When the Russian research vessel MV Vasily Golovnin sailed through the frigid waters of the Southern Ocean last December, few could have imagined the quiet breakthrough taking place beneath the waves.
On board, Indian scientists Suresh Kumar of India’s National Center for Ocean Information Services (INCOIS) and Jenson of the National Center for Polar and Ocean Research (NCPOR) in Goa were preparing to deploy the Autonomous Ocean Glider – a sleek, torpedo-shaped instrument designed to fly through the ocean depths without a propeller, powered only by buoyancy.
The expedition took off from Cape Town, South Africa en route to India’s second station ‘Bharati’, during which the glider was successfully deployed as part of the 44th Indian Scientific Expedition to Antarctica (ISEA). Over the next 61 days, from February 3 to April 7 last year, the glider traveled 1,300 km through some of the harshest sea conditions on the planet, collecting data on temperature, salinity, oxygen levels and chlorophyll.
Autonomous ocean glider | Photo credit: BY ARRANGEMENT
Battling harsh conditions at sea, the INCOIS-NCPOR science team later recovered the glider without any instrument damage during the return journey from India’s first Antarctic station ‘Maitri’ to Cape Town, “demonstrating the reliability and robustness of autonomous glider operation in extreme polar conditions”.
“These gliders enable us to continuously collect high-resolution data, even in remote and hostile environments. This achievement underscores India’s growing leadership in autonomous ocean observations and lays a strong foundation for future long-duration glider missions,” says Hyderabad-based INCOIS (Ocean Observations) Group Director E. Pattabhi Rama Rao.
The Southern Ocean, which surrounds Antarctica, is one of the most important climate regulators on Earth. Its eddy currents and icy waters influence global weather patterns, carbon cycles and sea level rise. At the heart of this dynamic system lies the “polar front”, the boundary where cold Antarctic waters meet warmer sub-Antarctic waters, resulting in strong air-sea exchange.
“Understanding this area is critical to predicting the impacts of climate change. Our glider mission is a step towards filling critical gaps in ocean observations,” says INCOIS Director TM Balakrishnan Nair.
INCOIS-deployed ocean glider recovering | Acknowledgments for the video: BY AGREEMENT
Unlike conventional research vessels or powered drones, ocean gliders do not rely on propulsion systems, but move by changing their buoyancy, allowing them to glide gracefully through the water column. This energy-efficient design allows for missions lasting several months and covering thousands of kilometers, the researchers say.
INCOIS deployed 10 gliders
So far, INCOIS has successfully conducted about 10 deployments of autonomous deep-sea gliders – eight in the Bay of Bengal and two in the Arabian Sea – under the ‘Deep Ocean Mission’. The goal of these deployments is to explore and monitor oceanographic parameters using buoyancy-driven motion. The latest success in Antarctic waters adds polar capabilities to India’s expanding ocean observation program.
Gliders are remotely controlled, monitored by satellites
The United States-based Slocum G-3 gliders can maneuver both vertically and horizontally at speeds of about 8 to 10 centimeters per second, enabling extended missions lasting several months. They can travel up to 20-25 kilometers per day, dive to depths of 1000 meters and are tracked by satellites. They are remotely controlled and continuously monitored from the institute’s command center here in Pragatinagar.
The gliders surface every five to six hours during 1,000-meter diving missions to transmit data while continuously measuring key ocean parameters using advanced biogeochemical sensors. While basic data is transmitted in near-real time as the gliders surface several times a day, detailed data sets are obtained when the system, “with an approximate lifespan of eight to nine months,” is retrieved from the water, the researchers explain.
Before deployment, the gliders are configured and loaded at the National Glider Test Facility established at INCOIS and then tested through sea trials in shallow coastal waters. The data collected from these gliders, combined with observations from other monitoring systems such as tide gauges, argo floats and buoys, greatly increases the understanding of the impact of climate change on sea level, cyclonic storms, waves, surges and marine ecosystems, explains Mr Nair.
Another mission
Bolstered by this success, INCOIS is now planning a bold mission: to deploy a next-generation ocean glider with increased battery life to undertake an unprecedented long-distance transect “from the near coast of Antarctica, near Bharati Station, to the coast of Gujarat covering an estimated distance of approximately 9,800 km”.
It would represent a first-of-its-kind long-distance mission not just for India, but globally “a meridian transect controlled solely by an autonomous ocean glider”. The mission is expected to enhance scientific understanding of air-sea interactions across the hemispheres. It will stand as a landmark and a matter of national pride, adds Mr. Nair.
Published – 02 Jan 2026 23:46 IST
