Author: Ilima Loomis / Source: Science News for Students
This is the first of a two-part series on preparations for upcoming human space missions to the Red Planet.
Mark Watney has found himself stranded on Mars. It’s 2035 and his crewmates, thinking him dead, have left him behind in their evacuation of the Red Planet. He faces years, all alone, trying to survive in the face of radiation, storms and little food.
That last problem turns out to be a solvable one. Watney is a botanist. And he figures out how to grow potatoes. The potato seedlings come from his Thanksgiving dinner. Water is derived from leftover rocket fuel. And his own poop becomes fertilizer.
This scenario, from the book and movie The Martian, is science fiction. It is, however, based on fact. NASA studied potatoes in the 1980s and 1990s as a potential crop for human space missions. And though no one is yet growing potatoes on Mars, scientists are already developing tools to grow food in space.
Why? People will likely travel to Mars sometime in your lifetime. NASA has said it plans to send people to Mars in the 2030s. And the private space company SpaceX may send its first crewed mission to Mars as early as 2024.
But ferrying humans to Mars would be a much bigger challenge than getting them to the moon. To pull it off, we first need to solve a lot of problems. Getting to Mars is just one of them. Then we have to figure out where our food and water will come from. Planners must also figure out how space travelers will get any tools they may suddenly need when they’re millions of miles from the nearest hardware store. It’s a huge undertaking, but researchers around the world are already on the job.
Space farmers
Today’s space travelers don’t go to the moon or Mars; they head to the International Space Station (ISS). It’s orbiting 381 kilometers (237 miles) above Earth’s surface. There, astronauts live for weeks to months. Among their tasks is conducting experiments and testing equipment that could be useful for future missions to the moon, an asteroid, Mars or beyond.
If you visited the ISS today, nearly every bit of food you ate would have been shipped up from Earth. The exception: leafy greens. Those are the first foods being grown on the ISS.
There are many reasons why NASA wants to learn to grow vegetables in space. Besides providing fresh food for astronauts, plants can provide life support by recycling air and water. “There’s also the psychological benefit that growing plants may have,” says Gioia Massa. She’s a plant scientist and the head of NASA’s Veggie Project at Kennedy Space Center in Cape Canaveral, Fla.
As Mark Watney learned on Mars, potatoes might be good survival food. They’ve got decent amounts of protein, some vitamins and other nutrients. They’re also rich in carbohydrates (sugars and starches). You couldn’t survive on potatoes alone. But they could help to keep you from starvation.
There are some downsides, though. Potatoes need to be cooked before they can be eaten. And potato plants need a lot of room to grow. So Massa and her colleagues started with something easier: lettuce.
In 2014, they sent ISS astronauts a garden. Lettuce seeds were packed into “plant pillows” with baked clay and fertilizer. Add water, some artificial light and voila! The lettuce grew!
But the astronauts couldn’t eat it.
They had to send it back to Earth to be studied. The next year, after NASA scientists confirmed it was safe, the astronauts grew a second crop. This time they were allowed to chow down.
The astronauts used this lettuce to garnish hamburgers. They also made lettuce wraps with lobster salad inside. “They got really creative,” Massa says.
Not surprisingly, gardening is different in space than it is on Earth. Without gravity, plants don’t know which way is up. But they adapt. They send their shoots toward light and their roots in the opposite direction. Fans are needed to circulate air. Otherwise, oxygen would gather in a ball around the plants, and they wouldn’t have enough carbon dioxide to do photosynthesis.
The Veggie scientists also had trouble providing the plants enough water. The fabric plant pillows containing the seeds, clay and fertilizer were designed to draw water from a reservoir. But they didn’t work fast enough. The astronauts ended up needing to water the plants by hand. Massa and her team are…
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