Food in Space: Defying (Micro)Gravity to Feed our Astronauts

When developing food and beverages for astronauts who will be in space for months at a time, microgravity conditions, extended shelf-life, and nutritional requirements must all be primary considerations. But, even with all such aspects met, if the taste or texture of the food is unappealing, the astronauts will not eat enough. And that will result in weight and bone density loss, which can impact both their health and their performance.

The National Aeronautics and Space Administration’s (NASA) five decades of providing food for astronauts has taught its Space Food Systems Laboratory (SFSL) at the Johnson Space Center (JSC) in Houston that the acceptability and desirability of space food also has to be a primary consideration, and it may be the most important. If the food isn’t eaten, all other aspects of it are moot. This is particularly true in the development of food for crew members who have extended tours of living and working on the International Space Station (ISS) and in preparation for Orion—the first spacecraft in history capable of taking humans to multiple destinations within deep space—and its projected trip to Mars in the 2020s.

It is extremely critical that the astronauts maintain their weight, explained NASA Advanced Food Technology Scientist Grace Douglas. If they don’t take in adequate calories, it will likely result in nutritional deficiencies and loss of body mass and bone mass—affecting both health and performance; and if the food is not appealing, the crew won’t eat enough. It is for this reason that NASA has increased the food choices over the years, and added options for individual bonus food containers.

Additionally, the importance of the appeal of foods became more significant with the longer duration of ISS missions over shuttle flights.

“You start to realize how important it is to give the crew food they really want to eat,” Douglas said.
 

Importance of Food.

Up to six crew members may work on ISS at any one time, with a full crew made up of three Russian cosmonauts, two U.S. astronauts, and one international astronaut (from Japan, Canada, or Europe). The U.S. provides the food for the three astronauts, while Russia sends the food for its cosmonauts—although all can, and do, share food on ISS.

The core U.S. menu for the ISS is standard and packed in eight categories (breakfasts, desserts and snacks, meats and fish, rehydratable meats, side dishes, vegetables and soups, and beverages and straws) from which the crew members assemble their meals. The usage rate of each set of the eight containers is determined by the combined caloric requirements of the three astronauts. Astronauts can have only one set of containers open at a time and cannot exceed the usage rate (typically seven to eight days) unless they consult with the ground crew.

Each astronaut also receives nine “bonus containers” for a six-month stay in space. For these, the crew members can choose their favorite foods from NASA’s more than 200 standard items or identify commercial products that they would like to have. These preferences can generally be accommodated as long as the requested foods meet the shelf-life and microbiological requirements. The U.S. also will provide up to four bonus containers for cosmonauts who desire them, and U.S. astronauts can request Russian bonus food to substitute for U.S. bonus containers, although astronauts rarely request more than one or two, said SFSL Manager Vickie Kloeris.

On the first missions to the space station, crew members were allowed to select all their own food, just as the space shuttle crews had always done. However the differences between the shuttle and ISS soon made this untenable. Not only does the longer duration have significant impact, but on shuttle missions, the crew and food were on the same ship. On ISS, the crew launches on the Soyuz while the food is sent on an unmanned cargo flight. Because of the limitations in the number and timing of the flights, it was soon found that the food selected by a specific crew member was not always arriving during his/her mission. NASA also learned that crew members have to be encouraged to drink fluids even when they are not thirsty. In microgravity, fluids shift to the upper body, so the body assumes it is hydrated, overriding one’s natural thirst mechanism; so astronauts returning to Earth tended to be dehydrated.

“So much of this is psychological,” said Kloeris, who has been with NASA’s food lab since 1985. “When I started with NASA, food had very low priority since shuttle missions were short.” Even the crew felt it to be unimportant, saying, “It’s like being on a camping trip—I’ll find something I like.” But as the missions got longer, food became more important. “It’s one of the few creature comforts they have on orbit,” she said.

