From Tang to Teriyaki: How the Space Food Systems Laboratory Keeps Astronauts Full and Focused

Food plays a huge role in our daily lives and our cultures. We celebrate with food, take comfort in our favorite snacks, and share a little bit of ourselves every time we cook for or eat with friends and family.

Food is just as important, if not more so, for the astronauts aboard the International Space Station.

“Food is essential for the astronauts’ health and performance, but also for their mental well-being, because we celebrate with food,” said Xulei Wu, food system manager for the International Space Station at NASA’s Johnson Space Center. “And if you have a bad day, food can cheer you up. It is important the crew can enjoy the food and share a meal with each other.”  

Nearly all the food U.S. Orbital Segment crews eat on the space station is made by the Space Food Systems Laboratory at Johnson and its Space Food Research Facility at Texas A&M University in College Station, Texas. Together, these teams produce over 200 different food and beverage options that make up the station’s standard menu. Each astronaut also gets to choose their favorite food and beverages to bring along. These “crew preference” items complement the orbiting laboratory’s menu but can also help to sustain morale. “It is very important that crew members have a good variety of food, so they don’t get menu fatigue,” said Wu.

Most space food is produced by NASA because astronauts have different nutritional needs and more stringent food safety requirements. “You would think something sold on the general market would be safe, but we have a much higher microbiological standard,” Wu said. If someone gets sick from something they eat here on Earth, they can quickly get medical attention. “There are much greater consequences if a crew member gets sick from food on the International Space Station.”

Food safety concerns actually inspired Wu’ s career path. She chose to study food science and engineering following a scandal in China, where she grew up and attended college. The scandal involved a company that was adding melamine to their baby formula to make it appear protein-rich, while causing kidney stones and kidney damage in infants. Wu worked at the largest freeze-drying company in North America after she obtained her master’s degree from Oregon State University in Corvallis, Oregon. When NASA advertised a job opening for a freeze-drying food scientist, she knew she had to apply. “I felt it was a perfect match for me, even though as a first-generation immigrant I never dreamed I could work at NASA – it was too far for me to reach,” she said. “I consider myself extremely lucky to be here.”

Formulating a new food for spaceflight is a lengthy process – it can take almost three to five years for one item to go from concept to consumption. It all starts with a brainstorm between the Space Food Systems Laboratory team and their colleagues in the Nutritional Biochemistry Laboratory, which defines the nutritional requirements for spaceflight. The group discusses what ingredients and flavor profiles would be helpful to add nutritional variety and balance to the standard menu. “We have a lot of different backgrounds and meal preferences, so that helps us come up with different ideas,” Wu said.

Once the group has narrowed their ideas down to a few options, Wu and her colleagues do what is called a benchtop test. “It is kind of like how we cook at home,” she said. The food scientists make and test a small number of servings of each new food, meticulously weighing ingredients as they work. When they are happy with a recipe, the food is processed so it becomes shelf stable. Then, the processed food is tested for acceptability and food safety. Wu said the team does this because processing can change the flavor and presentation of the food. For example, a mango salad – one of the most popular standard menu items – would look “very sad” when thermostabilized but worked quite well as a freeze-dried food.  “If a food does not look or taste good, no matter how nutritious it is, the crew member is not going to eat it,” she said.

The next step is to invite Johnson employees who are not involved in the food production process to taste test the new menu item. A 9-point hedonic scale is used to rate the food. An average score of six or higher is needed for the food to be added to the standard menu. “Most of the food we make has a score of seven or above, which is pretty good for space food,” said Wu.

Wu says people often ask her if she’s a chef. “I say no, I am a food scientist! A chef is more focused on the moment – something that's intended to be consumed right away,” she said. “For food scientists, we are focused on delivering this prepared food safely to the target consumers – in our case, the astronauts.”

The last step is to do shelf-life testing, where the team conducts more taste tests with Johnson employees to evaluate how a food changes in taste, texture, odor, and appearance over time. Wu said the lab is currently targeting a three-year shelf life for space station foods – that is how long it can take from the time an individual food pouch is made to the time a crew member eats it.

These days, many of the new foods introduced to the orbital outpost menu come through the Advanced Food Technology research team. That team is focused on developing more nutritious foods for long-duration missions beyond low Earth orbit, meaning they are targeting a shelf life of five to seven years. “Once it passes the three-year mark, we can use that for the space station,” said Wu.

It takes far less time to prepare crew preference items, but the process can still be complicated. These foods can be sourced commercially but they must pass several important tests – they must be shelf-stable, pass the microbiological tests, be packaged appropriately (no glass!), and not too crumbly. For some crew choices, like crackers, this can require a lot of market research to find which variety is sturdiest, plus testing to figure out the best way to package the food so it does not get crushed. “That is why we do not send potato chips,” Wu said.

Wu said the lab plans to offer the same standard menu to at least the first few Artemis crews, but those astronauts will choose everything they pack in advance. She explained, “Mass and volume is very restricted on the Orion spacecraft, so we want to make sure they pick the food they will definitely eat.”

For Wu, those foods would probably include the standard menu’s barbeque beef brisket, chicken strips in salsa, and the ever-popular mango salad. “I have so many favorites, because I am a foodie!”