We are experts on NASA’s efforts to grow crops in space including a harvest just in time for Thanksgiving! Ask us Anything!

Since 2015, using NASA hardware, scientists and researchers have worked with astronauts on the International Space Station to conduct a series of experiments to grow, harvest and eat a variety of crops in space with seeds sent from Earth. The most recent experiment has the ISS crew growing Mizuna mustard using two different light recipes and multiple harvests, with the experiment’s final harvest scheduled for later this week. This work builds upon decades of NASA and international research into growing plants in space.

These experiments are advancing the knowledge required to successfully grow a large variety of crops on long-duration missions, such as a crewed mission to Mars. Being able to crops grown in space provides many benefits including supplementing the astronauts’ packaged diet with essential nutrients and combating diet fatigue.

Here answering your questions are:


Plant Biology-related Questions:

Question: Which plants have surprised everyone the most with their performance and which ones have the most potential for going to Mars?

Answer: Hello! As I am part of the team responsible for researching new crops on the ground to be applied in space flight, the plant that I found to interestingly not do as well in flight than it did the ground was a cabbage called Tokyo Bekana. Also, while screening some peppers a variety that grew very large and tall (too large for current plant growth hardware VEGGIE and Advanced Plant Habitat, APH), dwarfed itself and became a manageable size when grown in APH analog hardware. -L.S.

Reply: Have there been any additional promising candidates for smaller plants and payloads such as beans, herbs, and spices?

Answer: Sure! We have tested peas which would be a good source of other vitamins like thiamine. We are starting to work on herbs that could be mixed in with the packaged diet. I think things like basil, dill, mint, etc. would be really nice. Astronauts seem to like strong flavors, so crops like the wasabi mustard we grew earlier this year might be very good. With the fluid shift astronauts experience some have said it is like having a head cold, with flavors and odors muted. They like the strong flavors and the odors of plants, so herbs will likely be very appealing! -Gioia

Question: Do plants grow differently in low-gravity conditions, and if so, how does that impact your research, the choice of crops to bring on a trip, and the requirements for their growth space?

Answer: Plants are what we call “plastic” in their growth, which means they deal with what their environment has to throw at them. They can’t run away, so they are very good at adapting. On Earth, gravity is the main stimulus for the direction of growth of shoots and roots, but in space secondary stimuli will become the most important, with things like blue light guiding the direction shoots grow and things like water and oxygen gradients guiding roots. So in general plants can grow pretty normally if the other environmental factors are maintained in the normal range. The big challenge in microgravity is watering – plant roots need both water and oxygen because they respire like us. Getting oxygen mixed with water in the root zone is a huge challenge because of the lack of natural convection, and so that can impact plant growth. Other than these environmental challenges plants grow pretty normally. We are selecting salad crops that you can pick-and-eat directly with low processing and no cooking now but in the future other types of crops can be grown. -Gioia

Question: How does a plant find water and nutrients in the soil without gravity?

Answer: The seedling relies on blue light, which is included in the LED system, to orient “up” and “down” in microgravity. The Veggie vegetable production system, for example, uses flexible “pillows” that include the arcillite media, nutrients, and water. The plant roots grow throughout the pillows, while the stems and leaves grow towards the lights. -Jess Bunchek

Question: Do plants still grow upwards with no gravity? Do they grow normal size stems or does the lack of gravity affect this.

Answer: This is a very good question! The seed will sprout as usual in microgravity. But how do the roots and sprout know where to go without gravity to guide it? Essentially we position the seed in a way where the roots will come out in the direction of the moisture we have ready for it. Also the lighting gives the sprout a direction to grow in. In this way we help to guide the plant in the lack of gravity. -J. Torres

Question: Which crops are you expecting to do best? And which crops would be the most welcome surprise to do well?

Answer: The crops that we expect to do best have high germination rates, grow quickly but not beyond the system size constraints, are generally liked by a wide variety of individuals, and are nutrient-dense. The most welcome surprise has probably been wasabi mustard. It was known to meet these requirements before flying, but it has been a pleasant surprise just how much the astronauts, scientists here at KSC, and other guests have enjoyed the wasabi mustard flavor. It has a sharp but pleasant “bite” that people love! -Jess Bunchek

Question: Is genetic damage from high energy radiation something that factors directly into your research, or is the assumption that a spacecraft will be sufficiently shielded that anything hardy enough to grow on the ISS would be able to make it to Mars?

Answer: This is a great question!!! The straight answer to your question is yes, genetic damage from high radiation is something that we are actively researching into. When we leave Earths magnetosphere we lose protection from radiation that we enjoy while on Earth, and even in Low Earth Orbit like the ISS. Will seeds germinate after that exposure? Will plants grow? Will this have an effect on plant growth? These are all questions we are working to answer in our ground research at Kennedy Space Center. One experiment exposes Lettuce, Tomato, or Mizuna seeds to different levels of radiation and then grows the seed till maturity documenting the effects along the way. This is a work in progress. -J. Torres

Question: Why is growing seeds in space difficult? What about space conditions leads to trouble growing normal plants?