In fact, many astronauts returning from six-month stays on orbit now have said that food is the most important psychological aspect of the ISS missions, she said, adding, “If it’s that important for six months, just think how important it will be for a three-year mission [e.g., to Mars].”

To ensure the appeal of food, the food lab has a sensory booth area and system that would feel at home in any food-processing plant. The food is rated by space-center personnel on a nine-point scale. “Every time a new food is developed, it is tested,” Kloeris said. “If it doesn’t average greater than six over time, it is reformulated or a different product is used.”

It is also to provide the comforts of home and ensure good health that the bonus-pack system was instituted, and that the Food Lab requires that the astronauts be able to eat hot food on all missions longer than two days—despite engineering’s preference to reduce mass and energy usage.

Fresh Foods in Space.

Certain foods, such a fresh fruits and vegetables and breads can be extremely difficult to provide in space. Tortillas have proven to be a very popular and shelf-stable option for bread—and are, in fact, one of the astronauts’ favorite foods. However, fresh fruits are only available when a new cargo ship arrives, and even then, the fruit must be eaten within a day or two. But it can be a very welcome change from the packaged foods.

In addition to fresh fruit, foods sent to space fall into seven categories:

• Freeze Dried/Rehydratable. This is the standard food most associated with space, and the vast majority of the foods are, indeed, freeze-dried. The dehydrated foods are processed at NASA’s Food Systems Lab. In space, water is added in the packaging through a septum-adapter assembly at the rehydration station. Once all the water is absorbed, the crew member cuts open the package and eats the food directly from the container. “We count on the wetness of the food to hold it together in microgravity,” Kloeris said.
  Examples: soup, macaroni and cheese, shrimp cocktail, scrambled eggs, cereal with dry milk.
• Thermostabilized. These foods are heat processed to destroy hazardous microorganisms and enzymes. The food is reheated in its package, then eaten directly from the container with conventional eating utensils.
  Examples: tuna, ravioli, chocolate pudding cake, tomatoes, eggplant.
• Intermediate Moisture. These ready-to-eat foods feature 15% to 30% moisture content chemically bound with sugar or salt. They are preserved by restricting the amount of water available for microbial growth, while retaining sufficient water to give the food a soft texture and enable consumption without further preparation.
  Examples: Dried peaches, dried beef.
• Natural Form. As off-the-shelf commercial products, these ready-to-eat foods require no further processing by NASA for consumption in flight. Because care must be taken to prevent the rise of crumbs in the microgravity atmosphere, they are repackaged in clear, flexible, single-serve pouches. “Bulk products that are dry are very difficult to deal with in microgravity,” Kloeris said. Additionally, all natural-form products must have at least a two-year shelf life and be certified by NASA prior to being accepted for use.
  Examples: nuts, cookies, tortillas.
• Irradiated. NASA received an FDA dispensation to use irradiation on meat, thus it produces nine meat items that are irradiated. The cooked, packaged meat is sterilized by exposure to ionizing radiation, making it stable at ambient temperature.
  Examples: Beef steak, smoked turkey.
• Beverages. All beverages are commercial, off-the-shelf powdered products, which are rehydrated at the rehydration station through a septum-adapter assembly, similar to freeze-dried foods. Once filled, the package is shaken or manipulated to mix the powder, and a specialized straw with a rigid tip holds the septum open for drinking. A commercial off-the-shelf IV clamp holds the straw shut between sips to prevent liquid from flowing freely from the package.
  Examples: coffee, tea, lemonade, orange juice.
• Condiments. Condiments are provided in commercially packaged, individual pouches or bulk plastic squeeze bottles; salt and pepper are in liquid form in polyethylene dropper bottles. Pepper is suspended in oil; salt is dissolved in water.
  Examples: catsup, mustard, mayonnaise, taco sauce, hot pepper sauce.

