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.
New Blood Test Can Detect Lymphoma Cells Before a Tumor Grows Back
David Kurtz making DNA sequencing libraries in his lab.
When David M. Kurtz was doing his clinical fellowship at Stanford University Medical Center in 2009, specializing in lymphoma treatments, he found himself grappling with a question no one could answer. A typical regimen for these blood cancers prescribed six cycles of chemotherapy, but no one knew why. "The number seemed to be drawn out of a hat," Kurtz says. Some patients felt much better after just two doses, but had to endure the toxic effects of the entire course. For some elderly patients, the side effects of chemo are so harsh, they alone can kill. Others appeared to be cancer-free on the CT scans after the requisite six but then succumbed to it months later.
"Anecdotally, one patient decided to stop therapy after one dose because he felt it was so toxic that he opted for hospice instead," says Kurtz, now an oncologist at the center. "Five years down the road, he was alive and well. For him, just one dose was enough." Others would return for their one-year check up and find that their tumors grew back. Kurtz felt that while CT scans and MRIs were powerful tools, they weren't perfect ones. They couldn't tell him if there were any cancer cells left, stealthily waiting to germinate again. The scans only showed the tumor once it was back.
Blood cancers claim about 68,000 people a year, with a new diagnosis made about every three minutes, according to the Leukemia Research Foundation. For patients with B-cell lymphoma, which Kurtz focuses on, the survival chances are better than for some others. About 60 percent are cured, but the remaining 40 percent will relapse—possibly because they will have a negative CT scan, but still harbor malignant cells. "You can't see this on imaging," says Michael Green, who also treats blood cancers at University of Texas MD Anderson Medical Center.
The new blood test is sensitive enough to spot one cancerous perpetrator amongst one million other DNA molecules.
Kurtz wanted a better diagnostic tool, so he started working on a blood test that could capture the circulating tumor DNA or ctDNA. For that, he needed to identify the specific mutations typical for B-cell lymphomas. Working together with another fellow PhD student Jake Chabon, Kurtz finally zeroed-in on the tumor's genetic "appearance" in 2017—a pair of specific mutations sitting in close proximity to each other—a rare and telling sign. The human genome contains about 3 billion base pairs of nucleotides—molecules that compose genes—and in case of the B-cell lymphoma cells these two mutations were only a few base pairs apart. "That was the moment when the light bulb went on," Kurtz says.
The duo formed a company named Foresight Diagnostics, focusing on taking the blood test to the clinic. But knowing the tumor's mutational signature was only half the process. The other was fishing the tumor's DNA out of patients' bloodstream that contains millions of other DNA molecules, explains Chabon, now Foresight's CEO. It would be like looking for an escaped criminal in a large crowd. Kurtz and Chabon solved the problem by taking the tumor's "mug shot" first. Doctors would take the biopsy pre-treatment and sequence the tumor, as if taking the criminal's photo. After treatments, they would match the "mug shot" to all DNA molecules derived from the patient's blood sample to see if any molecular criminals managed to escape the chemo.
Foresight isn't the only company working on blood-based tumor detection tests, which are dubbed liquid biopsies—other companies such as Natera or ArcherDx developed their own. But in a recent study, the Foresight team showed that their method is significantly more sensitive in "fishing out" the cancer molecules than existing tests. Chabon says that this test can detect circulating tumor DNA in concentrations that are nearly 100 times lower than other methods. Put another way, it's sensitive enough to spot one cancerous perpetrator amongst one million other DNA molecules.
"It increases the sensitivity of detection and really catches most patients who are going to progress," says Green, the University of Texas oncologist who wasn't involved in the study, but is familiar with the method. It would also allow monitoring patients during treatment and making better-informed decisions about which therapy regimens would be most effective. "It's a minimally invasive test," Green says, and "it gives you a very high confidence about what's going on."
Having shown that the test works well, Kurtz and Chabon are planning a new trial in which oncologists would rely on their method to decide when to stop or continue chemo. They also aim to extend their test to detect other malignancies such as lung, breast or colorectal cancers. The latest genome sequencing technologies have sequenced and catalogued over 2,500 different tumor specimens and the Foresight team is analyzing this data, says Chabon, which gives the team the opportunity to create more molecular "mug shots."