Answer: This is a very good question. Without gravity water moves differently and needs to be contained, this makes irrigation difficult. Also, the seed and plant does not have the gravity constant to guide its growth. Aboard the space station, the sun frequently rises and falls, making it an unreliable lighting source…so we have to supply the lighting. And ultimately, growing plants in space demands that an controlled environment is available. This means controlled temperature, Humidity, and other parameters. All of these aspects, along with the high CO2 environment of the ISS make growing plants in space challenging. -J. Torres

Reply: Thanks for the response! How do you mitigate the issue with irrigation? I imagined capillary action would have taken over in this situation to evenly distribute the water across the soil. Also, do plants require night or do you keep the lighting source on 24/7?

Answer: Capillary is one of the primary ways we distribute moisture in space. As a result we have to be very mindful of the materials we use for wicks and growth media.

So far the crops we have grown are done with a day/night photo period. in most cases 16 h on 8 off. -J. Torres

Question: So I understand that plants grow upwards towards the light, through their own system of hormones? But in space, with zero gravity I would assume that the plant would face any way so therefore would not know where “upwards” is. Am I being a bit dumb in thinking this is a problem or is this something that had to be overcome?

Answer: This is a great question! You are not dumb at all! Yes without gravity, how does the plant know where to go? We have to help it by positioning the seed in a way the roots will come out in the direction of our moisture system, and we use our LED lighting to help guide the plant to grow in the desired direction. -J. Torres

Question: What is the biggest issue you run into when trying to grow crops in space?

Answer: Water is the greatest challenge. Without convection in microgravity, humidity and oxygen can build up around the plants. The plant growth systems have fans and other methods to help create air flow. We also face the challenge of getting enough water to plant roots without drowning them. -JB

Question: You mention two different light recipes. Are these two different wavelength combinations and are the light intensity and duration changed? And if they are applicable to growing on earth, do you mind sharing some results about how important infrared light and the photoperiod actually are in growing plants?

Answer: Hello! In VEGGIE, we are using 2 different light recipes and yes, they are different wavelength combinations. 50:50 Red/Blue and 90:10 Red/Blue. The light intensity and duration are the same. These light recipes can be used to grow plants here on Earth successfully. In the lab, I’ve attempted to use Far Red (780nm) light to mitigate undesirable leaf intumescence in pepper plants, UV (389nm) to help develop a more nutritious leafy green by increasing the amount of anthocyanin. L.S.

Question: Doen the plants know where “up” is ? or they just follow the light (can you grow them upside down ?) ?

Answer: In microgravity, plants rely on other stimuli such as light — especially blue light — to orient themselves as “up” and “down.” The plant growth systems in space include blue light. We also check that the seeds are planted in the correct orientation to help them establish in microgravity with their “right side up.” -Jess Bunchek


Experiment-related Questions:

Question: How is the harvesting of plants in micro-gravity dealt with? There is typically debris from harvesting and trimming. Besides the plant growth itself, what other aspects of space crops is your team exploring? Do you see the possibility of automated space farms to support things like a colony on the Moon or Mars?

Answer: Hello! That’s a good question. Currently, the astronauts who have had an opportunity to harvest plants from VEGGIE, harvest much like you and I do at home. Using scissors, they either harvest the entire plant at once or harvest part of it, allow it to grow out again and then harvest again. We call this method Cut and Come Again. After the plants are harvested, the astronauts sanitize the produce using wipes that contain a citric acid based solution call Prosan. They are then allowed to eat the produce.

Other aspects of space crops we are exploring is characterizing the microbial and fungal communities that live on the plants and seeds. We are very interested in the automation of crop production as astronauts are very busy with exploration and habitat maintenance. Automation would allow the astronauts more time to do other things. L.S.

Question: Do you guys use soil or aquaponics? Do these plants require more maintenance than on Earth or can you plant and leave? Have you found any hard-and-true gardening techniques that just don’t work in space? Or techniques that work in space but not on Earth? Where do you see this research headed in 5 years? Or 10 years?

Answer: Hello, 1. In the VEGGIE Pillows and APH Science carrier we use arclite as the growth medium. Arcilite is red material they use on baseball fields. We are experimenting with some aquaponics, hydroponics, and other growth methods in our ground research labs.

2. The VEGGIE system on the ISS requires regular attention by the crew to add water to the plant pillows. APH has automatic watering and a controlled environment. Although a regular check of these plants while they are growing is needed.

3. Irrigation is very hard in microgravity. That is the biggest gardening technique that does not work the same way as on Earth.

4. Our overall goal is to supplement the crew’s diet using crops grown. In the next 5 -10 years we will continue to work towards that goal. J. Torres

Question: The intro says using seeds sent from earth – have there been any chances to use seeds created from previously space-grown harvests and if so have those seeds had any different properties or qualities than earth-based seeds?

Answer: During VEG-01 C the team grew Zinnias. This was a case where we grew a plant in space, collected the seeds, returned them to Earth, and grew them here in our Labs at Kennedy. At this point we have not researched the changes in traits and growth, but we have grown a plant in space, collected the seeds, and grew them on Earth. J. Torres

Question: Any bacteria or fungi coming with you to help out with nitrogen fixation etc? Are there protocols for the microbes on plants? What about any possible pests that could come with them? I’m curious about sneaky hitchhiking insects, for one. There could be some cool evolutionary divergence of shit up in space.