Although foods can be heated in space, there are currently no options for refrigeration or freezing, primarily because of the energy required to maintain these. However, research is being conducted in both areas, Kloeris said, adding, “If we don’t have it, we may not be able to go to Mars.” NASA’s food lab also continually works to reduce the mass of foods, without reducing acceptability. One product currently under development is that of a high-caloric, meal-replacement bar. While there are numerous protein bars on Earth, a meal-replacement bar for space must include all the nutritional requirements of a full meal—and taste good.
 

Nutritional Variation in Space.

It may seem that the astronauts could simply utilize the same foods as are in the military’s “MREs” (Meals-Ready-to-Eat). However, just as duties and operations of soldiers and astronauts are completely different, so too are their nutritional needs. The military needs higher sodium and fat to perform at optimum levels, while astronauts perform better with lower levels of both, Douglas said. This does not mean their diets are low-sodium or low-fat, though, because both are needed in space. Sodium exacerbates bone loss and inner cranial pressure issues, she said, and it is needed for flavor and preservation.

However, based on nutritional needs studies, the diets of the astronauts were recently lowered from 4,500 mg sodium per day to 3,100. One reason NASA is able to do this and still maintain flavor is because, Kloeris said, “The quantities we produce are so small that we can use more expensive herbs for flavor.”

Another area of concern for the ISS crew is that of sufficient Omega3 fatty acids in the foods. These are not required on Earth-food labels, nor are they being tested for stability over the shelf-life durations that will be required for long-duration missions (up to five years). But with studies finding that these fatty acids can play a role in mitigating bone loss in space flight, they are an important nutritional component. Unfortunately they also can degrade rapidly over time, thus it is an area NASA is continuing to research.

Long-term nutritional testing can be difficult and, obviously, requires extended time. Although accelerated shelf-life testing can provide some information, it cannot exactly duplicate space effects, Kloeris said. “It can often tell us what will change first, such as color or texture; and it often reveals the weak point in acceptability of the food. So you can get an idea, but it is not exact,” she said.

Because of all this, Douglas said, “we produce most of the food ourselves because of the specific nutritional requirements.” Nutritional needs are continually being assessed but, she added, “To change nutritional requirements, there has to be a lot of data behind it.”

Growing Veggies.

Another area of research is that of growing vegetables in space. While it may seem a simple matter of grounding it in the microgravity, there are questions of limited availability of water, produce washing, and nutritional aspects. In collaboration with Gioia Massa’s space biology team at the Kennedy Space Center, nutritional and sensory attribute tests are being conducted on ISS in growing lettuce in a plant-growth facility called Veggie and its plant “pillows.” The pillows within the chamber are filled with slow-release fertilizer and seeds and watered through a wick system. The system uses a flat-panel light bank that includes red, blue, and green LEDs for plant growth and crew observation and expands up to a foot and a half as plants grow inside. Even if tests show sufficient growth, further research must be conducted on effects space may have on the nutritional and safety aspects of the resulting produce. While some effects can be simulated on Earth, the solar radiation and other space anomalies cannot be reproduced. But research is continuing with the goal to eventually create a pick-and-eat system that can be used in space.
 

Continuing Research.

The impacts of microgravity and other space factors are key points of research. While general food requirements are based on those needed on Earth, with some provisions for microgravity, all the impacts of space are not known—such as: Do caloric requirements change in microgravity? One would intuitively think that astronauts would not need as many calories in space because they are not fighting gravity, but as far as research on the shuttle has detected, all indices are that microgravity does not change the caloric need. But, since shuttle flights were short, the question still remains: Will caloric needs change on longer missions? An experiment by the European Space Agency (ESA) called “Energy” is currently underway on ISS to try to answer that question for six-month stays in microgravity.

While providing sustenance for the ISS crews, the food, its intake, and effects also provide data for development of foods for future space treks, and enable preparation for the trip to Mars. Additionally, many aspects of the research and development in foods can benefit food for Earthly consumption as well. For example, its research on growing vegetables in space in the Veggie system has implications for improving growth and biomass production on Earth.

