At long last Earthlings may be on the verge of colonizing another planet—but those first Terran ambassadors will be plants, not humans.

NASA is expected to announce within days whether they will attach a one-liter “greenhouse” to its next Mars rover to be launched in 2020. A similar greenhouse would take a voyage to the moon with any team that manages to land a robot there by 2015 to snag Google’s Lunar X PRIZE. These experiments could illuminate whether human colonization of the moon or Mars could be possible.

NASA’s proposed Mars Plant Experiment, or MPX, aims to answer two questions: Can plants germinate and grow in Martian gravity? And can they thrive while being bombarded by cosmic rays? To find out, investigators would attach a small, clear cube filled with carbon dioxide to the rover’s shoulder, says Heather Smith, a deputy principal investigator for MPX. Inside would be 250 seeds of the Arabidopsis plant, a fast-growing cousin of mustard chosen because it has been studied exhaustively by scientists. After the rover lands the seeds would be soaked with water; heaters and LEDs would regulate their temperature. Over the next 10 to 15 days, via sensors and cameras, the world could observe the first beings we know of to be born, live and die on another planet.

The Lunar Plant Experiment, or LPX, was designed by the same team and uses similar methods. Each of the teams competing for Google’s Lunar X PRIZE, which will award $20 million to any private enterprise that lands a robot on the moon by the end of 2015, has agreed to carry the LPX with their robot if they succeed.

These wouldn’t be the first plant experiments in space: Humans have been putting seeds on rockets since the 1940s. In 1973 NASA sent rice seeds into orbit on the Skylab space station to measure how light and microgravity affected their growth. In 1995 scientists grew and reproduced wheat on Russia’s Mir space station; two years later they cultivated and harvested it. The International Space Station has been home to a small experimental garden called the Lada Validating Vegetable Production Unit for more than a decade. It appears to relax and comfort the space crew, but the plants are clearly under stress: A recent genetic study discovered that plants grown in space have twice the mutations as they do on Earth.

Plants grown in microgravity struggle to orient their roots and stems, but it’s unknown how that would play out in low gravity. Mars and the moon have roughly one third and one sixth of Earth’s gravity, respectively, perhaps enough to cue the plants to orient correctly, notes NASA senior scientist Chris McKay, a principal investigator in the MPX and LPX. “Plants don’t like zero gravity. Humans don’t like zero gravity. Not even cockroaches like zero gravity,” McKay says. “But we have no idea if the same is true for low gravity.”

The Mars experiment is one of 58 projects vying for space on the rover; NASA officials are expected to announce their decision Thursday. Although the competition is stiff, the MPX has the advantage of a relatively low cost—$6.76 million. If it is approved, the team will begin teasing out the challenges of sending sterilized seeds on a journey across the interplanetary space. But some of the greatest challenges to this experiment would also be the most mundane: “We still have to figure out how to keep a camera in a greenhouse from fogging up,” Smith says.

Meanwhile, back on Earth
Scientists have come up with a host of innovations that would help plants thrive elsewhere in our solar system, many of which are proving useful on our home planet. At the University of Guelph in Ontario, the Controlled Environment Systems Research Facility is developing automated food-growing boxes: Seeds go in the box and several weeks later ripe vegetables come out. Because water, minerals and electricity will be scarce in space, the boxes must use these resources as economically as possible. The team has developed sensors that can determine which minerals the plants have absorbed, allowing the system to specifically replace those rather than using fertilizer indiscriminately. The team is now developing a lighting system that works on the same logic: “We’ve got a nine-band LED system where you can tweak individual wavelengths across the rainbow and look at how different light recipes promote growth,” says researcher Cody Thompson. “It’s precision agriculture.”

This precision has obvious applications on Earth: Agribusiness giant Syngenta plans to use the technology to develop climate change resistant plants, says team director Michael Dixon; researchers in the medical marijuana industry hope it can help them develop ailment-specific strains. “Up until now, people have sorted out these questions in their backyard or in their basement, without any real science attached to it,” Dixon says. “Now they want science, and they have the profit margins to assume the risks.”

The technology could also provide food security in isolated or extreme environments. The Kuwaiti government has invested in prototype demonstrations to explore whether these systems could help their oil-rich but agriculture-poor nation become more food-independent. The Canadian government has funded a feasibility study exploring the viability of sending these “space gardens” to isolated mining and aboriginal communities in its arctic regions, where it’s common to pay $10 for a green pepper “that’s already half squishy when you get it,” Thompson says. Space garden technology would yield better veggies and lessen dependency on imports.

These earthly uses will, in turn, help scientists understand better how space agriculture could work, says Dixon: “After the surface of the moon or Mars, the next-worse place in the universe to grow plants is a snow bank in the Northwest Territories.”