Answer: All of our experiments are carefully prepared and packed in a clean lab before launching, which minimizes the risk of pathogens or animal pests contaminating the ISS environment. However, there are protocols in place for mitigating microbial contamination if the plants were to become infected. Research is ongoing to define and preserve the beneficial microbiome (for nitrogen fixation, like you suggest) without creating a risk of pathogen hitchhikers. -Jess Bunchek

Question: Do you foresee any knowledge gained from space agriculture to be useful for normal agriculture?

Answer: Yes! The hardware developments can help controlled environment agricultural systems such as vertical farms and greenhouses. Also, microgravity is a unique testing environment for fundamental plant science. This furthers our understanding of how plants function in general, whether in space or here on Earth! -Jess Bunchek

Question: I assume you guys are mostly planting low crops that live for a single harvest. How long do you guys think it will take for humanity to send plants that can survive multiple harvests, like a tomato plant or maybe even trees (assuming there’s enough space on the ship)?

Answer: We are very interested in becoming more sustainable and using long-lived crops. The growth systems are still developing to support these. So far we have been growing leafy crops, but we have moved from a single harvest, to our current practice of cut-and-come-again repetitive harvesting where we can do multiple harvests from a single leafy plant. The harvest on ISS tomorrow will be the fourth harvest from this current crop of mizuna mustard. Tomatoes and peppers are on the near horizon. We hope to grow peppers in the next year with tomatoes shortly after. Trees will be farther down the road, but they are not impossible. We have done ground testing of dwarf plum trees that can grow from a seed to fruit in a year. They are pretty small but sensitive to water stress, so we have to develop better microgravity watering approaches before we work more on those , but watering approaches are a major area of research right now at NASA! Finding enough space to grow everything is another challenge that we have teams of researchers working on. Gioia

Question: Random, but what project would you guys love to work on if you had adequate resources/funding?

Answer: Here at NASA we always try to keep the end result in mind. While we are currently focused on learning how to sustainably and reliably grow crops on the International Space Station our ultimate vision is to grow crops as part of permanent habits on the moon and Mars. In these applications, crop production will be one part of a complete Bioregenerative Life Support System. Ideally, working on such systems is our end goal since these systems will eventually be necessary to begin the process of enabling earth independence.—-Ralph

Question: What kind of crops are you guys eventually planing on growing? I can see something like tomatoes or potatos working out but something like corn may be problematic for space reasons. What are your thoughts?

Answer: A big focus of plant growth experiments on the ISS has been on ‘leafy green’ crops such as Outredgeous lettuce and Mizuna mustard. The next phase of ISS experiments aims to grow ‘pick and eat’ crops such as peppers and tomatoes. The size of plants grown on the ISS is a constraining factor given that the APH and VEGGIE units are relatively small. Candidate pepper crops for future ISS experiments need to be smaller than 40cm in height fit within the APH. Far into the future, size might not be as much of a constraint, but with current technology, growing corn would not be possible on the ISS. -Lexi L.

Question: How do you manage your soil? Do you have a special type of material you plant the plants in? Just having dirt seems like a hassle, with lots of loose pieces (sand and such) just floating about, getting in astronaut’s lungs?

Answer: Hello! That’s a great question- currently, we do not utilize soil for grow our plants. In VEGGIE pillows and the Advanced Plant Habitat, we use a granular clay material called arcillite. It is very similar to the stuff you see on baseball fields. Loose particles is an issue that we take very seriously, that’s why the plant pillows and the APH Science Carrier are meticulously packed so the arcillite stays contained. L.S

Question: How do you deal with the limited water available on a space station?

Answer: We use our preliminary testing to predict the amount of water needed to support the plant grow-outs. So far, water use has not been so great that it has created concern over the limited resources available on ISS. -Jess Bunchek

Question: Are any of the crops you’re investigating genetically modified using modern genetic engineering techniques? What was the reasoning, whatever the answer?

Answer: GMOs have started to be explored for space plant biology. An ideal plant to be grown in space is one that is small, produces a lot of fruit (or edible biomass in general), and matures quickly. Theoretically, plants could be genetically modified to have these ideal characteristics.

Here are some cool links on a Dwarf Plum study that involved GMOs:

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170011601.pdf

https://ntrs.nasa.gov/search.jsp?R=20170001309 -Lexi L.

Question: Water has a tendency to adhere to solid surfaces, and in microgravity this problem causes water to have difficulties spreading evenly into the root system. How does your team manage to work around these issues and keep the plants watered on the ISS?

Answer: It is really hard. We are actually doing a lot of work to try and develop better microgravity water and nutrient delivery systems in the future. Getting the water to the roots is one challenge, but an equally important challenge is to get oxygen into the root zone. Water and oxygen do not mix well in space but roots need both. Right now we use a substrate – a porous ceramic called arcillite – to try and get both water and oxygen in the root zone – but in the future we need a more sustainable reusable approach so we are looking at a variety of hydroponic methods.

Question: The hydroponic greenhouse at Amundsen-Scott South Pole Research Station was one of my favorite places to relax when I worked there. Did any of the lessons learned from that facility inform what you are going in the Space Station?

Answer: Great question! Isolation analogs like those in Antarctica and NASA-sponsored analogs like HERA are helping us better understand the importance of plants for nutrition and crew psychology during long-duration missions in extreme environments. -Jess Bunchek

Question: How do the plants stay in the soil in low gravity?

Answer: The plants grow in flexible “pillows,” which help contain the arcillite media, roots, fertilizer, and water. There is a gasket that separates the materials in the pillows from the stems and leaves growing outside the pillows to prevent debris from leaking out in microgravity. -Jess Bunchek

Question: What are the biggest challenges you’ve faced growing crops in that environment? How well do your crops compare to crops grown on the surface?

Answer: One of the biggest challenge is water delivery. Because of the way water moves in micro-gravity, we either have too much, or too little in the root zone. Nutritionally, crops grown in space are very similar to those grown in our ground studies. Due to watering difficulties on both the ground and in flight, plants can vary in size. L.S.

Question: 1.Do plants transport nutrients/H2O different in low or no gravity environments? 2.Is the plan to grow plants on a space station or a planet/moon/other? And why? 3. Does this different gravity affect the size or shapes of plants as the grow? Sorry I couldn’t pick just one question!

Answer: Let me try and address your second question. We are currently growing plants on the space station primarily for research. This effort is a precursor to growing them sustainably and reliably in order to provide supplemental nutrition and variety to the pre-packaged diet for the long duration missions to Mars. Since these missions may take in excess of three years the nutrition, they provide may be critical for maintaining crew health. We also need to learn more about the microgravity influence on plant health, performance and nutritional content. Along with the biology, we have to understand and develop the best hardware solutions for dealing with water/nutrient delivery, lighting and volume optimization. In parallel with our efforts on the ISS we are indeed looking forward to and planning for missions to the moon and Mars. Partial gravity environments and the eventual ability to develop larger surface habitats provide both unique challenges and opportunities. We are diligently working to prepare for them as well. —– Ralph

Question: are you going to experiment growing crops on a soil similar to the one in mars?

Answer: There are currently many martian soil experiments underway by many institutions. Search up Martian and Lunar Regolith plant growth experiments. Currently these experiments don’t take place on the ISS. -Lexi L.

Question: Have you done experiments on how being at the space, or Mars, may change the natural changes of the plants during the seasons of the year?

Answer: Plants grown on ISS use controlled systems (air flow, light intensity and photoperiods, water, nutrients) and environmental conditions (temperature, CO2 concentration, and relative humidity). We believe we will also use controlled systems on the Moon and Mars, which will help avoid potential fluctuations caused by seasons. -Jess Bunchek

Question: Are the plant’s absorption of CO2 and emission of oxygen in the ISS atmosphere measured/monitored? Was there any significant reduction in onboard atmosphere maintenance / processing due to the plants’ metabolism? Besides the co2, were any other “waste products” like reprocessed water from urine or other products used in growing the plants? Trying to get a measure here as to whether this growing experiment was purely a food growing demonstration, or were you also testing organic life support recycling with plants?

Answer: Veggie does not control or monitor the atmosphere but our other plant growth chamber, the Advanced Plant Habitat, (APH), has the ability to sense and control the atmosphere. It is a closed plant physiology instrument which allows gas exchange studies in space. Veggie uses air flow through the plants from the cabin environment, so we take in the ~3000 ppm CO2 of the crew cabin. In terms of water, right now we are using potable water but we are very interested in developing more resource recovery from wastes. Veggie loses water to the cabin which is re condensed and processed. APH recycles the plant transpiration water internally. We definitely need more recovery of nutrients from inedible plant materials, urine, and hopefully human solid waste, but we are not doing those things on the ISS yet. Those methods are still being developed and will likely be tested at later dates for space crop production. Gioia

Question: What volume of greenery is being grown? Is it enough to eat a few servings of salad per week per astronaut?

Answer: Right now we are testing only 12 plants in Veggie. We have a harvest every other week which is a salad per astronaut at that time. This is a science experiment looking at light quality impacts on plant growth, nutrient composition, and food safety, so we have to bring half the produce back to Earth for analysis. The astronauts get to eat the other half. Each Veggie (we have 2) holds six plants and has a growing area of 0.13m2. So it is a pretty small growing area. In the future we would like to develop a large system that would provide at least a salad a week per crew member. And that salad would include not just leafy greens, but also peppers, tomatoes, etc. Gioia

Question: What plants are the most promising for long-term space missions? Could the Astronauts sustain themselves on plants alone, or would something else be needed? If so, examples would be welcome.

Answer: NASA has studied a variety of staple and supplemental crops and data indicate that a complete vegetarian diet could be grown in 40-50m2. This would include staple crops like wheat, soybean, dried bean, peanut, potato and sweetpotato, rice, etc. as well as salad crops like tomato, lettuce, leafy crops, radish, pepper, strawberry, and also herbs for flavor. Right now we are focusing on the fresh salad crops because there isn’t a good way to cook or process the staple crops on the ISS. The packaged diet of thermostabilized food or freeze dried food is quite good and so that is the main part of the diet for now and in the near future. We would likely add the staple crops when we have more cooking and processing capability – like on the moon or Mars. Gioia

Question: How do you plan on dealing with excess oxygen buildup around the plants? Do you have a system to cycle extra carbon dioxide to the leaves and o2 to the roots?

