By Taylor Emerson ’18

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A large garden cart was the chariot of choice — or perhaps just of convenience.

The well-worn, green-painted metal hauler, largely used to ferry plants around the facility, stood in stark contrast to its freshly milled, carefully assembled, and now plastic-covered delivery. An accompanying group of seven researchers, plant scientists, and engineers flanked this slightly paradoxical arrival, as the group ushered it into the USU Research Greenhouses.

The entourage gathered in a small classroom just off the garage entryway, where they hoisted the package onto a table. A pair of scissors helped peel back the protective covering, as the group cut three sides of the plastic, flattening the sheet.

After brief deliberation, a quick countdown ensued.

“One, two …” said one of the engineers, as he and another lifted the metal object.

Then came a move akin to a magician’s tablecloth trick.

“… three,” as the sound of rustling plastic cleared the air.

“Oh wow, OK,” a member of the group exclaimed in initial shock.

“I didn’t think he was gonna actually do it,” another said, followed by a bout of collective laughter.

But there it was — the fruit of a collection of work dating back to the 1980s here at Utah State University — an engineering model of the Utah Reusable Root Module (URRM). A precisely machined stainless-steel piece of NASA-sponsored hardware that will help guide the future of growing plants in space.

“It’s a simple project,” says Bruce Bugbee, the director of the USU Crop Physiology Laboratory and co-principal investigator on the project. “It’s to build a new plant growth chamber for the International Space Station to grow fresh vegetables for the astronauts.”

Simple to describe, sure, but certainly less simple to execute.

Ultimately, how do you design a system that is meant to retain everything put into it — the soil and water — but still allow plants to grow through and    out of it so they can be harvested?

“And how do you do that in the space environment,” asks Curtis Bingham, project manager in the Civil and Commercial Space Division at Space Dynamics Laboratory, who’s helping to lead the engineering side of the project. “That was the biggest challenge.”

Another challenge was ensuring the system is precise with water — making certain it doesn’t under or overwater. 

“You can’t overwater, there’s nowhere to put the excess water,” Bugbee says. “So, it means you have to precisely water and precisely fertilize the plants. We’ve been trying to do that for decades on Earth — water exactly right, fertilize exactly right. Most of the time we get it wrong.”

To answer these challenges and more, the team built a stainless-steel rack and six accompanying stainless-steel planting trays, or partitions. While the rack only fits five of these roughly 1/2-foot-by-2-feet trays, the additional one acts as a backup option since the system is modular. Each is complete with automated moisture probes, ceramic watering tubes, and all the required electrical circuitry and data connections.

The idea is that all of this will slot into another in-development growth chamber called the Ohalo III that will house the necessary grow lights, among other aspects. Collectively, they will then be fitted to the EXPRESS rack aboard the ISS.

“To get hardware onto the International Space Station, it has to satisfy an enormous set of requirements,” Bingham notes, emphasizing the difficulty of this task.

All of this precision engineering and careful planning is filled with peat and enclosed to ensure nothing  ends up escaping as particles floating around the International Space Station. The type of enclosure, however — its structure and material make up — is one of the more final experiments the team is conducting.

“If we sent it as is, it’s going to float,” says Chihiro Dixon, a postdoctoral fellow in the Department of Plants, Soils, and Climate, who is a research assistant on the project. “The particles are going to escape everywhere. We don’t want that to happen, because if that happens, it’s a whole mess.”

What makes USU’s growth module unique is they’re attempting to be able to continually replant back into the same peat — harvest after harvest.

“So that there is no need to replace the root zones, as is necessary in the current plant growth systems on the International Space Station,” says Brendan Fatzinger, a Ph.D. candidate in plant science and a research assistant on the project.

To make this possible, the team had to develop a method to precisely and continually fertilize according to the needs of whatever crop is currently being grown. The idea is to develop a type of solid or powder that could be dissolved in water to then fertilize the plants.

“For the most part, the amount of nutrients that we put in, are hopefully equal to the nutrients that the plants need and are able to take out,” says Noah Langenfeld, a Ph.D. research assistant on the project. “So it’s a self-balancing system.”

All of this helps move the team toward an overarching goal of ensuring the entire system is as close to autonomous as possible — where the only maintenance necessary would amount to watering and thereby fertilizing.

“That’s most the work the astronauts have to do, outside of harvesting vegetables,” says Scott Jones, professor of environmental soil physics and co-principal investigator on the project.

To date, aboard the International Space Station, astronauts have grown three types of lettuce, Chinese cabbage, mizuna mustard, and red Russian kale — along with a few other plants — and the research team here at USU is looking to similar specimens to put their testbed through its paces.

“Right now, what NASA’s required from us is to grow lettuce and tomatoes and so that’s what we’re focusing on, primarily,” Fatzinger says. “But we’re also growing a lot of leafy greens, like mizuna, and also peas.”

The team is hoping to have its hardware flown up to, and installed into, the International Space Station in 2026. That would allow NASA and the astronauts to use and learn from the growth chamber until the ISS is retired — which, as of publication, is planned for some time after 2030. However, that four-year window isn’t the lifespan of the research.

“Just getting to the space station is an opportunity to test this,” Jones says, “but the ultimate goal is to put it on a ship going to Mars.”

That opportunity would stand not only as a historic milestone for humanity, but an immense achievement for USU, SDL, and a lineage of researchers.

Gail Bingham, a now-retired SDL scientist, had a hand in various research experiments aboard the International Space Station, as well as the Russian space station Mir, looking into plant growth techniques. Among the most notable aspects of his work is the Lada growth chamber, launched to the ISS in 2002.

Bugbee has worked on the question of growing plants in space since the early 1980s, including researching the feasibility of plant growth in a lunar environment and developing a dwarf wheat called Apogee. This wheat was grown aboard the International Space Station from April to June 2003.

Jones entered this field of study in the 1990s, investigating how roots, soils, and plants react in microgravity. He worked along with Bingham on an experiment aboard the Mir called Greenhouse-2 and had the opportunity to study soil moisture with the help of NASA’s KC-135 — otherwise known as the Vomit Comet.

“This research has been funded by NASA for 40 years,” Bugbee says. “We’ve had almost continuous competitive funding in multiple three-year increments. It is not trivial to get this exactly right in a closed system without gravity.”