Where Innovation Meets Ice: The Adaptive Design of Nereid

Engineering for Earth’s Extremes: From Polar Ice to Hydrothermal Discovery with Rosemary Loer

Greenland’s ice sheet is melting at an unprecedented rate, containing enough frozen water to potentially raise global sea levels by 23 feet. As these massive glaciers retreat and fragment, with some areas melting faster than others, scientists in the Jackson School of Geosciences at the University of Texas Austin face a critical challenge: how to study them up close in one of Earth’s most perilous environments to understand what’s driving these differences.

Working with Molly Curran (expedition leader), Mike Jakuba (technical lead), Allisa Dalpe, Victor Naklicki, Kevin Nikolaus, and Matt Silvia in the Deep Submergence Lab at the Woods Hole Oceanographic Institution, engineer Rosemary Loer describes the dynamic whirlwind where currents rush through underwater canyons, sediments fly in swirling clouds, and arctic winds pierce your lungs. Despite years of careful planning, Arctic fieldwork remains dauntingly complex.

Enter Nereid Under Ice (NUI), a hybrid vehicle developed through collaborative efforts in the Deep Submergence Lab. This versatile vehicle doesn’t just navigate turbulent waters near glaciers—it’s also explored the Aurora Hydrothermal Vent Field, where deep-sea creatures thrive in extreme conditions that might mirror extraterrestrial environments. Join us for a conversation about engineering adaptable systems for Earth’s most sublime seascapes.

Amelia Macapia: What was it like the first time you saw a glacier?

Rosemary Loer: Thinking about climate change, glaciers are something you hear about a lot, but seeing the sheer size of them in the fjords, you recognize how significant they are. It’s not just that you are seeing a new ecosystem—it’s almost like you are peering into a vital organ of the planet. It’s a place that’s alive and breathing, and it's spectacular.

There is nonstop noise, just popping and cracking ice all the time. It’s not just the big glacier, but all the little pieces that have fallen off and are floating around the ship. The air is very dry and cold, it totally burns you when you’re breathing.

The dynamic nature of these environments presents unique challenges for scientific discovery. There is constant motion: ice floating to and from the glacier depending on the wind patterns, pieces regularly calving (breaking) off, and the glacier itself moving at its own pace. This aliveness of the glacier and complex underwater terrain along the ice front is precisely why we want to develop new approaches to study these environments.

AM: These expeditions are a part of what has been involved in Nereid Under Ice (NUI), a hybrid vehicle that has pushed engineering to new levels, combining the precise control of a Remotely Operated Vehicle (ROV) and the independence of an Autonomous Underwater Vehicle (AUV). What are the traditional limitations of each of these types of vehicles?

RL: Many ROV’s have a large metal cable coming from the ship that restricts lateral movement. While an ROV can operate at great depths, it must remain in close proximity to the ship. Through the cable, we maintain communication with the vehicle, receiving live high-definition video to maneuver manipulator arms to take samples of sediment or geological formations, for instance.

AUVs, on the other hand, have no physical tether connecting them to the ship or the operator. Communication with the vehicle typically occurs via acoustic methods, meaning that high-speed video cannot be transmitted. But AUV’s offer higher maneuverability, as they are not as restricted by proximity to the ship or operator.

AM: Combining features of the two, what challenges does this hybrid approach solve that traditional underwater vehicles can’t handle?

RL: In ROV mode, NUI is tethered, but instead of using a heavy, thick, traditional cable, NUI utilizes a fiber optic cable—only two times the width of a human hair—decoupling it from the ship and allowing for significant lateral movement. Through this optic fiber, you get the live HD video, and you can control the manipulator arm. In AUV mode, NUI relies primarily on acoustic communication. If the fiber were to break, or if you wanted to intentionally run a mission in AUV mode, the vehicle can operate autonomously. You would not get the live video or the live manipulating of the arm, but you could send it basic commands over acoustic communications.

AM: Your team has maneuvered NUI in incredibly precarious environments, from the tumbling waters at the foot of glaciers to seafloor abysses. What are some of the challenges navigating through these environments?

RL: Getting as close as we did to glaciers is rare—despite extensive data, much remained unknown about what we would encounter. Scientists had predicted that freshwater currents would emerge from underneath the glaciers, likely pushing up heavy sediments. During our test dives, these predictions proved accurate but came with unexpected challenges: sediment would float out of the current, then rain down on our vehicle like an underwater snowstorm, substantially changing its buoyancy. With around 50 pounds of sediment accumulating, the vehicle became increasingly heavy and difficult to maneuver toward the surface.

The conditions forced our team to innovate. With visibility through the cameras reduced to near zero, our pilot Victor Naklicki masterfully adapted by relying on multibeam sonar—an acoustic device that emits soundwaves in beam formations to detect and map objects in the environment. It can be used for anything from mapping the seafloor to detecting fish in the water column, but Naklicki repurposed it to gauge our proximity to glacial walls, demonstrating the kind of real-time problem solving these missions demand.

This mission’s challenges contrasted sharply with our previous cruise. In the Aurora Vent Field, while sediment wasn’t an issue, our team needed precise navigation around hydrothermal vent sites, where hot fluids emerge from the seafloor. Each environment requires its own form of piloting expertise and creativity.

AM: As you’re speaking about that uncertainty and those split-second adjustments in the field, how does that factor into the design process?

RL: I work with an incredible team of engineers, we anticipate as many challenges as we can ahead of time based on what we know about an area. But a huge part of it is being flexible on the fly between dives. In Greenland, between-dive days were essential for vehicle preparations and modifications.

While we anticipated some sediment from glacial outflow, for instance, the sheer volume was unprecedented. We adjusted our dive plans by spending less time in sediment-heavy zones. We also repositioned one of our sonar systems from downward- to side-facing orientation to better meet the needs of the scientists.

AM: NUI has explored not only glaciers but also hydrothermal vents, why are those such important environments for scientists?

RL: We were in the Gakkel ridge in the Arctic, studying hydrothermal vents that are able to sustain life and a whole host of organisms in the absence of sunlight and temperature and at high pressure. If we know that on our planet these vents can sustain life, these discoveries may have exciting implications for Europa and Enceladus, where researchers suspect similar vents might exist beneath icy oceans. The technologies we’re developing to study our ocean’s depths are now helping us explore potential life forms beyond Earth, informing space expeditions like the October 2024 Europa Clipper launch: the search to understand if we’re truly alone in the cosmos.

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While discoveries like these have the power to revolutionize our understanding of life, our most pressing mission remains right here on Earth. The technology the Deep Submergence laboratory has developed with NUI has given us unprecedented access to our planet’s glaciers at this critical moment in their history. As these massive ice formations continue to retreat, NUI allows us to study not just what we’re losing, but also how these changes are reshaping our planet's vital systems. “It’s sobering to witness these changes firsthand,” describes Loer, but also reinforces why this work is so crucial—every piece of data we gather helps us better understand and respond to one of the greatest challenges our planet has ever faced.