In Search of Potable Water on Mars

Extracting drinkable water from the subsurface of Mars may seem like an audacious quest, one more suited to science fiction than reality. But that’s the very real challenge PhD student Lydia Ellen Tonani-Penha will be tackling for the next four years as a NASA Space Technology Graduate Research Opportunity fellow, hoping to solve a critical issue for future Mars explorers.

“This will be a taste of my dream job—to work at NASA,” Tonani-Penha says. As part of the program, she’ll be paired with NASA research collaborators each summer, contributing to their lab groups’ experiments and using their equipment. For at least the first summer, she’ll be heading to the Jet Propulsion Laboratory in California, and she looks forward to connecting with its director, former WPI president Laurie Leshin.

Her interest in purifying water on Mars was born out of an environmental disaster she experienced as a teenager, an obsession with science fiction—“The Martian,” in particular—and an intrinsic need
to understand how things work. And while her stellar academic journey hasn’t been completely easy, the first-generation college student and self-described nerd is excited to embark on her next ambitious adventure.

Tonani-Penha was just 13 years old and living in Linhares, Brazil, when the Samarco Mariana Mining Complex dam burst, sending 43 million tons of toxic waste down the Doce River, an environmental disaster that killed 19 people and dumped mercury, lead, and other chemicals into the drinking water. Although her coastal town at the mouth of the river had other nearby water sources, she was dismayed at the suffering of others living farther up the river who had no alternatives, as well as the lack of urgency to fix the problem.

“I didn’t see people trying to clean the water, which made me angry. So I said to myself, ‘You know what, let me try to do it.’” Tapping into an abundance of youthful energy, curiosity, and imagination, and with the enthusiastic support of her parents and her high school physics teacher, she proposed a surprisingly effective solution, surmising that running electricity through the water—a process she now knows is called electrokinetic dewatering—would make metal bond around an anode, “creating a nasty clump of mud and metal.”

The prototype, which filtered 90 percent of the metal from her river water samples, won multiple awards at international science fairs. She graduated from her Brazilian high school at age 16 and prepared to continue her promising academic journey—until her family moved back to the United States and she encountered a daunting roadblock.

“I didn’t know about FAFSA, or the Common App, or anything like that,” she says. “When I started applying to U.S. colleges, I got a lot of rejections. My application wasn’t the sharpest because I didn’t know how it worked. I was just winging it.”

An educational advisor recommended she study at a community college for a year or two and transfer to a four-year college. “I didn’t even know about U.S. community colleges. My advisor said, ‘There is
another door. Take it.’” She studied for a year at MassBay Community College, where she served as president of the engineering club and boosted her GPA (and, as an added bonus, even met her now-husband) and then transferred to WPI in the fall of 2020 as a sophomore.

Despite early pandemic restrictions, Tonani-Penha quickly found her stride as an undergraduate, serving as a senior fellow at the SWEET (Supporting WPI through Effective and Equitable Teamwork) Center.
In graduate school, she served as communications director in the Central Massachusetts chapter of the Association of Women in Science and joined the Women in STEM Book Club, among many other activities.

Her Interactive Qualifying Project team created an inclusive plan for the Thrive Support & Advocacy food pantry that serves youths and adults with intellectual and developmental disabilities and their families in Central Massachusetts. In addition to recommending possible diets for different populations—including those with food allergies and dietary restrictions—the plan also showed respect for diverse cultural cuisines. When the food pantry at Thrive officially opened in 2022, she and her teammates were able to see some of their recommendations come to life, including the installation of an ADA-compliant ramp.

For her master’s thesis, she worked with advisor Robert W. Hyers, the George I. Alden Chair in Engineering, professor and head of the Department of Mechanical and Materials Engineering, to model electromagnetic levitation experiments conducted on the International Space Station to improve the accuracy of thermal conductivity measurements. The experiments used electromagnetic fields to levitate and heat a metallic sphere in reduced gravity to measure the sample’s thermophysical properties.

The NASA Space Technology Graduate Research Opportunity fellowship required Tonani-Penha to focus on her own original research, so she shifted her focus back to the Martian water purification “proof of concept” she completed for her Major Qualifying Project. Her idea is to convert subsurface Martian ice, or frozen brine, into potable water using freeze crystallization. “In every one of our experiments, we reduced the concentration of brine. It was a very simple prototype, but it showed it had promise.” Freezing, rather than distilling, requires less energy, and the technique is already used for purification in other industries—for instance, it’s called “progressive freeze concentration” in the food industry and “layer melt separation” in metal product manufacturing.

With the tangible goal of allowing real-life astronauts to live on Mars (rather than just fictional astronauts like Matt Damon), Tonani-Penha is excited to be exploring the red planet.

“I think we could learn a lot more about our planet if we study Mars. We can see what went right with our planet that didn’t happen with Mars or what changed along the way because the geological history is there,” she says. “Mars tells a story. We should see what that story is.”