If you managed to find yourself on the ISS, you would have a decently sizable menu of thermostabilized and rehydrateable foods to choose from. Astronaut food has advanced considerably in the decades since “Mercury astronauts had to endure bite-sized cubes, freeze-dried powders and semi-liquids packaged in aluminum tubes.” But if humans are to continue to explore outer space, going further and staying longer, reheating and rehydrating food will not be sufficient: Astronauts will need to cook.
Larissa Zhou is a food engineer who is defending her PhD research at Harvard in September, where she developed a technology for cooking food in a liquid medium in space (spoiler alert: it’s a device for boiling pasta). Previously, Larissa spent 5 years as the chief food scientist at Modernist Cuisine, with Nathan Myhrvold and Francisco Migoya, leading a team of researchers and chefs on technical R&D for the award-winning 5-volume book Modernist Bread.
Larissa is passionate about shifting the embedded values inherent in the space food paradigm and advocating for delicious and inclusive orbital foodways. Beyond her interest in food, she is a massage therapist and is training to become a mountain guide. Our conversation with Larissa covered the complex challenges of developing food for life in space along with a healthy dose of terrestrial fare. The conversation has been condensed and lightly edited.
lee wilkins: What volume of food does your device accommodate?
Larissa Zhou: It’s a prototype that holds ~100 mL of water, so not much. During my flights, I was cooking three pieces of rigatoni! Down the line, it can be scaled up. There are probably fluid-related physics that will need to be accounted for at say, 3-5 L.
Another possibility is to have multiple small pots, of course. What’s cool is that on Earth, the cooking range looks the way it does because of gravity. Each pot needs to lie flat on a different part of the range. But since my pot is a wedge that doesn’t care about up or down, you could have a radial arrangement.
Dave Cox: What do you do with the cooking water once it's done? Cleanup is such a huge part of cooking and that feels like so much more of a hurdle in space.
LZ: You’re getting at one of the arguably more complex aspects of designing life support hardware for space: How does the individual system interface with other life support systems? Further iterations of the prototype will need to account for that. For example, what about volatiles (not necessarily from boiling, but what if you were baking?) and steam? On Earth, I can open the window. I can’t do that in space. I initially thought it’d be nice to be able to smell food, but in a space habitat, the atmosphere revitalization system needs to be able to handle that. A colleague also pointed out that some crew might be nauseous and super sensitive to smells. So even if I wanted to smell a baking cookie, maybe my crew doesn’t.
For your specific question about water: I’m thinking that the pot will need to have a port for injecting and evacuating water. Maybe two ports, one port for clean water and another for moving greywater to the water filtration system. That means the water filtration system better be able to handle water fouled up by food bits. That leads me to think that my pot should be a sous vide system in future iterations, which doesn’t foul the cooking water.
Spencer Wright: Besides boiling it in water, what’s the most likely way that food might be cooked in space?
LZ: My work is about cooking via heating and hydrating, which is what starches need. Some foods don’t need to absorb water and can get away with heating alone. So we should continue to develop tech that does that. It can be an oven, microwaves (I’ve seen mention that Tiangong, the Chinese space station, has a microwave; the ISS doesn’t have one; it seems to be more of a shielding and power budget issue than anything else), grill, etc. I think an air fryer, which is really a bench-top super powerful convection oven, is a really good candidate for being adapted to space. It’s versatile and enclosed already. I’d add something on the inside to hold the food in place, but that’s probably about it. The bulk of the work would be in systems engineering - how to get it to fit within the existing web of life support systems and mass, volume, and power constraints.
Hillary Predko: I'm curious about your tests in microgravity! How were they arranged? Also, in the video, it looks like other people are testing prototypes – how did people get involved and what other devices did you think were cool?
LZ: There really needs to be increased access to microgravity environments. I was lucky enough to be able to cross-register at MIT, which had just started a class through the Space Exploration Initiative. Students can apply with μg [microgravity] experiment ideas, and if accepted, they cover all the costs and help you from prototyping to flight paperwork. The people you see in the video are other students and the plane is flown by Zero Gravity Corp, the only microgravity flight provider in the US.
As for other projects, there were all sorts from testing a technical component of an optics system to a watercolor set-up in space. I really like that the initiative is all about promoting a holistic and sustainable approach to space exploration. If you want to learn more about the different types of microgravity testing platforms (drop tower, plane, sats, sub-orbital, orbital) and issues of accessibility, here’s a nice paper by one of my mentors Danielle Wood at MIT and her student Christine Joseph.
Chris Hector: Are optimal nutrition diets in space similar or different from what you would imagine an optimal terrestrial diet would be?
