Surviving the challenges of deep space exploration could rely as much on botany as astrophysics.
NASA sees plants not only as potential food sources aboard future spacecraft but as natural oxygen producers. The space agency is preparing for its first in-depth study of how growth and development of plants is affected by gravity, or more specifically the lack of it.
“The overall significance is what it could mean for space exploration,” says Norman G. Lewis, a Regents professor at Washington State University’s Institute of Biological Chemistry and principal investigator for the NASA-funded study. “Whether it’s colonizing planets, establishing a station, or for long-range space travel, it’s going to require maintaining air and food for artificially supported environments.”
The idea of growing food aboard spacecraft is nothing new. Several earlier experiments, in fact, already have demonstrated plants will grow in low Earth orbit.
But the WSU-led effort goes beyond simply proof of concept.
The multidisciplinary project brings together scientists from Pullman, New Mexico, and the Los Alamos and Pacific Northwest National Laboratories for a study of how plants change in microgravity environments.
Everything from their metabolism and genetics to protein and photosynthesis will be measured aboard the International Space Station. A control group of identical plants will be grown at the same time at Kennedy Space Center in Cape Canaveral, Florida.
The study will serve as a baseline or reference point for future NASA research, with the collection and analysis of big data sets showing changes in genes, proteins, and metabolites.
Among other things, the $2.3 million research grant will help determine whether plants develop the same characteristics, such as nutritional value and rates of oxygenic photosynthesis, in weightless environments as they do on Earth. The test facility at Cape Canaveral will duplicate the space station’s atmosphere so that gravity will be the only major variable.
Of particular interest will be the effect on carbon-absorbing compounds known as lignins, which plants use to form rigid outer cell walls to counteract Earth’s gravity and grow upright.
“In a microgravity environment, rigidity isn’t as important,” Lewis explains. “We know that astronauts and cosmonauts see bone and muscle loss. The body compensates by unloading what it thinks it doesn’t need anymore.
“So, with less lignin requirements, what will the plant think it should be doing? And what effect would those changes have?”
The connections between WSU and NASA’s space biology program run deep.
Thora Halstead ’50 pioneered the research field for NASA and managed the space agency’s Life and Biomedical Sciences and Applications Division. Much of the awareness of how cells respond to low-gravity environments can be traced to Halstead’s early research.
Lewis worked with Halstead on research projects as early as the 1980s. Later, when Lewis was considering an offer to join WSU’s faculty in 1990 he happened to mention it to Halstead, unaware at the time that she was an alumna. She enthusiastically endorsed the idea, he recalls.
For the latest project, Lewis, coprincipal investigator Laurence Davin, and researcher Mike Costa have converted a portion of a Pullman lab to the same dimensions of the plant habitat that soon will be on its way to the space station. They designed the experiments with equipment and supplies that can fit into the available square footage, and using procedures that can be conducted without gravity.
“We’re trying to replicate what they’ll be doing there,” Costa explains.
One of the major challenges, for example, is watering plants. You can’t simply sprinkle water over soil because, like anything else in space, it floats away. The experiments will rely on absorbent fabric and materials that trap the moisture so seeds can germinate and roots can draw nourishment.
NASA wants the experiments ready to go for potential launch this fall.
“We’re developing a reference point for space biology going forward,” Lewis explains. “This is a new frontier.”