If you’re fascinated by the idea of humans traveling through space and curious about how that all works, you’ve come to the right place.

“Houston We Have a Podcast” is the official podcast of the NASA Johnson Space Center from Houston, Texas, home for NASA’s astronauts and Mission Control Center. Listen to the brightest minds of America’s space agency – astronauts, engineers, scientists and program leaders – discuss exciting topics in engineering, science and technology, sharing their personal stories and expertise on every aspect of human spaceflight. Learn more about how the work being done will help send humans forward to the Moon and on to Mars in the Artemis program.

On Episode 164, Dr. Grace Douglas, lead scientist for NASA’s Advanced Food Technology at the Johnson Space Center, shares the challenges of supplying food for a trip to Mars. Douglas describes the importance of variety, preservation, and farming on this sixth episode of our Mars Monthly series, where we drop a new episode about a human mission to Mars on the first Friday of every month. This episode was recorded on August 17, 2020

Check out the Houston, We Have a Podcast Mars Page for more Mars Monthly episodes.

Transcript

Gary Jordan (Host): Houston, we have a podcast. Welcome to the official podcast of the NASA Johnson Space Center, Episode 164, “Eat Like a Martian.” I’m Gary Jordan and I’ll be your host today. On this podcast we bring in the experts, scientists, engineers, astronauts all to let you know what’s going on in the world of human spaceflight. Our Mars Monthly series continues. Last month we chatted with Chel Stromgren, on what to pack inside of a Mars transport habitat on a human mission to Mars. Well, one of those critical items that you’ll need to prepare for not only the trip to Mars, but something you’ll need on Mars and back from Mars is food– and plenty of it. On this episode we’ll be focusing on how we’re thinking about food from Mars, what kinds of food, how to preserve it, and even if they will farm it. So, here to go into detail on food for a human mission to Mars is Dr. Grace Douglas, Lead Scientist for NASA’s Advanced Food Technology here at the Johnson Space Center. I hope you’re hungry, because we’re about to eat like a Martian with Dr. Grace Douglas. Enjoy.

[ Music]

Host: Dr. Grace Douglas. Thanks, so much for coming on Houston We Have A Podcast today.

Grace Douglas: Great to be with you and talk about my two favorite things, space and food.

Host: [Laughter] I think they might be two of my favorite things as well. I find your background very interesting. Talk about how you got interested– before we even begin with eating like a Martian and some of the Mars missions– just how you got into this world of food science in the first place.

Grace Douglas: Well, food science is actually really interesting because it’s a little bit different than, you know, what people are most familiar with, which is, you know, going out to restaurants and even going to a grocery store and just buying food. It’s the science that gets it there. And so, in contrast to something like being a chef where you’re preparing food for that moment to be eaten and experienced in that moment, food science is how we get the food and from the origin to the grocery store or to the restaurant in a safe way and often times in a way that has a long shelf life for the consumer. So, it’s basically looking at the science of food from engineering, from microbiology, and from chemistry, and also from the sensory aspects of how you take those different scientific aspects and make sure you have an acceptable product that often has a long shelf life. So, everyone on Earth experiences food science in some way, even if they don’t know it. So, it’s a very, very important process.

Host: Yeah, we’re all directly impacted by it. Right? We all shop at the grocery store and that food has to get there somehow. And so, you started your career first with a bachelor’s at Penn State before continuing your education in food science and then eventually functional genomics. You’re talking to a fellow Penn Stater right here. I’m very curious on your experience in your bachelor’s at Penn State because I know food science is one of those things that Penn State prides itself on, especially with the Penn State creamery.

Grace Douglas: Yes, so you’ve had the creamery ice cream then.

Host: Oh, yeah, very much.

Grace Douglas: Oh, yeah, that is one of my favorites is being in the food science building, which is connected to the creamery. So, definitely, you know, I would say that the experience of food science, it’s interesting because food science is one of the probably best-kept secrets. You know, a lot of people that I talk to about food science were not even familiar that it was a career path and yet, it’s so important because everyone uses the products of food science and that experience at Penn State was definitely a great place to start food science because there are so many food companies in Pennsylvania, so many food companies in that area. It just has a great basis for understanding the importance of food science all the way from the product at the farm and in the field to the end product that goes out to the grocery store and how you go through that process.

Host: And so, after learning that from the Penn– from Penn State, now of course you had the wonderful experience of the creamery, which I’m very jealous about, and learning the food science there, but you continued your education and I found this interesting. You got a PhD in functional genomics from North Carolina State University. How does functional genomics factor into food science?