LZ: The current requirements are similar to USDA nutritional requirements, plus some higher requirements for some vitamins as countermeasures for life in space (extra radiation exposure, quicker bone loss due to lack of loading from gravity, etc). For longer stays in space, I think we have a lot more room to explore and learn. Nutrition on Earth is already a finicky, not well-understood topic. Much less space, much less for diverse groups in space.
Samantha Luc: How much thought is being given to the need to accommodate dietary restrictions for astronauts?
LZ: I don’t know the specifics, and it depends on the space agency. For example, when Malaysian Muslim astronaut Sheikh Muszaphar Shukor went to space in 2007, a whole set of guidelines for performing Islamic rites on the ISS were developed, including guidelines for fasting and halal food.
The current NASA space food system is that there’s a 200-item pantry that gets sent up and crew can eat whatever they want from it. It used to be a lot more tailored. They’d have the crew choose their preferences before the missions and then send up resupplies of particular items specific to the crew. But crew assignments change, missions get delayed, and I heard that the crew wasn’t happy having to eat, say, someone else’s preferred foods. Also, people get congested up there due to fluid shift, get stressed, nauseous, etc and all of a sudden prefer very different things. So NASA switched to a general pantry-style menu. But generally, my impression is that astronauts cannot afford to be too choosy. This is why I work on my chosen topics – to design systems that allow for a more diverse and equitable presence in space.
HP: Lee introduced me to the 9-point hedonic scale NASA uses for food satisfaction. They aim for food to be a 6, or something that the people eating it "Like Slightly." That seems like a low bar! How do you think we should conceptualize food satisfaction for people in space?
LZ: A human factors designer at JPL, Tibor Balint, came up with a version of Maslow’s hierarchy adapted for spaceflight. He used it to explain his motivation for designing a pillow for space. Why would he design a pillow? In microgravity, it wouldn’t be for neck support. He posits that it’s for comfort, for a reminder of home, for all the higher-level needs that humans have above and beyond basic air, water, food, and shelter. I love that paradigm.
Similarly, getting a 6 on the hedonic scale sounds like it’s barely edible, i.e. technically you can eat it. But is it eatable? Does it bring you pleasure and joy? It’s not quantifiable at the moment, and I’m not interested in quantifying it. We waste a lot of time trying to quantify something when we could just accept it’s important and design for it. I see that quantification mindset a lot in engineering, specifically around designing for humans in space. I worry that we’re headed toward a future of extraction and destruction in space if we maintain a narrow focus on the quantifiable, the monetizable, and the technical.
I get that quantification can be useful when justifying investment. NASA for example is using tax dollars and needs to justify that it’s better to invest in developing better food than in, say, maintaining the James Webb Space Telescope. So it needs to be a systematic rethinking of what values we want to guide our decision-making. Do we want 100 humans barely making it in space or 10 humans having a really good time in space who value sustainability, equity, and respect for each other and the environment? This means going for closed-loop systems (circular economies), which technically means recycling as much as possible and reducing waste, which takes a lot of time to develop. Maybe that’s ok.
There are folks thinking about this, drawing parallels between colonialism on Earth and what could happen in space. Sci-fi books and movies are great at playing out these thought experiments. We haven’t been great at caring for Earth, and the way we eat is a huge part of the problem. We destroy for food, we kill for food. So how we eat in space will play a huge role in shaping our space future. Pointing out what the embedded values are behind technical decisions and tying it to the large picture of why anyone ought to care about space food is part of my research.
LW: Do you have any thoughts on how the domestic labor of cooking is thought of in outer space?
LZ: Domestic life in outer space is a bit like writing science fiction. Before we go, we have the opportunity to reflect on what parts of our current culture we want to reproduce in space and what we’d like to change. When you say domestic, I think of cultural norms that say cooking in the home is women’s work. When I hear “chef,” I think of bad boy Michelin-starred chefs who are valorized. There’s something there about how we value and don’t value women’s work, or work in the home vs. the professional sphere.
I’ve discussed with colleagues that just as currently there’s an astronaut on each mission who’s the designated flight surgeon, future missions may have a designated flight cook. I want that cook to have the same social cachet as the surgeon, by the way. However, there’s also discussion that missions will move away from that because in isolation, only one person with medical experience or the ability to cook well doesn’t make for a resilient system. Instead, everyone needs to be cross-trained. NASA is slowly moving towards selecting more for excellent interpersonal and problem-solving skills and slightly less for specific technical specializations.
Ben Lachman: Looking beyond LEO [low earth orbit], I’m interested in what the hardest food groups will be to produce in a long-term space environment. One of my acquaintances is working on complex fats, but I’m interested in your take on other holes in our ability to move past LEO to extended cislunar missions and/or deep space exploration.
LZ: For sure protein. Most speculative designs for a settlement on Mars call for a vegetarian or vegan diet, with the idea that you’d grow soybeans in situ or pre-position soybean payloads to be turned into soymilk and then tofu. See this paper for more information.
