On Mars, we'll all farm underground. Our crops will grow in a greenhouse, where large, parabolic mirrors focus the sun's weak rays and transmit them through fiber optic cables. We'll harvest vegetables to eat—but also the purified water that evaporates from their leaves. We'll all be vegan, because raising animals for food will be too expensive. And, most importantly, the plants will give us oxygen.
"That's the starting point to a whole civilization right there," says Utah State University researcher Bruce Bugbee. This is Bugbee's vision, one he's been dreaming of and testing and revising for years as a plant engineer with NASA.
Astronauts going to Mars can eat all the freeze-dried food they're able to ship, but if humans are going to survive on the planet they'll need plants to produce oxygen. Not just any photosynthesizer will do: Mars is a difficult environment, with many challenges for farmers. Crops will need to be able to thrive in a small area, retain their nutrient content, and still taste good. Structures where they grow on the surface will need to withstand basketball-sized meteorites. The technology used to grow the plants will take massive amounts of energy. Mars also presents the ultimate recycling challenge, since astronauts can't pack all the water and nutrients they need on a two-and-a-half-year space flight.
Bugbee and his colleagues have been working on all these problems for decades, in a sometimes fantastical bid to support life on Mars (and, in the meantime, on space shuttles). Decades ago, NASA researchers ruled out some of the easiest plants to grow indoors, like algae: not enough sustenance, Bugbee says. Very tall crops like corn and sugarcane were also nixed because they wouldn't fit easily into the plant habitats.
What the astronauts really wanted was something green. "They say that having the texture and flavor and color and aromas of fresh foods apparently—and I believe it—really does add to the experience of eating," says NASA plant physiologist Raymond Wheeler.
Scientists started looking at traditional field crops like lettuce, tomatoes, and broccoli. Right now, astronauts are growing mixed greens 250 miles above Earth on the International Space Station, using two small, sealed greenhouse units called Veggie. NASA researchers have planned and adjusted and measured for everything—including which types of lettuce tastes best in space. Astronauts' clogged sinuses already make it so they "can't taste much of anything," according to Canadian astronaut Chris Hadfield, but the researchers are also curious to see whether the space environment affects a plant's flavor compounds and nutrient levels. Panels of specialists at NASA's Johnson Space Center in Houston typically conduct formal taste tests, but sometimes the researchers sample a leaf or two themselves.
What Bugbee and his team didn't expect is that the technology they created for this grandiose, futuristic mission would become somewhat eclipsed by those using it to farm on more familiar terrain.
In 2017, NASA commissioned a space farming project to figure out how to grow food on Mars, but they were also hoping to make some discoveries that could improve crop yields overall. The problems that space farmers of the future will face are similar to those already plaguing earthbound agriculture as climate change grows worse, including a dwindling water supply and poor soil. Now, researchers in Utah and three California universities—NASA's partners with the Center for the Utilization of Biological Engineering in Space—are working on projects that can sustain life not just on Mars, but on Earth.
"I think the reason NASA funds us is a powerful human fascination with being able to go inside a closed system and grow your own food," Bugbee says. "What if the atmosphere went bad and we had to build a big dome ... and go inside and live in it?"
In 1988, Wheeler built the first working vertical farm—growing plants on shelves, typically in a warehouse or storage container—at the agency's Kennedy Space Center. Wheeler's farm was 25 feet high and equipped with a hydroponic system for growing plants in water and high-pressure sodium lamps, the type commonly used for street lighting. All together, it was 20 square meters of growing space—almost 90,000 times less than the size of the average outdoor United States farm. According to Wheeler's calculations, it would take 50 square meters of plants to provide enough food and oxygen—and remove enough carbon dioxide—for one human in space. (Astronauts won't be using sodium lamps, though: A few years after Wheeler's innovation, a different group of NASA-funded researchers patented another significant piece of technology to indoor farmers: LEDs, which require much less electricity than sodium lights and are now used to power most greenhouses.)
Wheeler was focused on optimizing the area inside a chamber aboard a NASA space shuttle—and up seemed like the best way to go. "One of the things you have to think about in space is volume efficiency," he says. "You're vertically and dimensionally constrained." The team had to pick shorter crops: wheat, soybeans, potatoes, lettuce, and tomatoes.
In space, resources are limited: NASA scientists have to extract and reuse the nutrients from excess plant material and human waste; they collect water from the condensation that collects in the closed chambers. Here on Earth, water is also growing increasingly precious—climate change will make droughts more frequent and severe, devastating crop yields and making some staple crops like corn and soybeans obsolete. Every day, Earth looks a little more desolate, a little more like Mars.
