Bart Leahy

February 17th, 2017

Astronaut Shane Kimbrough tends the Veggie experiment on board the International Space Station. Photo Credit: NASA

KENNEDY SPACE CENTER, Fla. Children might not want to hear this, but, if they want to be the first astronaut on Mars, theyll need to eat their vegetables. To account for that painful truth, NASA has several space farming projects to ensure people living and working in space get fresh green stuff as part of their diet.

One project the agency has in work is the Advanced Plant Habitat (APH), an experiment scheduled to head to the International Space Station (ISS) later this year.

The Advanced Plant Habitat. Photo Credit: Jim Siegel / SpaceFlight Insider

This 18 18 18-inch (45 45 45-centimeter) enclosure contains a seed bed filled with thick sand-quality clay chips for soil, fertilizer, and pumped-in water. It is covered by a plastic top to keep the surface from floating around.

The enclosure also includes two small robotic arms, which take leaf temperatures and measure the interior humidity.

Thin-stemmed flowering plants called Arabidopsis (the white mice of the plant world) will be tested for different levels of humidity, water, and light, which consists of red, white, and blue light-emitting diodes (LEDs), to determine which combination of factors most effectively support plant growth.

After the astronauts plug APH into an existing EXpedite the PRocessing of Experiments to Space Station (EXPRESS) rackaboard, they can monitor the experiment using an existing computer called FARMER or let people on the ground run it.

The system runs on approximately three liters of water and, being a mostly closed-loop system, it can run for as many as six weeks without needing to be refilled.

APH is scheduled to be launched in two parts. The first will launch on Orbital ATKs OA-7 Cygnus launch and the other aboard SpaceXs CRS-11 or CRS-12 Dragon spacecraft.

One NASA plant experiment already aboard the ISS is called Veggie.

Filling approximately a 12 12-inch (30 cm 30 cm) area, Veggie is a soft plastic enclosure that can accordion from six to 12 inches high. The base of the enclosure contains half a dozen plant pillows containing ground clay chips and fertilizer, which substitute for the dirt they would use on Earth.

The enclosure includes an interior fan to draw in space station air and keep it moving around the plants. Without constant air movement, plants in zero gravity tend to build up bubbles of oxygen around themselves.

Kjell Lindgren (left) and Scott Kelly eat lettuce grown in the Veggie experiment during Expedition 44 in August 2015. Photo Credit: NASA

Veggie project scientist Gioia Massa explained that unlike the APH, the Veggie experiment is actually growing plants that astronauts can eat, like Chinese cabbage, bell peppers, and jalapeno peppers.

Astronauts are allowed to keep and eat half of the crop developed by Veggie, while the other half is packaged up and sent back to Earth for analysis.

Plants could be useful for more than just providing food for space travelers they could also supplement spacecraft life-support systems by providing oxygen.

Raymond Wheeler, Kennedy Space Centers advanced life support lead, is looking into growing plants using whats called controlled environment agriculture.

Plants will be much easier to grow on a planetary body like the Moon or Mars because gravity allows water to flow more naturally than in zero gravity. With planet-based agriculture in mind, Wheeler is studying Earth-based techniques such as hydroponics and LED-lighted greenhouses to maximize plant growth.

When asked whether any particular plants produce more oxygen than others, Wheeler told Spaceflight Insider, No, not really. But the more light plants get, the more oxygen they produce its almost a linear function. The trick is to identify plants that are more light-tolerant.

NASAs advanced greenhouses can produce useful outcomes on Earth as well. While its hard to beat Idaho for growing consumable potatoes in the ground, Wheeler explained that NASAs nutrient-film technique is ideal for growing seed potatoes, which provide the seed stock for the potatoes grown on Earth.

By planting seed potatoes in shallow, tilted trays with a thin layer of nutrient-laden water, they can grow in a clean, disease-free environment, which is better for producing high-quality seeds.

Ralph Fritsche, Kennedy Space Centers project manager for food production, is looking into multiple creative ways to keep plants fed and watered in zero gravity.

One approach to growing food on a Mars mission is to utilize microgreens, which doesnt take up a lot of room and can be cultivated in a couple of weeks. Photo Credit: Jim Siegel / SpaceFlight Insider

Another challenge with growing plants in zero-g is overcoming surface tension, as water tends to form in globules rather than flow in a way plants can access easily.

One approach to embedding seeds in a 3-D-printed, triangle-latticed box that draws water into crevices where roots can get at it.

Some other strong contenders for Mars veggies are microgreens, which are commonly found in salads at upscale restaurants. They dont take up a lot of room, are more flavorful, and can grow in a couple of weeks.

Fritsche also mentioned a project being conducted by the Buzz Aldrin Institute to investigate plants that grow in the Atacama Desert in Chile. It is hoped that edible plants could be combined with Atacama plants to adapt to conditions on Mars.

Something NASA is still working on is determining how much space and mass will be dedicated to providing fresh vegetables on the long haul to Mars. Most of the astronauts food will be prepackaged in some form, yet fresh fruits and vegetables will still be vital for their dietary health.

Fritsche said: The challenge is getting the engineers to talk with the plant biologists to determine the best mix of equivalent system mass.

In short, NASA still needs to determine how much hardware to grow and care for plants is needed compared to just shipping prepackaged foods.

Much of this space farming technology is still a work in progress, and the ISS is the testing ground for a lot of systems. When crews start living and working at more distant destinations, they will need to take a bit of Earth with them, to help them breathe and, yes, to make sure they eat their vegetables.

Tagged: Advanced Plant Habitat CRS-11 Cygnus Dragon International Space Station OA-7 Orbital ATK SpaceX The Range Veggie

Bart Leahy is a freelance technical writer living in Orlando, Florida. Leahy's diverse career has included work for The Walt Disney Company, NASA, the Department of Defense, Nissan, a number of commercial space companies, small businesses, nonprofits, as well as the Science Cheerleaders.

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NASA studying farming in space to support trips to Mars - SpaceFlight Insider