EPISODE 133: THE SCIENCE OF SPACE GARDENING

Transcript

Andrés Almeida (Host): A space garden aboard the International Space Station is helping scientists study how plants and vegetables grow in microgravity. NASA’s Vegetable Production System, known as Veggie, has successfully grown a variety of plants, including three types of lettuce, mizuna mustard, red Russian kale, and colorful zinnia flowers. It’s a complex process, but the research is revealing ways to provide astronauts with tasty, nutrient-rich food for long-duration missions. As humanity ventures farther into deep space, space farming will become a necessity. But can this technology benefit people on Earth, too?

Welcome to Small Steps, Giant Leaps, the NASA APPEL Knowledge Services podcast where NASA’s technical workforce shares project experiences, lessons learned, and novel ideas. I’m your host, Andrés Almeida.

Hey, Gioia, thank you for joining us on today’s episode.

Massa: Oh, it’s my pleasure to be here, Andrés.

Host: What do you do in your current role?

Massa: So, I’m a project scientist at Kennedy Space Center. And for me, that means I wear four hats. I work with external scientists who are doing research, for instance, on the space station, and I help their science be successful. I’m also a researcher myself, so I conduct research on the International Space Station. And I’m also part of a team now to do an experiment on the Moon, which is super exciting. And we also do a lot of ground-based research.

I also help out with strategic planning for space crop production, you know, figuring out what we need to do in the future, and also for space biology research and work with hardware developers when new hardware is being developed. And then, you know, my personal passion is also education and outreach and engagement, so I’m very involved with a lot of engagement activities.

Host: Wonderful. And you work on Veggie. Can you explain a bit about the hardware and technology used for Veggie?

Massa: Certainly. So, you know, we have a couple of types of plant growth chambers on the International Space Station, and Veggie is one of them, we actually have two what I would consider large plant capabilities. So, Veggie, which is kind of a very simple system, almost more of an astronaut garden. And then the Advanced Plant Habitat, which we call Veggie’s big sister, which is a much more complex plant physiology research chamber.

So, a lot of my career has been testing hardware and, and crops for Veggie. Veggie was launched in 2014 to the ISS — the first Veggie unit (we actually have two there now) — and it’s a very simple system. It consists of LED lights, red, blue, and green LED lights, and fans. And the fans pull the ISS environment through the plant growth canopy. Then there’s a base plate with a transparent extensible plastic bellows and the bellows attached to that light with magnets. And that’s pretty much all there is to the basic Veggie facility. There are some flexible arms that keep that base plate level. And there are, you know, fans to cool the lights independently of the fans that are bringing in the ISS environment.

Then we use different hardware within Veggie. So, depending on the experiment, the sort of basic hardware that I’ve primarily used is what are called plant pillows, which are sort of a soft textile grow bag for space, and we fill these with a baked ceramic clay and a controlled release fertilizer, and then we’ll have some wicks in there, and the seeds get planted in there. And there’s a way for astronauts to inject water into these. They also have a fabric bottom that sits on what we call a root mat reservoir, which is essentially a bag with a fabric surface that we can fill up with water and they can wick water to these. And they’re all attached together with some bungee cords that hold those, those pillows into the base plate. And so the pillows provide an area that the roots of plants can grow. And the astronauts can water them or they can water the reservoir. It’s a bit of a challenge from a fluid physics perspective. But you know, we’re learning a lot about that.

There’s other types of hardware that have been used within Veggie to grow plants. And the most notable are just these petri dishes for sort of smaller plant experiments. So we’ve used these with Arabidopsis, which is a model of plant, basically the fruit fly or the white rat of the plant world, used a lot in genetic studies. And investigators have also used these with tomatoes, just growing them to seedling stage. And those get attached to the Veggie base plate. They were basically put in these kinds of racks. So, they’re lined up in racks along Veggie so they get the Veggie lights. And we can put other types of things in there like sensors, we usually run sensors inside the Veggie unit small temperature, humidity data loggers to collect environmental data.

And another system that has been used and it’s going to be used shortly in Veggie are what we call apex growth chambers, which are essentially plastic boxes that are filled with substrate, and they have kind of a showerhead attachment in the bottom that you can water that substrate through. And then they have a plastic dome that goes over the top thing that can be removed um as the plants grow. And so, you know, depending on what we’re growing, you know, those are going to be used for some experiments with grasses that are coming up. So, they’re very good for tall skinny things.

