Science: Humans to Mars? Why Not?

The stresses on the crew would be unprecedented. Marsnauts could be exposed to high levels of radiation from cosmic rays and unpredictable solar flares. After a long stint in zero gravity, the space crews' muscles, including their hearts, would weaken, and their bones would lose calcium. And it may be inevitable that a small group of people living together in cramped quarters for years would fall prey to loneliness, boredom and squabbling. Admitted Sally Ride, who shared one of her two space flights with six other astronauts in the crowded confines of the shuttle: "You'd have to be very careful about the people you would choose."

Undaunted by these challenges, some space experts have already begun planning the Mars itinerary, devising a variety of baroque flight paths to save on energy and thus fuel. One trip, for example, would require a roundabout swing past Venus, which would lend the craft a gravitational boost in acceleration. On the voyage, the crew module would constantly spin, to provide artificial gravity, and would be equipped with an automatic solar monitoring system and a shielded "storm cellar" in the event-of a solar flare. To give the crew emotional solace in the blackness of space, the interior could be decorated with soothing colors like fawn beige and periwinkle blue.

Once on Mars, crew members could extract the traces of water that still exist in the atmosphere; the water could even be broken into its constituent oxygen (for breathing) and hydrogen (for fuel). Given the planet's abundant supply of carbon dioxide, greenhouse gardening should be possible during subsequent, longer stays.

In fact, some of the apparent similarities between earth and Mars are what makes the Red Planet so appealing a place to visit. A study of Mars could reveal critical insights about the meteorology and seismology of the earth; the strata that should be visible in the walls of the great rift valley would reveal the planet's geological history, exposed and waiting to be read. And the question that the Viking landers could not answer might be resolved: If the planet is so like our own, did life ever evolve there? Whether it did or not, Carl Sagan sees an opportunity for some provocative scientific research on the earth's sister planet. "Life is on one," he says, "and not the other. How come? It is the classic laboratory situation, one the experiment, the other the control."

Even without the rationale of superpower cooperation or scientific benefit, the delegates agreed, human beings will eventually land on Mars, driven by nothing less than good old-fashioned nosiness. "We will never be satisfied with data streams and pictures from some distant planet," said Schmitt. "We want to be there." Concluded James Beggs: "Humans to Mars? Why not?" --By Natalie Angier. Reported by Jay Branegan/Washington