Scientists Are Devising Clever Solutions to Feed Astronauts on Mars Space Flights
Astronaut and Expedition 64 Flight Engineer Soichi Noguchi of the Japan Aerospace Exploration Agency displays Extra Dwarf Pak Choi plants growing aboard the International Space Station. The plants were grown for the Veggie study which is exploring space agriculture as a way to sustain astronauts on future missions to the Moon or Mars.
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.
Today’s Focus on STEM Education Is Missing A Crucial Point
A student in a contemplative pose.
I once saw a fascinating TED talk on 3D printing. As I watched the presenter discuss the custom fabrication, not of plastic gears or figurines, but of living, implantable kidneys, I thought I was finally living in the world of Star Trek, and I experienced a flush of that eager, expectant enthusiasm I felt as a child looking toward the future. I looked at my current career and felt a rejuvenation of my commitment to teach young people the power of science.
The well-rounded education of human beings needs to include lessons learned both from a study of the physical world, and from a study of humanity.
Whether we are teachers or not, those of us who admire technology and innovation, and who wish to support progress, usually embrace the importance of educating the next generation of scientists and inventors. Growing a healthy technological civilization takes a lot of work, skill, and wisdom, and its continued health depends on future generations of competent thinkers. Thus, we may find it encouraging that there is currently an abundance of interest in STEM– the common acronym for the study of science, technology, engineering, and math.
But education is as challenging an endeavor as science itself. Educating youth--if we want to do it right--requires as much thought, work, and expertise as discovering a cure or pioneering regenerative medicine. Before we give our money, time, or support to any particular school or policy, let's give some thought to the details of the educational process.
A Well-Balanced Diet
For one thing, STEM education cannot stand in isolation. The well-rounded education of human beings needs to include lessons learned both from a study of the physical world, and from a study of humanity. This is especially true for the basic education of children, but it is true even for college students. And even for those in science and engineering, there are important lessons to be learned from the study of history, literature, and art.
Scientists have their own emotions and values, and also need financial support. The fruits of their labor ultimately benefit other people. How are we all to function together in our division-of-labor society, without some knowledge of the way societies work? How are we to fully thrive and enjoy life, without some understanding of ourselves, our motives, our moral values, and our relationships to others? STEM education needs the humanities as a partner. That flourishing civilization we dream of requires both technical competence and informed life-choices.
Think for Yourself (Even in Science)
Perhaps even more important than what is taught, is the subject of how things are taught. We want our children to learn the skill of thinking independently, but even in the sciences, we often fail completely to demonstrate how. Instead of teaching science as a thinking process, we indoctrinate, using the grand discoveries of the great scientists as our sacred texts. But consider the words of Isaac Newton himself, regarding rote learning:
A Vulgar Mechanick can practice what he has been taught or seen done, but if he is in an error he knows not how to find it out and correct it, and if you put him out of his road he is at a stand. Whereas he that is able to reason nimbly and judiciously about figure, force, and motion, is never at rest till he gets over every rub.
What's the point of all this formal schooling in the first place? Is it, as many of the proponents of STEM education might argue, to train students for a "good" career?
If our goal is to help students "reason nimbly" about the world around them, as the great scientists themselves did, are we succeeding? When we "teach" middle school students about DNA or cellular respiration by presenting as our only supporting evidence cartoon pictures, are we showing students a process of discovery based on evidence and hard work? Or are we just training them to memorize and repeat what the authorities say?
A useful education needs to give students the skill of following a line of reasoning, of asking rational questions, and of chewing things through in their minds--even if we regard the material as beyond question. Besides feeding students a well-balanced diet of knowledge, healthy schooling needs to teach them to digest this information thoroughly.
Thinking Training
Now step back for a moment and think about the purpose of education. What's the point of all this formal schooling in the first place? Is it, as many of the proponents of STEM education might argue, to train students for a "good" career? That view may have some validity for young adults, who are beginning to choose electives in favored subjects, and have started to choose a direction for their career.
But for the basic education of children, this way of thinking is presumptuous and disastrous. I would argue that the central purpose of a basic education is not to teach children how to perform this or that particular skill, but simply to teach them to think clearly. We should not be aiming to provide job training, but thinking training. We should be helping children learn how to "reason nimbly" about the world around them, and breathing life into their thinking processes, by which they will grapple with the events and circumstances of their lives.
So as we admire innovation, dream of a wonderful future, and attempt to nurture the next generation of scientists and engineers, instead of obsessing over STEM education, let us focus on rational education. Let's worry about showing children how to think--about all the important things in life. Let's give them the basic facts of human existence -- physical and humanitarian -- and show them how to fluently and logically understand them.
Some students will become the next generation of creators, and some will follow other careers, but together -- if they are educated properly -- they will continue to grow their inheritance, and to keep our civilization healthy and flourishing, in body and in mind.
Do New Tools Need New Ethics?
Symbols of countries on a chessboard.