Depending on what we’re growing, we’ll use different hardware and we can get different numbers of plants or extract the plants in different ways from that hardware. So, Veggie is really a platform for doing these types of science and even for astronauts to garden. We’ve even had like bags of algal cultures, algae in Veggie, so lots of different things that you can do is if you just need lights and a fan, and we can control the light, we can study different light responses. So we’ve done that with leafy green crops, we’ve grown tomatoes in Veggie, we’ve grown Zinnias in Veggie and we’ve had flowers. So, it’s pretty versatile.

APH, the Advanced Plant Habitat, is much more complex, but we can get a lot of more data because it has over 180 sensors, and it controls different aspects of the environment. So, we do plant physiology studies with, with plants in there, and we’ve even grown chili peppers in there.

Host: That’s pretty fun. With all these complexities, what are some of the challenges you face with Veggie?

Massa: There are quite a few, you know. Veggie, because it’s so simple, most of the environment is controlled by the space station. So, you know, plants have a need for different environmental conditions to be within a certain range for them to grow well, and temperature, you know, humidity, and atmosphere, you know, carbon dioxide, and oxygen all have to be kind of within a certain range. But luckily, that range overlaps pretty well, with what, you know, the human comfort range.

So, Veggie is using the environment from the space station. But the water and the nutrient delivery in Veggie has probably been our biggest challenge. You know, we we’ve had issues where we get not enough water and things dry out. And then we have had issues where we get too much water and you get kind of a flood situation and the water can even start to, you know, coat the plants. And if it, it releases nutrients from the fertilizer, then you can get salt buildup. So microbial growth can be an issue.

We, we’ve had an issue where the fans, we thought, were on but they weren’t on. It’s actually a bit of a software feature, I guess you would call it. If power is lost to the hardware. And then it’s restored, everything comes back on. But for some reason, I think there’s you know, a challenge with the code and the fans don’t come on automatically, you have to turn them on. And we didn’t realize this at first.

So, we had an experiment, and you know, the power was lost to the whole unit there in the EXPRESS racks on the International Space Station. So, these are essentially, you know, like an entertainment center. So, it provides power, provides data, provides cooling air, and even cooling fluids if you’re if your hardware needs it. And Veggie doesn’t require too much.

But you know, when power was restored, the lights came back on and the indicator for the fan came back on, but we didn’t realize the fan actually wasn’t on. And so, water had built up in there.

You know, if you’re in microgravity, and you have no fans, then you have no natural convection. So, your atmosphere doesn’t mix. Heat doesn’t rise. That’s why I love the birthday candle you know experiment in space. You can see a candle on Earth with the orange kind of pointed flame The point is from convective currents, whereas in space, it’s just a very blue small ball with the candle because you’re limited by the rate of diffusion of getting that oxygen to fuel the flame so it’s just heat does arise and air doesn’t move. And then so without air movement, we weren’t drawing away the excess moisture from the plants. There was no evaporation, no transpiration, which is the way that plants get rid of water through their leaves. And so, water was just building up. And this led to you know, too much water and people have said, “Well, you could have just opened the bellows.” But if you do that in Veggie, you actually bypass the air movement entirely so it actually can make the situation worse.

Like things that you think of on Earth, you know, well, there’s not enough air movement, you open a window, you open a door — in space that that doesn’t, that doesn’t help necessarily, you know. You have to have that that air path. You know, I’m a plant scientist so I get to learn all of these, you know, mechanical engineering aspects of the experiment, fluid physics. And so, it’s been really, really challenging, but also really fun.

So fluids has been the biggest challenge that we have for Veggie. So making sure that we have good ventilation. You know, once we switch the fans back on, things are fine. But before then we got fungal growth, we had excess water, it was just, it was a hot mess.

And you’re on the ground, you know, we’re not there, and astronaut crew time is so valuable, and they’re so busy. So, it’s not so easy to just say, “Hey, can you go make sure the fans are on or turn them on?” You know, especially if we didn’t know, we’re trying to troubleshoot these things. And we’re looking at the power draw, and we’re looking at this and the other, but you know, so much of it is, it’s really unclear. So, we’re guessing from photographs, “Oh, that doesn’t look good, you know.” So APCH is a lot more user friendly in that way, in that we can control it all from the ground. And we have cameras, and so we have the ability to have insight into, you know, oh, this is this is not working, or this, the sensor is showing these data, whereas Veggie, a lot of it is kind of like, Guess, hope, you know, wish for the best. But we’ve had wonderful support from the crew, and they’ve just, they’ve really gone out of their way to make our experiments work. And we’re very grateful for that.

Host: So, just like the plants that the astronauts grow aboard the space station, you have to adapt your research.

Massa: Exactly.

