To send humans back to the moon would not be advancing. It would be more than 50 years after the first moon landing when we got there, and we'd probably be welcomed by the Chinese. But we should return to the moon without astronauts and build, with robots, an international lunar base, so that we know how to build a base on Mars robotically.
Buzz AldrinOne of the major problems with long-term deep space human flight is the requirement for radiation shielding.
Buzz AldrinI believe that space travel will one day become as common as airline travel is today. I'm convinced, however, that the true future of space travel does not lie with government agencies -- NASA is still obsessed with the idea that the primary purpose of the space program is science -- but real progress will come from private companies competing to provide the ultimate adventure ride, and NASA will receive the trickle-down benefits.
Buzz AldrinRussia perhaps is still entertaining the possibility that the moons of Mars might have access to ice or water.
Buzz Aldrin