Mission to Mars
UF plant researchers are developing a way to grow plants in space
Anna-Lisa Paul grew up reading the science fiction of the late Arthur C. Clarke, but she never imagined that someday she’d be sending experiments to the International Space Station and helping to plan the colonization of Mars.
“By the time I started high school in 1971, I had read most of the fiction Clarke had written,” says Paul, a UF plant molecular biologist. “These books contributed profoundly to who I became as a person. They helped me decide that I would be a scientist when I grew up; no question about it.”
Rob Ferl was equally fascinated by the Apollo program.
“I grew up in the Apollo era,” says Ferl, a professor of molecular biology at UF’s Institute of Food and Agricultural Sciences and director of the Interdisciplinary Center for Biotechnology Research. “So my interest in space was with me since I was probably 10 years old, but the opportunity to work with it didn’t arise until space flight became a more accessible science venue in the space shuttle era.”
Today, Ferl and Paul study biological adaptation to space by developing plants and the systems to grow them that could be on Mars within decades as the forerunners to full-scale greenhouses used to supply food, water and oxygen to the first Mars colonists.
“Wherever humans go, they’re going to have to take their plants with them,” says Ferl. “In the case of Mars, it’s likely the plants will arrive first as part of sophisticated studies of terrestrial biology.”
Ferl and Paul have long been interested in how plants respond to environmental stresses. In the early 1990s they began experimenting with “reporter genes” that allowed them to see when plants were experiencing certain environmental stresses.
By splicing a gene from a fluorescent jellyfish into the Arabidopsis mustard plant — a “model” species often used in plant genetics experiments — they were able to make the plant’s roots glow green when it was suffering from low oxygen stress.
“At about the same time, there was some anecdotal information coming back from space shuttle experiments that plants were acting like they weren’t getting enough oxygen,”
Paul says. “We were in a unique position to contribute to this research because we had plants that had been engineered to tell us if they were oxygen stressed. We had always been interested in how plants reacted to extreme environments; space was just another environment for us.”
So, over the ensuing two decades, Ferl and Paul have expanded their space-based plant research, sending an experiment up on the space shuttle and preparing for a long-term experiment on the International Space Station next year.
“The space station allows us to see what happens to these plants over the longer term,” Paul says. “Most organisms can survive difficult trials for a short period of time, but what we learn in a day is not the same as in a month. You can’t just multiply by 30.”
Along the way, Ferl and Paul have become as much engineers as plant scientists, learning to design and build the sophisticated “capsules” in which their tiny botanical astronauts travel.
“Using reporter genes is everyday stuff in the lab,” says Ferl. “The real challenge of deploying this technology is to take all of this equipment and shrink it down into a unit that is capable of being lofted into space, where we might not be there to look after it.”
The researchers have reduced their laboratory to a box about six inches square by a foot long. Inside, light emitting diodes bathe the plants in only the wavelengths they need to thrive.
“We don’t waste energy by delivering frequencies of light that plants don’t need,” Ferl says.
A fluorescent imager reads the messages the plants’ glowing roots are sending, converts them into bytes and beams them back to Earth.
Much of what the researchers have gleaned about the design of the experiments is based on their interactions with, and understanding of, how astronauts work.
“The biggest limitation on the shuttle or the space station is crew time,” Paul says. “The less you require the crew to do, the more useful science you can get accomplished.”
“The cost of launching a space shuttle experiment is not nearly as much as the cost of astronaut time,” says Ferl, adding that they try to design their space experiments in a very astronaut- friendly way.
To try to understand some of the astronauts’ constraints, Ferl and Paul regularly take their experimental packages on NASA’s parabolic flight plane — affectionately known as the “Vomit Comet” — which simulates weightlessness through a series of steep climbs and dives.
On board, the researchers and astronauts learn things about their equipment they wouldn’t know otherwise: does the door stay shut, do the plant boxes fall out, can they easily slide the whole contraption into its bay on the space station?
Back on Earth, the researchers are using data from the hugely successful Mars Exploration Rovers — Spirit and Opportunity — to see how Arabidopsis will grow in Mars-like soil.
One graduate student is trying to grow plants in soil created to mimic the chemical composition of the soil the rovers have encountered during their multi-year journeys across the Martian surface.
According to researchers at NASA’s Jet Propulsion Laboratory, the Mars Rovers have found the Martian soil to be mostly silicon and iron, with significant levels of chlorine and sulfur.
Paul says that knowing what the Martian soil is like allows researchers to develop plants that will do better under those unique conditions.
“The idea is to overcome a lot of the limitations of growing in an extreme environment by engineering both the habitat and the plant,” she says.
Crater Test
Ultimately, to be useful, extraterrestrial greenhouses are going to have to be more than foot-square boxes. So to test both the science and logistics of growing plants on the moon or Mars, each summer Ferl and Paul travel to one of the most desolate spots on Earth — Devon Island in the Canadian High Arctic.
“There exist a number of places on the surface of the Earth that are in one way or another similar to the environment on an extraterrestrial body,” Ferl says. “Devon Island is one of those places.”
