I doubt that we could even land a man on the moon today, as the system would be so complex that a snafo would surely arise. Proof of this are mars landers which failed, and a lot of blunders with NASA satelites, also throw in space shuttle failures,
It is true that we lack the hardware (propulsion, not navigation) to land a man on the moon today, but that is more a reflection of politics than science--we have no \"Evil Empire\" to beat in a space race.
However, it is unfair to cite Mars lander problems as evidence of incompetence at NASA--those were unmanned probes where the risk/benefit considerations favored \"go,\" even at the risk of destruction, rather than \"no-go\" because of the risk of life. Those catastrophic failures occurred during descent/landing, which was a sufficiently insurmountable challenge on the moon--far closer than Mars--as to prevent the USSR from ever achieving a soft-landing.
The shuttle failures have both occurred because known problems were ignored in a drive to stay on-time, on-budget, on-schedule in an inherently dangerous endavour which has seen much of its gee-whiz wonder, lofty goals, and public madate to \"kick Russkie butt\" eroded over time.
Oh well, perhaps space travel will become old world, and in the future we will just simulate space exploration on a computer.
How will we simulate discovering the unknown? :wink:
