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.
Shoot for the Moon: Its Surface Contains a Pot of Gold
An astronaut standing on the Moon.
Here's a riddle: What do the Moon, nuclear weapons, clean energy of the future, terrorism, and lung disease all have in common?
One goal of India's upcoming space probe is to locate deposits of helium-3 that are worth trillions of dollars.
The answer is helium-3, a gas that's extremely rare on Earth but 100 million times more abundant on the Moon. This past October, the Lockheed Martin corporation announced a concept for a lunar landing craft that may return humans to the Moon in the coming decade, and yesterday China successfully landed the Change-4 probe on the far side of the Moon. Landing inside the Moon's deepest crater, the Chinese achieved a first in space exploration history.
Meanwhile, later this month, India's Chandrayaan-2 space probe will also land on the lunar surface. One of its goals is to locate deposits of helium-3 that are worth trillions of dollars, because it could be a fuel for nuclear fusion energy to generate electricity or propel a rocket.
The standard way that nuclear engineers are trying to achieve sustainable fusion uses fuels that are more plentiful on Earth: deuterium and tritium. But MIT researchers have found that adding small amounts of helium-3 to the mix could make it much more efficient, and thus a viable energy source much sooner that once thought.
Even if fusion is proven practical tomorrow, any kind of nuclear energy involves long waits for power plant construction measured in decades. However, mining helium-3 could be useful now, because of its non-energy applications. A major one is its ability to detect neutrons coming from plutonium that could be used in terrorist attacks. Here's how it works: a small amount of helium-3 is contained within a forensic instrument. When a neutron hits an atom of helium-3, the reaction produces tritium, a proton, and an electrical charge, alerting investigators to the possibility that plutonium is nearby.
Ironically, as global concern about a potential for hidden nuclear material increased in the early 2000s, so did the supply of helium-3 on Earth. That's because helium-3 comes from the decay of tritium, used in thermonuclear warheads (H-bombs). Thousands of such weapons have been dismantled from U.S. and Russian arsenals, making helium-3 available for plutonium detection, research, and other applications--including in the world of healthcare.
Helium-3 can help doctors diagnose lung diseases, since it enables imaging of the lungs in real time.
Helium-3 dramatically improves the ability of doctors to image the lungs in a range of diseases including asthma, chronic obstructive pulmonary disease and emphysema, cystic fibrosis, and bronchopulmonary dysplasia, which happens particularly in premature infants. Specifically, helium-3 is useful in magnetic resonance imaging (MRI), a procedure that creates images from within the body for diagnostic purposes.
But while a standard MRI allows doctors to visualize parts of the body like the heart or brain, it's useless for seeing the lungs. Because lungs are filled with air, which is much less dense than water or fat, effectively no signals are produced that would enable imaging.
To compensate for this problem, a patient can inhale gas that is hyperpolarized –meaning enhanced with special procedures so that the magnetic resonance signals from the lungs are finally readable. This gas is safe to breathe when mixed with enough oxygen to support life. Helium-3 is one such gas that can be hyperpolarized; since it produces such a strong signal, the MRI can literally see the air inside the lungs and in all of the airways, revealing intricate details of the bronchopulmonary tree. And it can do this in real time
The capability to show anatomic details of the lungs and airways, and the ability to display functional imaging as a patient breathes, makes helium-3 MRI far better than the standard method of testing lung function. Called spirometry, this method tells physicians how the lungs function overall, but does not home in on particular areas that may be causing a problem. Plus, spirometry requires patients to follow instructions and hold their breath, so it is not great for testing young children with pulmonary disease.
In recent years, the cost of helium-3 on Earth has skyrocketed.
Over the past several years, researchers have been developing MRI for lung testing using other hyperpolarized gases. The main alternative to helium-3 is xenon-129. Over the years, researchers have learned to overcome certain disadvantages of the latter, such as its potential to put patients to sleep. Since helium-3 provides the strongest signal, though, it is still the best gas for MRI studies in many lung conditions.
But the supply of helium-3 on Earth has been decreasing in recent years, due to the declining rate of dismantling of warheads, just as the Department of Homeland Security has required more and more of the gas for neutron detection. As a result, the cost of the gas has skyrocketed. Less is available now for medical uses – unless, of course, we begin mining it on the moon.
The question is: Are the benefits worth the 239,000-mile trip?
Should Organ Donors Be Paid?
A depiction of selling a human heart for cash.
Deanna Santana had assumed that people on organ transplant lists received matches. She didn't know some died while waiting. But in May 2011, after her 17-year-old son, Scott, was killed in a car accident, she learned what a precious gift organ and tissue donation can be.
"I would estimate it cost our family about $4,000 for me to donate a kidney to a stranger."
His heart, lungs, kidneys, liver and pancreas saved five people. His corneas enabled two others to see. And his bones, connective tissues and veins helped 73 individuals.
The donation's impact had a profound effect on his mother as well. In September 2016, she agreed to donate a kidney in a paired exchange of four people making the same sacrifice for four compatible strangers.
She gave up two weeks' worth of paid vacation to recuperate and covered lodging costs for loved ones during her transplant. Eventually, she qualified for state disability for part of her leave, but the compensation was less than her salary as public education and relations manager at Sierra Donor Services, an organ procurement organization in West Sacramento, California.
"I would estimate it cost our family about $4,000 for me to donate a kidney to a stranger," says Santana, 51. Despite the monetary hardship, she "would do it again in a heartbeat."
