Salad grown in space: Experts reveal what meal astronauts should eat on long space missions
The ideal meal for an astronaut, according to experts, looks surprisingly similar to something you would find on a trendy food influencer's Instagram.
After extensive comparative research, a team of researchers in Australia estimated that the "optimal" fresh meal for space travellers is a vegetarian salad.
With long deep space missions planned in the future, the issue of feeding crews is getting more pressing. It’s not about pacing sufficient reserves anymore: it’s now about focusing on foodstuffs that can be cultivated in space.
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And "space farms," as the research team from the University of
Adelaide calls them, come with several constraints.
In a paper published in December, the US Space Agency (NASA) noted that the space food system had to be organised with resource minimisation in mind.
"All inputs and output - mass, volume, crew time, water, power, and waste - must be minimised relative to the food produced," according to the briefing.
Soybeans, kale and sunflower seeds
A vast variety of crops was studied by the team as well as animal products, though the authors recognised that "for long-term travel, there is little research on how to include animal source food products in astronauts’ diets".
The scientists evaluated various combinations of fresh ingredients by employing a mathematical modelling technique known as linear programming.
The team prioritised the sustainability of space food, opting
for ingredients that demanded minimal fertilizer, time, and space for growth, and considered the potential for recycling waste.
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The result was a vegetarian meal composed of soybeans, poppy seeds, barley, kale, peanuts, sweet potato and/or sunflower seeds.
But is it appetising? To evaluate whether it meets the taste criteria, the team prepared the optimal space meal, presenting the components as a salad, and conducted a taste test with four individuals on Earth.
One tester gave rave reviews, saying they "wouldn’t mind eating this all week as an astronaut".
2,800 calories needed for a male astronaut
The space constraints are not just about the plants grown, it’s also about the specific needs of astronauts.
Researchers calculated that a 40-year-old male astronaut needed around 2,800 calories per day, which represents around 1.2 kg of food per day - compared to 2,000 calories on Earth.
Living in space comes with additional challenges though, for example, additional energy is required in case of extravehicular activities that usually last over five hours, according to the study’s authors whose findings were published in ACS Food Science & Technology.
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Moreover, the stress placed on the human body in space means that the diet has to include nutrients like calcium and vitamin D for bone health severely impacted during the missions.
The astronaut’s intake requirements are also higher for the nine essential amino acids. These organic compounds play a crucial role as they are necessary for the synthesis of proteins in the body.
Essential amino acids can’t be produced by the human body on its own and must be obtained through the diet.
However, the meal didn’t get a perfect score and researchers noted that supplements would be needed to provide the missing micronutrients.
What are currently the astronauts’ meals?
Space food is a delicate combination of environmental prerequisites, astronauts' biological requirements, and palatability.
During the earliest space missions, when the focus was on "resources and safety" rather than "nutrition and acceptability," NASA observed that astronauts weren’t eating enough and therefore losing weight.
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Currently, more than 200 standard foods and beverages are available on the International Space Station (ISS).
The list includes pizzas, Kung Pao chicken, burritos - made with tortillas that don’t leave crumbs - and even occasionally ice cream during resupplying missions.
However, alcohol is banned on the ISS for safety reasons.
"Astronauts can share food with their crewmates at their own discretion," NASA states.