So I am optimistic we'll be returning to the Moon within the next 20 years. The reasoning is that technology is advancing to the point where its less and less of a 'big deal.' The last remaining hurdle is 'on-orbit refueling'.<p>Today, the last remaining challenge of landing on the moon, is carrying enough fuel for a trans-lunar injection orbit into orbit, and then for the lander to land on the moon itself.<p>With modern launch vehicles, it is straight-forward to launch a moon landing mission as three components (command module, lander, and engine/fuel. And link them together in orbit. However, there is a significant penalty to not launching all at once into the correct earth orbit to later elongate into a trans lunar orbit. So a 'modern' mission actually would need <i>two</i> loads of fuel in orbit, one to move the whole assembly into a prepatory orbit, and then one to move from that orbit to the moon.<p>If we have on-orbit refueling then you manage a depot of fuel for the second step, and the sequence becomes launch lander, dock it with a tug. Launch command module, attach that to the tug. Move the tug (with its command and lander modules) into the same ecliptic as the moon's orbit. Then refuel, and <i>then</i> use the tug to move you to the moon.<p>By re-using the tug multiple times the costs drop dramatically. (like $100M every time you re-use it, that is a tug you didn't launch from earth).<p>People want on-orbit refueling so that we can have longer lived satellites. (there are perfectly serviceable communication satellites in 'dead' orbits because they no longer have the fuel for station keeping.)<p>Once we get that capability it won't be a question of 'will' to get to the moon, it will simply be a question of money. And there is enough disposable income amongst the young billionaires of the world that getting the money won't be an issue either.