Exploring Mars: Astronaut Versus Astrobot

Money aside, many other facets make robotic exploration both more feasible and attractive than manned endeavors. Robots don’t have families that they will miss (or that will miss them in any profound manner). They don’t need to be shielded from cosmic rays like people do. What’s more, the technology that allows robots to rove around Mars and do other scientific legwork is constantly improving.

“Robots get better every day, and humans haven’t changed appreciably in 160,000 years,” says Park. He maintains that astronauts would have a limited capacity to do research given their confinement to spacesuits on a desolate, frozen desert of a planet. Solar-powered robots, on the other hand, “live on sunshine, and they don’t complain about the cold nights,” he says.

Another reason why advocates say it is better to send robots is the concern that humans may inadvertently contaminate Mars with life forms from Earth. “You can’t look for life with life,” argues Park. As a simple example, Park points to the copious amounts of bacteria-laden, excretory waste that astronauts would generate on an extended stay on Mars. If accidentally released into the environment, these microorganisms could infiltrate Martian soil around a base camp. Even assuming the microbes couldn’t survive on Mars, their presence could still skew lab results and potentially void the entire hunt for extraterrestrial life.

It is possible that machines could also accidentally bring stowaway creatures from Earth with them, such as super-hardy, spore-forming bacteria. But the chances of this occurring are considerably less than with microbe-ridden humans roaming about.

“My guess is that astronauts would eventually find life on Mars,” says Park, “and that it would end up looking very familiar.”

The Human Touch

But as rugged and comparatively cheap as robots may be, they can only do what they were programmed to do. “The scientific gain is limited to the design parameters of the robot,” says Sulzman, the NASA space radiation expert. “Take Phoenix, for example—it can’t move and it has an eight-foot arm. Suppose its cameras show that the most interesting thing is 10 feet away?”

The relative lack of mobility hampers the currently deployed Martian rovers, named Spirit and Opportunity. In the four and a half years that they have been there, they’ve traversed only about five and seven miles, respectively, says Chris Carberry, the executive director of the Mars Society, a pro-exploration advocacy group based in Lakewood, Colo. While Carberry says he greatly admires the accomplishments of robotic missions over the years, he points out that “a human crew could cover the total distance those rovers have in an afternoon.”

The communications delay that will hamper future Martianauts in corresponding with Earth also hinders robotic probes now. But unlike these metallic explorers, humans can think for themselves and act quickly in an emergency situation. If a big dust storm comes blowing through, for example, an unthinking, largely remote-controlled robotic craft may be lost, whereas humans could take appropriate actions in real time to preserve the mission and themselves.

Supporters also argue that humans can perform science experiments and manual operations with ease compared to a remotely operated robot. In the little over two months that Phoenix has spent on Mars, it has dug several shallow trenches, analyzed a few batches of soil and completed a few other basic tasks like viewing dirt granules under a microscope. “A human with a shovel digs as far as Phoenix ever could in just a couple scoops, and then the lab work is easy,” says Carberry.

In the end, one of the most compelling arguments for sending humans to Mars is public interest. As NASA is taxpayer funded, to some extent the organization is beholden to what the general public wants—and robotic missions simply cannot generate the sort of buzz that putting people in space can create. “As humans, we would like to see humans doing these things,” says Sulzman. Even Maryland’s Park acknowledges that public morale is tied to the “spectator sport” quality of manned flight.

“Ultimately,” says the Mars Society’s Carberry, “the power to inspire is one of the most important parts of space exploration.”

Also on Scienceline:

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