It might happen in the 2020s, with ESA, Russia and China especially keen. China especially has several robotic missions in the near future, building up to sending humans there eventually. Robotic missions to the Moon will resume as soon as next year with many Google x-prize contenders. I think myself that it’s good to have a robotic exploration phase first. And most of the modern ideas have robots operated telerobotically from Earth and also working autonomously building the first bases on the Moon before the humans get there.

I think the ESA is the most advanced in their plans in some ways, with their ideas for a lunar village and ideas for 3D printing the habitats. It’s the most international of all the ideas, many nations joining together with separate habitats in a lunar village with shared resources as well.

Bigelow aerospace is developing inflatable habitats that would be useful for a lunar base also.

NASA is the one exception here, they are so focused on Mars and they think the Moon is a distraction for humans. Though that’s just since Obama. The Bush administration wanted to go to the Moon first and we have no idea what the next president will advocate as none of them so far have said anything either way about a return to the Moon. They are building the large SLS but it’s first human flight will only do a loop around the Moon. Will just have to see what the next administration think.

But whether they send humans to the Moon or not, NASA also are involved in sending robots back to the Moon in various ways.

So far nobody has any definite dates for sending humans back to the Moon, but there are reasonably definite dates for various robotic missions. In my “Case for Moon First”, here is my summary of the robotic missions for the near future: Case For Moon First - ROBOTIC MISSIONS TO THE MOON, ALREADY PLANNED, OR NEAR FUTURE