Robert Zubrin (left) and Robert Park debate the role of humans in space exploration at the Ethics and Public Policy Center headquarters on February 5. (credit: J. Foust)

Seeking a rationale for human space exploration

by Jeff Foust
Monday, February 9, 2004

It would be difficult to find two people whose opinions on human spaceflight are farther apart than Robert Park and Robert Zubrin. Park, a physics professor at the University of Maryland who is perhaps better known as the director of the Washington office of the American Physical Society and author of their “What’s New” weekly newsletter, is a staunch opponent of human spaceflight, arguing that robotic missions can do science just as well and for far less money. Zubrin, founder and president of the Mars Society, is an equally staunch supporter of human space exploration, arguing that, if anything, the new Bush space initiative takes too long to send humans to the Red Planet. Their polarized viewpoints made the two popular spokesmen when the media or Congress needed someone to argue for or against human spaceflight.

Although the two have been on radio programs together to discuss space issues, the two had never debated in person before last week. On Thursday evening the Ethics and Public Policy Center (EPPC) brought together Park and Zubrin for a 90-minute debate titled “Worlds Beyond Our Own: A Discussion of President Bush’s New Vision for Space Exploration”. The event attracted a standing-room-only crowd of about 75 people in the EPPC’s downtown Washington, DC, offices, including a number of people from NASA Headquarters and several Congressional staffers, eager to see these two square off. The arguments made by both during the debate were predictable, and it’s unlikely very many people left the debate having changed their minds in either direction. The debate, however, highlighted a larger issue that the Bush space initiative—or any other future government space endeavor—has to face: the difficulty in developing a rationale, a set of reasons, for embarking on this venture that will pass muster with the American public.

Humans, robots, and science

Many of the differences between Park and Zubrin have centered upon the role humans on Mars can play in scientific investigation. Park has argued that, in essence, humans are overrated: robots can perform the same quality of science as humans on the surface of Mars, at an order of magnitude lower costs. Zubrin, on the other hand, has claimed that humans alone can perform the type of science required to answer some of the critical questions about the planet, including whether life one existed, or exists today, there. The two spent much of the debate describing their positions on this issue and criticizing the opposing viewpoints.

The central thesis of Park’s argument is that space exploration, while important, is simply best left to robots rather than humans. “We judge the success of society by the extent to which tasks that are dangerous or menial are done by machines. Space travel, I have to tell you, is both menial and dangerous,” he said. “Dangerous for obvious reasons. Menial because they don’t really fly that ship. The robots fly the ship. They’re just expensive passengers, terribly expensive.”

“The usual factor that’s used to do anything in space is that it costs at least ten times as much to do it with a human as it does to do the same thing robotically,” Park said. “I think it’s closer to 100.” Park said that sending robots instead was “more democratic” because everyone could participate virtually by watching the images and other data returned by the spacecraft. “I feel like I’m along on the mission. This is, in fact, the way I think that exploration will be done in the future and it makes a hell of a lot of sense.”

If humans were to go to Mars, he argued, they would be capable of doing no more than robots, and perhaps less. Robots, like the Mars Exploration Rovers currently on the planet, have better sight than the human eye. “If a human were on Mars, what else could he do?” Park asked. “On Mars, he would be locked in his spacesuit.”

Worse, he said, after Mars there would be no place else in the solar system humans could travel to. “If we insist on exploring Mars with human beings, that’s the end,” he claimed. “In our solar system, every place else is—the gravity is too great, the temperatures are too high. Mars is just about it.”

Zubrin, naturally, was not swayed by those arguments. He was, in general, far less impressed with the capabilities of robotic missions that Park. He noted that, for example, fossil hunting on Earth requires a combination of arduous journeys to reach interesting sites and delicate, dexterous handing of rocks at those sites to look for evidence of fossils. “This is way beyond the ability of robotic rovers like Spirit and Opportunity,” he said. “You could parachute 100 Spirits and Opportunities into the Rocky Mountains, and you would not find a dinosaur fossil.”

Robots in general, he concluded, are simply not sophisticated enough to perform even simple tasks, let alone search for evidence of life with the same degree of sophistication as a human. “There is not a robot on this planet that you can send to the grocery store and pick up a bag of unbruised apples,” he said. “So, if they can’t do a trip to the grocery store, how’s it going to explore a planet?”

Zubrin also pointed out a simple solution to the problem Park noted with humans encumbered by spacesuits and thus not able to, for example, directly touch a rock. “A simpler approach is just to bring the rock inside the hab [habitat],” he said. “Then you can hold it in your hand, and look at it, and do absolutely everything that a field geologist on Earth can do with it.”

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