Host: Can you share interesting results that may have changed the direction of what you do?

Massa: Well, you know, we learn something every time we fly. And so, for instance, you know, visiting, as I mentioned, we had water issues, we had fungus issues, but we were able to come up with ways to overcome those. And we got a lot of help from astronaut Scott Kelly, who said, “You know, I should probably be the one deciding on when to water and how much to water.” And we said, “Yes, exactly, you know, we, we can’t judge this as well from the ground as you can from space.” So, we’ve actually gone to a lot more autonomous activities where the astronauts kind of can take control of the plants and when to water and we give them guidelines, but they you know, they’re amazing individuals. So that was one thing that really changed the way that we were doing a lot of our earlier technology demonstrations.

We had to change midstream a lot. So, you know, we had a tomato experiment in Veggie, a couple of years ago. And the tomatoes first we didn’t have enough water, so things dried out, and we got poor germination. So, we had to kind of adapt and do a bit of a “Hail Mary” pass and try to add a lot of extra water to recover those, then we ended up with too much water later on in the experiment. And we were getting, you know, some microbial growth, but we also got these, like, fascinating aerial roots that grew on the tomatoes. Tomatoes always have a few aerial roots. But these were just massive.

And then we realized, okay, there must be getting way too much water in the regular root zone, because it was just making these crazy routes. And unfortunately, a lot of the tomatoes didn’t stay on the plants, they boarded prematurely, or they fell off the nest. And so, we didn’t have enough tomatoes for the crew to eat, which I think was disappointing for them. It was definitely disappointing for us, but we got all the samples back and, and instead of, you know, getting the taste test data, which we’d hope to get, we were able to get some different types of biological data from the samples.

So, you know, we’re always learning but sometimes it can be, it can be frustrating, but we have a really great team. And I think that is what helps in those difficult times. You know, we’ve reached out to the team and we’ve said, “Okay, you know, what, what could we do since we can’t do this, you know, what, what data can we get?” And the team has so many great ideas and you know, so it’s sort of, we build up ourselves and you know, get back to our Happy Places.

When we have teams that help us come up with solutions to these problems, so it’s something Yeah, I just I’m so lucky to do what I do and to work with the people that I work with.

Host: That’s a nice sentiment. 

You mentioned astronaut Scott Kelly, who had said that tending to the plants boosted morale and well being. Is that an outcome you had hoped for and expected? And what other behavioral benefits are you seeing?

Massa: Yes, that was something that we were really delighted to hear. You know, he was so happy and excited to be growing plants, and he was there for such a long mission.

And then, you know, having first the lettuce on his mission and then the Zinnias. I think he spoke about it multiple times. He did speeches when they first harvested the lettuce. And, you know, it just it was so impactful to us that you know, this, this thing that we had put all of our love and, and and effort into made an important part of his experience. It was very gratifying.

So, you know, we have since been collecting actual behavioral health data from the astronauts. We had a subsequent experiment, the VEG-04 experiment, and then the VEG-05 tomato experiment, where we began doing surveys of the astronauts to look at how plants impact their well-being, getting lots of crew engaged in plant care.

And so, we’ve been collecting data pre-flight, in-flight, and post-flight and looking at, you know, how much time they spend with the plants, how they enjoy the different activities, do they find the plants a source of sensory stimulation, and other data points.

So, we’re still compiling all of that, but in general, we’ve had really positive responses from the astronauts and even those that don’t necessarily enjoy the plant care find it very meaningful. to have plants in that environment. But many of them, you know, have spent a lot of time over and above their, their scheduled activities with the plants. We’ve seen Instagram stories from some of the crew, we’ve seen holiday photos and all sorts of things. In general, they’ve just been really supportive. And they tell us, you know, that they love having the plants there that they want to have more plants so, so that’s been super gratifying.

They love the smell of the plants, which is something that I found really interesting, we get all these photos back of like astronauts that are like, you know, sniffing plant leaves, and they said that, you know, when they open the bellows of the Veggie or the door of the Advanced Plant Habitat, it’s almost like being in the produce section of a grocery store and it’s just an aroma that they’ve really missed on the space station.

And then, of course, they really enjoy having them as, you know, a supplement to their diet and whenever they’re, whenever there’s a harvest that they get to eat, they’ll get everything out of the pantry and they get real creative and, you know, we’ve seen cheeseburgers and tacos and all sorts of fun things. They’ve even done some, you know, creative side dishes with the produce. So that’s a lot of fun.

Host: That is fun. It’s one of those human factors to consider for long-duration missions, too. So what are the challenges of scaling up this technology for a long-term human presence at the Moon or a human mission to Mars?

