Most importantly, humans react spontaneously to the exploration environment, bringing instant creativity to bear on any new circumstance, opportunity or problem. Discovery of the critically important orange pyroclastic glass during the Apollo 17 mission illustrates this fact in spades. And, if any of the human field geologistsreading this page had been exploring Mars in place of the recent pair of rovers, they would have quickly resolved any doubt about the nature of the outcrops. They would have explored far more terrain, integrating their findings into the big picture of martian history. Human explorers would have been able to test the hypotheses that Opportunity was exploring sulfur-rich evaporites or the oxidized remains of the martian equivalent of an “epithermal” sulfide deposit, confirming or rejecting either idea in favor of a better one based on close observation and judicious use of a geological hammer.

He concludes with three arguments for human space exploration beyond science.