Missions also are being simulated on Earth at the JSC Human Exploration Research Analog (HERA). (See photo, above) At HERA, volunteers who have “demonstrated motivation and work ethic similar to the ‘astronaut stereotype’” (including demonstrated technical skills, an advanced degree or equivalent years of experience, and passing of NASA’s long-duration space flight physical), undergo tests designed to simulate that which will be encountered in space, including food and dietary testing.

NASA also partners with the military on research in food and packaging technology, such as that conducted at Natick Labs, and is involved in a number of consortiums, such as the National Science Foundation-initiated public/private partnership of Center for Advanced Processing and Packaging Studies (CAPPS) and the applied food research Institute for Food Safety and Health (IFSH). “There is a lot being done in academia funded by the industry, the military, and NASA,” Kloeris said. Additionally, NASA provides external research funding, such as academic grant programs through the NASA Research Announcements, and Small Business Innovation Research (SBIR) programs.
 

Defying (MICRO)Gravity.

Although appeal is a primary factor of the food for astronauts, the microgravity of space has to be factored into every item and every package. If the food or beverage were to float away upon opening, it would not only be difficult to eat, it would be a physical hazard as it could get into crew members’ eyes or nostrils or damage equipment. For this reason, all foods and beverages are packaged as single servings, beverages are in valved containers, and special precautions must be taken with any items that could crumb.

It may seem that contracting to produce these foods for NASA could provide profitable business for a food manufacturer, but that route has been tried and terminated. Not only are there unique developmental needs for space food, but the quantity of food required is too small for automated runs and, thus, is cost prohibitive for commercial manufacturers.

Because of this, all the food eaten in space is manually produced in NASA’s in-house pilot processing plant on one-of-a-kind equipment—developed specifically to produce and package space food, or it is further processed or repackaged at NASA from off-the-shelf commercial items. For example, NASA may purchase boxes of cereal, divide it into individual portions, add dry milk, then repackage it into rehydratable containers. Or an astronaut may request a specific cracker or cookie for his/her bonus pack. If the item passes NASA’s shelf-life and safety checks, it will be purchased commercially, then portioned out into single-serving packets.

Sometimes, commercial packets can even be sent as is, such as the individual pouches of seafood found in many grocery stores, which were being packed into the food containers during QA’s NASA visit. NASA also has partnered with Texas A &M University to establish a retort facility where thermostabilized pouched foods for ISS are produced per formulations developed by the food scientists in the Space Food Research Facility in Houston.

Although the requirements for space food are distinctly different from those of the military, the technology of space food is based on that of MREs. Thus, in the past, NASA periodically rented a military MRE facility to produce its thermostabilized pouched food. Then as the war in Iraq went on, the military could no longer give up the time at its facilities and keep all its soldiers fed. So, in 2007, NASA established its own facility via the partnership with Texas A&M. Bringing production in-house has actually been beneficial, Kloeris said, because NASA can now produce its own food on a continuing basis. This means that shelf-life dates can be staggered, rather than having everything expire at the same time because it was all produced at the same time.

With a staff of about 20 in NASA’s Space Food Systems, including scientists, researchers, dieticians, logistics personnel, and production technicians, the team maintains an inventory of each of the standard foods and beverages at all times. Generally, bite-sized commercial foods are packaged quarterly; freeze-dried foods produced semi-annually; and thermostabilized products annually or bi-annually.
 

Space Food Safety.

NASA has about 200 foods and beverages in its standard inventory, for which the ingredients or commercial items of each underwent specific safety steps prior to being used. “When we buy commercial food products,” Kloeris said, “we buy it all from the same lot, and there are specifications for each food on tests to run, such as microbial, moisture, sensory, etc.”

For the thermostabilized items processed at Texas A&M, data is gathered from the retort runs and sent to a commercial processing authority. If results are accepted, a Letter of Commercial Sterility is issued for the run. But the product is still not deemed to be flight ready until the outside of each pouch is cleaned at NASA and a label and Velcro are attached to the pouch. Although NASA has microbiological specifications for each food it sends to space, it recently had a panel of food microbiology experts review all its micro testing and make recommendations for improvement.

