NASA Samples Antarctic Water to Inform Search for Life on Icy Worlds

Researchers Mariam Naseem and Marc Neveu of the University of Maryland and NASA’s Goddard Space Flight Center in Greenbelt, Maryland, welcomed the new year from a ship at the very tip of the Antarctic Peninsula. Their goal? Collect samples of seawater most closely comparable to that in oceans beyond Earth.

Many icy worlds in our solar system — such as Jupiter’s moon Europa or the dwarf planet Pluto — are believed to contain vast oceans of liquid water beneath thick layers of ice. Some of these “ocean worlds” contain key ingredients for life, including carbon, nitrogen, and chemical energy, leading scientists to ask a fundamental question: could these hidden oceans support microorganisms? On Saturn’s moon Enceladus, subsurface water can erupt into space through a process called “cryovolcanism.” Cryovolcanism offers unique opportunities for robotic spacecraft to sample ocean material without drilling through miles of ice.

On the flip side, the journey from ocean to space could modify signs of life. For example, organic molecules like amino acids could be lost or altered as liquid water rapidly freezes or vaporizes upon encountering the vacuum of space. To study these effects, Naseem and Neveu use a custom lab setup, the Simulator of Ocean World Cryovolcanism, which injects liquid water into a vacuum chamber that mimics the conditions of space. 

Since 2022, Naseem, Neveu, and their colleagues have studied how solutions of organic compounds and salts change when injected into vacuum. Building upon this initial knowledge, they set out to understand the behavior of natural samples. In nature, interactions between molecules, minerals, and particles are more complex than in “oceans-in-a-tube” made in the lab, and natural samples are likely closer to erupted samples on ocean worlds.

No sunshine reaches the oceans inside icy worlds, limiting how much life can grow. On Earth, we can find dark, isolated water masses in Antarctica, for example, in the permanently ice-covered Weddell Sea east of the Antarctic Peninsula and the deep Circumpolar Current that constantly circles the white continent. A rare chance to access these remote environments came in mid-2024, as the Explorers Club, an independent society of researchers, organized a selection of projects to be undertaken aboard an icebreaker cruise ship equipped with research equipment and facilities operated by the company Ponant.

The journey from selection, to preparation, to sample collection was arduous. Even before boarding the ship in mid-December, the two-person team stood on the shoulders of about 50 people who played key roles, such as ensuring safety, enabling transport of frozen samples back to Maryland, and having the tools for their analysis ready to go.

On five occasions, the team stepped onto sea ice, cored it out partway, and collected water that was either trapped within the ice or flowed through its pores, as it does on ocean worlds during eruptions.

Sampling seawater thousands of feet deep, equivalent to depths of 3 to 60 miles on lower-gravity ocean worlds, involved lowering a rack of sampling bottles from the back of the ship. On Dec. 30, the team deployed the rack through a ship-wide opening in the 50-foot thick ice that blankets the Weddell Sea. Pressure from the surrounding ice kept closing the opening, so the ship’s crew had to pivot engine pods to steer blocks of ice away, while moving to stay aligned with the sampling rack as its cable was pulled away by deep currents. Killer whales also surfaced in the pool, making the operation even more dynamic!

The next day, New Year’s Eve, the team was in a perfect spot to sample the deep Circumpolar Current. Through careful coordination with the crew, who shepherded the ship in synchrony with the deep current, sampling succeeded at 3,675 feet (1,120 meters), a depth record for the ship. Another reason to celebrate as 2026 rolled in!

The precious samples are now in Maryland. Along the way, the team found creative ways to keep them frozen despite three unplanned changes of flights from Ushuaia, Argentina, to Washington, D.C. In the lab, the samples will be thawed and split into two. One half will be injected into the simulator, while the other half will be analyzed directly. Both samples will be analyzed using specialized chromatography techniques to track changes in salts, amino acids, and fatty acids. By comparing original and simulator-injected samples, Naseem and Neveu will determine how eruption into space alters ocean material, and how those changes might affect the search for life beyond Earth.  

By Marc Neveu and Mariam Naseem

NASA’s Goddard Space Flight Center, Greenbelt, Md.