Gardening in Outer Space: A Conversation with Simon Gilroy

What would it take for humankind to become a multi-planet species? And what species ought to make the trip with us? These questions aren’t as far-fetched or uncommon as they might initially seem. Billionaire entrepreneur Elon Musk has announced his plan to make trips to Mars affordable, showing animations of a terraformed red planet teeming with plant life to awed crowds. A less glittery scene from the Hollywood movie The Martian features a marooned astrobotanist, played by Matt Damon, attempting to survive on potatoes grown in Martian soil and his own feces. In 2014, three Chinese researchers survived 105 days in a simulated lunar habitat by growing and eating cereal grains, vegetables, and mealworms. Then, in summer 2015, astronauts aboard the International Space Station ate the first space-grown salad—one leaf of red lettuce per person.

Fictional and nonfictional scenarios alike suggest that the metal and plastic canisters that protect astronauts from the void likely will not be enough to keep human beings happy and healthy during long-term space travel. Plants—both edible and ornamental—provide important sustenance both on and off Earth. I recently spoke with Simon Gilroy, a plant biologist at the University of Wisconsin–Madison, about the scientific and cultural significance of growing plants in space. Gilroy has carried out several experiments in which he has studied how plants respond to the unusual cabin ecosystem of the International Space Station. Although primarily focused on how microgravity research might help improve agricultural practices on Earth, Gilroy has given a great deal of thought to the larger cultural implications of his work for imagined futures in space.

Simon Gilroy, professor of botany at the University of Wisconsin-Madison, meets with his graduate students conducting independent research in Birge Hall on March 2, 2018. Gilroy is a recipient of a 2018 Distinguished Teaching Award. (Photo by Bryce Richter / UW-Madison)

Keeping people alive in space is hard enough—growing plants requires its own set of creative approaches to fostering life. By considering the psychological and cultural utility of plants in addition to the challenges inherent in bringing green companions into the cosmos, our conversation suggests the need for scientists and humanists alike to further complicate an ongoing discussion about not only the words we use to describe our non-human surroundings, but also the material limits of nature and the environment.

As entrepreneurs, futurists, and scientists attempt practical steps towards colonizing the Moon and Mars, perennial questions about planetary protection and environmental ethics will likely abound. If large human populations do eventually settle on alien worlds and bring agriculture with them, questions about food and land justice, agrarian governance, and agricultural labor that have persisted across space and time on Earth will likely emerge anew on strange new worlds. Ultimately, in considering the politics of space travel, we must also consider the politics of plants.

Stream or download our conversation here. Interview highlights follow.

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Interview highlights:

This transcript has been edited for length and clarity.

Lisa Ruth Rand: How did you get into this line of work? Why botany, and why “astrobotany”? Can you tell us what “astrobotany” is?

Simon Gilroy: It’s one of those great stories of coincidence. For a very long time my lab and all the researchers there have been interested in how plants work out what’s going on around them. And plants are super good at it. If it’s hot, they know that it’s hot, and they trigger responses to that. If there’s something eating them, they know that they’re being eaten, and they trigger responses. We’re just interested in how they do these things without a brain and all the other things that we take for granted.

One of our research programs looks at how plants understand that they’re flooded. In the spring the Mississippi River is almost guaranteed to flood some farmers’ fields. Those plants will survive for a while; if it’s too long, they’re toast. If it’s not, they totally know what’s going on and they respond to it. We’ve had a research program on this issue for a long time that has nothing to do with space.

A zucchini plant, floating freely in the International Space Station’s Destiny laboratory, is featured in this image photographed by an Expedition 30 crew member. Photo by NASA, February 5, 2012.

Now, our research program studies how plants sense the direction of gravity, and that’s clearly something NASA is interested in. We realized that because of the weird physics that go on in space flight, flooding is actually a big deal in space. So, we have this research program which exactly fits, even though we had no thought of it being a flight program. And then the stars aligned: Space X started doing commercial flights to the Space Station, which gives us access. NASA has always been excited about the possibility of growing plants in space for lots of different reasons, and we have a research program that kind of fits in one area. The ball starting rolling. It’s pretty damn awesome!

LRR: Can you tell me about your project growing cotton in outer space?

SG: The project is organized by a group called CASIS, The Center for Advancement of Science in Space, and sponsored by Target Corporation.

Cotton is a terrible crop in many ways. It’s a very thirsty crop. It uses an enormous amount of water to grow. If you grow it intensively, it requires a lot of chemicals as well. But it’s a major agricultural crop. Many people’s livelihoods depend on it—around the world. The idea is to learn something new about cotton that maybe in the future will have some kind of agricultural impact. We do that using the space environment and the really unique things we can do in space.

