On October 10, 2024, a robotic submarine set off from Martha's Vineyard to sail around the world. It has no crew, no engines in the traditional sense, and moves like an underwater glider, riding gravity and ocean currents. It's called redwing And its mission is simple to say, impossible to accomplish: circumnavigate the globe collecting oceanographic data for five years straight. Non-stop. Well, almost. It will only stop for maintenance in a few strategic locations: Gran Canaria, Cape Town, Western Australia, New Zealand, the Falklands, and possibly Brazil. Then back to Cape Cod. Seventy-three thousand kilometers underwater. The first time an autonomous underwater vehicle has attempted such a feat. It's like sending a drone on a tour of the planet. Only down here there's no GPS, no easy routes, and the ocean is unforgiving.
A glider that moves without an engine
redwing is a Slocum Sentinel Glider next generation, developed by Teledyne Marine in collaboration with the Rutgers University. The Sentinel Mission, as the company has been named, has the support of the NOAA,An Ocean Decade and Marine Technology SocietyThe name Redwing is an acronym: Research & Education Doug Webb Inter-National Glider, tribute to Doug Webb, pioneer of autonomous underwater gliders, died in 2024 at age 94.
How does it work? One detail above all: no propellers. Redwing regulates its buoyancy using a four-liter hydraulic thruster, the largest ever mounted on a glider. When it wants to descend, it compresses the internal oil and becomes denser than water. When it wants to ascend, it expands and becomes lighter. The result? It dives to a depth of up to 1,000 meters (the height of three stacked Eiffel Towers), then ascends, gliding on fixed wings. The technical specifications They speak of a cruising speed of 0.75 knots, with the possibility of accelerating up to 3.5 knots thanks to two auxiliary thrusters mounted aft.
Magellan's route, but at a depth of a thousand meters
The route chosen for the Sentinel Mission It follows the first circumnavigation in history: that of Ferdinand Magellan, completed between 1519 and 1522. Only, Redwing will travel it underwater. Departure from Woods Hole, Massachusetts. The first stop is Gran Canaria, off the northwest coast of Africa. Then Cape Town in South Africa, Western Australia, New Zealand, the Falkland Islands in the South Atlantic, a possible passage through Brazil, and back to Cape Cod. Seventy-three thousand kilometers in about five years.
Every 8-12 hours the glider surfaces. It transmits the collected data to the NOAA and receives new navigation instructions. Onboard sensors record water temperature, salinity, currents, and general ocean health parameters. Information is shared in real time with scientists, oceanographers, meteorologists, universities, and schools around the world. The goal is to improve understanding of how the oceans influence global weather systems.
Oceans cover 70% of the Earth's surface and drive the planet's climate. Yet vast regions remain under-monitored. As I told you in this article about cyborg jellyfishUnderwater exploration is undergoing radical innovation. Instruments like Redwing allow for continuous data collection over time and geographic scales impossible with traditional research vessels.
Students at the virtual helm
The mission also has a strong educational component. More than 50 students from the Rutgers University, at Center for Ocean Leadership (COOL), contributed to the development of the navigation software that guides Redwing across the oceans. Their task? Plan the optimal route, taking into account ocean currents, charging points, geopolitical borders, and weather conditions. It's a problem-solving exercise applied on a planetary scale.
The mission also includes a live online observation platform, outreach campaigns, and educational content to engage students and the general public. The idea is to transform Redwing into a floating (or rather, gliding) classroom to teach oceanography, physics, engineering, and climate science as the glider traverses the seas.
Extreme autonomy
The Slocum Sentinel Glider is designed for missions lasting more than two years without human intervention. Its primary lithium batteries can power up to eight sensors simultaneously. Its dimensions have been optimized: 33 centimeters in diameter and over 240 centimeters in length. It can carry 3,5 times more batteries than standard G3 series gliders. According to Teledyne Marine, the Sentinel is the fastest glider in the world thanks to its oversized buoyancy engine and optional thrusters.
The control architecture is the same as the standard Slocum gliders: remote piloting, flight control, satellite communications. But everything has been scaled to withstand extreme conditions. Strong currents, drastic variations in water density, freezing temperatures. The system must function in every scenario.
Fun fact: It was science fiction in 1989
The Sentinel mission fulfills a prophecy. In 1989, the magazine Oceanography Magazine published a science fiction piece imagining an international race between autonomous underwater gliders to circumnavigate the globe. The original concept was conceived by Doug Webb, the pioneer to whom Redwing is dedicated. It took 35 years, but the technology caught up with the vision.
If all goes as planned, Redwing will return to Cape Cod in about five years with an unprecedented dataset on ocean health. If something goes wrong, well, we'll still have learned something about what it takes to keep a machine alone in the deep for years. In either case, the Sentinel Mission marks a turning point in autonomous underwater exploration.
How many more machines will follow its path in the coming decades?
