In September 1519 Ferdinand Magellan set sail to prove that the world could be circled by sea.
More than 500 years later, Redwing—a robotic underwater glider no bigger than a surfboard—will attempt a modern,
uncrewed equivalent. Over the next five years the vehicle will migrate through every major ocean basin,
gathering an unprecedented trove of oceanographic data while demonstrating the long-range potential of low-power robotics.
What Is an Underwater Glider?
Unlike propeller-driven autonomous underwater vehicles (AUVs), gliders change their buoyancy to rise and
sink, converting vertical motion into forward momentum with fixed wings. This technique:
- Uses 1–2 W of power on average—about the same as a small LED night-light.
- Allows missions measured in months to years instead of hours or days.
- Makes the craft virtually silent, minimizing disturbance to marine life and improving acoustic sensing.
Redwing’s Technical Specs
• Length: 1.9 m
• Weight: 82 kg
• Depth Rating: 1,000 m
• Max Speed: 0.8 knots (gliders trade speed for endurance)
• Power: Hybrid lithium primary cells and a 50 W solar trickle charger embedded in the deck
• Comms: Iridium satellite when at the surface; acoustic modem networking below
• Sensor Suite: CTD (conductivity-temperature-depth), dissolved oxygen, nitrate, pH, fluorometer, passive acoustics, microplastic collector
The Route: A Robotic Homage to Magellan
The planned path mirrors the historical voyage as closely as modern geopolitics, currents,
and exclusive economic zones will allow:
- Launch from Seville, Spain, transit the Atlantic, and enter the South American coastal corridor.
- Navigating Patagonia’s fjords and the Strait of Magellan to cross into the Pacific.
- Island-hopping across Polynesia, then northward toward the Philippines (where Magellan was killed in 1521).
- Crossing the Indian Ocean, rounding the Cape of Good Hope, and re-entering the Atlantic.
- Return to the Iberian Peninsula by late 2029.
Scientific Objectives
Redwing is more than an engineering stunt; it is a mobile observatory designed to fill gaps in
in situ ocean data:
- Climate Baselines: High-resolution vertical profiles of temperature and salinity will refine heat-content models that drive hurricane forecasting and climate projections.
- Carbon Cycle Monitoring: pH and dissolved CO2 sensors will track ocean acidification across latitude bands seldom visited by research vessels.
- Fisheries Health: Passive acoustics will map migratory routes of cetaceans and large fish, informing conservation zones.
- Microplastics Survey: A mesh intake and onboard FTIR spectrometer will quantify plastic load from coastal shelves to the open ocean gyres.
Engineering Challenges
A five-year deployment is unheard of for a single glider mission. To succeed, the team has tackled several hurdles:
Biofouling Control
A UV-LED array and silicone-based hull coating deter algae and barnacle growth that could compromise buoyancy.
Energy Budgeting
The glider enters an ultra-low-power “hibernation” state when drifting with currents, waking periodically
to collect data and call home. Solar top-ups during daylight surfacings extend battery life by ~18 %.
Autonomous Navigation
A probabilistic route planner weighs surface-current forecasts, bathymetry, and geopolitical boundaries.
When Iridium signals are blocked, inertial dead-reckoning and star trackers take over.
Why It Matters
Satellite remote sensing excels at measuring the ocean’s surface, but 90 % of marine heat is stored
below 700 m. Ship time is expensive—roughly US $35,000 per day for a modern research vessel.
Long-endurance gliders like Redwing offer a scalable alternative, potentially enabling a planet-wide mesh
of autonomous sensors at a fraction of the cost.
What Comes After the Voyage?
If Redwing completes its circumnavigation intact, the mission will validate designs for even deeper, polar-capable variants.
The same navigation stack could be adapted for under-ice exploration on Europa or Enceladus, where liquid water
oceans are hidden beneath kilometers of ice—a tantalizing prospect for astrobiology.
For now, the ocean is our proving ground. As Redwing slips beneath the Atlantic swell, it carries forward the spirit
of Magellan—pushing the edges of the known world, this time with microchips and pressure hulls instead of sails and timber.