To ensure traceability, every item in every pack has a bar-coded serial number traceable back to its originating lot. If there were to be a recall on any commercial product—or ingredient—NASA would know immediately and be able to tell the astronauts which foods not to eat. A control set of each food also is kept in the SFSL, so if a crew member reports an issue, the lot can be checked.

To ensure proper preparation by the astronauts, each item is labeled with specific preparation instructions, such as, “Add 100 ml of hot water, then heat for 10 to 15 minutes.” But once the food is prepared, Kloeris said, “Crew members develop their own method of opening the packages on orbit.” Some cut an X in the top of the packaging to use it like a bowl, others will snip off an end and dip into the package with a utensil. “They do their own thing,” she said.

If you wonder how astronauts are able keep their food and drink containers from floating around in space without having to hold it in their hands at all times—think magnets and Velcro. Utensils are magnetic, so they will naturally adhere to the steel surfaces, and an adhesive-backed Velcro hook is adhered to all packages. Velcro pile is then adhered to the table, on horizontal and vertical surfaces around the station, and on crew members’ flight suits, with extra pieces of sticky-backed Velcro available for the crew to add where needed. (If you look closely at the photos at right and on page 10, you can see the Velcro pile pieces on the space station walls and equipment.)
 

Space Life of Food.

With standard ISS space missions lasting six months, the process through which the food must go to reach the station means that it needs to have a two- to three-year shelf life. Once processed and packaged, the individual foods are packed into standard or bonus bulk packs, stowed, then shipped to the launch site ... then stowed again to await the next cargo flight. “It could be up to a year before the food is launched, so it really needs a three-year shelf life,” Douglas said. The goal is to maintain three- to six-months’ worth of food on the space station at all times. And because certain bulk packs are designated for specific crew members, these need to arrive at the right time to be there for them. But, because space on the cargo flights is limited, food is always in competition with other supplies, Kloeris said. “It’s a constant trade.”
 

Preparing for Mars.

In preparation for the projected trip to Mars, NASA is continuing to conduct additional tests and lengthen ISS missions, and the food lab must keep pace with it. The most imminent is that of the projected spring 2015 launch of the joint one-year mission of American Scott Kelly and Russian Mikhail Konienko—twice as long as a typical space-station mission. Researchers expect the year-long mission to yield knowledge on the medical, psychological, and biomedical challenges that crews may face on future, more-distant flights.

Providing food for the one-year mission is fairly similar to that of previous ISS missions, but the extended time will help provide valuable insight to any changed dietary needs of the crew, as well as the impacts of longer space times on both the crew and variety of food. It is critical knowledge, because once the mission to Mars is undertaken, there will be no possibility for resupply. With nearly 26,500 pounds of food needed for that mission, Kloeris said, NASA has discussed pre-positioning cargo on Mars prior to the manned flight. In that case, the food must have a shelf-life of at least five years—maintaining both food safety and quality (i.e., acceptability and nutrition) throughout. There are some NASA thermostabilized pouched foods that currently have five-year shelf lives and some Earth foods that could last virtually forever from a safety aspect, but they would be survivability foods only, with texture, color, and nutrition degrading over time.

When assessing the quality of food intended to feed those of us who stay grounded on Earth, most food manufacturers consider consistency to be a key component. But in the production of food for our travelers to space, the only consistent quality that is critical is that of acceptability. “Because the crews constantly change, they don’t have an expectation that a food will taste a certain way,” Douglas said. “But it has to be acceptable.”

We all know that food and nutrition are essential to our health and well-being. But if the taste or texture of a food is unappealing, we won’t want to eat it—whether we are sitting at a table on Earth or are one of the select few chosen to float in a space station 240 miles above it.

The author is Editor of QA magazine. She can be reached at llupo@gie.net.