After the Shuttle program finishes NASA will start aiming at the moon and possibly mars.
I live in houston and my wifes dad works as a saftey manager at NASA, from I can tell you Mars is definantly not on the agenda....yet
You are correct about the Moon, however he was telling me that they are presented with the problem of what kind of space craft to develop to travel back to the moon. With the presidency not backed behind NASA as kennedy did back in the 60s the administration will have a hard time arguing for a one launch, one mission space craft. The space craft, like the saturn 5, will have to carry enough fuel to not only escape earths gravity, but also orbit, and as well as the moons orbit. And the reason why the Saturn 5 rocket was so big was to carry the fuel needed to escape earths orbit, if you look at the saturn 5 diagram only about 5% of the rocket was for the actual astronauts and equiptment to carry out the lunar landings, the rest was space to carry fuel. The new model of space crafts that are being developed to replace the shuttle would not be able to carry anywhere near enough fuel to go to the moon and back.
So the problem is gaining enough funding from the government of today, and in todays economy, to research and develop a new space craft. Not saying its another saturn 5 rocket, but the same idea on the basis of letting parts that hold the mass quanities of fuel to be destroyed. A smart person would say that the parts should just stay on the entire flight, and have it refuel, well let me put it to you this way...try to re-enter the earths atmosphere with a craft the size of the saturn 5 and expect a smooth re-entry without any break ups. It would be next to impossible, the bigger the craft the more area of something to get hit by a small rock and jepordizing the entire mission as a whole. Thats why the parts were supposed to be broken off after takeoff.
Just sit tight, the moon is definantly a possiability IF NASA can get the funding for research and development on a new space craft...for now all thats going to change is the shuttle.