Grace Douglas: So, I actually still worked in the food science department at North Carolina State University and I focused on probiotics. As we start to learn more about the genome, genetics, the microbiome, functional genomics is becoming a big part in how we look at basically every part of our lives, medicine to food to health. So, you know, looking at probiotics, we were looking at them from a whole genome perspective and how we could best choose those, best utilize those, understanding how the genome functions as a whole and how different genes interacted within it, and even if we could take those and utilize those in other ways. So, one of the things we would look at is could we put other functional genes into those genomes and basically create other uses for those beneficial microorganisms. So, that was– that was the tie-in to food science for functional genomics and that’s, you know, across the board an important tie-in because you can use that when you’re looking at crops, when you’re looking at animals, when you’re looking at any factor of food to the end user, there is a genomic aspect because everything on Earth that we’re going to end up eating has a genome.

Host: Now, I want to pull back for just a second to better understand what food science is all about. I think you did a great job of describing it right up front, but especially its considerations for space because the topic today is food for Mars, and it is complicated because of this aspect of food science. You talked about right at the beginning of what it takes to get food on the shelf and the life cycle and the shelf preservation of that food. So, I’m very curious, if you– if someone were to ask you, you know, what is food science, what are the things you have to be concerned about for food in space, how would you start?

Grace Douglas: Yes, and a lot of them are very similar to the things that we have to be concerned about here on Earth, especially as we have a growing population. So, in space we have to make sure that the food is safe for the crew to consume. We have to make sure that it’s nutritious. We have to make sure that it’s acceptable, so the crew want to consume it and we have to make sure that it fits within the resources that are on the mission. And those are the four probably most important aspects– and they’re all equally important. You can have nutritious food and if it’s not consumed it doesn’t matter if it was nutritious. And you can have a food system that provides everything you need, but if it doesn’t fit within the resources, you cannot take it with you. So, all of those things are pretty much equally important. We need to consider all of those when we’re developing food for spaceflight. And, in fact, all of those things are also important here on Earth because we need to make sure we have nutritious food, safe food, acceptable food, and that we’re fitting within the resources even here on Earth, which becomes a bigger and bigger challenge as the population grows. So, in fact, some of the technologies that can be considered for Earth are the same as those that might be beneficial in spaceflight or vice versa as we move forward. So, in general, for spaceflight we have a bigger challenge in that we’re sending food for the crews and so it needs to be shelf stable, a lot of times for several years. And that’s true even on the International Space Station. By the time that food gets made and shipped to launch and launched into space and we always need to have extra food in space, so by the time that the crew consumes it, it needs to have a multiple-year shelf life. So, as we go on to longer missions, such as missions to Mars, it’s likely we’re going to need even longer shelf lives. So, that can be a challenge, especially because on Earth we do eat a lot of fresh foods. And food science goes into the fresh food production as well, especially as far as the safety aspects, making sure that that food goes through processes to get it safely to the end consumer. But when we’re in spaceflight, the challenge is that we don’t have a lot of those fresh foods, so everything that we’re providing is mostly processed foods and that’s not really how we eat on Earth. We do eat processed foods, but not completely a processed food system. So, we– one of our challenges is trying to develop as many of those what you’d normally eat fresh food– so fruits and vegetables, things like that– in very acceptable processed ways so that the crew continues to want to eat those and provide the variety that crew can find different foods that they want and get all the nutrients that they want. It’s a common assumption that high-performing people like astronauts will eat whatever you tell them to eat or eat whatever they have to eat to be highly successful in the mission, but food is just psychologically important as much as anything and so everyone wants to eat what they want to eat. And when you’re talking about a closed system in spaceflight where there is a limited choice, we want to try and provide as much acceptable variety that would be as acceptable to a general population as possible because we don’t always get to know who is going to be the crew that’s going to be in space at any particular time in advance enough especially to even on the ISS get all of the food that that crew chooses to those crew members. So, we actually provide a standard menu on the ISS and about 75% of the foods that they consume are from the standard menu and we try and provide generally acceptable foods and then they do get some foods that they choose, that we send specifically for crew members and that tends to work with the resupply schedules currently on ISS. Originally we’d started with preference menus where crew chose all the foods that they wanted to eat, but because the food did not fly with the crew, it was resupplied and the resupply schedules would change and sometimes crew members would change, the crew on station did not always coincide with the foods that they selected and that does not work out very well if it was foods that they did not want to eat. So, we found that the best method is to provide a standard menu and provide as much preference as we can for those crew, but what we hear a lot is that one of the most important factors is just having variety, having choice in what they’re going to be eating. More variety is better.

Host: So, then how do you– there seems to be an– things– all of these factors that you’re considering, Grace, for all of these things about what crews and astronauts on the International Space Station, they seem to be pulling at each other. Right? So, you have nutrition, but you can’t just focus on nutrition, you’ve got to focus on variety because there is that psychological aspect. There’s– you have to focus on shelf life, you have to focus on taste. So, what are– what are you doing– what are you learning about life on the International Space Station that’s informing you on how to balance all of these– I guess you can call them requirements?