When Wheeler started, the term "vertical farming" didn't exist yet. Today it's a $10 billion industry attracting interest from Silicon Valley and start-ups all over the world. Its acolytes believe the technology will one day completely replace conventional field agriculture, allowing businesses to grow crops year-round and indoors, insulated from the next drought or flood and the effects of climate change. "People imagine that we'll grow everything indoors, in skyscrapers in the middle of Manhattan," Bugbee says. "It's a wildly popular idea."
Sonia Lo, the chief executive officer of the biggest vertical farming company in the world, Crop One Holdings, says she believes vertical farming can "liberate agriculture from climate change and geography."
Crop One announced it would break ground on the world's largest vertical farm last November in Dubai: a five-story, 130,000-square-feet warehouse, capable of producing three tons of leafy greens a day. The company is also growing chard, arugula, and other greens in large, sealed rooms—year-round. "I made my whole management team stand in the supermarket and give out samples of what we were growing in the middle of the Boston winter," Lo says.
Soon people across the U.S. can try it too. Crop One is building new farms in the northeast, southwest, and California, where it will grow food to sell through its FreshBox Farms brand.
While researchers have been quick to condemn vertical farming's promises as over-hyped, even the industry's greatest critics acknowledge that this approach eliminates some of the challenges with conventional agriculture: Since vertical farms are located in compact warehouses, they're often located much closer to their markets than, say, the corn belt is to a city, allowing producers to cut down on food waste and save on transportation costs—a major contributor to U.S. greenhouse gas emissions. The lettuce grows in a controlled environment, free of pests and pathogens, meaning farmers can grow food without pesticides or herbicides, which have a massive environmental and human-health cost. Vertical farmers can also recycle their nutrients—like astronauts do in space—preventing phosphorus or nitrogen from flooding into the world's waterways and wreaking havoc with algal blooms. And indoor growth systems can be very productive: When all the conditions are right, researchers have surpassed record crop yields in the field by as much as six times.
Lo says that a vertical farm using 100 percent renewables has one-tenth of the carbon impact of a conventional farm. But few companies have reached this goal; most are still moving toward a combination of renewable energy and non-renewables to power the electric lights used to grow the plants. It takes a lot of land to generate that much solar—about five acres of solar panels to supply the light for just one acre of indoor farm, Bugbee estimates. That's why many have resorted to fossil fuels, breaking one of vertical farming's great promises. "It takes massive amounts of fossil fuel energy, so, environmentally, it's really a disaster," Bugbee says. "Those people have used many of the principles that we've developed through NASA."
Bugbee's current project could help with that. His lab at Utah State is using LEDs and fiber optics to grow plants under different types of lights, with different ratios of colors—ultra violet, blue, green, red, far red (out of the limit of human vision)—to manipulate both photosynthesis and plant shape. The goal, he says, is to find "the most efficient system possible." Right now, the technology is too expensive: millions of dollars to light one building. But eventually, he believes fiber optics will replace electric lights for good.
But there are other qualms with vertical farming: Instead of helping to colonize space—the future that Mars researchers envision for their technology—vertical farms might take over city real estate, at a time when housing costs are extremely high. In some countries and some industries, it already has: Japan has had flourishing plant factories for the last 10 years. The fledgling cannabis industry has also started to ramp up its indoor production, poised to become even more profitable.
Lo says it won't be long until greens grown indoors cost the same as those in the field. "Field-grown food will continue to rise in cost, and course the climate is also changing," she says. "From a cost perspective, vertical farming will become competitive very quickly."
Others are more skeptical: "Economically, will they succeed? That question is still ongoing, because they always have to compete with field agriculture," Wheeler says. "What's their cost to pay for electric power? What are their labor costs? Are these operations sustainable? All of this is sort of a living experiment right now."
Technology for farming in climate change may be a by-product of NASA's research, but it has helped the agency ensure funding for its work in space. In response to the skeptic who doubts whether it's worth figuring out how to farm for a Mars mission we might never see, one only has to point to vertical farms in Boston or Seattle that already use some of NASA's innovations.
But Bugbee believes these earthly pursuits can be just as futuristic (or deluded) as those meant for space. "People that do it say they're going to save the planet ... but they have to have a lot of fossil fuels," he says. "It'll tell you all kinds of rosy pictures about it—that it saves water, it saves fertilizer."
He's not quite comfortable with his research being used to prop up this industry, now flooded with billions of dollars of venture capital. "I'm not doing it to make this more possible on Earth," he says. "We get asked all the time about the spinoffs: Could you do this, could you do that."
We may never make it to Mars. It will be years until NASA is ready for a journey to the red planet, and many more until Bugbee would be able to build his greenhouse underground, tucked away from meteorites. But if Earth continues on this collision course, Mars could come to us.