CALS student helps NASA cultivate crops for space

While grocery shoppers in North Carolina and throughout the country are concerned about iceberg lettuce being contaminated with cyclospora, NC State University student Sawyer Exum is focused on how two other varieties of lettuce, Outredgeous and Dragoon, can tolerate high amounts of ammonium as a nitrogen source in hydroponic systems in outer space.

© North Carolina State UnviersityAstronauts from Crew 11 with NC State student Sawyer Exum at the Kennedy Space Center.

Exum, a biological and agricultural engineering technology major, spent this summer tackling the challenge of growing out-of-this-world leafy greens during an internship at NASA, working alongside scientists and experts researching space crop production under simulated International Space Station (ISS) conditions. One of the crops they're studying is Outredgeous lettuce, a bright red, sweet-tasting variety that made history in 2015 as the first plant grown and eaten by astronauts aboard the ISS.

© North Carolina State UnviersitySawyer Exum setting up the pH control system for an active research experiment created to test if the Outredgeous variety of lettuce can maintain pH in a hydroponic system using only plant nitrogen uptake.

"I manage hydroponic systems in simulated International Space Station conditions by elevating carbon dioxide levels to around 3,000 parts per million," Exum says. "My tasks include monitoring pH, electrical conductivity and temperature; planting and harvesting; data analysis; calibrating sensors; troubleshooting issues with the pH control system by finding any bugs with the code or updating the automation with changes when needed; fixing frayed wires or cleaning sensor electrodes when necessary; and working with lab equipment like spectrophotometers to determine concentrations of chemical compounds in a nutrient solution like ammonium or nitrate."

His work with lettuce has opened up a world of possibilities for Exum to explore new methods for hydroponic systems.

"I'm studying how pH control affects lettuce's ability to tolerate ammonium as a nitrogen source in hydroponics," he says. "The goal is to show that, with proper pH control, plants can thrive on ammonium. Another important project I'm contributing to uses plant nitrogen uptake to control pH without the use of acid or base in hydroponics."

It turns out ammonium can be sourced from waste streams like urine, making it valuable for sustainable space agriculture. Applications from space crop production research could also reduce costs and improve efficiency for agriculture on Earth.

The experience has also ignited new ambitions for Exum. While working on-site at NASA's Space Systems Processing Facility in Florida near Cape Canaveral, he got to meet astronauts from Crew-11 and Artemis 2. Now, his long-term goals include being an astronaut.

"I want to push the boundaries of science and technology with applied research," Exum says. "If that path leads to becoming an astronaut, that would be incredible. Being here and working with NASA research scientists who are open to having conversations has made that goal feel more attainable."

© North Carolina State UnviersityScientists with Sawyer Exum in front of the Ohalo III system at the NASA Kennedy Space Center. Left to right: Oscar Monje, research scientist, Stephen Robinson, astronaut and professor at UC Davis, Sawyer Exum, summer intern, and Gioia Massa, project scientist.

Building a path for exploration

Growing up in Alamance County, North Carolina, Sawyer Exum was the first 10-year-old in the state to earn a scuba diving certification. A naturally curious kid, he loved science and math because these subjects explained how and why things work. He was also in a Spanish immersion program from kindergarten through eighth grade and attributes his love of learning to his mom being a teacher and his dad being a photographer.

Exum was a sophomore in high school when the COVID-19 pandemic disrupted traditional schooling for students around the world. The sudden shift to learning and socializing online had a profound impact on him.

"I became disengaged and struggled to stay interested," Exum recalls. "That feeling lasted through my senior year of high school. After graduating, I wasn't sure what I wanted to do. So, instead of jumping straight into college at NC State, I did an immersion program in Hawaii."

Through Pacific Discovery, an experiential education program, Exum lived and worked on a sustainable farm in Hawaii, where he was introduced to permaculture, an agricultural approach focused on designing systems that work with nature.

"That experience sparked my interest in plants and environmental systems, and I haven't been able to shake it since," he says. "It made me realize I was interested in agriculture, plants and environmental systems."

Exum went on to enroll at NC State in January 2023 as an exploratory student. He initially decided to pursue business because it seemed practical, but he didn't enjoy the classes and began to feel the same disengagement he had in high school.

"After completing my first year, I considered not returning. But I had a conversation with a friend and decided to give college another shot," he recalls. "I reflected on my Hawaii experience and explored majors more seriously. That led me to biological and agricultural engineering technology in CALS, which combined my interests in agriculture, science, math and hands-on applications.

"Since then, I've gained valuable classroom experience and started doing undergraduate research. I've also explored robotics, plant pathology, computer vision, and controls engineering."

Pursuing high-impact experiences

As Exum's love of learning returned, he wasted zero time finding opportunities to do research and get hands-on experiences. In the summer of 2025, he interned at Altria, where he did pathology research focusing on tobacco and soilborne fungi. He later saw a posting about NASA's space crop production internship.

"The application period had closed, but the opportunity stuck in my mind. When I saw it open again on Christmas Day, I applied," he says. "A few months later, I was invited to interview, and I received the official offer two months after that."

Exum believes experiences outside of the classroom help you become a more critical thinker with the ability to make more connections between what you learn and what you do.

When he hasn't been working in the state-of-the-art labs at NASA's Space Systems Processing Facility, Exum has enjoyed time with other interns, going to the beach and scuba diving on the weekends. For him, it's all about the experience.

"Don't be afraid to reach out to people," he says. "Ask questions, show interest, and connect with people doing work you care about. That initiative can open doors to many opportunities, including really interesting internships."

Source: North Carolina State University