🍄 How Does Your Space Garden Grow?

From extraterrestrial photosynthesis to protein shakes sourced from astronauts’ breath, scientists scope out lunar living to prep for planets further-flung.

Feb 23, 2024

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*(Credit) Rachel Armstrong: Experimental Architecture, stratospheric sky garden and platform for the cultivation of proto life.*

Hello, we’re Alice and we are always in a state of wander. Is there a blueprint for survival on the red planet? Or a manual for the moon? Astrobiologists and astrobotanists are working on it as they attempt to assemble the ultimate suitcase for the big move to Mars. Plants, food, people … can we fit it all in, will it even work there, or shall we just get some new stuff? Last week ALICE made moves in microgravity looking at the future of medicine and now we turn to spacefarers’ food, the perils of planting in orbit… (and humans 2.0)

“When we do send things into outer space, where should we go?” pondered physicist
Michio Kaku, the #1 New York Times bestselling author of The God Equation [2021] to ALICE in 2002. “Some people say Mars. Well, yes, Mars is a very attractive place, and on a time-scale of thousands of years, we do have to leave the Earth.” Now retired from research, Kaku is professor of theoretical physics at City College, New York. “When you take a look at the probability of meteor impact, environmental damage, the Earth is a risky place to be. And, as Carl Sagan said, we should be a two-species planet. We should be a species based on two-planets in case one planet is destroyed.”

NASA agrees and hopes to send crewed missions to Mars as soon as next decade. But first, to the moon, by way of its ambitious Artemis program. ”Mars is calling,” says NASA. “We need to learn what it takes to establish community on another cosmic shore. So let’s camp close before pushing out. The moon is a treasure trove of science. It holds opportunities for us to make discoveries about our home planet, about our sun and solar system.”

Fly me to the moon

It’s a long shot. Getting back there since Apollo 17—the first crewed moon mission in 1972—has been something of rocky road. A successful un-crewed test flight in 2022 was due to be followed by a crewed lunar flyby mission (Artemis II) in November 2024, but it was recently announced that this mission would now go ahead in September 2025, due to hardware issues.

Just thinking ahead, humanity gets there and then what? The moon is cold and dripping with dangerous radiation. “If you were transported to the Moon this very instant, you would surely and rapidly die,” writes planetary geologist Paul Byrne for The Conversation. “That’s because there’s no atmosphere, the surface temperature varies from a roasting 130 degrees Celsius (266 F) to a bone-chilling minus 170 C (minus 274 F).” Byrne is Associate Professor of Earth, Environmental, and Planetary Science at Washington University. “If the lack of air or horrific heat or cold don’t kill you, then micrometeorite bombardment or solar radiation will. By all accounts, the Moon is not a hospitable place to be. Yet if human beings are to explore the Moon and, potentially live there one day, we’ll need to learn how to deal with these challenging environmental conditions.”

Gravitational fields forever

Not a problem, says NASA. “We will learn how humans can survive and thrive in a partial-gravity environment. With improved spacesuit designs, mobile habitats and robotics repositioning supplies. This kind of continuous lunar presence is a natural extension of all that we’ve learned in low Earth orbit, and what we will accomplish there will ensure the monumental missions to Mars are within reach.”

“We’ll need habitats, air, food and energy, as well as fuel to power rockets back to Earth and possibly other destinations,” continues Byrne. “That means we’ll need resources to meet these requirements. We can either bring them with us from Earth—an expensive proposition—or we’ll need to take advantage of resources on the Moon itself. And that’s where the idea of ‘in-situ resource utilization,’ or ISRU, comes in.” ISRU is the harnessing of local natural resources at mission destinations, instead of taking all needed supplies from Earth, to enhance the capabilities of human exploration.

(Watch: Space Station Live)

Rocket shoots and leaves

“In Douglas Trumbull's technically proficient science‐fiction film ‘Silent Running,’ the trees are dying in vast, spaceborne, closed ecological systems on the way to Saturn,” astronomer Carl Sagan observed in The New York Times, 1978. “After weeks of painstaking study and agonizing searches through botany texts, the solution is found: Plants, it turns out, need sunlight. Trumbull's characters are able to build interplanetary cities but have forgotten the inverse‐square law. I was willing to overlook the portrayal of the rings of Saturn as pastel‐colored gases, but not this.”