Scarcely a week goes by without the announcement of another breakthrough owing to advancing biotechnology. Recent examples include the use of gene editing tools to successfully alter human embryos or clone monkeys; new immunotherapy-based treatments offering longer lives or even potential cures for previously deadly cancers; and the creation of genetically altered mosquitos using "gene drives" to quickly introduce changes into the population in an ecosystem and alter the capacity to carry disease.
The environment for conducting science is dramatically different today than it was in the 1970s, 80s, or even the early 2000s.
Each of these examples puts pressure on current policy guidelines and approaches, some existing since the late 1970s, which were created to help guide the introduction of controversial new life sciences technologies. But do the policies that made sense decades ago continue to make sense today, or do the tools created during different eras in science demand new ethics guidelines and policies?
Advances in biotechnology aren't new of course, and in fact have been the hallmark of science since the creation of the modern U.S. National Institutes of Health in the 1940s and similar government agencies elsewhere. Funding agencies focused on health sciences research with the hope of creating breakthroughs in human health, and along the way, basic science discoveries led to the creation of new scientific tools that offered the ability to approach life, death, and disease in fundamentally new ways.
For example, take the discovery in the 1970s of the "chemical scissors" in living cells called restriction enzymes, which could be controlled and used to introduce cuts at predictable locations in a strand of DNA. This led to the creation of tools that for the first time allowed for genetic modification of any organism with DNA, which meant bacteria, plants, animals, and even humans could in theory have harmful mutations repaired, but also that changes could be made to alter or even add genetic traits, with potentially ominous implications.
The scientists involved in that early research convened a small conference to discuss not only the science, but how to responsibly control its potential uses and their implications. The meeting became known as the Asilomar Conference for the meeting center where it was held, and is often noted as the prime example of the scientific community policing itself. While the Asilomar recommendations were not sufficient from a policy standpoint, they offered a blueprint on which policies could be based and presented a model of the scientific community setting responsible controls for itself.
But the environment for conducting science changed over the succeeding decades and it is dramatically different today than it was in the 1970s, 80s, or even the early 2000s. The regime for oversight and regulation that has provided controls for the introduction of so-called "gene therapy" in humans starting in the mid-1970s is beginning to show signs of fraying. The vast majority of such research was performed in the U.S., U.K., and Europe, where policies were largely harmonized. But as the tools for manipulating humans at the molecular level advanced, they also became more reliable and more precise, as well as cheaper and easier to use—think CRISPR—and therefore more accessible to more people in many more countries, many without clear oversight or policies laying out responsible controls.
There is no precedent for global-scale science policy, though that is exactly what this moment seems to demand.
As if to make the point through news headlines, scientists in China announced in 2017 that they had attempted to perform gene editing on in vitro human embryos to repair an inherited mutation for beta thalassemia--research that would not be permitted in the U.S. and most European countries and at the time was also banned in the U.K. Similarly, specialists from a reproductive medicine clinic in the U.S. announced in 2016 that they had performed a highly controversial reproductive technology by which DNA from two women is combined (so-called "three parent babies"), in a satellite clinic they had opened in Mexico to avoid existing prohibitions on the technique passed by the U.S. Congress in 2015.
In both cases, genetic changes were introduced into human embryos that if successful would lead to the birth of a child with genetically modified germline cells—the sperm in boys or eggs in girls—with those genetic changes passed on to all future generations of related offspring. Those are just two very recent examples, and it doesn't require much imagination to predict the list of controversial possible applications of advancing biotechnologies: attempts at genetic augmentation or even cloning in humans, and alterations of the natural environment with genetically engineered mosquitoes or other insects in areas with endemic disease. In fact, as soon as this month, scientists in Africa may release genetically modified mosquitoes for the first time.
The technical barriers are falling at a dramatic pace, but policy hasn't kept up, both in terms of what controls make sense and how to address what is an increasingly global challenge. There is no precedent for global-scale science policy, though that is exactly what this moment seems to demand. Mechanisms for policy at global scale are limited–-think UN declarations, signatory countries, and sometimes international treaties, but all are slow, cumbersome and have limited track records of success.
But not all the news is bad. There are ongoing efforts at international discussion, such as an international summit on human genome editing convened in 2015 by the National Academies of Sciences and Medicine (U.S.), Royal Academy (U.K.), and Chinese Academy of Sciences (China), a follow-on international consensus committee whose report was issued in 2017, and an upcoming 2nd international summit in Hong Kong in November this year.
These efforts need to continue to focus less on common regulatory policies, which will be elusive if not impossible to create and implement, but on common ground for the principles that ought to guide country-level rules. Such principles might include those from the list proposed by the international consensus committee, including transparency, due care, responsible science adhering to professional norms, promoting wellbeing of those affected, and transnational cooperation. Work to create a set of shared norms is ongoing and worth continued effort as the relevant stakeholders attempt to navigate what can only be called a brave new world.