Space-A is for both active duty and retired service members. Although I am retired now, I haven't used it since I was active duty, so I'm not sure how the waiting lists work on this side. I do know it is free for both active and retired along with their dependents. It's a gamble on availability, so if you have some place you MUST be by a specific time, I wouldn't suggest it. But if you have no time commitments, it's a great way to travel pretty much around the world.
I guess this leaves me out since I am not a retired or active military, my father is a WWII and Korean vet thought. It sounds like a nice option, I was checking the web site and it seems it is for military personal only.