With the first presidential debate coming up on Wednesday, it is striking — if not surprising — how bland and predictable the candidates have been in discussing America’s role in space.  True, President Obama and his challenger, Mitt Romney, each responded at length to a question posed by ScienceDebate 2012 about the nation’s goals in space. But while both emphasized the importance of space exploration, with Mr. Obama briefly mentioning the need for monitoring the Earth, neither candidate, and neither party, has addressed the scientific question of why we want to bother with exploring space.  The issues that were addressed explicitly — national pride, technological innovation, national security — may be interesting and relevant, but they are largely spinoffs of what is usually claimed to be a grand scientific adventure. This is not a new phenomenon. Tapes of John F. Kennedy in the Oval Office released last month made it clear that from his perspective, science was irrelevant to the space race he proclaimed back in 1962. What counted was beating the Russians to the Moon.  Maybe scientists should simply face reality and accept that science doesn’t play a central role in the government’s equation. Yet as much as GPS navigation is of great help to me, and as fun as it looks to be an astronaut floating around the International Space Station, I suspect I am not alone in being far more excited by the images produced by NASA’s unmanned space probes — which do the science, after all.  For example, every time I see a Hubble Space Telescope photograph showing hundreds of galaxies, each containing billions of stars whose light has taken billions of years to travel to the Hubble cameras, it inspires me to ponder whether they may have been surrounded by now-frozen planets harboring long-dead civilizations.  And closer to home, I have to admit that I am in love with Curiosity.  When that NASA rover landed on Mars this summer, I was privileged to be near the deep-space antenna in Tidbinbilla, Australia, where the signals from Curiosity were beamed before they were forwarded to the Jet Propulsion Laboratory in Southern California. I haven’t been as excited to watch a spacecraft land on another body since I was a kid and stayed home to watch Neil Armstrong and Buzz Aldrin land on the Moon.  Maybe I was more excited about Curiosity, not just because I was closer to the action but because the astounding complexity of the landing was achieved without any direct human intervention, in just nine minutes — considerably shorter than the time light takes to travel from Mars to Earth. Knowing that the spacecraft had either landed or crashed 15 minutes earlier made the anticipation seem even more pronounced.  And that is why unmanned space exploration seems to me much more exciting and scientifically worthwhile than human spaceflight, especially at a time of restricted budgets and nascent technology. Sending Curiosity to Mars cost only about 10 times what it would cost to make a movie about sending Bruce Willis to Mars — and perhaps a hundredth of the cost of actually sending humans there and back.  Many of my colleagues are geologists who are not shy about pointing out that a human geologist could do in a few days what Curiosity may do in a year or two. But we aren’t likely to send geologists there anytime soon — and if we did, they wouldn’t be able to stay much longer than a few days, while Curiosity can silently and gently move about the planet for a decade or more, powered by its plutonium generator. Moreover, by the time we might get around to sending humans, in two to three decades at best, robots will have advanced to the point where they might easily compete in real time.  In terms of scientific payoff, it makes far more sense to spend money on Mars rovers, since 99 percent of the cost of sending humans into space involves keeping them alive and getting them back, leaving precious little for science.  But cost aside, I find the adventure more exciting. The thought of Curiosity braving the Martian days and nights alone — rolling slowly along, zapping rocks and occasionally picking them up, sending stunning, detailed photos of an alien terrain like a tourist using a cellphone to communicate with loved ones back home — is both heartwarming and bittersweet. Every time I go to the NASA Web site and open up a new photo of the day’s tour, I feel as if I am there. If it takes a year to get to the base of a nearby mountain, who cares? I will enjoy every step of the journey even more because it is a gentle one.  Over the coming decades we may send more robotic explorers to even harsher climes, maybe to explore deep oceans on Jupiter’s moon Europa, or to search on comets for telltale signs of life’s origins. We may send powerful telescopes into space that may one day photograph distant worlds that may harbor life. For me, sending these probes where no man or woman has gone before is every bit as thrilling as imagining Captain Kirk being teleported down to an alien surface.  And while such probes may do less for national security than sending satellites to orbit the Earth to spy on our friends and enemies, I am reminded of a statement by Robert R. Wilson, the first director of the Fermi National Accelerator Laboratory. When asked during a Congressional hearing whether the particle accelerator would aid in the defense of the nation, he said it would not — but it would help keep the nation worth defending.  Lawrence M. Krauss is the director of the Origins Project at Arizona State University, a professor in its School of Earth and Space Exploration and a founder of ScienceDebate 2012. His books include âThe Physics of Star Trekâ and, most recently, âA Universe from Nothing.â
To one physicist, exploring space with remote technology like the Mars rover seems more worthwhile, and more exciting, than human spaceflight.