"When astronauts first go to Mars, it'll be difficult for them to bring everything they need to survive. Even the first tentative explorations could last as long as two years--but spaceships can only carry a limited amount.

"We might have to do what explorers have done for ages: live off the land," says chemical engineer Ken Debelak of Vanderbilt University...

...It's a meager atmosphere, compared to Earth's, and it's about 95 percent carbon dioxide (CO2). But that turns out to be an advantage. The carbon dioxide, says Debelak, can be used to harvest almost everything else.

Inside martian rocks and soil lies a bounty of useful elements: magnesium and hydrogen for rocket fuel, oxygen to breathe, water to drink. What's needed is a solvent to get them out, and that's where the carbon dioxide comes in handy..."