So growing plants in space in not exactly a walk in the park.

“There are a few reasons you couldn’t just chuck plants on the moon – they wouldn’t survive the lunar temperature or the radiation,” Jessica Atkin, a grad student at Texas A&M University, tells New Scientist. Atkin recently scooped a world-first by growing chickpeas in engineered moondust mixture. “You’d have to grow them inside the habitat with the same protections as the astronauts.”

But even planting in a spaceship has its problems. Lack of gravity, for example. “Roots display a property called geotropism or gravitropism, meaning they grow in the direction of gravity’s pull,” writes space expert Leah Crane in New Scientist. “When they’re in microgravity, such as on the ISS, they grow in every direction and tend to strangle one another. Microgravity also makes it difficult to water plants, as the water does not trickle into the soil in the same way. Researchers on the ISS and around the world are working on potential solutions to those two problems, including developing special lighting rigs to direct growth and wrapping sponges around the plants’ roots.”

Space cakes, anyone?

Astrobotany, the study of life and interactions of plants in space environments, is coming on space-leaps and bounds. Experiments have shown how wheat plants grow 10 percent taller in microgravity, and the future could be growing crops in space and packing them back to Earth.

The big dipper

And then there’s Atkin’s potential space hummus. She and her team have successfully grown chickpeas in lunar soil by adding a combination of worms to provide nutrients and fungus to remove toxins. “The moon doesn’t have soil like Earth does,” Atkin said in a statement. And unlike earth’s terrain, lunar soil lacks organic matter rich in nutrients and microorganisms, which are vital for plant growth.

"This adds to other challenges, such as reduced gravity, radiation and toxic elements." The plants survived and flowered.

Building an off-world greenhouse however, is challenging. “You need all of these other things for plants to thrive,” says Atkin. “I think a lot of the time people don’t see what’s going on underneath the ground and what a productive little world is down there contributing to our plants.”

So, how does your space garden grow?

Perseverance pays off. On the International Space Station [ISS], there’s a space garden in bloom. The Vegetable Production System, known as Veggie, helps NASA study plant growth in microgravity while adding fresh food to the astronauts’ diet. It’s also helping with mental health. “There were definitely days where I would go over to our tiny greenhouse, which is about the size of a couple of shoe boxes, and just smell the plants,” astronaut Christina Koch told New Scientist. “Just to smell something that was organic, that actually did a lot for me.”

Flowers in your air

It typically holds six plants and each one grows in a “pillow” filled with a clay-based growth media and fertilizer. So far it’s successfully grown three types of lettuce, Chinese cabbage, mizuna mustard, red Russian kale and zinnia flowers.

The pillows help to distribute water, nutrients and air in a healthy balance around the roots. Otherwise, the roots would either drown in water or be engulfed by air because of the way fluids in space tend to form bubbles. In the absence of gravity, plants use other environmental factors, such as light, to orient and guide growth. A bank of light emitting diodes (LEDs) above the plants produces a spectrum of light suited for the plants’ growth.

The ultimate restaurant launch

"Happiness is bacon squares for breakfast.”
—Apollo 8's Command Module Pilot Jim Lovell, midway to the moon in 1968.

“If we are realistic about becoming a multiplanetary species, we have to learn how to reduce or cut the umbilical cord that connects us to Earth,” Pablo de León, team lead of Kernel Deltech, the space-oriented division of the company Eternal Bioworks, tells Scientific American. De León has designed fake cheese and burgers made from a protein-rich fungus for a futuristic space meal as part of a NASA-led competition called the Deep Space Food Challenge. Entrants had to show systems that could operate for three years and feed a crew of four on a prospective space mission. Detailed tests are underway and a winner will be announced this year.

