Scientists Are Devising Clever Solutions to Feed Astronauts on Mars Space Flights
Astronauts at the International Space Station today depend on pre-packaged, freeze-dried food, plus some fresh produce thanks to regular resupply missions. This supply chain, however, will not be available on trips further out, such as the moon or Mars. So what are astronauts on long missions going to eat?
Going by the options available now, says Christel Paille, an engineer at the European Space Agency, a lunar expedition is likely to have only dehydrated foods. “So no more fresh product, and a limited amount of already hydrated product in cans.”
For the Mars mission, the situation is a bit more complex, she says. Prepackaged food could still constitute most of their food, “but combined with [on site] production of certain food products…to get them fresh.” A Mars mission isn’t right around the corner, but scientists are currently working on solutions for how to feed those astronauts. A number of boundary-pushing efforts are now underway.
The logistics of growing plants in space, of course, are very different from Earth. There is no gravity, sunlight, or atmosphere. High levels of ionizing radiation stunt plant growth. Plus, plants take up a lot of space, something that is, ironically, at a premium up there. These and special nutritional requirements of spacefarers have given scientists some specific and challenging problems.
To study fresh food production systems, NASA runs the Vegetable Production System (Veggie) on the ISS. Deployed in 2014, Veggie has been growing salad-type plants on “plant pillows” filled with growth media, including a special clay and controlled-release fertilizer, and a passive wicking watering system. They have had some success growing leafy greens and even flowers.
"Ideally, we would like a system which has zero waste and, therefore, needs zero input, zero additional resources."
A larger farming facility run by NASA on the ISS is the Advanced Plant Habitat to study how plants grow in space. This fully-automated, closed-loop system has an environmentally controlled growth chamber and is equipped with sensors that relay real-time information about temperature, oxygen content, and moisture levels back to the ground team at Kennedy Space Center in Florida. In December 2020, the ISS crew feasted on radishes grown in the APH.
“But salad doesn’t give you any calories,” says Erik Seedhouse, a researcher at the Applied Aviation Sciences Department at Embry-Riddle Aeronautical University in Florida. “It gives you some minerals, but it doesn’t give you a lot of carbohydrates.” Seedhouse also noted in his 2020 book Life Support Systems for Humans in Space: “Integrating the growing of plants into a life support system is a fiendishly difficult enterprise.” As a case point, he referred to the ESA’s Micro-Ecological Life Support System Alternative (MELiSSA) program that has been running since 1989 to integrate growing of plants in a closed life support system such as a spacecraft.
Paille, one of the scientists running MELiSSA, says that the system aims to recycle the metabolic waste produced by crew members back into the metabolic resources required by them: “The aim is…to come [up with] a closed, sustainable system which does not [need] any logistics resupply.” MELiSSA uses microorganisms to process human excretions in order to harvest carbon dioxide and nitrate to grow plants. “Ideally, we would like a system which has zero waste and, therefore, needs zero input, zero additional resources,” Paille adds.
Microorganisms play a big role as “fuel” in food production in extreme places, including in space. Last year, researchers discovered Methylobacterium strains on the ISS, including some never-seen-before species. Kasthuri Venkateswaran of NASA’s Jet Propulsion Laboratory, one of the researchers involved in the study, says, “[The] isolation of novel microbes that help to promote the plant growth under stressful conditions is very essential… Certain bacteria can decompose complex matter into a simple nutrient [that] the plants can absorb.” These microbes, which have already adapted to space conditions—such as the absence of gravity and increased radiation—boost various plant growth processes and help withstand the harsh physical environment.
MELiSSA, says Paille, has demonstrated that it is possible to grow plants in space. “This is important information because…we didn’t know whether the space environment was affecting the biological cycle of the plant…[and of] cyanobacteria.” With the scientific and engineering aspects of a closed, self-sustaining life support system becoming clearer, she says, the next stage is to find out if it works in space. They plan to run tests recycling human urine into useful components, including those that promote plant growth.
The MELiSSA pilot plant uses rats currently, and needs to be translated for human subjects for further studies. “Demonstrating the process and well-being of a rat in terms of providing water, sufficient oxygen, and recycling sufficient carbon dioxide, in a non-stressful manner, is one thing,” Paille says, “but then, having a human in the loop [means] you also need to integrate user interfaces from the operational point of view.”
Growing food in space comes with an additional caveat that underscores its high stakes. Barbara Demmig-Adams from the Department of Ecology and Evolutionary Biology at the University of Colorado Boulder explains, “There are conditions that actually will hurt your health more than just living here on earth. And so the need for nutritious food and micronutrients is even greater for an astronaut than for [you and] me.”
Demmig-Adams, who has worked on increasing the nutritional quality of plants for long-duration spaceflight missions, also adds that there is no need to reinvent the wheel. Her work has focused on duckweed, a rather unappealingly named aquatic plant. “It is 100 percent edible, grows very fast, it’s very small, and like some other floating aquatic plants, also produces a lot of protein,” she says. “And here on Earth, studies have shown that the amount of protein you get from the same area of these floating aquatic plants is 20 times higher compared to soybeans.”
Aquatic plants also tend to grow well in microgravity: “Plants that float on water, they don’t respond to gravity, they just hug the water film… They don’t need to know what’s up and what’s down.” On top of that, she adds, “They also produce higher concentrations of really important micronutrients, antioxidants that humans need, especially under space radiation.” In fact, duckweed, when subjected to high amounts of radiation, makes nutrients called carotenoids that are crucial for fighting radiation damage. “We’ve looked at dozens and dozens of plants, and the duckweed makes more of this radiation fighter…than anything I’ve seen before.”
Despite all the scientific advances and promising leads, no one really knows what the conditions so far out in space will be and what new challenges they will bring. As Paille says, “There are known unknowns and unknown unknowns.”
