Brandon -

PPPPP
Seeing as the ride's already been tested, and there's no super-huge ugly towers, it's not a drop ride.
SlamminSammy - it will APPROXIMATE weightlessness. Disney is about telling a story. Often, it's an illusion, but it often works, too.
http://www.etcusa.com/ats/ats_gfet.htm
That's the company that was contracted to provide the simulators. Disney has a higher capacity version of those that I linked to. They can rotate on a second axis. They can APPROXIMATE weightlessness.
Trust me. This stuff gets thought up and rigged up and ridden and tested and examined and reexamined 40 billion times before an attraction is given the green light. It can be done.
The four rings are for the centrifuges. The second ring you showed was for one of the planets.
If you want to poke fun, go ahead.
Yes, I take these things seriously, and yes I follow them with great interest. I do want it to be my job one day, after all.