Radishes and Rockets
Radishes: you've probably never given them much thought, or respect, for that matter. They're crunchy, a little spicy, and add some color to your salad. But they're not exactly a dietary staple, and growing them certainly isn't rocket science -- or is it? Surprisingly, at NASA the two are related.
Image at Right: The Space Life Sciences Lab at NASA's Kennedy Space Center, Fla., is a cooperative effort betwen NASA, the state of Florida, and multiple universities. Image credit: NASA
When astronauts venture into space, they need food. Restaurants aren't an option on the Moon, and if space travelers run out of something on the way to Mars, they can't just stop at the supermarket. Aboard the International Space Station, the crew depends upon supplies ferried from Earth by the Space Shuttle and the Russian spaceships.
But on longer journeys to fulfill NASA's mission to the Moon, Mars and beyond, successfully growing food in space will be essential to supplementing their prepackaged diet. And the lowly radish, which gets so little respect, is actually an excellent candidate for the kind of experiments that will help our astronauts sustain themselves on long space flights.
Image at Left: Healthy radishes being grown at the Space Life Sciences Lab. Image credit: NASA
NASA's Kennedy Space Center in Florida is home to the state-of-the-art Space Life Sciences Lab. The 100,000-square-foot facility represents a partnership between NASA and the state of Florida. It's here that research is under way to perfect the methods for equipping our astronauts with the ability to become farmers in space while fulfilling the Vision for Space Exploration.
"The overall goal of what we try to do with the plant research is looking at candidate crops to support long-duration space missions." says Dr. Gary Stutte, one of the principal investigators at the facility. "Then we look at the various environmental factors and conditions affecting growth."
Image at Right: Dr. Gary Stutte examines radish plants being studied for future crop growth in space. He and other researchers hope to determine how to keep the plants healthy in the growing conditions within a spacecraft. Image credit: NASA
A spacecraft has its own self-contained environment. This research will help produce guidelines for maintaining a safe and healthy atmosphere for both plant growth and the crew that will share this setting. Researchers want to determine how the continuous exposure to common contaminants in the spacecraft might affect the growth and development of the space veggies.
So why choose the radish as the focus of the experiments? The easy-to-grow vegetable has been identified as a salad crop for space missions because it is small, grows rapidly, provides essential nutrients and gives variety to the diet.
The experiments under way are conducted in specially designed plant-growth chambers. Within that closed environment, it's possible to measure the effects of different levels of the common contaminants present in a spacecraft on plant growth, while controlling other factors like temperature, water, light and nutrients. The goal is finding safe, allowable levels of these contaminants within the plant-growth chambers that will be used to raise crops aboard long-term space missions.
Image at Right: Special plant-growth chambers allow scientists to control growing conditions and introduce common contaminants found in spacecraft that may affect the plants. Image credit: NASA
But just what kinds of contaminants are present in a spacecraft that could affect these plants? There are many, and some come from surprising sources. The current radish experiment at Kennedy is focused on one common by-product.
Since water floats in space, astronauts depend heavily upon moist wipes similar to those you might use to wash your hands when traveling. These wipes contain alcohol that evaporates into the spacecraft's air and is maintained at a level safe for humans. But this airborne alcohol -- in just a small percentage of the allowable safe limit for the crew -- can kill the radish plants and affect even the soil they grow in. Grown in air with just 10 percent of the allowable alcohol limit, the radishes are undersized. With 25 percent of the limit, the plants die.
Multiply this problem with other contaminants present in a spacecraft -- benzenes, isoprenes, aldehydes, to name a few -- and the researchers have their jobs cut out for them.
"It's something we need to worry about if (the salad crops being studied) are going to be a life support," says Stutte. "The levels may be healthy for humans but harm the plants. Other things might be very harmful to humans but be safe for the plants. These are the kinds of questions we look at."
So the next time you pass the through the produce section of your neighborhood supermarket, try to have a little respect for the radish, a tiny vegetable destined for space exploration.
Cheryl L. Mansfield
NASA's John F. Kennedy Space Center