One definite “known” for astronauts is that growing their food is the ideal scenario for space travel in the long term since “[taking] all your food along with you, for best part of two years, that’s a lot of space and a lot of weight,” as Seedhouse says. That said, once they land on Mars, they’d have to think about what to eat all over again. “Then you probably want to start building a greenhouse and growing food there [as well],” he adds.
And that is a whole different challenge altogether.
[Ed. Note: This is the third episode in our Moonshot series, which will explore four cutting-edge scientific developments that stand to fundamentally transform our world.]
Kira Peikoff was the editor-in-chief of Leaps.org from 2017 to 2021. As a journalist, her work has appeared in The New York Times, Newsweek, Nautilus, Popular Mechanics, The New York Academy of Sciences, and other outlets. She is also the author of four suspense novels that explore controversial issues arising from scientific innovation: Living Proof, No Time to Die, Die Again Tomorrow, and Mother Knows Best. Peikoff holds a B.A. in Journalism from New York University and an M.S. in Bioethics from Columbia University. She lives in New Jersey with her husband and two young sons. Follow her on Twitter @KiraPeikoff.
My Wife's Fight Against Cancer Inspired 38,000 People to Raise Millions for Research
It was 15 years ago this month, but I'll never forget those words. When my wife Jen and I asked her oncologist about our plans to start a family, he calmly replied, "Well, I wouldn't do so unless Dave is prepared to be a single father."
About 50 percent of all people with cancer have a rare type, like the one Jen was fighting.
Time stood still. The danger crystalized — we were in a battle for my beautiful bride's life, and the odds were not in our favor.
We felt every emotion expected. Anger, sadness, confusion, frustration, and especially fear. But we made a very intentional choice to take that fear, put it to the side, and do everything we could to live our lives together to the fullest.
We focused first on Jen's health and learned everything we could about MFH Sarcoma. I was with her every step of the way — for hundreds of medical appointments, six intense surgeries, and twenty different types of chemotherapy. During such a challenging time, our choice to reject fear allowed us to live our best lives. Our careers blossomed, we enjoyed several international vacations, and Jen inspired thousands of fellow patients through her blog and speeches.
When we researched treatment options we learned that Jen was not alone. About 50 percent of all people with cancer have a rare type, like the one Jen was fighting. However, rare cancers don't get the funding they desperately need so effective treatment options are hard to find. The lack of funding felt unfair — and urgent. We didn't worry about everything that can go wrong when starting a new venture. Instead, we jumped in head first and convinced a small group of friends and family to ride stationary bikes with us to raise money for rare cancer research.
Jen Goodman Linn, riding a stationary bike for Cycle for Survival.
(Courtesy David Linn)
From those humble beginnings, Cycle for Survival grew steadily. After starting from scratch, Jen and I ran Cycle for Survival on our own for two years. We quickly realized that if we wanted to help as many people as possible, we needed the best partners. In 2009, we agreed that Memorial Sloan Kettering Cancer Center would take over the ownership of Cycle for Survival and Equinox officially became the Founding Partner. Flash forward to today, and Cycle for Survival has raised more than $220 million! I'm proud that 100% of every donation, yes every penny, goes directly into life-saving rare cancer research within six months of the annual indoor cycling events, which now take place in 17 cities nationwide.
While Cycle for Survival's trajectory was heading straight up, Jen's health struggle was devastatingly swinging up and down. With her incredible spirit and tenacity, Jen would beat the cancer through chemo and surgery, but then it would frustratingly come back again and again. After going into remission six times, it returned with such a vengeance in 2011 that even the world's leading doctors were forced to say, "I'm sorry, there's nothing more we can do."
Those were the most difficult words I've ever heard, by far. I hope no other family has to hear these crushing words.
When Jen died soon after, I didn't know what would happen to me, to my life, and to Cycle for Survival. I do remember making two very important choices at the time. First, I chose to get out of bed and put one foot in front of the other. It wasn't easy. Tears, pain, and grief would hit at any hour of the day or night. I did have a great support network of family and friends who kept me moving forward. One friend in particular changed the route of her morning runs so that I would join her and start getting back to exercising.
My second key choice was to stay involved with Cycle for Survival. At times, it was an excruciatingly difficult decision because I felt the depth of my loss each and every time I stepped into one of the events. However, it was also rewarding and energizing because I could see firsthand how many people it was helping, even though it was too late for Jen.
I began to travel across the country with the Cycle for Survival staff. My hope was to spread the word about rare cancers; along the way I met a lot of wonderful people who shared their stories with me. What I soon realized is that each of us faces obstacles in our lives. For me, it was losing the person who I wanted to spend my life with. For others, it might be challenges with their kids or in their professional lives. The common theme is that we don't have control over the fact that we have to face these challenges. But the biggest lesson I've learned is that we very much do have a choice in how we react.
I made the choice to do everything I can to help rare cancer patients and their families and it has been transformative and healing for me. The small group who rode in the first Cycle for Survival event has grown into a powerful movement of nearly 40,000 riders making a real difference. If Jen were diagnosed today, there are new treatments available– including genomic sequencing, targeted therapies, and immunotherapies – that could help her. Those weren't even options a short time ago. That's the result of funding research.
A recent Cycle for Survival event shows the passion and power of the community.
(Courtesy David Linn)
I also want to share one more choice I made. Remember that friend who changed the route of her morning runs so I could start exercising after Jen died? Well, over the years friendship grew into love, and we're now building a home together and can't wait to see what the future holds for us.
So with all that in mind I ask – when you face those inevitable challenges in your life, how will you choose to react? Remember that even in the midst of hopelessness, you can find choices. Those will be the decisions that define and guide you.