The team hopes that that their blood cancer test will become available to patients within about five years, making doctors' job easier, and not only at the biological level. "When I tell patients, "good news, your cancer is in remission', they ask me, 'does it mean I'm cured?'" Kurtz says. "Right now I can't answer this question because I don't know—but I would like to." His company's test, he hopes, will enable him to reply with certainty. He'd very much like to have the power of that foresight.
Lina Zeldovich has written about science, medicine and technology for Popular Science, Smithsonian, National Geographic, Scientific American, Reader’s Digest, the New York Times and other major national and international publications. A Columbia J-School alumna, she has won several awards for her stories, including the ASJA Crisis Coverage Award for Covid reporting, and has been a contributing editor at Nautilus Magazine. In 2021, Zeldovich released her first book, The Other Dark Matter, published by the University of Chicago Press, about the science and business of turning waste into wealth and health. You can find her on http://linazeldovich.com/ and @linazeldovich.
The First Mass-Produced Solar Car Is Coming Soon, Sparking Excitement and Uncertainty
Reporter Michaela Haas takes Aptera's Sol car out for a test drive in San Diego, Calif.
The white two-seater car that rolls down the street in the Sorrento Valley of San Diego looks like a futuristic batmobile, with its long aerodynamic tail and curved underbelly. Called 'Sol' (Spanish for "sun"), it runs solely on solar and could be the future of green cars. Its maker, the California startup Aptera, has announced the production of Sol, the world's first mass-produced solar vehicle, by the end of this year. Aptera co-founder Chris Anthony points to the sky as he says, "On this sunny California day, there is ample fuel. You never need to charge the car."
If you live in a sunny state like California or Florida, you might never need to plug in the streamlined Sol because the solar panels recharge while driving and parked. Its 60-mile range is more than the average commuter needs. For cloudy weather, battery packs can be recharged electronically for a range of up to 1,000 miles. The ultra-aerodynamic shape made of lightweight materials such as carbon, Kevlar, and hemp makes the Sol four times more energy-efficient than a Tesla, according to Aptera. "The material is seven times stronger than steel and even survives hail or an angry ex-girlfriend," Anthony promises.
Co-founder Steve Fambro opens the Sol's white doors that fly upwards like wings and I get inside for a test drive. Two dozen square solar panels, each the size of a large square coaster, on the roof, front, and tail power the car. The white interior is spartan; monitors have replaced mirrors and the dashboard. An engineer sits in the driver's seat, hits the pedal, and the low-drag two-seater zooms from 0 to 60 in 3.5 seconds.
It feels like sitting in a race car because the two-seater is so low to the ground but the car is built to go no faster than 100 or 110 mph. The finished car will weigh less than 1,800 pounds, about half of the smallest Tesla. The average car, by comparison, weighs more than double that. "We've built it primarily for energy efficiency," Steve Fambro says, explaining why the Sol has only three wheels. It's technically an "auto-cycle," a hybrid between a motorcycle and a car, but Aptera's designers are also working to design a four-seater.
There has never been a lack of grand visions for the future of the automobile, but until these solar cars actually hit the streets, nobody knows how the promises will hold up.
Transportation is currently the biggest source of greenhouse gases. Developing an efficient solar car that does not burden the grid has been the dream of innovators for decades. Every other year, dozens of innovators race their self-built solar cars 2,000 miles through the Australian desert.
More effective solar panels are finally making the dream mass-compatible, but just like other innovative car ideas, Aptera's vision has been plagued with money problems. Anthony and Fambro were part of the original crew that founded Aptera in 2006 and worked on the first prototype around the same time Tesla built its first roadster, but Aptera went bankrupt in 2011. Anthony and Fambro left a year before the bankruptcy and went on to start other companies. Among other projects, Fambro developed the first USDA organic vertical farm in the United Arab Emirates, and Anthony built a lithium battery company, before the two decided to buy Aptera back. Without a billionaire such as Elon Musk bankrolling the risky process of establishing a whole new car production system from scratch, the huge production costs are almost insurmountable.
