The story began in October 2025, when Redwing, a new-generation autonomous ocean glider, slipped beneath the surface of the Atlantic Ocean. Deployed by the Teledyne Webb Research team, the Sentinel Mission aimed to achieve the first circumnavigation of the globe by an autonomous underwater vehicle. Redwing is a Slocum Sentinel glider, a long-endurance autonomous platform combining low power consumption, high endurance, and flexible sensor integration. It measures temperature, salinity, and detects marine animals that are tagged with acoustic sources. The Sentinel Mission project aimed to demonstrate how autonomous technologies can transform global ocean observing. It is led by Teledyne Webb Research in collaboration with Rutgers University Center for Ocean Observing Leadership and the US Integrated Ocean Observing System, and supported by the United Nations Decade of Ocean Science for Sustainable Development. Like thousands of ocean observing platforms, Redwing contributes to the Global Ocean Observing System (GOOS)—a program co-sponsored by the Intergovernmental Oceanographic Commission (IOC) of UNESCO and the World Meteorological Organization (WMO). GOOS provides leadership for a global system of sustained ocean observations, coordinating a network of nearly 9,000 instruments operated by 64 countries. Together, this system delivers essential data for weather and extreme event forecasting, climate adaptation, coastal and maritime risk responses, biodiversity stewardship, and sustainable ocean economies worldwide. “Throughout its journey, Redwing collected key oceanographic data in some of the most remote and under-sampled regions of the world, contributing to a better understanding and preservation of the ocean—a central objective of the Sentinel Mission,” said Shea Quinn, Mission Project Lead at Teledyne. For weeks, the mission progressed smoothly across the Atlantic before, three months in, the situation changed. “On 16 January, I received an abort alert,” says Cordie Goodrich, operational lead and pilot at Teledyne. “Redwing had surfaced unexpectedly and was unable to dive again.” Data analysis suggested