Grace Douglas: Yes and that– so, as we go forward into looking at exploration missions, the International Space Station is definitely some place where we can learn a lot and another place that we are trying to learn things from is from ground-based analogues where we can have subjects simulate missions and we can try and see how their health and performance outcomes look on different diets or diets that we think we can implement within missions. And so we have all– we have those tools that we’re looking at right now and one of the other things that we are trying to do is make sure that we can have a food system that meets the shelf life and that meets the nutrition requirements and the acceptability requirements for the length of the mission. So, there is actually a couple of different factors in research that we have to look at. So, one is the food itself, looking at making sure that that food is going to be nutritious and acceptable for those lengths of time and then another one is making sure it fits within the resources. And then the third part is making sure it really is supporting the crew, which is looking how the crew is using it on ISS, how we can better manage that, or looking at it within those analogue environments. And so those are really the three different parts. And so as far as the food itself, one of the things that we do look at is other technologies. Are there other technologies besides the ones we’re using? Which we freeze dry food, we use retort thermostabilization, all of our foods are packaged in lightweight flexible packaging, which is– a big part of that is to preserve resources. Canned, heavier packaging material uses a lot of resources and those foods tend to have a long shelf life, but at the same time, if we need to get a longer shelf life, we need to figure out, well, what are the requirements to get that, and so some of the things we can look at is alternative storage methods. So, can we use cold storage? That’s another resource challenge for long duration. And then are there other food systems that we might be able to start to integrate that could provide some nutrition and fresher nutrition? And that definitely introduces a lot of other challenges, but they are important challenges to start looking at now. If we’re going to start exploring and start becoming more Earth-independent, we need to start understanding how we produce the foods and not just take foods with us. So, some of the considerations for that are all the resources that go into producing foods and that would also include crew time. And so, when you’re looking at a mission, you have to understand how much crew time you have, how whatever system you’re putting into that mission influences all the other systems, including the air system, including the water system. So, all of those things have to be considered, including the waste system. And additionally, once we start getting out into deep space, we’re going to have to consider how radiation might affect these food systems and if you’re trying to grow some sort of foods, we don’t fully yet have an understanding of how that might influence growing those foods. So, those are all important considerations when we start looking at food systems that we might use in the future in comparison to the prepackaged food system that we do use today.

Host: I feel like there is a lot that we use today that can inform some of those– some of those items as we explore further out, as we go to Mars. Let’s zoom in on the International Space Station for a second and just take a deeper dive into what we– what we know, what we know about preserving food and providing nutrition for astronauts aboard the International Space Station. You were mentioning ways to preserve food and you mentioned freeze-dried and thermostabilized food. What are these types of food that are, I guess, considered space food?

Grace Douglas: Yeah, so freeze-dried foods are just like normal foods that you would eat, but we remove the moisture on Earth and then it gets added back in spaceflight. So, once they add the water back, it’s basically just like the food you would expect it to be. So, if it’s freeze-dried spinach, once you add the water back, it’s like spinach as you would expect it to be. So, the thermostabilized foods are foods that go through a high-temperature process and both of these processes are meant to help preserve the foods and prevent microbial spoilage and also foodborne illness. So, when we freeze dry the foods, there’s actually still microorganisms still there, but we test the foods and make sure that they are safe to eat, that there is no pathogens and that the levels of microorganisms are very low, and because there is no water, the microorganisms can’t grow. Once the water gets added back, they could grow, so the crew has to eat the food within a short period of time just like you would consume food on Earth so that you don’t get a foodborne illness from it sitting out. They don’t have refrigerators and freezers on the ISS to store food and we don’t know yet if we’ll have them on deep space missions. They are a big resource use. And so, once the water gets added, they have to eat that food. The thermostabilized foods are heated to such a high temperature in their final packaging that they’re commercially sterile, so there’s nothing left in there to grow, and so they can just– once– they can just be eaten as is, they already have the water in them, but once they’re opened, they have to be consumed pretty quickly because they can become contaminated once they’re open just like foods here on Earth.

Host: So, let’s– so what do we know? You talked about freezers for or cold storage for Mars missions, but zooming again once — on the International Space Station, what do we know about freeze-dried foods and thermostabilized foods, how long they preserve on the International Space Station?