Massa: Well, you know, the International Space Station has some unique challenges with microgravity with, you know, the lack of convection, a lot of those things may be less of a factor on the Moon or on the surface of Mars where we’ll have some gravity, where we have convection.

So, it may actually be a little bit easier that we might be able to use more terrestrial-type growth systems on those planetary surfaces. And that’s something that, you know, we’ll find out moving forward. But the big challenges, once we leave Earth’s protective magnetic field, are going to be space radiation. That’s going to be a huge challenge for the astronauts as well as the plants. And we don’t know how that may impact things like long-term seed viability. You know, if we’ve got both solar radiation and cosmic galactic radiation, those could be a factor.

Operating, you know, at reduced atmospheres is something else that we’re considering. Plants are actually pretty robust. At lower pressures, as long as you can keep, like, the partial pressures of the gases that are important to them like oxygen and carbon dioxide. In a certain range, plants can actually go down to really low pressure. So, we’re not super concerned about that. But that will, of course, impact other aspects of the growing system.

On a surface, you’ve got challenges, like, you know, regolith, or dust. And those, of course, will also impact the plants. There has been discussion about potentially growing plants using lunar or even Martian regolith that’s been remediated in some way. That’s probably not going to happen in the near term. We’ll probably use approaches like hydroponic systems in the near-term, things that that are a lot easier to control. It may be possible to extract some of the minerals that the plants need from the regolith to use more of those resources in situ.

And maybe someday there will be the ability to grow using that regolith directly but because that regolith poses hazards, you know, like the dust hazards to the crew and perchlorates on the surface of Mars, it’s probably not something we want to be bringing in the habitat anytime soon. So, there would definitely need to be a lot of trade studies in place to see, you know, what makes the most sense for a different scale of mission. But, you know, I think everything will start small.

And we actually have a lunar payload that we’re a part of, the LEAF team (Lunar Effects on Agricultural Flora), that will launch on the Artemis III mission. So that’s being led by a company called Space Lab Technologies and Kennedy Space Center. Our team here is a part of that team. So we’ll be able to learn a lot about you know, plant growth under the lunar radiation and the lunar gravity levels. But that’s going to be a really tiny, you know, experiment that will come back and some will stay on the Moon and continue to grow.

Obviously, scaling up for something like a crop production system will happen when we have more of a permanent or a longer-duration presence on the lunar surface.

And as you scale up, you’re going to have a lot more need for automation. Plant health monitoring, using different technologies to determine, “Okay, ooh, something’s going wrong with the watering system. You know, let’s have some machine learning/A.I. control of that process. Oh, wow, our nutrients are a little off. I see this plant looks yellow,” you know. The astronauts aren’t gonna have time to do those activities every day. They’re not going to have time to maintain all the plants every day.

So, we want to get to an automated system as much as possible. And ideally 100% automation where the crew could just intervene when they want. You know, when they want to pick the ripe strawberry or the ripe tomato. Of course, they should be able to but because they’re going to be exploring and working on the Moon exploring and working on Mars, we want to free up that time, we don’t want them having to do subsistence farming on, you know, off Earth because that’s a lot of work.

So, I think there’s a tremendous opportunity for robotics automation and, you know, systems that learn moving forward.

Host: Could this research benefit people on Earth?

Massa: This research can definitely benefit people on Earth. We work in an area of trying to live more sustainably and that’s something that I think we certainly need on Earth. And we’re very hopeful that if we can learn how to develop approaches and technologies to be able to, to live sustainably off the earth, then we can apply a lot of those to living on the earth. 

You know, we have this amazing, beautiful planet. And it’s [got] tons of, you know, resources. It’s got a lot of buffer capacity for the things that that we use, we’re not going to have those resources in that buffer capacity in these sort of small microcosms that we’re planning for the Moon and Mars. So, we have to figure out all the puts and takes and the ins and outs of a system much more precisely and try to be able to control them. But if we can do that in these small systems, then, then it certainly can translate to how we live here.

And we’ve seen a lot of spinoffs from this type of research over the years that have had tremendous benefits. LED lighting for plants was first funded by NASA research. And the first patent for that was to a NASA-funded center. And now that’s something that’s being used all over in indoor agriculture, greenhouses and warehouses, factory farms all over, all over the world.

We recently sent one of our scientists (she worked at a facility that was designed by the German Aerospace Center in Antarctica) to grow crops in Antarctica, and learned about growing plants in these explosive, passive, hostile environments. So, you can imagine that same type of research could translate well to disaster areas or, or growth in some of the extreme environments that that are not considered arable here on Earth.

