What happens to the genes of organisms as they travel from the ground, through Earth’s atmosphere and into space? Does their expression change? Are the changes subtle or dramatic? Do they happen quickly or gradually?
Answering such fundamental research questions is essential to our understanding of the impact of space travel on humans and other organisms. Two researchers from the University of Florida in Gainesville have been chipping away at the answers since the 1990s—using plants.
Soon, co-principal investigators Robert Ferl and Anna-Lisa Paul will launch their “space plants”—Arabidopsis thaliana to be exact—along with advanced cameras and sensors for imaging them on Blue Origin’s New Shepard rocket. The flight test, facilitated by NASA’s Flight Opportunities program, is the latest suborbital experiment to help the investigators further examine the cornerstone questions of two decades of biological research.
“About half of the genes in our bodies encode the exact same proteins in plants,” explained Paul. “And that’s very exciting because it means that as we look at how plants behave in the absence of gravity, we can translate many of those basic biological processes to humans.”
And it turns out that plants behave quite differently in space compared to on the ground. In particular, plant growth is distinctly unique, with roots branching in skewed or random patterns rather than extending down from the shoots like they typically do on Earth.
Ferl and Paul began studying how plants respond to microgravity on the molecular level with space shuttle experiments in the late ‘90s, the findings from which they later applied to longer term observations with nine experiments on the International Space Station.
“What we learned from those early experiments was certain notions of how plants adapt to space. And then we compared that with how they behave on the ground,” said Ferl. “That’s monumental, but it doesn’t tell us what happens in the transition. Essentially nowhere in the history of space biology have scientists had the opportunity to fully examine the transition from 1 g to 0 g and back.”
Enter parabolic flights, many of which were facilitated by NASA, where Ferl and Paul were able to start examining that transition during 30-second periods of microgravity.
“Those flights gave us the first hints that plant adaptation happens very rapidly,” said Paul. “We could get small glimpses into the transition using fluorescent imaging to study different types of molecule signaling and look at what genes are turned off, what genes are turned on and when that happens.”
Ferl and Paul have now adapted their fluorescent imaging hardware to suborbital vehicles, where they continue studying the transition phase—the new frontier of their work. Of particular interest is calcium signaling, which is known to flip the switch on or off for specific genes in response to external stimuli, such as wind blowing across the leaves, the hungry bite of a caterpillar, or something more dramatic—like a change in gravity.
“Our very first spaceflight experiment indicated that being in space changes some aspects of calcium signaling,” explained Ferl. “And calcium signaling in particular is very similar between plants and animals, so we want to better understand that role in response to transitions in gravity.”
Suborbital flights are now enabling imaging of molecular changes during gravity transitions in real time—and with longer durations of microgravity than possible on parabolic flights. A suborbital flight on Virgin Galactic’s SpaceShipTwo in December 2018 and a launch on New Shepard in January 2019 have hinted at some surprising findings.
“Our early suborbital data about how genes are responding is telling us that the calcium signaling during the transitions in gravity is working in ways we did not anticipate,” noted Paul. “And that, of course, is very exciting because it means there is much to learn.”
While Paul and Ferl can’t say just yet what this means for their findings, data from the upcoming flight, which is scheduled to launch from Blue Origin’s West Texas launch site no earlier than Dec. 10, 2019, will help confirm earlier suborbital findings, potentially leading to a new breakthrough in their research with significant implications for human space exploration.
“Understanding the biological processes of plants in space can give us insight into those processes in humans, but the plants are important in and of themselves,” said Paul.
Ferl added that while they and other scientists have grown successful plant harvests in sustained microgravity in space station experiments, their ongoing work is helping to understand the underlying metabolic changes that allow those plants to adapt to spaceflight.
“Understanding what it takes to help plants thrive in space—as a food and oxygen source and for other needs—is crucial to any exploration initiative where the goal is a long-term habitat,” said Paul.
More Tech Aboard New Shepard: A Method for Managing Trash in Space
Seven other Flight Opportunities-supported payloads will also be tested on New Shepard, including the Orbital Syngas Commodity Augmentation Reactor—OSCAR for short. OSCAR, just like the Grouch, loves trash. The system uses two chemical processes, oxidation and steam reforming, to turn things like food packaging, old clothing and even human waste into water and a mixture of gases that include hydrogen, carbon monoxide, carbon dioxide and methane. OSCAR is one of several logistics reduction technologies NASA is investigating that could be useful for long-duration space exploration.
A multi-disciplinary team made up of early career researchers at NASA’s Kennedy Space Center in Florida is working on the project to help manage trash and waste in space and transform it into useful resources. The project is an Early Career Initiative funded by NASA’s Space Technology Mission Directorate.
NASA estimates that a crew of four astronauts will generate approximately 5,500 pounds of waste during a one-year mission. Future long-duration missions, such as sending humans to Mars, will require new methods for trash handling and disposal. If OSCAR can turn trash into gases that a crew can use, it would greatly reduce the space needed for waste storage, while also making it biologically safe.
“Trash management should be a primary consideration for long-duration deep space human spaceflight,” said Anne Meier, OSCAR’s principal investigator at Kennedy. “OSCAR will be the first time we look at some of the engineering operations and science involved in the design for such a system to work in microgravity.”
OSCAR’s launch on New Shepard will enable researchers to add to data from previous lab and drop tests, evaluate the performance of the reactor, and inform future designs. The instrument will use trash simulants for this suborbital test flight.
About Flight Opportunities
The Flight Opportunities program is funded by NASA’s Space Technology Mission Directorate and managed at NASA’s Armstrong Flight Research Center in Edwards, California. NASA’s Ames Research Center in California’s Silicon Valley manages the solicitation and evaluation of technologies to be tested and demonstrated on commercial flight vehicles.
By Nicole Quenelle
NASA’s Armstrong Flight Research Center
