As shown at far right in this diagram from wikipedia, the Delta IV Heavy is a US rocket vehicle capable of placing 23,000 kg into low earth orbit.
This happens to be almost one fifth of the payload capacity of the Saturn V Moon Rocket of the 1960s which placed American astronauts on the Moon. So . . . could six Delta Heavy’s do the work of one Saturn V in orbiting the components of a present-day lunar mission?
If so, then we don’t have to develop a new heavy-lift launch vehicle — and as a consequence have to spend tens of billions of dollars over the course of a decade or more — before going back to the Moon. We can use the existing Soyuz design for an American space capsule, and existing Delta Heavy hardware to place lunar mission components into low earth orbit, and it can all happen for a few billion dollars in the next few years.
The main thing is building a new lunar lander module, but that shouldn’t take long. Because if it does, the Chinese will beat us!
Engineer Zero 
Actually it wouldnt even take a Delta heavy. Why not buy a mod. Soyuz from Russia, as they are forsale, then place simply a kicker stage into orbit, with which it could dock. With a beefed up heat shield, for the high speed return, a lunar orbital mission could commence. This could be done very quickly, and I personally do not know why the Russians havent done it? A mission of this type would boost our desire to leave LEO, which is over due.