Answer: Veggie uses a fan to pull fresh air in from the cabin through the plant canopy. This air has elevated CO2 as the CO2 on ISS is generally around 3000 ppm with 6 crew members. This airflow carries fresh CO2 to the leaves and removes the oxygen. Getting Oxygen into the root zone is much trickier. We are working with space fluid physicists to help design microgravity watering systems which will add air to the root zone – things like hydroponic systems which intentionally introduce bubbles. Gioia

Question: How does pollination work if/when required? (is it even a concern) and would manual methods work at a scale required for colonization/mass food production? (if we wanted to avoid introducing “alien” insects on a foreign body, for example…).

Answer: Currently, we are evaluating plants that self-pollinate. So, an brief increase in airflow or a small shake from an astronaut would help ensure the flowers are fertilized. These manual methods would be quite laborious on a large scale. So researchers are suggesting robots to carry out this task. L.S.

Question: How do you decide which plants go to space and which not? What happens when plants get plant diseases?

Answer: There are several factors that we currently use to make crop selections. First we are targeting specific nutritional needs based on the contents pre-packaged food system as some key nutrients like Vitamin C and Vitamin B1 and degrade to unacceptable levels over time. We also look at crew acceptability as far as taste, and texture. Then there are the practical aspects such as productivity, edible biomass verses inedible biomass and the volume and resources the crops require to grow. Right now our focus has been on leafy greens and similar crops. In the near future we will be expanding our efforts to fruiting crops such as peppers which are high in vitamin C.——Ralph

Answer: We test the crops on the ground before flying into space, but that isn’t always a good indication if a crop might grow well. We are working to try to get higher fidelity ground growth systems to better mimic the space environment but gravity makes a big difference. To prevent plant disease we surface sterilize our crop seeds and clean all of our growth materials, but unfortunately there are a number of microbial contaminants in space. If the plant growth is good, plants generally out compete any pathogens. When plants are stressed, usually by too much or too little water, fungi might get established and if plant stress continues these can cause plants to suffer. We closely monitor photos and will remove any plants that are visibly ill. Astronauts also wipe down any areas with visible contamination with sanitizing wipes. Gioia

Question: Do you plan to hand pollinate each plant or is there an automated system?

Answer: In previous spaceflight experiments the astronauts hand pollinated each plant using a beestick – essentially a small brush. For peppers we are just planning to use airflow to pollinate and for tomatoes we are asking the astronauts to tap the stem to vibrate the pollen from anthers to stigmas. We are not sure that this will work but this variety of tomatoes has pretty closed flowers which seem to trap the pollen. When we grew zinnias in 2015 we had the astronauts just handle the plants a lot and this was sufficient to produce viable seeds in the returned flower heads. Gioia

Question: What have you found to be the most successful method of watering the plants? And is it true that spicy peppers are a favorite because of the dulled taste in space?

Answer: Watering plants in space is a huge challenge. Many traditional hydroponic systems will not work on the ISS because they rely on gravity to transport water to the plants. Two systems on the ISS, VEGGIE and the APH, deliver water to the plants in two different ways. VEGGIE has ‘Plant Pillows’ that are watered in small portions at a time. Without the presence of gravity, water can effectively starve plant roots of air if they don’t drink it fast enough. The APH waters plants automatically, again very little at a time. From what we’ve heard from astronauts, you’re correct in spicy peppers being a favorite. Taste buds are effectively dulled in space due to the lack of gravity making blood flow differently in the head. There are plans to send New Mexico chile peppers to the ISS some time next year. -Lexi L.

Question: What will be the first fruit grown and eaten in space? There are some dwarf tomatoes that should be within size constraints!!

Answer: The Russians have grown a variety of crops including peas on MIR and then ISS, and I am pretty sure they ate those. For NASA we will be growing dwarf peppers hopefully in 2020 and tomatoes in 2021 and plan to have the astronauts eat those. Gioia

Question: This may be an odd question, but they have done experiments on playing music for plants and/or talking nicely vs. meanly to plants and they respond to the happier sounds… have you done any experiments with sound for space plants?

Answer: Jessica Meir recently played her piccolo in front of the Veggie vegetable production system units on ISS during the ongoing Veg-04B experiment. While many articles have not reported plant growth benefits from music, we played a piccolo in front of our Veg-04B control treatment grow-out here on the ground…just to be sure! -Jess Bunchek

Answer: That was me. I played the piccolo for the Veg-04B ground plants 🙂 It’s hard job; but somebody has to play the theme from Star Wars for science, LOL! L.S

Question: Hello I have a few questions that you hopefully can answer 1 What are the plants that have already been planted in space 2 What type of conditions do you simulate in and will you try conditions that are more alien

Answer: Some of the crops that we have grown in space include ‘Outredgeous’ lettuce, Mizuna, ‘Extra Dwarf’ Pac Choi, ‘Dragoon’ lettuce, and ‘Toyko Bekana’ cabbage to name a few… On the ground, we simulate relative humidity, carbon dioxide concentration, lighting and temperature. L.S.