Grace Douglas: So, depending on the food, they can last for several years. So, there are some nutrients that are more labile, right, vitamin C and thiamin tend to degrade a little bit quicker than some of the other nutrients. So, within about one to three years you start seeing some nutrients degrade to unacceptable levels and for some foods you also see that the quality degrades to unacceptable levels, meaning you might not really want to eat that food after one year, two years, and/or after three years. So, there is not a lot of foods that make it beyond two to three years, even as far as quality, and so that becomes a concern when you want your crew to continue eating those foods. And this is all at room temperature storage that we have right now on the International Space Station. So, if we had refrigerators or freezers, possibly we can get longer storage times because cold storage will extend the time that those nutrients and those food quality aspects remain stable, but right now we don’t know exactly what temperature will provide the extension that we need and also when you have cold storage you do see other things change as well. So, if you freeze food, you notice a lot of times there is a texture difference, so we would have to make sure that how we’re freezing those foods, how we’re storing those foods over time, and how we’re preparing them in the end that the foods that were frozen– if we were able to go that route– were still acceptable even after that process. So, there is a lot of considerations and a lot of testing that has to be done to make sure that over these lengths of time and over these different mission profiles that these would actually be real solutions.

Host: Now, on the ISS, on the space station, I mean there’s not really a– too much of an opportunity, it sounds like, to have food stay on the shelf for three years. There’s enough resupply because we’re in low-Earth orbit, we’ve got easier access to resupply the space station than on a Mars mission. So, the shelf stable room temperature foods seem to do just fine for the station, but let’s just say, you know, if an astronaut were to open a thermostabilized package or freeze-dried that’s past its expiration date, past this time where food and nutrients are starting to break down, what’s exactly happening there where if I was an astronaut and I were to eat that food two years down the road and some of those nutrients were to break down, what would be the– what would be the negative effects of eating food that is past its expiration date?

Grace Douglas: Right. And so, the way that we package and process foods, they’d still be safe.

Host: OK.

Grace Douglas: As long as the packaging remains intact, they’d still be safe to eat. But what would happen is they might not like the food so much, they might eat less of it, which can cause weight loss, and we do see that even on the International Space Station today, we see it on a lot of missions that crews tend not to eat the full amount of calories that they’re given. There is a lot of potential reasons for that that have been hypothesized without a really clear answer. And some of that, you know, definitely providing variety, providing highly acceptable foods can help with that. This is a unique environment where we are eating mostly processed foods. They do get some fresh foods on the resupply vehicles, like apples, oranges, things like that, but that’s still pretty rare, and they do get their preference foods. But when you talk about what will happen health-wise as the food breaks down, if they– if they’re not eating enough of it or if they’re missing a nutrient, they could become deficient in that nutrient and so on a long duration mission this could lead to illness and even eventually loss of life. So, this is definitely something we want to prevent by understanding our food system and understanding how crew is selecting food before we go on these missions.

Host: Very significant. The other item you threw in there was on variety and on preference. Now, there is a nutritional aspect, there is a scientific aspect here to make sure that the crews are getting the nutrients they need, but it sounds like this preference and having food that they want to eat– there’s a little bit of artistic element to here. You have to create a good meal. You have to act a little bit like a chef. So, how do you balance between providing the right nutrition for astronauts, making sure that they’re healthy on their mission, but then also adding an artistic flair with good and tasty meals that they’ll want to eat?

Grace Douglas: Yes, so we have some food science– we have food scientists in the lab who develop the foods for the astronauts. We do a lot of our development internally because we are trying to meet the nutritional requirements and we are also trying to provide less sodium and less sugar than is in a lot of the commercially available processed foods. However, we do take care to use fresh ingredients. We use a lot of spices and we try to provide a wide variety of items that would be considered generally acceptable and we go through the process of when foods are developed in the lab, we do sensory testing within the lab and then we also look at how foods are consumed on the ISS regularly and try to figure out if foods are less consumed can we replace them with something that might be more consumed? And this can help us too as we go forward to missions that might have less preference food because they don’t have resupply or even in the case where food may be prepositioned ahead of crews getting there and we might have to provide more of a standard menu and less preference food. So, these are– so there are a lot of considerations like that and it’s interesting when you mentioned the idea of being a chef. There is a challenge in that because when you are a chef you are often just producing something for that moment. And, if you were to take that item that you produced in that moment, a lot of times it hasn’t been processed to the level where it would be safe for long amounts of time or stable for long amounts of time. And so, once you take these items and you process them to be stable, they are very completely different items. So, a lot of times the process to produce that final item is quite different than what will go through the process to produce an item for a restaurant. There is a lot of consideration with how these ingredients will work overtime together through the process. The process has a huge impact on ingredients, and it can actually have an impact on flavor. And then just to make sure that over time that texture is also going to hold up. So, it is quite a different process to make sure that these foods make it through the shelf stable processing.

Host: Well, then let’s dive into that. What exactly is the shelf stable processing?

