>>6
I thought they did. I'll assume they didn't for the sake of your question.
Honestly, I don't know. I believe they did land on the moon. If I had to guess, I'd say it's because there isn't any particularly useful reason to. I mean, yeah, we could colonize it or set up some sort of military base, but I'd imagine there are some international treaties against it.
>>7
I don't know what that means. A (very) quick google search didn't help. Would you please explain?