Question: Thanks for taking the time to do this ama. I am a high school science teacher and I teach my students about hydroponics. I have mentioned in class that NASA has hydroponic systems on the ISS. I am wrong telling them that? If irrigation is the biggest issue, how do you irrigate the crops? What types of crops have been grown on the ISS?

Answer: Hello, this is a great question!! Our current VEGGIE and APH plant growth systems aboard the ISS have different irrigation methods. VEGGIE pillows require a crew member to manually add water to it. APH has automatic irrigation and is essentially designed to behave like a Standpipe or manometer. Currently there are not hydroponic systems aboard the ISS, but we experiment with different versions of hydroponics for future plant growth experiments in micro gravity. We have grown lots of leafy greens up to this point; lettuce, Mizuna, Pak choi, and even Zinnias. Hello to your class from the VEGGIE team at NASA Kennedy Space Center -J. Torres

Question: Beyond all the issues with light cycles, gravity and so forth, do you see any potential for increased crop yields or nutrient density from the unique growth changes that occur as a result of space

Answer: We are actually testing this now in the Veg-04B experiment, which concludes this week. We are running a ground control while this study is being conducted on ISS to help us look at these factors. Stay tuned for the results when they are released! -Jess Bunchek

Question: What about potatoes though?

Answer: Potatoes may play a role later on when we actually have surface habitats on the moon and Mars as a way of adding calories to the diet. Currently we are focusing on Pick and Eat crops which provide nutritional support as opposed to significant caloric content. Part of the reason for this is that we are limited in infrastrcture and resources in a microgravity setting. —-Ralph

Reply: I appreciate your honest answer and it’s cool to know. However, it was a joke referencing the book The Martian. Can I ask what the difference between nutritional support and calorie content is?

Answer: You’d be surprised how many people ask and aren’t joking…. Think of nutrition as being what is currently provided by leafy greens via vitamins, phytochemicals and bioactive compounds verses staple crops which are high in calories. For example crops like potatoes and wheat.——Ralph


Miscellaneous Questions: 

Question: How much of the direction is placed on what can be cooked for optimum nutritional support before you decide what to grow? Have you considered genetically altering crops to flourish in space? Are mushrooms on your list?

Answer: We work closely withe the food group at Johnson space center and look specifically for plants that are high in key nutrients which may be low in the packaged diet. We have no cooking now on the ISS (except the new cookie oven!) so we are focusing on pick-and -eat crops to help supplement the packaged diet. The astronauts mix these foods with other things in the diet.

We are looking at this – these would be custom space crops plants that could flourish in this environment with it’s associated stresses. We have not had crops genetically engineered yet but have a list of traits that are of interest.

They are interesting. We would be especially interested in edible fungi that could be grown from inedible plant parts. -Gioia

Question: What do you think will be the main source of dietary protein for future space/Mars missions?

Answer: Hello! In the near term, the main source of dietary protein will be prepackaged foods. Hopefully, our research will allow for other crops, like green peas or peanuts, which contain larger amounts of protein, to be grown. L.S.

Question: Besides „just growing“ the crops, is it possible to use them as sort of „air filtering“ system? Basically to design a closed loop using plant, humans and potentially some microorganisms.

Answer: This is a great question!! A scientist named Bill Wolverton did 20+ years of botanical air filtration research at NASA. His work showed that plants can filter out VOC’s through phytoremedeation. Also one byproduct of plants is Oxygen. But they also respire CO2 during the night hours. For this reason using plants to filter air does not match the efficiency of using existing filtration technology. But there is potential in this idea. It has yet to be developed to a point where it is something that can be employed. There is room for research and development in this area. -J. Torres

Question: How you deal with the problem of pesky insect? I mean, is it possible (or better) if there’s no insect involved at all when growing the crops?

Answer: Many of our current experiments revolve around plants that don’t require pollination or that are self-pollinating. For many plants that we are currently working with such as lettuce, tomatoes, and zinnias, no bugs are intentionally involved in the growth process. Here in our labs on Earth, insect contamination does occur and it is a BIG deal. If bugs such as fungal gnats are found in any of our experiments, the consensus is usually to kill the experiment right away and sterilize the growth chambers used for the experiment. For ISS experiments, the goal is to never introduce bugs to avoid contaminating its environment. -Lexi L.

Question: What’s a pseudonaut? Is NASA following the progress of the alternative meat companies like Beyond Burger in creating a vegetable meat replacement?

Answer: Pseudonaut is a portmanteau of pseudo + astronaut. The job includes running ground tests before and during the flight studies to verify logistics such as the astronauts’ procedures and required timelines. These tests are also vital for becoming as familiar with the crops and studies as possible, so the astronauts have the best science support possible. -Jess Bunchek

Question: how do you cook the food you grow?

Answer: All of the crops we have grown so far have been consumed raw. We have not grown any crops yet that require cooking or processing. However, the ISS now has an oven for baking cookies! -Jess Bunchek

Question: PICS!?!?!?! please?

Answer: Here’s an album of photos from the Veggie plant growth system 🙂 https://go.nasa.gov/2QSRPrm 

Question: What’re your thoughts on aquaponics, or some other self-sustaining system, and their viability in a space station or colony?