Grace Douglas: So, that would be like freeze drying or thermostabilization. And so, I can give an example of that actually. We had worked on a guacamole product. There was avocados that are actually high pressure processed so that they deactivate the enzymes and so the avocados stay green over time. So, this was an opportunity when these avocados became available that were high pressure processed to try and make a freeze-dried guacamole for spaceflight. And it was interesting because we– the first challenge was getting a guacamole product that would pass the microbiological testing. A lot of the ingredients in guacamole are products that you use fresh and they have a higher microbial count and we have very tight microbial requirements for spaceflight to make sure that we’re making sure our crews are healthy over time. So, we– once we got a product that met all the microbiological requirements and was also considered acceptable fresh, once we freeze-dried it and rehydrated it, it wasn’t able to make it through sensory testing as an acceptable product for most people because the processing had changed the texture of the product enough that it wasn’t what people expected when they had guacamole. So, sometimes you can overcome those challenges by adding other ingredients and, you know, we work on products a lot and do those types of things and sometimes a product just you realize that type of processing is probably not going to work right now for people’s expectations.

Host: That is very interesting. I know– I mean, I buy avocados all the time and I know, as soon as you cut into it, it starts to brown and you’ve got to eat it fast, so that’s definitely an interesting problem to have. You finally, you know, you finally get to the point where, hey, we can keep these things green for a longer period of time and get guacamole, but it’s that– it’s that preference thing. It’s that– I like the, you know, the term you use– I think its sensory testing– very interesting because that is a huge factor. Not only do you successfully remove the enzyme and kept it green, but if it doesn’t pass the taste test, you know, then maybe it’s not good for the crew because that is a very serious consideration for what can be qualified as space food.

Grace Douglas: Right, right. And just for clarification to that, those high pressure processed avocados are actually commercially available products. Wherever we can, we use commercially available products. When we’re developing products in-house, it is to meet specific nutritional requirements. So, if we need to find lower-sodium options or lower-sugar options, so fruits and vegetables, a lot of those items are available in the grocery store, but they’re available in cans, which are very heavy or in higher-sodium versions than we can provide to our crew when they’re eating an entire processed meal. So, where we can find items from the grocery store, though, that do meet the requirements of spaceflight, we use those.

Host: Very interesting.

Grace Douglas: In this– in this case though, we had to take the high pressure processed avocados through the next step to make them shelf stable for spaceflight, which would have been in this case we were trying to freeze dry them and the texture just was changing so much.

Host: I see. OK. So, it was that freeze-drying process that changed the texture. Very interesting. Now, I know on top of the packaging of food and doing this processing to get it freeze dried, to get it thermostabilized, one of the things that when you’re talking about a mission to Mars that is on peoples’ minds, really, when it comes to space food is growing food. I feel like a lot– it can be, at least at face value, a way to overcome a lot of these challenges when it comes to keeping something shelf stable for a long period of time. Just farming plants and growing new, you know, vegetables, whatever it may be over time to supplement an astronaut’s diet. I know there has been experiments on the space station so far for both growing and eating plants. So, how have those efforts been?

Grace Douglas: Those are very important as we try to understand how to grow plants and what the requirements are going to be for a long duration spaceflight and to figure out what the challenges are. So, right now I would say that, you know, it’s been very exciting that they’ve been able to grow plants and that crews have been able to consume some of those. It’s– what’s been grown so far has been leafy green products and I know that there is plans to try and get some tomatoes grown up there in the future. I think that what we’re learning is definitely going to help to provide more efficient processes and also to provide more reliable processes because one of the big concerns with growing food is that if it doesn’t grow and you were depending on it, now you have insufficient food, which can be a very, very big concern when you’re going on these missions. So, insufficient calories can be as dangerous as insufficient nutrition to crew health and performance and ultimately leading to illness or even loss of life. So, we want to make sure that we get these processes to a point where we have reliable processes where we have plenty of food if we’re planning on growing food and that we really understand what the requirements are resource-wise. Which is another good one too, to make sure that as we’re implementing these, we can make sure that we have the right resources on a mission and that we can support these new processes or that we can find more efficient ways to do– to produce these foods. But it is very important to start doing this work now because if we’re going to become Earth-independent, if we’re going to do more exploration, we need to figure out how to grow the food. And also, it becomes very important for crew because, as we leave low-Earth orbit where they do get some fresh food resupplied– and they say that food is incredibly important on the International Space Station when they get apples or oranges or something like that. There will not be an opportunity to have any fresh food resupplied as we go deeper into space and the missions get longer, and so having the ability to grow any fresh food is going to be very important, even if it’s just supplemental to the rest of the diet. So, as we go on some first missions where food might just be supplemental and we really start learning about the impacts of radiation on the seeds and on growing the food, we’ll gain a lot of information and hopefully still be able to provide supplemental food to the crew and that will grow into a bigger system over time. It’s also quite possible that as we go on some of these missions, there will be several different types of food systems that could make up a system. It might not be all processed. It might not be all grown. That’s not how we eat on Earth. We don’t eat all fresh food, we don’t eat all processed food, so finding the right integrated food system for these missions that meets the resource requirements, the nutrition, the acceptability, I think is going to be the biggest goal. And making sure that we have a food system that supports crew health and performance.

