re:Robot v Human
Well, sending humans to Mars costs 100 times more than robots and thus takes much longer to realize.
Robots DO rely on humans for all kinds of on the spot decisions, there is a human interface even with robots being the tools on the spot.
Robots get better, cheaper, smaller, faster all the time.
Robots have no daily needs like humans.
I'm intrigued by the argument that's coming back all the time for the MER case: humans could have explored in 2 days what it took 6 months for the robots to accomplish....
Well, there's an answer: build mobile, agile and fast robots...The pace at which robots evolve is so impressive, I'm sure the argument will become more and more favorable to robots.