what is the biggest impediment for man to go to Mars?”
From a technical perspective, the biggest impediment is in the first 100 miles; that is the cost of getting the space vehicle into low earth orbit so that it may be assembled and sent to Mars. While the cost per pound to orbit may have come down, it is still quite expensive, and considering the duration of a trip to Mars, the need for a return vehicle, life support systems, etc., it would be a huge undertaking, with lots of engineering challenges, but nothing that can’t be overcome. The other question is do we have the political will to stick to a plan that may run over 10-15 years? With the huge deficits that this country has, it would be difficult to sell politically. An international mission may be more fiscally palitable, but getting the technology-savvy countries to work together over that period of time is difficult too.
