If the human race ever gets around to manned deep space missions, we're going to want gardens. It's only common sense to bring a renewable food supply along into the cosmic void. But also, by turning an otherwise drab metal tube into a more Earth-like environ, plant life stands to make us much happier, and thus, less likely to kill each other in confinement.
NASA's well aware of this, which is why the space agency's recently published technology roadmaps outline its goals for developing "bioregenerative food systems"—aka space gardens—that'll green up our monotonous habitats and add fresh veggies to the otherwise shrink-wrapped diet.
One of the enormous challenges with a manned deep space mission is ensuring that our astronauts don't starve, asphyxiate, or otherwise run out of vital resources. A sizable chunk of any long-term mission's storage space will be occupied by food, but a renewable source of calories could go a long way toward freeing up precious room and reducing the need for costly resupply missions.
"Current space food is double-packaged to increase shelf life. However, current shelf life will not support missions lasting three or more years," NASA writes. "The development of a bioregenerative food system can reduce the quantity of food being resupplied, provide fresh food to the crew, and even be tied into life-support systems. Food packaging mass and volume would also be minimized, due to the food being produced with minimal shelf-life requirements."
"As the missions go farther, and stay longer, then, of course, if you can begin to expand these systems, now you can generate oxygen"
What exactly these space gardens might look like is not yet clear. (If you've got a green thumb, NASA is soliciting public feedback on the technology roadmaps until June 10th.) The space agency has been conducting plant science research for years, studying things like how to actually water a plant in low gravity, what sorts of light are best to use, and what sorts of plants make the most sense, nutritionally, to supplement the rest of an astronaut's diet.
A major technical consideration will be how to integrate a garden with the rest of the ship. Plants can have a significant effect on their atmosphere, sucking down carbon dioxide for photosynthesis and releasing oxygen. One of the big criticisms leveled against the Mars One is that the colonists' indoor gardens might produce unsafe oxygen levels, leaving entire habitats prone to spontaneous combustion. For space gardens to work, we'll probably need some way of separating our plants' air from that of the rest of the craft. But as Ray Wheeler, a botanist with NASA's Kennedy Space Center, explained in a press release several years back, if we're smart, we can use these aspects of plant life to our advantage.
"As the missions go farther, and stay longer, then, of course, if you can begin to expand these systems, now you can generate oxygen," Wheeler said. "You can remove and reduce the carbon dioxide. And you could couple wastewater treatment systems with these plants as well. You could do multiple life support functions as you begin to scale these up."
And, let us not forget the big added incentive for making this work: We want happy astronauts.
"A bioregenerative food system could boost astronaut psychological well-being and morale, since growing food and consuming fresh food might have positive psychological impacts," NASA writes. "This contribution of plants to crew well-being is an area that requires further research."
While gardens didn't save humanity's heroes in Sunshine (a movie that underscores why rigorous psych evaluations are always a good idea for space-bound humans), astro gardening has so many potential benefits, the idea certainly merits further development.
Let's just make sure we really get that oxygen bit right. Nobody wants their greenhouse becoming a molotov space cocktail.