While some contend it's exploitative to entice organ donors and their families with compensation, others maintain they should be rewarded for extending their generosity while risking complications and recovering from donation surgery. But many agree on one point: The focus should be less on paying donors and more on removing financial barriers that may discourage interested prospects from doing a good deed.
"There's significant potential risk associated with donating a kidney, some of which we're continuing to learn," says transplant surgeon Matthew Cooper, a board member of the National Kidney Foundation and co-chair of its Transplant Task Force.
Although most kidneys are removed laparoscopically, reducing hospitalization and recuperation time, complications can occur. The risks include wound and urinary tract infections, pneumonia, blood clots, injury to local nerves causing decreased sensation in the hip or thigh, acute blood loss requiring transfusion and even death, Cooper says.
"We think that donation is a cost-neutral opportunity. It, in fact, is not."
Meanwhile, from a financial standpoint, estimates have found it costs a kidney donor in the United States an average of $3,000 to navigate the entire transplant process, which may include time off from work, travel to and from the hospital, accommodations, food and child care expenses.
"We think that donation is a cost-neutral opportunity. It, in fact, is not," says Cooper, who is also Director of Kidney and Pancreas Transplantation at MedStar Georgetown Transplant Institute in Washington, D.C.
The National Organ Transplant Act of 1984 makes it illegal to sell human organs but did not prohibit payment for the donation of human plasma, sperm and egg cells.
Unlike plasma, sperm and eggs cells—which are "renewable resources"—a kidney is irreplaceable, says John J. Friedewald, a nephrologist who is medical director of kidney transplantation at Northwestern Memorial Hospital in Chicago.
Offering some sort of incentives could lessen the overall burden on donors while benefiting many more potential recipients. "We can eliminate the people waiting on the list and dying, at least for kidneys," Friedewald says.
On the other hand, incentives may influence an individual to the point that the donation is made purely for monetary gain. "It's a delicate balance," he explains, "because so much of the transplant system has been built on altruism."
That's where doing away with the "disincentives" comes into the equation. Compensating donors for the costs they endure would be a reasonable compromise, Friedewald says.
Depending on the state, living donors may deduct up to $10,000 from their adjusted gross income under the Organ Donation Tax Deduction Act for the year in which the transplantation occurs. "Human organ" applies to all or part of a liver, pancreas, kidney, intestine, lung or bone marrow. The subtracted modification may be claimed for only unreimbursed travel and lodging expenses and lost wages.
For some or many donors, the tax credit doesn't go far enough in offsetting their losses, but they often take it in stride, says Chaya Lipschutz, a Brooklyn, N.Y.-based matchmaker for donors and recipients, who launched the website KidneyMitzvah.com in 2009.
Seeking compensation for lost wages "is extremely rare" in her experience. "In all the years of doing this," she recalls, "I only had two people who donated a kidney who needed to get paid for lost wages." She finds it "pretty amazing that mostly all who contact don't ask."
Lipschutz, an Orthodox Jew, has walked in a donor's shoes. In September 2005, at age 48, she donated a kidney to a stranger after coming across an ad in a weekly Jewish newspaper. The ad stated: "Please help save a Jewish life—New Jersey mother of two in dire need of kidney—Whoever saves one life from Israel it is as if they saved an entire nation."
To make matches, Lipschutz posts in various online groups in the United States and Israel. Donors in Israel may receive "refunds" for loss of earnings, travel expenses, psychological treatment, recovery leave, and insurance. They also qualify for visits to national parks and nature reserves without entrance fees, Lipschutz says.
"There has been an attempt to figure out what would constitute fair compensation without the appearance that people are selling their organs or their loved ones' organs."
Kidneys can be procured from healthy living donors or patients who have undergone circulatory or brain death.
"The real dilemma arises with payment for living donation, which would favor poorer individuals to donate who would not necessarily do so," says Dr. Cheryl L. Kunis, a New York-based nephrologist whose practice consists primarily of kidney transplant recipients. "In addition, such payment for living donation has not demonstrated to improve a donor's socioeconomic status globally."
Living kidney donation has the highest success rate. But organs from young and previously healthy individuals who die in accidents or from overdoses, especially in the opioid epidemic, often work just as well as kidneys from cadaveric donors who succumb to trauma, Kunis says.
In these tragic circumstances, she notes that the decision to donate is often left to an individual's grieving family members when a living will isn't available. A payment toward funeral expenses, for instance, could tip their decision in favor of organ donation.
A similar scenario presents when a patient with a beating heart is on the verge of dying, and the family is unsure about consenting to organ donation, says Jonathan D. Moreno, a professor in the department of medical ethics and health policy at the University of Pennsylvania.
"There has been an attempt to figure out what would constitute fair compensation," he says, "without the appearance that people are selling their organs or their loved ones' organs."
The overarching concern remains the same: Compensating organ donors could lead to exploitation of socioeconomically disadvantaged groups. "What's likely to finally resolve" this bioethics debate, Moreno foresees, "is patient-compatible organs grown in pigs as the basic science of xenotransplants (between species) seems to be progressing."
Cooper, the transplant surgeon at Georgetown, believes more potential donors would come forward if financial barriers weren't an issue. Of the ones who end up giving a part of themselves, with or without reimbursement, "the overwhelming majority look back upon it as an extremely positive experience," he says. After all, "they're lifesavers. They should be celebrated."