Even an Iron Chef couldn’t master what a food-centric cadre of NASA scientists do every day: Devise tasty, healthy meals for astronauts to take into low-Earth orbit and beyond — perhaps even to Mars.
Feeding people in space is harder than it sounds. Meals have to contain enough nutrients to keep the human body functioning in near-zero gravity. Slicing, dicing and stir-frying are impossible because ingredients float around. And now that NASA has set its sights on manned trips to Mars, packaged food has to last longer than ever to keep dinner from spoiling (SN Online: 7/26/10).
Fortunately, new research reveals how to make long-lasting space chow both possible and palatable. Plant scientists are testing new methods to farm crops in orbit, so that astronauts could snack on space-grown salad. Engineers are inventing new ways to package food to keep it fresh for up to five years.
Soon, NASA hopes to have a menu plan that would put Bobby Flay to shame.
Space food was born in August 1961, when cosmonaut Gherman Titov nibbled a few crackers while orbiting Earth. Seven months later U.S. astronaut John Glenn sucked applesauce from an aluminum tube on his way around the planet, even though NASA had no idea what it would do to his body. Later, Mercury astronauts flew with toothpastelike tubes and compressed cubes of nutrition.
“We learned that no one really wanted to eat that,” says Maya Cooper, a food scientist at Lockheed Martin in Houston who works with NASA’s Johnson Space Center. “As the crew came back, so did the meal-in-a-pill,” she said in August in Denver at a meeting of the American Chemical Society.
Astronauts aren’t supposed to diet, so NASA began giving them tastier options. Apollo flights got hot water and bowls that could be used in space, opening up the possibilities of soups and gravies. By the 1970s, astronauts aboard the Skylab space station had their own refrigerator and freezer, which they could break into for filet mignon, lobster and other treats to reheat — the only time Americans in space have had such a luxury. Shuttle and later space station astronauts dined on thermostabilized foods that didn’t require refrigeration.
But elaborate, packaged meals weigh a lot and create a lot of trash — not the streamlined approach NASA wants for long space voyages. Six astronauts eating 3,000 calories a day for three years, the length of a Mars mission, adds up to 20 tons of prepared food that would need to be launched, Cooper says.
So she and other scientists are exploring menus that combine packaged food with vegetables grown in space, known as “bioregenerative” crops because they generate oxygen as well as food.
Cosmonauts have been growing food aboard Soviet and Russian spacecraft for decades, notes flavor chemist and space journalist Neil Da Costa. Their orbiting greenhouses have provided scallions and other greenery to accompany national foods such as borscht and quail eggs. The Russian segment of the International Space Station has a tiny garden, or “salad machine,” providing a few fresh vegetables to the crew.
American research into space crops has waxed and waned with available funding over the years, says Raymond Wheeler, a plant physiologist at NASA’s Kennedy Space Center in Florida. Early work focused on growing algae to produce oxygen and remove carbon dioxide from the craft. By the 1980s, scientists started to look more at growing food crops; in 1988 researchers at Kennedy set up a chamber with a tightly closed atmosphere to mimic a space growing environment, where they churned out wheat, potatoes and other major crops in a 20-square-meter garden.
Today, Wheeler and his colleagues grow hydroponic test crops, from radishes to lettuce to cherry tomatoes, in smaller-scale greenhouses at Kennedy. Along with reducing trash and launch mass requirements, such crops would give astronauts a little diet variety and psychological lift. “It would add colors and textures and flavors and antioxidants — a combination of things that might be better than just straight vitamin supplements,” Wheeler says.
By tweaking the environmental conditions, the researchers are figuring out how best to get things growing. And as any gardener who tends crops in a closet knows, lighting is a key to success. LED lights use little energy and provide focused light in a narrow spectrum that is ideal for space crops, Wheeler has found. Experiments at Kennedy show that plants need a blue LED light, since blue light helps them orient themselves, combined with red light to stimulate chlorophyll production. Adding a little green light naturalizes the appearance to human eyes, which would let astronaut farmers better assess whether a plant is sickly.
Growing crops in Florida is one thing; growing them in weightlessness is another. Fluids behave differently in near-zero gravity: The way the nutrient liquid bathes the roots changes, as does the way that the plant takes up the fluid. In a mock-up space habitat in Arizona, Wheeler’s team has been testing a system developed by ORBITEC, in Madison, Wis., that uses a “rooting pillow” with capillary action to wick moisture through roots.
In September, the team finished two weeks of successfully growing lettuce, mizuna greens, radishes and other plants brought from Kennedy. Next year, the researchers plan to tend the crops for a longer time and use more full-color light to better assess plant health and growth.
To hit the right balance between space-grown and Earth-made foods, Cooper and colleagues have fashioned three possible space menus: one relying mainly on bioregenerative crops, one with packaged foods and one with a combination of the two. The goal is to get the right calorie count and nutrition into foods that astronauts will actually eat. So far, her team has found that many of NASA’s packaged foods have more nutrition than thought, but with low caloric density because they contain so much water.
Cooper suspects that astronauts will continue to eat mainly packaged foods supplemented with crops they grow themselves. But packaging becomes a problem on long trips. Plastics, foils and other existing space food wraps aren’t designed to keep goods fresher for longer than the 18 months NASA currently requires; a Mars voyage would need a five-year approval.
The long haul
One idea for long-term packaging is to improve the vacuum seal so that less oxygen is trapped within, where it can make the food break down and turn mushy. Another is to improve the packaging itself. For instance, NASA scientists are testing how cereal, peanuts and cottonseed oil do over years when wrapped in different plastic and foil materials. So far, a combination of plastic laminate coated with aluminum oxide works best, Cooper’s team reported in March in the Journal of Food Science.
Other work explores whether the natural freezer of deep space could be an obvious place to tuck frozen meals. Cooper’s team is testing how space food packets hold up in an ultracold freezer at −80° Celsius. One worry: The packaging might simply shatter from the cold over time.
Of course, even the best-preserved food isn’t worth much if the astronauts get tired of eating it. Routine space menus can cycle through the same set of meals every 10 days for months on end. “That’s a long time to eat the same stuff, especially if there’s a dish in there you don’t like,” Cooper says.
Witness the last-ditch creative cookery of the “Mars500” crew, six people in Moscow who have been living in an enclosed space for 520 days, simulating the psychological confinement of astronauts traveling to Mars. As they’ve become bored with cupboard offerings, the crew members have been fashioning some unusual dishes. A recent experiment: “pizzas” made out of onion crackers, canned fish and the occasional slice of Chinese bamboo.