What will the first humans on Mars eat? One scientist has the answer.

A mission to Mars could launch as early as the 2030s, taking a small crew of humans on a 5-year round trip to the red planet. One of the biggest questions about this mission isn't what kind of rocket ship we'll need, but how we'll feed people for five years in vacuum, and on an alien world. NASA senior research scientist Maya R. Cooper told attendees at the American Chemical Society's annual meeting in Denver that the 5-year round-trip mission to Mars would require 7,000 pounds of food per person. And she's made a list of what kinds of food they'll be eating.

A summary of Cooper's presentation from the ACS clarifies:

"That's a clear impediment to a lot of mission scenarios," Cooper said. "We need new approaches. Right now, we are looking at the possibility of implementing a bioregenerative system that would involve growing crops in space and possibly shipping some bulk commodities to a Mars habitat as well. This scenario involves much more food processing and meal preparation than the current food system developed for the space shuttles and the International Space Station."

Bioregenerative systems involve growing plants that multi-task. They would supply food, of course. But just as plants do in natural environments on Earth, those growing in bioregenerative systems also would release oxygen for the astronauts to breathe, purify the air by removing the carbon dioxide that crews exhale and even purify water.

Ideally, these plants would have few inedible parts, would grow well with minimal tending and would not take up much room. Ten crops that fit those requirements have emerged as prime candidates for the Mars mission's kitchen garden. They are lettuce, spinach, carrots, tomatoes, green onions, radishes, bell peppers, strawberries, fresh herbs and cabbages.

Basically she's outlining the kind of scenario we saw in the film Sunshine, where a crew of astronauts headed to the Sun live in a ship whose biosystems are run largely through a massive greenhouse that helps to supply food, air and clean water to the crew. If such a system couldn't work, or could only supply part of the food required, Cooper suggests that we could send autonomous spacecraft to Mars ahead of the mission, carrying bulk foods with "long shelf-lives" that the crew could consume while on the planet exploring.

Either way, we're looking at a form of space travel that humans have never experienced before. And the fact that NASA is taking this trip seriously enough to be looking at possible food sources is one of the most encouraging things we've heard about the future of human spaceflight in quite a while.