Host: So, yeah, let’s focus on a Mars mission then. Let’s see and investigate how what we have learned on the space station needs to grow and amplify and change for a mission to Mars. You’ve already discussed a couple elements. You know, we’ve had a lot of experience on the space station with freeze drying and thermostabilizing food. The trick there is keeping food shelf stable and with the right nutrients that don’t break down over time for this mission to Mars. You talked about working within mission resources and I know that that has still yet to be defined, but I’m curious as to some of the considerations that you’re bringing forward from a food scientist perspective on the resources that you think would be required for a mission to Mars. The cold storage is one that I think is very, very interesting and, from your perspective, how that would be utilized on a Mars mission, I guess in terms of what you’re thinking for the requirement for that cold storage, maybe size, maybe how much of the food would need to be frozen or colder, however have you, but some of the things that you’re thinking about and bringing forward to the table for a Mars mission?

Grace Douglas: Yeah, I think a lot of that is still unknown how much of the food would have to be stored cold and we’re doing some studies right now to see which foods might do better frozen, which foods might do better with just some refrigeration temperatures, or which foods will be fine if we just store them at room temperature because there will be some foods that will store fine at room temperature. And so, figuring out what that looks like is still forward work, but I would see that cold storage would be very beneficial to store some of the bulk food. And when we look at, you know, going forward on a mission to Mars, I think one of the big things to consider is whether a mission is exploration or colonization and how much crew time you do have. If you have crew that are exploring and are doing a lot of EVAs and don’t have a lot of time to spend on other things, then it’s similar to our lives where we come home at the end of the day and we want to be able to make a delicious, efficient meal, and we want the process to be acceptable. So, when we’re looking at food for these long duration missions, we need to consider that these are explorers and a lot of times they don’t have the training in food science or the training in food processing that you would consider if you were doing from a ground-up sort of food system. So, that makes it a little bit more challenging too and that’s part of the reason that prepackaged foods have been so beneficial because all we do is add water and heat them. It’s very easy to prepare them in spaceflight. When crew are very busy, it’s very easy for them to still– to still prepare and consume all of their meals. And so, when we’re on these long duration missions, I think one of the considerations is if we are on exploration missions that is this something we would want to do in our own kitchens. Is this something that we can do efficiently and quickly, and we want to do over and over again? Because the processes– the acceptability of the process can be as important as the acceptability of the final product to making sure that crew are getting their nutrition. And then also, making sure that they have time to eat together. We’ve heard that that can be very, very important for crew cohesion, having space together and time to gather together as an entire crew.

Host: Yeah, yeah. Definitely. That comradery. I know even now they, on the space station that’s something they regularly do and, as you’re saying, find very important. I’m curious to talk more about, you know, you talk about prepackaging food and storing it for a long time, that’s something that would be a consideration. I’m curious on your thoughts about the other end. Consideration you’ve given to– I guess what would it look like or what you would have to make sure would be part of a mission to Mars if they were, I guess, either processing or creating their own food on the surface. Is that– is that one of the things you were talking about? If the– an alternative to relying only on prepackaged foods?

Grace Douglas: Right. And so the Mars food system hasn’t been defined yet, you know, and prepackaged foods are a very good candidate because they are easy to prepare, easy to consume, they already have a safe and long history in spaceflight, but there are some challenges with them that they– that nutrition does degrade over time, that quality does degrade over time. So, on longer missions it would be nice to get a fresh component. However, there is just a lot of challenges to consider when you’re looking at other food systems too, and so all of the things that have to be considered would be things like the hardware you have to bring, how that integrates with other systems. If there is, you know, a heat load coming off of that system, you have to start considering touch temperatures when you’re in spaceflight. If you’re in microgravity, a lot of things become more challenging, you know, what’s the waste stream coming off of the system, what’s the water usage through the system, and then that extra water has to go through a recycling process. So, very quickly some things that look like they might even be less of a mass and volume burden because you’re producing them in flight, the ingredients going into them or the infrastructure requirements or the requirements during processing, including crew time, can become very heavy. So, there is a lot of considerations there and there could be also a lot of things that could help with that, such as new technologies or robotic technologies, and a lot of those things too could help on Earth as we go forward and our population expands and we need to find ways to feed the population with less resource use.

Host: Yeah, another — I’m actually curious to investigate the — that Earth application that you’re talking about, but there was one more on a mission to Mars that I found interesting was and you did mention this one before was the radiation factor and how radiation could affect food.

