Sure if you want to
I don't really have a problem with cooperation, but it's not a must. I saw a show on TV several weeks ago about a trip to Mars. The commentator said that no single country could do it alone. That's 100% garbage, any developed country could easily do it alone. They seem to confuse the lack of will with the lack of ability.
It's this belief that only a team effort can make progress in space that's gonna cause us to be in for a rude awakening. The Chinese are going to go to the Moon, and then else where, and they're not going to wait for us.