Answer: Aquaponics has the potential to provide a contribution to the long term food production needs of colonies on the moon or Mars. However, successful aquaponic systems are not easy to establish and maintain. They are certainly beyond the scope of anything we could include on a space station in the relatively near future. Their size and complexity would make them unfeasible. We need to remember that behind all of our decisions, we have to consider the mass balance associated with the systems we fly and the food they produce. Crew time is also a major consideration.—-Ralph

Question: How does one get into this line of work? I’m a high school student and am very interested in space biology stuff.

Answer: Hello! I went to Tuskegee University for Plant and Soil Science. While there, I was able to learn about hydroponic plant growth of herbs, sweet potatoes and peanuts for terrestrial space missions (Mars). L.S.

Answer: Hello! Intern here! One of the best ways in the door to NASA is through its internship program. You must be at least 16 years old to apply to be an intern, but many interns are much older as well. I’m a 17 year old college student interning over at Kennedy Space Center. There’s a range of internships available for all levels of education from marketing to biology to virtual reality. You can apply for a NASA internship through nasa.force.com! Another great program for students to get into NASA is the NASA Pathways program. You can apply to those positions through usajobs.gov. -Lexi L.

Question: Do you have any recommendations on how to get involved in this field? And/or how did you all end up in this field? I’ve looked into some of NASA’s internships and fellows but haven’t quite found what I’m looking for.

Answer: Jacob and I both came to NASA KSC via the internship program while in our graduate programs, so I recommend revisiting that option. If this isn’t a route that suites you, many universities across the U.S. collaborate with our research. Plus, companies that produce crops via CEA are always applicable to our mission! Good luck and hope to see you apply to the internship program. -Jess Bunchek

Answer: Hello! I did my masters at Tuskegee University in controlled environment production as well. As a student, I feel the best way to get in this field is to research areas of interest to NASA in graduate school, and apply for and hopefully get an internship. Search “Crop Production” and “Kennedy Space Center” in the search NASA internship portal. Good luck! L.S.

Question: How did you become involved in scientific research such as this? Throughout your academic and professional careers what courses did you take or work experiences did you have that you feel have been most beneficial to your current work and or research?

Answer: Each of us has come to NASA from a unique background with unique experiences. Our academic backgrounds include agronomists, botanists and plant chemists/biologists/physiologists, but we also have polymer chemists, engineers, physicists, and environmental scientists. There is no one path to working in this area! The overarching factor and goal is that we are all deeply motivated by this mission and work selflessly as a team. -Jess Bunchek

Question: Growing things in space has been a fascination of mine for some time now, truly a awesome and inspiring concept! But I am wondering what kind of education or steps in life I can take to become part of the development of something like this. A little of topic, but I would appreciate any kind of answer.

Answer: People from all sorts of backgrounds contribute to our plant growth research. We utilize people with backgrounds in everything from mechanical engineering to air flow to botany. We get help from many experts in plant biology, but another whole component of making these plants grow in space is creating the systems that the plants grow in such as VEGGIE and the APH. One way into this area of research is through studying space plant biology which is starting to become more popular at several universities through graduate programs. -Lexi L.

Question: What is the practical importance of growing crops in microgravity? I mean if we are going to colonize some planet/moon, we will have to grow in presence of gravity.

Answer: Before we actually set up shop on Mars we need to get there and get back on our early missions. Right now the prepackaged food system will not meet the requirements for certain key vitamins and nutrients for those long duration missions. These missions are expected to last possibly more than three years. In order to keep crews healthy and operating at peak performance the crew diet will require supplementation that we expect in part to be met with the fresh crops we grow along the way.——Ralph

Question: I believe I recall hearing that all the live biometric readings of the astronauts indicate that they seem most calm and least stressed while working on the gardens in the space station. Is this true?

Answer: We are working with the Human Research Program at NASA Johnson Space Center to study the astronauts’ responses while working with the ongoing Veg-04B study. Stay tuned for results when they are released! -Jess Bunchek

Question: Do you worry about the vegetables becoming sentient and taking over the space station? Sounds like a setup for a sci-fi flick.

Answer: Haven’t seen any sentient vegetables yet… Write it! -Lexi L.

Question: So, I figure there has to be a pool on the first french fry in space. More generally, is there an experimental space cooking plan in the works, or is the focus still purely on getting things to grow at all?

Answer: Cooking requires hardware and resources that we currently do not have. Mostly because vehicle space and power is at a premium. Eventually when we establish a permanent presence it’s expected that habitat volumes will increase, that hardware will become available and cooking will play a significant role. Interestingly, the last time we had an actual galley for the crew to cook their meals was back during the Skylab program.——Ralph

Question: In the case of a long distance mission, would human waste be used as fertiliser? How else would the vitamins and nutrients stay present?

