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Is Mars Worth the Trip?
November/December 2004

In January, President Bush set a goal for America’s space program: return to the Moon by the year 2020 and establish a base there for eventual piloted missions to Mars. “We’ll build new ships to carry man forward into the universe, to gain a new foothold on the Moon and to prepare for new journeys to the worlds beyond our own,” said Bush. Here, two Yale faculty members offer differing critiques of this idea.

The Last, Lonely Trek
by Bettyann Holtzmann Kevles, Lecturer in History at Yale and author of the book Almost Heaven: The Story of Women in Space

Two American explorers, Spirit and Opportunity, traveled more than 250 million miles to arrive safely on Mars this past winter. Thanks to them the red planet is no longer unknown territory. These adventurers have been sending back a stream of images and technical data about the Martian landscape, even evidence of ancient rivers. When their solar cells eventually fail, contact will end and we will bid them farewell. Some of us will be sad, but not grief-stricken, for in the end Spirit and Opportunity are only robots.

Their success has changed the nature of Martian exploration. They have given us an enormous amount of information about the planet’s mineral resources and evolutionary past and answered many technical questions. But robots cannot spot something that reminds them of something altogether different; they cannot perform the kind of insightful random association that is a characteristic of great artists and scientists. This is a good reason to follow robots with human explorers.

Not so long ago the prospect of piloted missions to Mars seemed imminent, if not immediate. Plans to send people beyond Earth’s orbit changed, however, after seven astronauts died on the shuttle Columbia in 2003. The shuttles were grounded, the purpose of the entire astronaut program came into question, and the program itself remains in limbo. President Bush tried to re-inspire the country about space travel, but the response has been an overwhelming lack of interest from Congress and much of the public. In contrast, a huge audience watched Spirit and Opportunity on Mars. The Cassini-Huygens mission, which entered Saturn’s orbit in July, is providing another dose of instant visual gratification without any risk to human life.

Columbia’s demise heightened NASA’s determination to make human space travel risk-free. This standard is problematic enough for shuttles. The greater risk from a Martian expedition suggests we are far from ready to send people on a three-year round-trip expecting their healthy return. A short list of known dangers includes cosmic radiation more intense than radiation in low Earth orbit, ionizing radiation from solar storms, and loss of bone density (and subsequent bone fragility) from extended periods of weightlessness. There are also potential emotional and psychological problems for a crew of half a dozen men and women—from different countries with different native languages—on an extended, taxing, life-threatening journey.

Recently I interviewed some 40 astronauts and cosmonauts. They know the risks better than anyone. Yet with few exceptions, all agreed that, if the opportunity were offered, they would go to Mars “in a heartbeat.” Only one had a reservation: she wanted a guaranteed round-trip ticket.

The Apollo astronauts also expected to come back home. John Kennedy promised in 1963 that before the decade was out the United States would “send a man to the Moon and bring him back safely.” That has been the expectation in space travel ever since, but it may be an unrealistic goal when it comes to Mars.

We could get there sooner and at less expense if we began by providing only one-way tickets. Food, shelter, and scientific supplies could be delivered beforehand by robots, to ease the transition for astronauts planning to live out their lives on Mars. We could send mature astronauts with plenty of experience and not so many years left to sacrifice, if sacrifice they must. Older astronauts willing to risk the journey would become scientist-journalists, remaining in constant contact with Earth, broadcasting their insights and discoveries while receiving messages from friends and family. In exchange for this one-way ticket they would win a place in history. Better still, they would have the unique experience of exploring a new world—a signal attraction for every individual who chooses a career in space.

Eventually, in a future impossible to foresee, the political and economic climate may change, speedier spacecraft might be developed, and humanity—because we are a curious species—might establish some kind of Martian space station. The time may come when such a station would attract young people eager to ensure the continuation of our kind in the event that an asteroid or some now-unpredicted catastrophe threatens life on Earth. For humans are also a self-important species, and we would struggle to preserve ourselves against oblivion.

In time, round-trip transportation might be regularized and Mars could become a way station for travelers venturing farther into the solar system. Or it might simply remain an outpost, like the Moon today, where humans once walked, and left.

That is the future. For the moment, politics and economics being what they are, we will have to be satisfied with highly skilled robots programmed by brilliant teams of very human scientists and engineers.

A Virtual Trip Through Time
by Charles Bailyn, the Thomas E. Donnelley Professor of Astronomy

At first, it seemed promising: a sweeping presidential initiative rededicating the country to space exploration. Once again, the Right Stuff would be exploring the Final Frontier. But within a few days, as NASA reorganized, the costs began to emerge—among them the decommissioning of the Hubble Space Telescope, the most successful scientific instrument in history. While an immediate outcry from scientists, politicians, and many members of the public has prompted NASA to study creative ways of keeping the Hubble aloft, it’s worth considering whether sending human beings back to the Moon, and eventually perhaps also to Mars, is really an appropriate goal for cosmic explorers in the twenty-first century.

For “exploration” means more than keeping a handful of human beings alive in a place just a few light-seconds distant from Earth. Consider the so-called “Ultra-Deep Field,” for which astronomers used the Hubble Space Telescope to identify the faintest objects ever seen. The astronomers turned Hubble into a time machine by focusing it on an apparently empty region of space for several weeks. The telescope produced an image of the visible light from almost 10,000 galaxies, including about a hundred that are more than 13 billion light-years away. That means their light was emitted more than 13 billion years in the past, and their images in the Ultra-Deep Field show them as they were long ago.

The universe itself is thought to be about 14 billion years old. Significant changes have taken place since the photons detected by the Hubble telescope began their journey. The distant galaxies in the Ultra-Deep Field are different from the more modern galaxies we observe nearby. In the past, galaxies were smaller, bluer, and less regularly shaped. Billions of years of galactic mergers and growth have led to the majestic elliptical and spiral shapes of galaxies like our own. This process, long hypothesized, has now been confirmed by observing how the properties of galaxies change as they recede further and further into the past. Thus the Hubble reveals the state of the universe not as it is, but as it was, and allows us to probe times and places where no human being will ever travel.

Other cosmic explorers besides Hubble are revealing new aspects of the universe. Orbiting observatories are recording not just optical light, but also X-rays, infrared, and ultraviolet radiation from deep space. Innovative technologies are allowing terrestrial radio, microwave, and optical observatories to rival and even surpass their space-based cousins. Recent discoveries include the identification of hundreds of planets orbiting distant stars, details of the physics of black holes, and, most remarkably, the discovery of “dark energy”—a kind of cosmic anti-gravity that apparently suffuses the entire universe.

We are building new cosmic neutrino detectors and gravitational wave observatories. Robot explorers are traveling to all parts of our solar system. Space probes are revealing aspects of the physics of the Sun and the geology of the Earth that may significantly enhance our ability to survive on this planet. All of these endeavors together are far less expensive than sending humans to Mars. And many of them may be delayed, canceled, or cut short, as the Hubble telescope might still be, in order to siphon money and effort into the Moon/Mars initiative.

Sending people back to the Moon is akin to crossing the Atlantic Ocean in a sailboat: an exciting adventure for those involved, but no longer a feat likely to be celebrated through the ages. Sending people to Mars would be memorable as a “first,” but—after all we are learning daily from the much cheaper, more-efficient Mars robots—resoundingly anticlimactic.

The true frontiers of the twenty-first century will be crossed not by transporting our bodies, but by extending our senses, allowing us to see what no-one has seen before.  

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