In early 2024, the Ran, a six-meter autonomous submarine, disappeared without a trace beneath Antarctica’s Dotson Ice Shelf. This mysterious loss has left scientists with more questions than answers, but the data it collected before vanishing has already forced them to rethink everything they thought they knew about ice melt.
Sent by the International Thwaites Glacier Collaboration (ITGC), the Ran was on a mission to explore the most extreme and inaccessible parts of Antarctica. The submarine had already mapped areas never before seen by human eyes, uncovering hidden underwater structures that contradicted current climate models. Even though it disappeared without a trace, the data it collected before its loss could change the way we understand sea level rise and climate change.
A Journey Beneath The Ice
The Ran was designed to explore the base of the Dotson Ice Shelf, a region of Antarctica that had long puzzled scientists. This area, buried under millions of tons of ice, was so extreme that only unmanned vehicles like the Ran could handle the conditions. Equipped with advanced sonar systems, the submarine spent 2022 completing 14 successful missions, mapping over 130 square kilometers of previously unknown terrain.
The submersible was fully autonomous, meaning it operated without the usual communication systems or GPS. It relied entirely on pre-programmed instructions and onboard systems to navigate through the icy depths.
Illustration of the circulation and interaction between ocean and ice beneath the SIS system. Credit: Science Advances
However, when researchers tried to resume operations in 2024, it never came back from its first dive. The exact cause remains unknown, with theories ranging from technical failure to the possibility of the submarine becoming trapped or entangled in underwater formations.
Discovering Unexpected New Data
Despite its sudden disappearance, the Ran made some groundbreaking discoveries before it vanished. According to a recently published study in Science Advances, the submarine mapped and documented underwater features that defied conventional expectations, such as droplet-shaped formations, frozen plateaus, and unexpected erosion patterns.
As Anna Wåhlin, an oceanographer leading the study, pointed out, the data showed that our assumptions about how ice melts could be totally wrong. Its observations pointed to complex processes at play beneath the ice that current models hadn’t accounted for. But with the submarine now lost, scientists are faced with the challenge of filling in the gaps and continuing the work that the Ran started.
An autonomous submarine exploring Antarctica’s icy waters. Credit: Filip Stedt
What’s Really Melting Under There?
One of the key questions the ITGC set out to answer was why some parts of the Dotson Ice Shelf melt faster than others. Thanks to the Ran, scientists discovered that the western part of the ice shelf, which faces the more turbulent waters of the circumpolar current, is eroding at a faster rate than the eastern part, which remains more isolated. What the Ran collected will be essential in improving these predictions, giving scientists a better idea of how quickly ice sheets could melt down the line.
The team behind the mission remains committed to continuing the research. While the disappearance of the submarine is a painful setback, the discoveries made during its operational period provide valuable insights into the forces shaping our planet’s climate.
A peek at how the ocean moves beneath the ice shelf. Credit: Science
As mentioned in press release featured by University of Gothenburg, the team is already looking for ways to replace the tiny underwater robot and resume their work.
“After Ran was lost beneath the Antarctic ice in January 2024, a new vehicle will now take her place. Ran II will continue the mission to advance understanding of ocean processes and climate change.”