Two ski-equipped Twin Otter aircraft spent the 2024/25 austral summer attempting something rarely achieved in Antarctic science: circling an entire continent while collecting critical data from one of the most important, and least visible, boundaries on Earth.
The mission, known as SWIDA-RINGS, was designed to survey Antarctica’s grounding line, the zone where ice resting on bedrock begins to float and form ice shelves. Although largely hidden beneath the ice, this boundary plays a central role in controlling how quickly the Antarctic Ice Sheet loses mass to the ocean and therefore influences future sea-level rise projections. Preliminary results from the campaign were presented at the European Geosciences Union General Assembly in 2025.
The scientific Twin Otter served as a flying laboratory. Its instrument package combined deep ice-penetrating radar, snow radar, lidar, optical imagery, gravimetry and atmospheric sampling equipment. Together, these sensors measured ice thickness, mapped snow accumulation, documented surface conditions and gathered information about the geology concealed beneath the ice. Researchers from the Technical University of Denmark, the University of Kansas and other international partners collaborated on the airborne survey.
A second Twin Otter handled logistics, a role that proved just as important. Operating around Antarctica requires careful coordination with national research stations, fuel depots, helicopters and support vessels. According to the campaign team, the aircraft network enabled access to remote coastal sectors where little reliable ice-thickness information currently exists.
That knowledge gap remains a major challenge. The Scientific Committee on Antarctic Research (SCAR) notes that more than half of Antarctica’s approximately 62,000-kilometer ice-sheet margin remains inadequately constrained by direct observations. Without accurate measurements of ice thickness and bed topography in these coastal regions, estimates of ice discharge and overall ice-sheet mass balance remain uncertain.
The expedition also demonstrated the practical value of international cooperation. During operations near Princess Elisabeth Antarctica, one SWIDA-RINGS aircraft helped move a meteorite-recovery team, equipment and snowmobiles after crevasse hazards disrupted a planned ground route. The episode highlighted how Antarctic field programs often support one another when conditions demand flexibility.
The full scientific value of the mission will emerge as the radar, gravity and imagery datasets are processed and released. For now, the circling Twin Otters have delivered something equally important: new observations from the continent's most critical frontier, where Antarctica's future interaction with the ocean is decided.