At 6,000 meters below sea level, temperatures are just above freezing. The pressure of the water column is 600 times the pressure one feels while standing on a beach, or approximately the weight of two Indian cows on a single fingernail. There has been no sunlight for the last 5,000 meters.  None of this seems especially daunting for scientists at the National Institute of Ocean Technology in Chennai, who are gearing up to build an ocean submersible that can carry a three-member crew to this depth.

Exploring the ocean deeps is like exploring space – it’s a vast area of unknown. Researchers are trying to plug the gaps in knowledge about the ocean’s physical qualities, chemical composition and marine life at these depths. NIOT scientists have already begun this process with a Remotely Operable Vehicle, a submersible that is tethered to a ship and controlled from there.

In 2012, two scientists from the institute won the National Geoscience Award for using the ROV with its cameras, sensors and sonar equipment to find gas hydrates in the Krishna Godavari basin and polymetallic nodules at Rodrigues Triple Point in the central Indian Ocean basin. Harvesting gas hydrates, solid compounds that contain natural gas, and polymetallic nodules, which are tiny manganese crystals, could improve the country’s energy prospects.

NIOT’s objective is to build a manned submersible to push the boundaries of research in the Indian Ocean further. In three years, the institute plans to build a vehicle with a chamber big enough for three people and sturdy enough to insulate them from the extremely high pressures and extremely low temperatures 6,000 meters down.  The pilot and passengers will be able to see first hand what scientists were looking at through the ROV’s cameras. The vehicle will also have manipulators to explore the materials around them.

High-pressure environment

“We should first have an enclosure that can withstand that pressure with human beings inside," said NIOT director MA Atmanand. "It is very much different from a space vehicle where the pressure difference is only one bar. The atmosphere after a kilometer is vacuum so you don’t have to build heavy enclosures for a spacecraft.”

The enclosure could be made of titanium or some other special and sturdy alloy, and extra care will be needed to make sure that all components are welded together firmly. For a manned mission, the vehicle will also have to ensure a supply of oxygen and have scrubbers to remove the carbon dioxide exhaled by the passengers. The vehicle will need to run for a minimum of eight hours so it will require a reliable battery and an emergency exit system in case something goes wrong.

To achieve all this within the relatively short deadline it has set itself, NIOT has decided to seek the help of an international partner. So far, only the United States, Russia, China and Japan have manned ocean submersible programmes that have reached the 6,000-meter depth.

The most famous deep ocean trip was made by Hollywood writer, director and producer James Cameron in 2012 when he rode the bathyscaphe he helped build 11,000 meters down to the bottom of the Marina trench – the deepest point on Earth. Cameron is releasing a documentary about his trip, Deepsea Challenge 3D, later this month.

According to Atmanand, NIOT has floated a tender for an international partner because it doesn’t want to reinvent the wheel. The institute, the only one in India to build civilian submersibles, is mastering deep-sea technology quickly despite the country’s late start in the field. Atmanand believes NIOT’s work will lead to many more spinoffs.

“The Scripps Institution of Oceanography in the US is 111 years old," he said. "Our institute is hardly 20 years old. Unfortunately we started in the country quite late and compared to space and nuclear technologies we are lagging far behind. All these things empower the country to take up high-tech activities.”