Star chefs

The Brooklyn-based Air Company, one of the five American finalists, designed a system that could use the carbon dioxide expelled by astronauts in space to produce alcohol, which could then be used to grow edible food. “It sounds like magic, but when you see it actually operating, it’s much more simple,” Stafford Sheehan, cofounder and chief technology officer of Air Company, tells MIT Technology Review. “We’re taking CO2, combining it with water and electricity, and making proteins.”

“Currently the pre-packaged food that we use on the International Space Station has a shelf life of a year and a half,” says Ralph Fritsche, senior project manager for space crop production at NASA’s Kennedy Space Center in Florida. “We don’t have a food system at this point in time that can really handle a mission to Mars.” Longer missions to the moon would present a similar problem.

“Right now on the space station, astronauts receive regular shipments of a wide variety of freeze-dried and prepackaged meals to cover their dietary needs – resupply missions keep them freshly stocked,” writes NASA. “When crews venture further into space, traveling for months or years without resupply shipments, the vitamins in prepackaged form break down over time, which presents a problem for astronaut health.”

What else we are wandering…

🥬 Eat your microgreens (and a side of soldier flies)
Another finalist for NASA’s Deep Space Food Challenge is Interstellar Lab in Florida, which has designed NUCLEUS, a modular set of small toaster-size capsules. Each capsule is self-contained, with its own humidity, temperature, and watering system. Different vegetables—and protein-packed insects such as black soldier flies — could be cultivated so that astronauts can grow their own food in space. “We’re bringing a little bit of the Earth ecosystem into space,” Barbara Belvisi, the company’s founder and CEO told MIT Technology Review. “You can grow mushrooms, insects, and microgreens at the same time.” Astronauts would need to spend three to four hours per week cultivating the crops, but for the most part it would be AI-controlled. “NASA didn’t want to get rid of full human intervention,” says Belvisi. “It was still needed to give some occupation to the astronauts.”

🧠 Humans 2.0: Never mind a two-planet species, the late theoretical physicist and mathematician Freeman Dyson, was thinking about a two-species planet. “If you live on Mars you don’t want to live inside a space suit—you want to be able to walk around in the open air, that requires having a different kind of skin than the one we have—probably you’d have thick fur like a polar bear,” Dyson told ALICE in a 2001 interview, “So the people who live on Mars will look very different within a few generations. They will be a different species. In the long run it might be a good idea for humans to speciate. I don’t think there’s anything wrong with it—except it can’t happen on one planet, this planet is too small to have two human species on it.”

Trees 2.0

“It’s possible to imagine that in other places plants were warm blooded, particularly on Mars,” Freeman Dyson, the late theoretical physicist and mathematician told ALICE.

“If there were plants on Mars, as the climate got colder and colder, in order to survive they might have learned to grow greenhouses. Just like turtles grow shells or the polar bear grows fur. They all have their tricks. Plants could learn to grow greenhouses. As far as I know, that hasn’t happened on this planet. It would be helpful if they were trying to survive on Mars. It’s possible it did happen – that there really are warm-blooded plants hiding away in places on Mars where we haven’t looked. That’s something I would look out for. I don’t say it’s likely, but certainly possible. You can imagine these greenhouses in places on Mars where there’s water not too far below the surface, we know there’s water on Mars. It’s likely in some places it’s not very far down. You could have a greenhouse on the surface with some plants growing inside and roots going down through the ground—reaching a point where there’s water and minerals and chemicals that are needed to survive. Those things actually could be there. If we went to Mars, it would be a very good idea to take warm-blooded plants with us. So we would have a habitat. These things could be very big—trees 100 feet high, growing huge big greenhouses so then all you have to do is open the door and walk in. That would be a habitat for animals and people, anything else you can imagine. The colonizing of the planet could be a much easier thing than doing it the hard way with steel and glass. You can have a plant that grows a greenhouse and then it will have all kinds of microbes inside taking advantage of the environment. Then you will have other plants and animals—a complete ecology. But chances are, it will grow. It’s not something you have to manufacture. Once it’s there, it’ll evolve by itself.”

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