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Concept Mission Suggests ‘Tasting’ Moon of Saturn to Search for Life

June 13, 2016

A tiny moon orbiting Saturn might be the perfect place to discover extraterrestrial life — and a University of Idaho graduate student led a project suggesting a way to find out.

Shannon MacKenzie, a doctoral student studying physics in the UI College of Science, led a multi-university team at NASA’s 2015 Jet Propulsion Laboratory Planetary Science Summer School that created a concept mission to the moon Enceladus. The team’s concept was published online June 7 in the journal Advances in Space Research.

Their mission, Testing the Habitability of Enceladus’s Ocean, or THEO, would explore the warm, salty ocean beneath the moon’s icy surface for evidence of life, but in an unusual way.

“Enceladus's ocean is relatively easy to get to — it’s jetting out into space in geyser-like plumes from four long fissures at the moon’s south pole,” MacKenzie said. “So we don't need a complicated lander with a drill to figure out if that ocean is a habitable environment. We can put a spacecraft in orbit instead to ‘taste’ the plume and conduct other observations to really quantify whether or not this little moon is a habitable world.”

NASA’s Cassini spacecraft has already observed the ocean has liquid water and some simple organic molecules, such as methane and ethane. THEO’s direct sampling technique would allow researchers to find out if the ocean has more complex molecules or other evidence of biological processes.

THEO instruments would also provide closer observation of the ocean’s ice crust to figure out how it responds to forces like tides, map the heat coming out the fissures, measure the ocean’s salinity, and measure Enceladus’ gravity field, which would allow researchers to estimate the amount of liquid in the ocean. The mission would use new technology to be solar-powered, a first for a Saturn mission.

Although THEO will not be submitted as an actual mission, concept studies like it give researchers room to be creative and serve as lab experiments for testing out what kinds of missions are possible, MacKenzie said. She and the students on her team didn’t come in as Enceladus experts, and their outsiders’ perspectives led to new ideas and insights.

“It takes a lot of time and effort to put together even a concept mission,” Mackenzie said. “When real mission proposals get selected, they are usually successful because they are standing on the shoulders of several rounds of mission concept design, like THEO, and proposal writing.”

Preparing a concept through the Planetary Science Summer School also gives future university and NASA researchers the skills they need to work on real missions someday.

“We are the future of space exploration,” MacKenzie said. “You can’t take a class in how to write a mission proposal, how to close a mission design, how to balance the needs and wants of the science team with those of the engineers, etc. Those are all vital skills for building a successful mission that can only really be learned by experience. Thankfully, JPL recognizes that and invests in us through the Planetary Science Summer School.”

MacKenzie’s studies aren’t limited to Enceladus. She works with Jason Barnes, an associate professor of physics at UI, to study Saturn’s largest moon, Titan, using data from Cassini. MacKenzie examines Titan’s liquid methane seas, as well as the materials they leave behind when they evaporate. She won the university’s inaugural Three-Minute Thesis competition for her work. A video of her presentation is available at

Media Contact:
Shannon MacKenzie
Graduate Research Assistant and NASA Earth and Space Sciences Fellow, UI Department of Physics

Tara Roberts
University Communications

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The University of Idaho, home of the Vandals, is Idaho’s land-grant, national research university. From its residential campus in Moscow, U of I serves the state of Idaho through educational centers in Boise, Coeur d’Alene and Idaho Falls, nine research and Extension centers, plus Extension offices in 42 counties. Home to nearly 12,000 students statewide, U of I is a leader in student-centered learning and excels at interdisciplinary research, service to businesses and communities, and in advancing diversity, citizenship and global outreach. U of I competes in the Big Sky and Western Athletic conferences. Learn more at