But Aptera's founders believe they have found solutions for the entire production process as well as the car design. Most parts of the Sol's body can be made by 3D printers and assembled like a Lego kit. If this makes you think of a toy car, Anthony assures potential buyers that the car aced stress tests and claims it's safer than any vehicle on the market, "because the interior is shaped like an egg and if there is an impact, the pressure gets distributed equally." However, Aptera has yet to release crash test safety data so outside experts cannot evaluate their claims.
Instead of building a huge production facility, Anthony and Fambro envision "micro-factories," each less than 10,000 square feet, where a small crew can assemble cars on demand wherever the orders are highest, be it in California, Canada, or China.
If a part of the Sol breaks, Aptera promises to send replacement parts to any corner of the world within 24 hours, with instructions. So a mechanic in a rural corner in Arkansas or China who never worked on a solar car before simply needs to download the instructions and replace the broken part. At least that's the idea. "The material does not rust nor fatigue," Fambro promises. "You can pass the car onto your grandchildren. When more efficient solar panels hit the market, we simply replace them."
More than 11,000 potential buyers have already signed up; the cheapest model costs around $26,000 USD and Aptera expects the first cars to ship by the end of the year.
Two other solar carmakers are vying for the pole position in the race to be the first to market: The German startup Sono has also announced it will also produce its first solar car by the end of this year. The price tag for the basic model is also around $26,000, but its concept is very different. From the outside, the Sion looks like a conservative minivan for a family; only a closer look reveals that the dark exterior is made of solar panels. Sono, too, nearly went bankrupt a few years ago and was saved through a crowdfunding campaign by enthusiastic fans.
Meanwhile, Norwegian company Lightyear wants to produce a sleek solar-powered luxury sedan by the end of the year, but its price of around $180,000 makes it unaffordable for most buyers.
There has never been a lack of grand visions for the future of the automobile, but until these solar cars actually hit the streets, nobody knows how the promises will hold up. How often will the cars need to be repaired? What happens when snow and ice cover the solar panels? Also, you can't park the car in a garage if you need the sun to charge it.
Critics, including students at the Solar Car team at the University of Michigan, say that mounting solar panels on a moving vehicle will never yield the most efficient results compared to static panels. Also, they are quick to point out that no company has managed to overcome the production hurdles yet. Others in the field also wonder how well the solar panels will actually work.
"It's important to realize that the solar mileage claims by these companies are likely the theoretical best case scenario but in the real world, solar range will be significantly less when you factor in shading, parking in garages, and geographies with lower solar irradiance," says Evan Stumpges, the team coordinator for the American Solar Challenge, a competition in which enthusiasts build and race solar-powered cars. "The encouraging thing is that I have seen videos of real working prototypes for each of these vehicles which is a key accomplishment. That said, I believe the biggest hurdle these companies have yet to face is successfully ramping up to volume production and understanding what their profitability point will be for selling the vehicles once production has stabilized."
Professor Daniel M. Kammen, the founding director of the Renewable and Appropriate Energy Laboratory at the University of California, Berkeley, and one of the world's foremost experts on renewable energy, believes that the technical challenges have been solved, and that solar cars have real advantages over electric vehicles.
"This is the right time to be bullish. Cutting out the charging is a natural solution for long rides," he says. "These vehicles are essentially solar panels and batteries on wheels. These are now record low-cost and can be built from sustainable materials." Apart from Aptera's no-charge technology, he appreciates the move toward no-conflict materials. "Not only is the time ripe but the youth movement is pushing toward conflict-free material and reducing resource waste....A low-cost solar fleet could be really interesting in relieving burden on the grid, or you could easily imagine a city buying a bunch of them and connecting them with mass transit." While he has followed all three new solar companies with interest, he has already ordered an Aptera car for himself, "because it's American and it looks the most different."
After taking a spin in the Sol, it is startling to switch back into a regular four-seater. Rolling out of Aptera's parking lot onto the freeway next to all the oversized gas guzzlers that need to stop every couple of hundreds of miles to fill up, one can't help but think: We've just taken a trip into the future.