And I don't believe we are going to be able to study the universe as much as it needs to be studied using only robot probes. There is not a geologist on Earth that you could convince that he could do just as good a job with a robot and camera substituting for him as he could on site with a hammer and his own eyes. Ask Jack Schmitt. ... Tom wrote.

Another point of view (his enthusiasm and honesty can be catchy):

At Mars Mission Control in Pasadena, Calif., the chief scientist for the rover Spirit, which landed a week ago, said he's all for human expeditions.

''There's no greater fan of robotic exploration than me. But the best exploration, the most complete exploration, the most comprehensive exploration is going to be done by humans,'' said Steven Squyres of Cornell University.

From: Chicago Sun-Times. (moderate annoying pop-ups).