Ignoring history? I'm sorry Larry but that is what you are ignoring by promoting a failed approach. What technical lessons do you claim will be ignored by setting Mars as a goal? There is no reason past technical lessons have to be ignored if Mars is chosen as a goal. There is no reason technology can't be tested incrementally once again where warranted.

Your whole premise is extremely questionable. We have already demonstrated the lift capacity needed to reach Mars. We have already had astronauts spend as much time in 0 g in a single stretch as they would spend traveling to and from Mars. We have already built life support systems with life spans longer than a Mars mission. We have built several generations of space suits for different applications. Space station astronauts have experienced radiation doses within a factor of 2 or 3 what would be expected on a Mars mission.

The remaining obstacles are miniscule compared to what we faced in reaching for the Moon. You keep evading that issue Larry. It's the key one that makes the incremental approach silly after all.

Name a single remaining obstacle anywhere close to the top 5 we had to face in getting to the Moon. We didn't even know if people could live or function for any length of time in 0 g for pete's sake. Closed loop life support is not one required in Mars Direct by the way. The recycle efficiencies required by Mars Direct seem reasonable to me and are no where near 100%. I don't know how they compare to those on the ISS however.

Regards,
Mark