In addition to being an extremely dry polar desert similar to the environment on Mars, Devon Island is the site of Haughton Crater, an impact crater 20 kilometers in diameter that was formed 23 million years ago when a large meteorite struck the island.
Since 1997, the area around the crater has been home to the Haughton-Mars Project, an international research site where scientists from all over the world come to “practice” for missions to Mars. The project is managed and operated jointly by the Mars Institute and the SETI Institute with support from the Canadian Space Agency and NASA.
Fittingly, for Ferl and Paul, their laboratory at the Haughton-Mars Project is the Arthur Clarke Mars Greenhouse, a 288-square-foot commercial structure specially modified to endure the harsh Arctic climate. Initial sponsorship support for the greenhouse was provided by NASA, SpaceRef Interactive Inc., the SETI Institute, Simon Fraser University, the University of Guelph and the CSA.
Since its installation in 2002, researchers have been working to make the greenhouse ever more autonomous, as it would have to be on Mars.
Ferl says that just getting the team’s gear and equipment to Devon Island is an exercise worthy of space travel.
“One of the very special things about many of these analog sites, especially the Haughton-Mars Project, is that it is an analog not only for the physical makeup of the land — the soil and temperature extremes — but it’s also an analog for the operational extremes you might find,” Ferl says. “Communications are difficult, logistics are difficult. Many of the concepts that are inherent in long-distance, extraterrestrial travel can be simulated in fairly high fidelity.”
The “season” for research on Devon Island lasts just six weeks in July and August, so scientists have to get a lot done in a short amount of time.
Paul hopes that this year, when the first scientists arrive, plants will already be growing in the greenhouse.
“When everyone leaves in August, the greenhouse is on its own,” she says. “It figures out when to power down and when to wake up in the Ômorning’ months later. Sensors tell propane tanks when to light and warm up the environment and when to begin irrigation.”
In a world with little native vegetation, where tents are secured to the ground with railroad spikes and sub-zero temperatures and 40-mile-per-hour winds are the norm in July, Paul says the greenhouse is a natural gathering place.
“The greenhouse is a place to get warm, to socialize, to see things growing,” she says. “It becomes like a cozy kitchen in the dead of winter. When you’re out where there’s nothing else living — whether that’s Devon Island or Mars — it’s a connection to your home environment.”
Ferl is confident crops will be grown on both the moon and Mars in the future. It’s just a question of when, he says.
“Under the right conditions it only takes a few square meters of growing area to provide enough oxygen, pure water and food to support a single person,” Ferl says. “There are still plenty of technical obstacles to overcome, but this is something we can and will do.”
Rob Ferl
Professor, Department of Horticultural Sciences
(352) 392-4711
Anna-Lisa Paul
Associate Scientist, Department of Horticultural Sciences
(352) 392-1928
Experiment Tests Bacteria Hitch hiking To Mars
If a trip to Mars seems like it would be a tough journey inside the spaceship, imagine what it would be like on the outside. Earth bacteria can be extraordinarily tough — rugged enough, in fact, to survive on the outside of a space capsule.
Now, a set of experiments on the International Space Station is testing exactly what effect the rigors of space could have on bacterial spores on a Mars-bound vessel.
“We’re pretty sure that it’s possible that this life could survive out there — but exactly how possible? And what happens to it if it does?” says Wayne Nicholson, a UF astrobiologist working from NASA’s Space Life Sciences Laboratory at the Kennedy Space Center.
One of the biggest benefits of knowing how bacteria are affected by space could be to know when a space-altered bacterium is found on Mars. Even though all Mars landers are meticulously cleaned and disinfected before launch, researchers are hopeful the data from Nicholson’s experiment will allow them to anticipate any possible contamination of life-detection equipment aboard future landers.
Bacterial spores have been shown to survive on satellites that had been in orbit as long as six years. Some of Nicholson’s previous research has shown that bacterial spores could theoretically survive on bits of rock thrown into space after a large meteor strikes the Earth. It is even possible that the planets have been swapping organic material and even living organisms through such cosmic shrapnel.
As far as near-term human space exploration goes, the chance of this natural exchange is probably of little concern. However, the statistical likelihood has increased with humanity’s ability to send its own packages to other worlds.
“It might be pretty unlikely, but one of these spores could hitchhike the distance to Mars on the surface of one of these devices and then could find its way into the sample,” Nicholson says. “It would be important to know that we were detecting genuine citizens of the Red Planet, and not merely accidental terrestrial contaminants of our equipment.”
Nicholson is working with a spore-forming bacterium known as Bacillus subtilis. His experiment is one of several being conducted on an external platform of the space station called EXPOSE, in collaboration with NASA and researchers at the German Aerospace Center and the European Space Agency.
The EXPOSE platform is installed outside of ESA’s Columbus laboratory module.
Living samples of several microorganisms will be exposed to space for more than a year, returned to Earth and tested for survival, and for genetic and physiologic changes induced by space exposure.
Some bacteria can enter a form known as a spore, in which they shut down their metabolic processes while creating a thick shell. In this form, they can stave off extreme temperatures and even high levels of harmful radiation.
“Life has all sorts of tricks up its sleeve,” Nicholson says. “I can’t wait to find out what it comes up with.”