Strawberries May Be Ideal Crop for Space Farms of the Future

Astronauts on long space voyages would probably get pretty tired of freeze-dried meals, so scientists have long been trying to figure out how to grow space food to supplement their diets. According to researchers at Purdue University, strawberries may be one space-friendly crop. They say a low-maintenance strawberry cultivar called Seascape would do pretty well in space. It produces fewer berries than other cultivars, but they're bigger and just as tasty.

Growing plants in space comes with several challenges, not the least of which is providing artificial light. Artificial-sunlight lamps need lots of power, and they generate heat, too, so a spacecraft or space base would need enough power to cool things down. There are no winds or insects to pollinate the plants, which is especially problematic for flowering fruits like tomatoes and strawberries. Roots grow differently in low-gravity environments. And water is a precious commodity, so space crops must do well with small amounts.

NASA has been studying the problem for years, but scientists are still weeding out plant varieties to find the best ones.

How Space Farming Works

 

Ever wonder where we will build homes and expand neighborhoods as we use up more and more of Earth's habitable land? Perhaps space will be the next suburb? But before we start sending children on an intergalactic school bus ride, we must figure out new ways to accomplish everyday tasks in space, like growing food. International organizations are devoting time and resources to the development of sustaining human life beyond Earth. Some of the space programs' goals include the upcoming return to and eventual settlement of the moon, along with the pending manned voyages to Mars.

The International Space Station (ISS) provides a cooperative platform on which to research the critical challenges of putting humans in space for a sustained period of time. And researchers must overcome these challenges before any long flights and permanent habitats in space can happen.

Space farming requires greater understanding if humans are to survive in space without constant contact from Earth. Space farming simply refers to growing plants in space. At first glance this might not seem too tricky, but the inherent properties of space and our ability to travel and live in its environment greatly complicate the situation.

Luckily, the ISS has a whole team of astronauts (green thumb not required) from around the world specializing in a variety of scientific and engineering fields. Astronauts conduct experiments and improve our knowledge of cultivating plants in space, as well as many other critical arenas of science. Earth-bound researchers and scientists analyze the results and conduct their own experiments, thinking up new theories and possible solutions to test.

Farming in space: how would we do it?

Look at what we'd have to consider to set up a farm in space.

Under pressure

Low atmospheric pressure can make plants think they’re dying of thirst. Experiments conducted at the University of Florida under simulated Martian pressure conditions showed that Arabidopsis thaliana, a member of the broccoli plant family, reacted badly to rarefied conditions. This will need to be addressed as the Martian atmosphere is only 4/1000ths the pressure of Earth’s and Martian greenhouses will have to be kept at low pressure to make leaks less dangerous. In low pressure environments water evaporates more easily, and the plants dry out even in humid conditions. This triggers the plants’ drought defences, which can damage crop yield.

Poor soil

Lunar soil, in reality pulverised rocks known as regolith, lacks any of the nutrients necessary for plants to grow. On Mars the situation is worse, with the Martian top surface containing chemicals that are actually harmful to organic molecules. Importing huge quantities of topsoil or compost is impractical because of the weight involved and so astronauts will have to grow plants hydroponically, using water that they mine from the surface of the Moon or Mars. They will have to introduce the necessary nutrients, brought from Earth, into the water, then compost and recycle everything for the next harvest.

Space Allotments

NASA studies have shown that each astronaut will need at least 100m2 of crop space to grow all the food they require. Stored supplies could reduce this by half. Such a space requirement may not sound like much, it’s about the size of a large garden allotment, but multiply that by a six-man crew and the structure to house the garden is indeed considerable. Perhaps trees could be grown to reinforce the greenhouse structures rather than using more precious metals or plastics. The upside is that all those plants will provide plenty of oxygen for the astronauts to breathe.

Light Issues

Providing plants with natural light could be a problem, especially in spacecraft en route to Mars. Plants can be picky about what colour light they grow in – they thrive in red and green light, but not in blue. LED lights could be the perfect solution because they use little power and can be tuned to exactly the right light for each crop. Cary Mitchell, of NASA’s Specialized Center of Research and Training for Advanced Life Support at Perdue University, has developed strings of LEDs that hang down between plants providing all-round illumination. He calls them ‘lightsicles’.