Grace Douglas: Yeah, so the few studies that have been done with the prepackaged food, there hasn’t been much impact from radiation. And so, you know, there is still further work that could be done in that area, but from what we’ve seen so far there is not much of a risk to food that’s already processed and prepackaged from the amounts of radiation that you’d be expecting to get in spaceflight. However, when you’re starting to grow food and you have seeds or any other type of food that you’re trying to grow in spaceflight, or you have ingredients that you’re storing and those all need to have a long shelf life too. And so, anything that’s going into the system, whether it’s equipment, whether its ingredients needs to have a long shelf life and it needs to function and provide the nutrition to the crew after storage in deep space. So, there is a lot of unknowns still there as far as how deep space storage might impact food and the growth of food.

Host: Are there any studies, maybe on the International Space Station, maybe on the ground, maybe in these analogues that you’re talking about where we’re trying different methods or researching some of these considerations that we’re talking about for a mission to Mars? For example, storing food in cold storage and taking it out after a couple years and seeing how it held up or perhaps some radiation testing with plants that are even grown in space or on the ground. Anything, any ways that we’re preparing now for what we need to be informed about for a mission to Mars?

Grace Douglas: Yes, there are a lot of people doing a lot of studies and– I mean this is beyond even NASA. There is studies in to how and into alternative processes that might be able to help food have a higher quality and nutrition initially that could give it an extended shelf life. We’re always looking for better packaging. We’re also and there are studies that are going on looking at impacts of radiation on various factors such as seeds, so there is definitely a lot more work that can be done in all of these areas, but there is a lot of ongoing work that’s being done around the country.

Host: Now, I want to go back to that, those comments you were making about Earth and Earth applications and how food science, one of the key things I think looking forward that you mentioned was how food science and how it relates to population growth on Earth. Now, what is it exactly about things we have to be concerned about and looking about to satisfy the population growth?

Grace Douglas: Well, so, there is a lot of considerations with the population growth on Earth. There is a limited land mass. There is a lot of food waste that occurs even currently and there is a limited supply of fresh water. So, finding ways to more efficiently use water, more efficiently use the land, find crops that grow more efficiently as we have global warming, finding crops that do better in those conditions, or developing those through genomic techniques are all things that we can do. And then also finding very efficient ways to do — to provide foods that are safe through food processing, to every area of the country and minimizing food waste by doing this in very efficient ways. And so there is parallels between trying to do this in spaceflight, reducing water usage, finding more efficient technologies and more efficient ways to process those foods, and even process small amounts of those foods, depending on where you’re trying to do this or how you’re trying to get food to different groups of people or even in disasters or emergencies. And so, there is parallels through trying to find efficient ways to do that or find efficient ways to reduce the use of water and provide more food with less.

Host: Grace, in your career, I’m wondering and curious about how you’ve seen food science progress, particularly on the International Space Station. I wonder if there has been lessons learned from the — you know, we’re coming up on 20 years of continuous human habitation and there is definitely some advances, I believe, that have occurred with life on the station and eating food on the station, a lot of things that we’ve learned. Things that you’ve seen in your career that have progressed significantly to improve the way astronauts eat on station.

Grace Douglas: Yeah and I would say a lot of that is just providing more variety. Getting the choice up there, getting the variety, and getting higher quality foods and healthier foods too. Options with healthier processed foods. So, one of the big changes that was made with the space food system in the last ten years was a significant sodium reduction and that was specifically done because sodium can exacerbate a lot of negative health impacts and it can exacerbate things like bone loss. And so, the sodium content in a processed food system tends to be higher than in a food system where you’re eating some fresh foods, and so one of the big, one of the big challenges was to reduce that sodium content and they were able to do that by developing foods using different spices, using high-quality ingredients, and then also trying to provide a wide variety of food so that crew could find foods that they did like. One of the other things that we’ve seen in spaceflight is crew really enjoy having options with condiments. It is one of the things that they can customize, so providing condiments. Preference foods is very important to crew, which is a challenge as we move forward to missions that might have less preference food due to lack of resupply opportunities and the potential that some food might be prepositioned even before a crew is selected. And so, there are — I would say that the biggest advance was probably providing a wide variety of foods in the lightweight flexible packaging so that it would meet resource requirements, shelf life requirements, and also provide the crew just with a lot of options.

Host: Very interesting. Now, for a Mars mission, how are you feeling based on the position we’re in now with the variety, with that standard menu that you were talking about? Do you think it needs to be expanded upon to satisfy a crew member that would be on a Mars mission for several years to make sure they do have enough variety? Do you think that we’re sitting pretty good now or do we need to have even more variety?

Grace Douglas: So, and that’s definitely a challenge is figuring out what, how to set up a food system for a mission to Mars where you might not have this resupply. You know, when you have more variety, the challenge is you still only have the same mass and volume that you’re sending the food in. So, right now a lot of the foods on the International Space Station are single servings. They’re, you know, they’re smaller servings, so crew can choose a lot of different foods in a day. And when you’re sending food to the International Space Station, whether you send — if you send more variety, then you’re sending less of each type of product. So, if you send ten asparagus, then you might — versus five asparagus, if you only send five asparagus, you might also be able to send five broccoli. And if you, you know, so you can kind of see in the same box you can either have a lot of something that somebody might like, or you can have a lot of variety. So, once you start getting to a lot of variety, you might have two or three of a serving of one type of product. And so, if you really like that product, then you might only see it once a week or once every two weeks.