Scientists have developed some genetically engineered cotton that is much more stress-resistant in the field. But we don’t know why. We know what we’ve engineered into it, but we don’t know why it’s more resistant. One of the hypothesis is that its roots grow in a different way…. But roots grow down because they’re sensing gravity, so it’s hard to do experiments on this because we can’t get rid of gravity on Earth. We do know one place where we can do that research—to ask genetically what’s going on— and that’s on the Space Station.

LRR: A common thread in many of these projects seems to be how plants react in times of disaster. Have you some given thought to the ways your research might help the agricultural industry or the garment industry or any number of industries that use these plants deal with a rapidly changing climate on Earth?

SG: We do basic plant biology. We aren’t at the level of developing new crop lines. But the understanding of how plants sense what is going on and then deal with that environmental change is the physiology—the plant machinery—that is available to help you think how you would breed a better plant. If we’re going to go fast, and go in a targeted way, the mechanism becomes important. And we’re after mechanism.

LRR: What other plants have you already grown in space? You mentioned that astronauts tend to like having the presence of a plant in this controlled, built environment. What have been some of the responses of the astronauts to the kinds of plants you’ve grown already?

Arabidopsis seedling. Image courtesy of astrobotany.com.

SG: We’ve concentrated—up until the cotton—on a plant called arabidopsis, which is the lab rat of plant biology. It’s a small little weed, and there are a lot of really technical, experimental reasons why it’s the plant to work on. No one in their right mind is going to eat an arabidopsis plant. We’ve done most of our space flights using that particular plant. We have colleagues who’ve grown things like lettuce, which is a big NASA target crop. The astronauts have harvested lettuce, they’ve eaten it, and it’s fantastic. Having access to that fresh food that they’ve grown themselves is a big deal.

Plants like zinnias have also been grown. Growing plants in space is hard, and at first the growing environment for the zinnia plants hadn’t been optimized. They had fungus on them, they were wilted, and they weren’t growing well. The astronaut in charge of that facility, Scott Kelly, asked “Can I just look after these plants like a good gardener?” He nursed them back, got them to flower, and made a bouquet for his girlfriend for Valentine’s Day. So these aren’t just crop foods, but plants that would stop you from going stir crazy.

LRR: How does the human factor determine what you study in terms of plants being part of a larger interplanetary future for humanity or just a future in space? Leafy and flowering plants are beautiful and taste good and are familiar, but for instance in the Lunar Palace experiment a lot of the participants’ diet was based on meal worms and things like water spinach. So, what I’m curious about is how these kinds of tastes and associations factor into even determining your research program? How do you envision the future of or how do you envision the priorities of studying plants in space and not just in terms of how to improve agriculture on the ground, but how to use this knowledge for imagining futures in outer space for humans?

SG: There are two big themes. One of them is that we’re going to take plants that support us. Plants and microbes make the Earth; we sort of just hang out with them. And those two groups of organisms working together are going to be at least an important foundation. Now the question is do we take the Earth with us? And do we rebuild the Earth in space? Or do we go: “You know that is unrealistically hard and what we need to do is modify the organisms or the environments and not take the Earth with us but get Earth’s biology to thrive somewhere else.” That is a fantastically complicated question, and we don’t know the answer to it.

Featured image: Astrobotany logo, courtesy of astrobotany.com.

Podcast music: “Gloves” by Julian Lynch. Used with permission.

Simon Gilroy is a Professor of Botany at the University of Wisconsin-Madison, having moved his lab from PennState to Madison in 2007. He is an avid gardener, and while growing up in the UK was enthralled by space exploration. His research now blends these two passions and focuses on how plants sense and react to the world around them and especially how plants respond to the unique challenges of growing in space. Website. Facebook. Contact.

Lisa Ruth Rand is an A. W. Mellon Postdoctoral Fellow at the University of Wisconsin–Madison. She earned her Ph.D. in the History and Sociology of Science at the University of Pennsylvania in 2016, and she is writing a book manuscript, entitled “Space Junk: A History of Waste in Space.” Her writing has appeared in The Appendix, The Atlantic, Isis, and Popular Mechanics. Her article on reentering radioactive space debris will appear in the January 2019 issue of Environmental History, and she contributed a chapter to the recent Smithsonian publication Living in the Anthropocene: Earth in the Age of Humans. Her contributions to Edge Effects include “Biosphere 2: Why an Eccentric Ecological Experiment Still Matters 25 Years Later” and “NASA and the Explosive 1960s: A Conversation with Neil Maher.” Twitter. Contact.