the movie Armageddon. People leaving MS who do not feel good can go to the First Aid location and rest in cots for free. The First Aid location was between Future World and the World Showcase.
I also confirmed CM previews were M-W, so thanks WDWmagic for guiding us right and advising us not to go until Thursday.