Host: And so, the challenge is that, how do you come up with a menu that will satisfy a crew member for, let’s just say two years and then that person will come back from the mission and be happy with the selection. You know? How do you predict their selection, their crew preference for two years? It sounds like that’s a, that’s a big challenge.

Grace Douglas: So, the way that we look at the food system is how can we provide the most food that most people would find acceptable because we don’t know what individuals are going to want. And we can provide a whole lot of variety, but if somebody does really like a product and they can only find it once a month because we’ve provided so much variety, we’re not necessarily helping that person if they really wanted to eat that product more often. So, there is a balance between providing the right variety and also having foods there that would be considered core foods that people would want to eat a lot of and we can start figuring that out partially by looking at how the food system is used on the International Space Station. So, we can see the foods that are used a lot that might be considered more like core foods and foods that might not be consumed as much and that can help us define menus and how we can provide the right foods to crews going forward in ways that are more general and also that help crew have their core foods that they want to eat, but also have variety around that. Because if we think about what we eat every day, a lot of us will eat some of the same foods every day, we really like those foods, but we also like variety. So, that is a challenge to find that balance for a general population where you do not know who is going to be flying. There is another way to think about this. So, you know, if somebody on Earth develops a food product and 1-2% of the people really like it and buy that product, you probably have a good market on Earth. But if we develop a food product and only 1-2% of the astronauts like it, we’re probably in trouble. So, we really do have to focus on trying to find stuff that a large variety — a large number of people would enjoy eating.

Host: See, I feel like I would be a pretty good astronaut if only for the fact that I like pretty much all kinds of food. So, just give me your standard menu and I will be happy for two years. I’ll eat the same thing. I’ll eat a variety of stuff. I think at least that aspect, I think I’m set for a mission to Mars.

Grace Douglas: Well, there you go, then you should go to Mars.

Host: [Laughter] That’s it. That’s all you need. You just need a very broad palate. Grace, I’m curious about, you know, we’re talking about Mars missions here, but we do have the Artemis program coming up here, we have the Gateway orbital platform around the Moon. I wonder if there is anything in the near future in terms of exploration that we can utilize to test out some of the different, maybe even technologies, techniques, whatever you want to call it for food science on a mission to Mars. Is there anything that you’re looking forward to?

Grace Douglas: Yes. So, I would say some of the missions that are upcoming are actually a little bit more challenging because they’re short and because they are also very limited in resources and so some of those missions might have different challenges. But, in general, having the opportunity to have Gateway or other, you know, opportunities to position experiments in spaceflight or store foods out there in the spaceflight environment for long amounts of time can definitely help us to understand and validate what’s going to happen to food systems over time.

Host: Very interesting. Well, Grace, this was — this was incredible to talk about. Definitely one of my favorite things to discuss is food, just in general, but when I do get to talk about it on the podcast, it is a pleasure. So, Dr. Grace Douglas, thank you so much for coming on Houston We Have a Podcast.

Grace Douglas: Thank you. I enjoyed it.

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Host: Hey, thanks for sticking around. I hope you found this conversation with Dr. Grace Douglas as fascinating as I did, and I hope you’ve been enjoying our Mars Monthly series. This is the sixth in our installment. We’re going to finish out, round out the year with continuing Mars Monthly episodes. I think we might even extend a little bit into next year, so I hope you’re enjoying them. Stay tuned. They come out on the first Fridays of every month. You can check out our list of Mars Monthly podcasts and other podcasts episodes at NASA.gov/podcasts. Click on us, Houston We Have a Podcast. We have all of our episodes listed there. You can listen to them in no particular order. We also have some collections. If you go to that episode webpage, off to the left, we have the collection of, of course, these Mars Monthly episodes, but we also have collection of space station episodes, Apollo episodes. Be sure to check them all out again, in no particular order, just click on the ones that you find interesting. Trust me, I think they all are. If you want to talk to us on social media, we’re on the Johnson Space Center pages of Facebook, Twitter, and Instagram. Use the hashtag #AskNASA on your favorite platform to submit an idea for the show, just make sure to mention it’s for us, at Houston We Have a Podcast. This episode was recorded on August 17th, 2020. Thanks to Alex Perryman, Pat Ryan, Norah Moran, Belinda Pulido, Jennifer Hernandez, and Michelle Rucker. Thanks again, to Dr. Grace Douglas for taking the time to come on the show. Give us a rating and feedback on whatever platform you’re listening to us on and tell us what you think of the show. We’ll be back next week.