2 Indian aquanauts make record-breaking dives into Atlantic Ocean

Indian Express

2 days ago

In preparation for the country's Deep Ocean Mission, two Indian aquanauts have undertaken dives to nearly 4,000 metres and 5,000 metres in the Atlantic Ocean, on board the French vessel, Nautile. These are the deepest ocean dives ever made by Indians, with most submarine dives being restricted to above 500 metres, and a previous record of 670 metres being set by aquanaut Commander (Retd) Jatinder Pal Singh.
The dives took place on August 4 and 5. While Singh descended 5,002 metres, R Ramesh descended to 4,025 metres. An Indian flag, along with a French one, was floated during the dive.
From deployment to retrieval, the mission to travel to the depths of 5,000 metres took about 9.5 hours. 'It took about two and a half hours to reach the depth. Once there, I spent around four hours at the depth working with the robotic arm, checking how to work with and without the light at a place where there is never any sunlight, how to work with the life support system if the CO2 systems are shut off, what has to be done in case of power failure, or how long will it take for the vessel to reach the surface in case of an emergency,' said Singh, who was a Naval submarine pilot.
The experience from the two dives would help India's upcoming Samudrayaan mission. India plans to build its vessels to send three aquanauts to the depths of 6,000 metres by 2027.
'These dives was meant for our team to gain hands on experience on several aspects of such deep sea missions such as pre-dive preparatory tasks, piloting the vessel, ascending, descending and living in the vessel, using the robotic manipulator to collect samples from the outside, tracking the vessel, and retrieving it after the mission,' said Dr M Ravichandran, Secretary, Department of Earth Sciences.
Another important learning from the dives was on communication protocols with the use of acoustic telephones. 'Thousands of metres underwater, you cannot use normal communication methods. Our phones use air as a medium to transmit radio waves to enable communication; these cannot penetrate the depth of water. So, for underwater communication, sound waves are used, and there is a delay of a few seconds in that,' Ravichandran said.
The collaboration with France came after years of negotiation, as most countries are reluctant to share deep-sea technologies. In fact, India developed its own acoustic phones and will manufacture the titanium sphere that will carry the aquanauts.
'For depths of 6,000 metres, a titanium sphere will be needed for the crew. This sphere is currently being manufactured by the Indian Space Research Organisation,' he said, adding that it requires highly specialised and precise manufacturing techniques. He explained that the sphere has to be of 80mm thickness uniformly, 'even if at one place it is 79.8 mm thick, it will collapse under the immense pressure'.
Under the Samudrayaan mission, a shallow water dive up to 500 metres—using a steel sphere instead of the more complex titanium one—is likely to take place in mid-2026. The integration of the titanium sphere and deep water testing is likely to occur by mid-2027, before the final mission scheduled for 2027-28.