Answer: Recycling wastes and recovering resources is really important for future sustainable living off Earth. We have started working on recycling compounds from human urine which is a challenge because human urine has sodium and plants don’t tolerate lots of sodium. But there are so many important compounds in urine we are trying to find ways to extract them without the sodium. Human solid waste is a little more challenging, and food safety implications mean we have to be very careful preventing human-associated pathogens from contaminating our crops. Using bioreactors with thermophilic bacteria at high temperatures might be a way to remove valuable fertilizer compounds without pathogens. But a lot more work needs to be done in these areas. Fertilizer is heavy, however, so we need to figure out how to recycle as many things as possible. These include inedible plant materials (e.g. roots and stems and leaves of a tomato plant) to get the nutrients back out to grow the next crop. Techniques like composting, leaching, and biochar formation might all be opportunities to reclaim these nutrients. Gioia

Question: What’s an interesting fact us “normal” people would find intriguing about the process

Answer: We have heard astronauts say that they thought when they returned to Earth they would want a burger or pizza, but what they found they craved the most was a fresh salad. Having access to fresh veggies seems to be something many of the astronauts really like. Some have also commented on how the scent of fresh plants was so welcome! Gioia

Answer: That is true for us who have been in space analogs as well. I had an opportunity to spend 30 days in an analog called HERA at Johnson Space Center. After only that short amount of time, we all craved a salad! L.S.

Question: For any colonizing / growing large yields of crops, how is the plant respiration taken into account? From what I’ve looked into the ‘mission to mars’ is going to try and sustain their food just from plants, but I don’t see how they will handle the oxygen at that level, are explosions a concern?

Answer: At least initially, and likely for some time, we will not be relying on the crops we grow to provide the entire food system for the crew. Pre-packaged and shipped food will still provide the bulk of the crew diet. Over time it is expected that the variety of crops we grow will expand to include traditional staple crops and that will offset some of what we have to ship from earth. Other new technologies currently being researched on earth will also eventually be added to the food system. Perhaps even before the first mission to Mars. Plant respiration is something we already factor in when it comes to the design of life support systems we design for flight vehicles. When we look further to future Mars habitats these will be designed as part of complete Bioregenerative Life Support Systems designed to balance the production and consumption of Oxygen and Carbon Dioxide.====Ralph

Question: What is the purpose of harvesting crops in space? Which crops do you prefer harvesting, and why?

Answer: One of the main goals of harvesting crops in space is to prepare for future missions. Proposed Mars missions can last as long as 5 years without resupply and in that time, the nutrients in food that would be sent on such a mission would degrade to the point that they wouldn’t be able to sustain astronauts and provide them with the vitamins necessary to thrive on a long-duration mission. By conducting plant growth experiments on Earth and the ISS, we are setting up future Moon and Mars plant growth experiments. -Lexi L.

Question: What sorts of unexpected challenges have there been?

Answer: The challenges of watering were one of the things I least expected. I knew it would be a challenge but I didn’t realize how hard it would be to predict how much water plants would use in the space environment. Another surprise was that one variety of Chinese cabbage we grew, ‘Tokyo Bekana’ grows really well at Earth-levels of CO2 but grew badly at the elevated CO2 on ISS. This is the only variety that had that different response. A last challenge that I found very interesting was the difficulty in determining when air flow was turned off. This was something that happened with our zinnias and it is surprisingly hard to detect whether the fans are working as expected. Gioia

Question: How much m3 would a spacefarm take up to be able to sustain a human ?

Answer: Our working estimate is roughly 40-50 square meters per person. How we optimize that into a habitat volume most efficiently is research that we are currently looking into.—-Ralph

Question: Hey Jess!! Who would you say was your best office-mate in 412 ASI? It’s so great to see you doing such amazing things!! I hope you’re loving it down there!! -Anthony

Answer: Hi Anthony! The big jade plant on my desk was a solid companion in the 412 office. Great to hear from you, and say hello to the whole 4th floor team for me please! -Jess

Question: I’ve heard some unsubstantiated claims recently that large portions of farmland only have about 60 harvests left in them before the soil is ruined. That combined with the climate change issues makes me wonder if we might have to find an extra-terrestrial solution to food production. Is it possible to scale up the methods you’re using here to, let’s say to start, a town-size scale? Does that seems to any of you to be at all possible in the future? What obstacles might stand in the way?

Answer: Actually, I don’t think we will ever be growing plants for food in space and shipping them back down to earth. A lot of the methods we use for growing crops in space tie back very well with the controlled environment agriculture work being done here on earth already. So there is a lot of commonality in terms of the challenges we face (limited resources, sustainable and efficient production etc.). I have participated in conferences that have suggested that one approach to meeting the food challenges of our plant in the decades to come would be by the development and replication of large vertical farms the size of skyscrapers. While there is still a lot of research to be done in that area I think that would make for a better long term solution.——Ralph

Question: How successful are your space crops, who is responsible for tracking growth, how do we know you’re real and not karma fishing

Answer: Determining what is successful is something that we actually are working on. For space crop growth we are actually figuring out metrics of success. It is a combination of how well the plant grows, what the edible biomass yield is, how nutritious the crops are, how delicious the crops are (organoleptic attributes), or if they are safe to eat? All of these and more are indicators of success. We also are looking at the behavioral health implications – how taking care of plants makes the astronauts feel. Trying to put all these together is a challenge and we work together as a team of plant scientists, chemists, microbiologists and psychologists. We track growth from photos the astronauts send, and from mass measurements they make on the ISS (using a slingshot-like mass measurement device) and from frozen samples that get returned to Earth. I guess you know I am real because I am far too nerdy to be a robot! Gioia