Even the fertilizer that we’ve been using for space is controlled release fertilizer that was developed on a company from by a company was developed by a company that had NASA assistance in developing this formulation. But they developed it to reduce fertilizer runoff on Earth from field-based agriculture and, you know, earth-based agriculture. And that fertilizer runoff is what’s causing a lot of challenges in our lakes and estuaries. So they’ve developed this formulation that we’re now using in space as well, but it limits the amount of nutrients to just what the plant needs, you know, that are being released at a given time. And so, there’s just a lot of, sort of, circular stories like that involved with the research that we do. And, you know, I’m sure there’s going to be a lot more in the future. 

Host: That is fascinating. What do you see as the next step in space plant biology research?

Massa: So, the next steps in our research are to really, you know, understand the different environments whether it’s, you know, the microgravity environment of the space station, or partial gravity environments of the lunar or Martian surface, and try to identify good crop candidates that will grow well in those environments, but also technologies that will work well in those environments.

We’ve been doing a lot of work on plant health monitoring, in collaboration with the USDA as well as some other groups trying to detect stress in the plants before it becomes limiting to their growth. So we can use techniques like hyperspectral imaging or thermal scanning or even, you know, sniffing of different compounds. Non-destructive approaches to try to tell, “Oh, this plant is stressed.” There’s a nutrient issue. There’s a water issue or perhaps there’s a pathogen of fungus or bacteria. And so, we have a lot more work to do in that area, but that will give us an ability to have insight into what’s going on with the plants. Before we would probably ever see that, you know, and some of our tests have shown that you can detect water stress, for instance, three days before, like a trained horticulture person can identify that those plants are stressed.

So that can help us solve problems with, you know, our growth systems, like, “Oh, a valve is stuck.” Well, we’ll know that much earlier than if we had, you know, if we waited for the plants to show the symptoms, by which point they may also be may already be dying. So those types of early warning systems I think are going to be really critical.

And for human health, as well, you know, food safety is something that, that we need to do a lot of work in that area. Because we don’t want to get astronauts sick. I mean, the whole point is to support the astronauts. So, we need to figure out ways to make sure that we can detect problems so that you know, “Gey, don’t eat that one, that one’s got something bad on it, you know.” On the space station, it’s not even easy to wash your hands necessarily, after you use the bathroom, right? And so, the potential of human associated microorganisms to, to be in the air to get on the plants is a real thing. So, we’re very concerned at trying to ensure in these systems.

There’s also partners and NASA funded groups working on genetic engineering of crops, or different types of foods for food systems. So, I think that research will be very interesting moving forward, there’s a lot of crops already available that you know, are good candidates. And we’re working through identifying, you know, which are the best candidates for space? So, lots to do there.

And then, and then it’s sort of like an integration question, you know, putting all the pieces together at different scales. And so, trying to think how can we become more sustainable, more efficient, smaller, you know, smaller sensors, better control systems, using more biological processes in the controls? Like, I mean, plants are not just being grown for food, but they also help to recycle the atmosphere, they can help to recycle the water. So how can we integrate those parts into the environmental control system? So, I think it’s just kind of a systems integration challenge.

Host: All welcome challenges, I’m sure. Lots to do.  

Gioia, before we let you go, what was your giant leap in your career? 

Massa: So, my giant leap actually happened before my career, but it was really what got me inspired by all of this. And that was when I was 12 years old, I was taking an agriculture class. Seventh grade, I was taking my first agriculture class. And my teacher got invited out here to Kennedy Space Center to learn about the research that was going on. They had an education professional development session, and he was here for a week learning about all of the plant research and he brought back tons of videos. He had his little camcorder with him the whole time. This was in the ‘80s. And he brought back tons of videos and I just, I watched them all and I was completely captivated. I had no idea that space agriculture was a thing. And I decided then that that’s what I wanted to do.

So, I’m very lucky to have a lot of supportive mentors over the year that helped boost me to be where I’m at and it continues that I have wonderful coworkers and mentors who help keep me enthusiastic and excited and I just want to pass that on to others. 

Host: Seems like you are. That’s wonderful.

Massa: Thanks. 

Host: Gioia, thank you so much for sharing your time with us.

Massa: It was great to be here, Andrés. Thank you.

Host: That’s it for this episode of Small Steps, Giant Leaps. For a transcript of this show and more about Gioia Massa, or the topics we discussed today, visit our resource page at appel.nasa.gov. And don’t forget to check out our other podcasts like Curious Universe and Houston, We Have a Podcast.