Getting green life on a red planet
Food production is a ‘major limiting factor’ for surviving trip to Mars
On Thursday morning, Mike Dixon woke before dawn to harvest some corn. To pick it, he drove to the university campus, passed through a security perimeter, unlocked his lab and eased open a massive hypobaric chamber.
Dixon is no ordinary agriculturist. The University of Guelph professor studies how to grow plants on other planets — a crucial resource for the long-distance space travel required to send humans to Mars.
“The food production capability of green plants is the major limiting factor in how far away from Earth we can go and how long we can stay,” says Dixon. “We simply can’t carry enough food to survive indefinitely. We need to produce our own food, and the only critter that does that at the moment is green plants.”
At his Controlled Environment Systems Research Facility, Dixon and his team subject a rotating selec- tion of crops to a battery of environmental stresses comparable to what they might experience in the harsh Martian environment.
NASA’s Curiosity rover has shown that Mars was once much more like Earth — though seasons are twice as long as ours. The robot uncovered evidence of ancient stream beds and some of the key chemical elements for life in its soil, suggesting life could have existed billions of years ago. But something happened to turn Mars into an inhospitable “red planet”: it barely has an atmosphere, and the average temperature is -60 degrees Celsius. “We’re not going to instantly go to Mars, plant a garden and live happily ever after,” says Dixon.
The 14 hypobaric chambers in Dixon’s lab allow the researchers to control one significant difference between Mars and Earth: atmospheric pressure. Our planet averages just over 100 kilopascals at its surface; Mars averages less than one. If plants refused to thrive in anything lower than the full Earth atmospheric pressure, “we’d be done,” says Dixon.
The chambers also allow the scientists to control the availability of water, light, nutrition, carbon dioxide, heat and humidity, all while measuring the plants’ responses. In general, Dixon’s research has shown that plant life is exceptionally resilient. Plants retain most of their productivity even at a tenth of the Earth’s atmospheric pressure. The upshot is that astronauts on Mars could conceivably grow their own food in an inflatable tent, a much more realistic scenario than recreating full Earth conditions in a greenhouse.
One make-or-break variable, however, remains out of grasp — at least for now. Radiation is cosmic enemy No. 1 when it comes to earthly life in space. But those conditions are very hard to mimic here: to truly measure the effect of radiation, the best laboratory is outer space.
Space agriculture research benefits earthlings too. Dixon’s corn experiment is part of a program investigating drought-tolerance characteristics, helpful for withstanding the effects of climate change. Other research is transferable to Canada’s far north, which currently relies on expensive imported food. The demands of space travel are also helping scientists learn how to recycle resources better.