There’s been a little bit of research in decades past on aquaponics in space. The idea would be to find fish species that can be fertilized on Earth but then shipped in suspended animation (not the correct biology term, but hopefully you get what I mean) so they don’t grow gigantic during transit, and then raise them on the planetary surface. See this paper for more on that approach.
The fact that cows are inefficient producers of calories for us really hits home when your system is super constrained. On Earth, we can sort of feign ignorance (as a struggling vegetarian, I feel this keenly), but when packing for space, the inefficiency is inexcusable.
There has been some work on 3D printing meat in space. The nice thing is you don’t have to raise the animal. Partial gravity environments provide a lot of fun possibilities. Just spitballing here, the diminished gravity isn’t necessarily a problem – maybe the physics of extruding meat (if that’s the method) in a partial gravity environment (Mars is ~2/5 of Earth gravity) are not as difficult to engineer around. Then, the thing to work on would be, how does it interface with all the other life support systems? Could your extrusion platform also double as a plancha? How does the growth media fit into the food supply chain? What about waste products? The more closed-loop of a system you’re aiming for, the more the waste needs to be accounted for as an input for another subsystem. If you were in microgravity, let’s say in the transit portion of the trip on the way to Mars, maybe you could extrude into the air and the surface tension of the meat substrate would hold it together so it’s a growing blob of ground meat. Or give it a fork to grow around, and then zap it with microwaves.
HP: You're coming up to the end of your PhD – how have you found the process overall? Does academic research feel like the right space to explore the topics you're interested in?
LZ: It’s funny, space is what’s called an ICE (Isolated, Confined, and Extreme) environment. Antarctica is another. Submarines too. Covid lockdown as well. These are all analogues of each other for those who study how to thrive in such environments. I’d call the PhD an ICE environment too – it’s certainly isolated and extreme. There was no other place I could have tried to work on how to cook in space other than in academia. It’s too hard and the state of the art just barely suffices, so industry isn’t incentivized to work on it.
HP: I'm curious what the work environment was like when you worked on Modernist Bread – I imagine an immaculate test kitchen and lots of neat gadgets! How big was the R&D team and how did you organize your research?
LZ: Yes, there are photos of the MC kitchen on the internet. Let’s see, here’s one. When I was there from 2012-2017, 3-5 chefs were working with Head Chef Francisco Migoya and I had a research team of 3-5 contractors and interns, who had some kind of food science background. We started by listing all the questions we had about bread (urban myths, I wonder how that works, this baker swears by this, etc) and then transforming them into experiments. We had to stop adding to the list after 3 years because the book was already way too big. The team would do experiments, and gather data. I was primarily in charge of managing all this and synthesizing the data into what it told us about what was going on in the dough, then thinking about the implications for recipe development. “If this is the mechanism at play, what does this mean for how a home baker should improve their set-up? What about a professional baker?” That sort of thing.
DC: Do you have a favorite backpacking meal? I am always hunting for ways to avoid buying freeze-dried food because it's so expensive!
LZ: Yes! My favorite backpacking meal is RAMEN! Shin ramen + canned vegetables + tofu (if car camping and I don’t care too much about weight). I recently bought a huge box of dehydrated vegetables and scoop from it as needed.
Another backpacking favorite for carbs is couscous. You don’t even need to boil it, just pour hot water over and it hydrates. I use packets of coconut oil or olive oil (Trader Joe’s is very good for single-serving packs) for fat. I’ve always wondered about edible packaging for outdoor recreation, to reduce waste.
CH: What interesting cooking trends or techniques are you following or playing around with currently?
LZ: I’m coming up empty. I used to be super into the new and novel, but now it’s all about the basics. Generally asking myself “What can I make quickly and reliably that’s delicious?” Maybe I can say that I’m in a ramen phase. My friend came back from Indonesia and we did a tasting of all types of Indomie packaged ramen.
I love Shin ramen, but I’m not a fan of the single-serving packaging – I want a giant bulk can of Shin powder. For now, I buy dried ramen (a catch-all term for all the dried non-pasta noodles) in bulk and add mushroom powder for umami to make it taste good. Recently, I’ve been into soft-boiling egg and ramen in the same pot (but you’ve got to watch the timing).
A big thanks to Larissa for taking the time to share her expertise (right before her PhD defense)! Members can find her on Slack at @Larissa Zhou and otherwise, you can find her publications here.
Thanks also to Heather Hava and the SIRONA team for agreeing to share their work in this piece. To learn more about this bioregenerative life support system, see their research papers (part 1, part 2), and this video overview. The SIRONA team won the 2019 Most Innovative Award in NASA's BIG Idea Challenge.
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