Emily Swaim
- Astronauts need more calories and nutrients than someone on Earth.
- But packaged food loses nutritional value in space, so what will humans eat on long space missions?
- Scientists figured out the best meal for astronauts and it's worth trying for yourself.
In the not-so-distant future, humans may trek to Mars or beyond. These deep-space trips are going to be quite the commute — Mars takes at least seven months to reach with current technology.
Never mind the psychological toll it may take on astronauts' mental health or the physical repercussions their bodies risk from space radiation. Let's talk basics: food.
Astronauts need to eat — a lot. However, long-distance space explorers won't be able to rely solely on pre-packaged foods and vitamins as they do on the International Space Station because some of the nutrients inside those products tend to degrade after one year.
Moreover, because of how microgravity affects human metabolism, astronauts need a lot more energy to function than people on Earth. A 40-year-old, 154-lb man in space, for example, might need 2,700 calories a day instead of 2,000, according to research.
As a result, during long space missions, at least some of the astronauts' diets will likely come from fresh, renewable crops grown on the spaceship.
The perfect astronaut meal: space salad
Koichi Wakata/Japan Aerospace Exploration Agency
To that end, an international team of scientists calculated 10 different combinations of crops that could be grown on deep-space missions and published their results in the American Chemical Society's peer-reviewed journal Food Science & Technology.
In their study, the researchers considered an astronaut's nutritional needs, how much space the crops would take up, and also the amount of water each plant requires.
The "winning" crop combo had the best synergy between nutrition and efficient farming.
It's got high vitamin levels and contains crops that grow within 50 days to 100 days and take up relatively little square footage. And, with the exception of seeds, a large proportion of each plant is edible.
Using only the crops from their winning combination, the scientists crafted a recipe for a vegetarian space salad, which I tried out myself.
How it tastes
Emily Swaim
I decided to make the meal and determine for myself what this space salad of the future would be like to prepare. I was pleasantly surprised at how flavorful it was.
The recipe is designed to meet the nutritional value for three male astronauts, offering each one about 900 calories per serving. Here's a list of the ingredients, according to the study.
You'll need:
642 grams of sweet potato (about 5 small potatoes)
223 grams of pearled barley (about 1 cup)
155 grams of poppy seeds
79 grams of kale
63 grams of soybeans
25 grams of peanuts
18 grams of sunflower seeds
An astronaut would ideally eat this meal once a week as part of a rotation of dishes, said study co-author Volker Hessel, who's a professor of sustainable chemical engineering at the University of Adelaide.
I could definitely see myself eating the space salad that often. The salad was easy to make and took about 30 minutes from prep to plate. Plus, all that protein made it filling.
Long space flights require special diets
NASA/Lacey Young
The study authors developed the space salad based on NASA's nutritional guidelines for long space voyages, using computers to calculate the most nutritious, resource-efficient combination. Business Insider reached out to NASA's Space Food Systems Laboratory for comment but it didn't respond.
In addition to more energy, astronauts will also need more of certain vitamins like calcium and magnesium — to prevent astronauts' skeletons from wasting away in zero gravity. They'll also need potassium for homeostasis, which balances and stabilizes all the body's systems.
Now, thankfully, research from the International Space Station suggests the nutritional content of crops grown in space is usually close to that of their Earth-bound cousins.
Therefore, we can calculate approximately how much nutrition astronauts would earn from eating this space salad.
For example, one serving of the space salad has:
52 g of poppy seeds, which carry 749 mg of calcium (62% of recommended daily intake for astronauts
214 g of sweet potatoes, which offer 807 mg potassium (17% of daily intake)
74 g of barley that provides 16 mg of magnesium (4% of daily intake)
But of course, not every astronaut is going to need exactly the same diet.
Future research
NASA
The scenarios in the study were designed for male astronauts, alone. Female astronauts will likely have different requirements for nutrients like magnesium and iron.
Therefore, the authors said they plan to adjust the diet plans to include female astronauts in future research.
Making things even more challenging, Hessel said each team member's body will react differently to the stresses of space.
Plus, an astronaut's dietary needs may change during the trip.
For instance, when an astronaut spends an hour outside the ISS to perform an extravehicular activity, NASA's 2020 nutritional guidelines recommend they eat an extra 200 calories that day.
The computer simulations in the study should be able to craft new diets as needed. "We can give recommendations for new requirements virtually the same day," Hessel said. But a shuttle's food supply will need to be flexible enough to account for these changes.
What about meat?
Getty Images
Meat-lovers don't need to worry: the future of space doesn't have to be vegetarian. Past astronaut meals have included dehydrated shrimp cocktail, beef brisket, and even teriyaki chicken.
Future space explorers may also eat a lot of lab-grown meat, which is currently in the middle of the FDA approval process and may soon be available in restaurants.
Scientists are also working on raising fish in space so astronauts can have fresh meat. The study authors say fish could be an ideal part of a space ecosystem, since astronauts could feed them excess plant material and then harvest their droppings for fertilizer.
If you wanted to add meat to your space salad, I'd recommend pairing it with a lighter option such as chicken or tuna. But if your astronaut heart yearns for more exploration, you could try any salad additions you like.