Investigating ocean worlds

NASA’s Astrobiology Program has selected four new interdisciplinary research teams as part of its Interdisciplinary Consortia for Astrobiology Research (ICAR). These teams will explore a wide range of topics across the field of astrobiology, from the cosmic origins and formation of planetary systems to the origins, evolution and potential existence of life beyond Earth.

Faculty from Arizona State University’s School of Earth and Space Exploration will take part as one of four research teams participating in the ICAR program.

Researchers Everett Shock and Kirt Robinson from the school will join as co-investigators on a new research effort: Investigating Ocean Worlds (InvOW): A Systems-Level Approach to Understanding Organic Carbon Cycles. The project is led by Christopher German from Woods Hole Oceanographic Institution and is tackling one of the most profound questions in science: Could ocean worlds beyond Earth harbor life? 

The 2023–32 Planetary Science and Astrobiology Decadal Survey identified the search for life on icy moons such as Europa and Enceladus as a top priority. Planned NASA missions to these distant destinations will rely heavily on analyzing organic matter, compounds that may carry evidence of biology. InvOW’s goal is to ensure those missions are prepared to read the chemical “signals” correctly.

“Think of a NASA mission to an icy ocean world as a six-year road trip across the solar system,” said Robinson, assistant research scientist in ASU’s School of Earth and Space Exploration. “We want to make sure that when the spacecraft arrives, it can tell whether the environment is more like a barren desert or a lush forest; how hospitable the environment might be; and whether life might be responsible for what the spacecraft detects.”

Much like rolling down a car window and recognizing the scent of farmland or fresh pine, the team will interpret what the spacecraft senses when it “sniffs” molecules released from these icy surfaces. Those chemical fingerprints could reveal whether subsurface oceans are habitable or even inhabited.

Unlike geological research here on Earth, missions to ocean worlds cannot bring back samples of rocks or water to analyze. Instead, they will rely on analyzing particles and molecules released at the surface or into space. Saturn’s moon Enceladus, for instance, ejects icy plumes from its hidden ocean, while Jupiter’s moon Europa may release smaller amounts of material from beneath its frozen crust.

“What we’ll have to work with are tiny organic compounds,” said Shock, professor in ASU’s School of Earth and Space Exploration. “Our challenge is to squeeze the maximum information about geologic and biological processes out of those molecules. It’s like doing geology with organic chemistry.”

By integrating physical, chemical and biological perspectives, InvOW aims to reveal how organic matter is transformed on ocean worlds from nonliving origins to possible biological signatures.

ASU researchers are pioneering a new field of scientific research: planetary geology from organic chemistry. This new field aims to decipher planetary processes using molecular evidence. Their work will help optimize science returns from flagship NASA missions such as Europa Clipper, Titan’s Dragonfly and future concepts targeting Enceladus.

“This is about preparing for the next era of exploration,” Shock said. “When we finally reach these worlds, we want to be ready to recognize the chemical whiffs of life.”