How India’s ‘aquanauts’ will undertake deep sea exploration under Samudrayaan Project

What are the Samudrayaan project’s aims?

With India’s 11,098 km-long coastline, the government has long pushed for a blue economy policy — harnessing ocean resources for economic growth. The deep ocean is home to several unexplored minerals, fuels, and biodiversity resources. It is also where a crucial medium of modern global telecommunications is found in the form of undersea cables, which are laid on the ocean floor.

Additionally, only a few countries presently possess deep-sea exploration capabilities, including the United States, Russia, China, Japan, and France. India will join this select group of nations with the Samudrayaan Project, which is among the six components of the Deep Ocean Mission approved by the Union Cabinet in 2021.

At the cost of Rs. 4,077 crores over five years, the mission will:

•  Develop technologies for deep sea mining, underwater vehicles and robotics, as and a crewed submersible (which needs support from a larger vehicle).
•  Develop an ocean climate change advisory service, with observations and models for future projections of climate variables.
•  Look for technological innovations to explore and conserve deep-sea biodiversity.
•  Conduct deep ocean surveys, mainly to look for mineral deposits. Of particular interest are polymetallic nodules, which comprise layers of iron and manganese hydroxides and are found on the ocean floor, often containing materials such as nickel, rare earths and cobalt.
•  Develop technologies to derive energy and freshwater from the ocean.
•  Establish an advanced marine station for developing capacities in ocean biology and engineering.

The National Institute of Ocean Technology, as the coordinating agency, is developing the submersible for the Samudrayaan Project.

What is Matsya-6000?

It is the vehicle that will carry the aquanauts. Designed somewhat like a big fish, it will contain a “personnel sphere” with a diameter of 2.1 metres to house the humans. The vehicle will be capable of sustaining three humans for 12-hour missions, with systems to support them for up to 96 hours during an emergency.

Matsya 6000.

For the initial test, carrying humans to a 500-metre depth, a steel sphere will be used. A wet test was conducted off the coast of Chennai in February.

Steel, however, is not strong enough to bear the atmospheric pressure at 6,000 metres under the sea — up to 600 times what is felt at sea level. Therefore, the actual personnel sphere will be made of a titanium alloy.

What are the challenges?

In the depths of the ocean, environmental conditions are extremely inhospitable for humans. Several factors have to be considered:

Vessel development: The first challenge is developing a vehicle capable of sustaining life in the deep sea. A titanium alloy with 80 mm thickness was chosen due to its strength, but it is not commonly found, and not many countries are willing to share their reserves.

Dr M Ravichandran, Secretary of the Ministry of Earth Sciences, said, “When we say 80mm thickness, it has to be precisely the same across the sphere. Even a 0.2mm deviation could lead to the collapse of the structure under such intense pressures.”

The sphere is to be fabricated through a precise technique called electron beam welding, where a focused beam of high-velocity electrons melts and joins the materials. The Indian Space Research Organisation (ISRO) will carry out the process.

Maintaining environment: Given that the aquanauts will be restricted to the personnel sphere, life-support systems will be needed to maintain the environment within. They must ensure that the oxygen levels remain at a certain level and the carbon dioxide levels are managed, with equipment known as scrubbers absorbing it.

The spheres will also be equipped with packed re-breather oxygen systems, which will be deployed during an emergency. They can recirculate exhaled air after removing carbon dioxide and adding oxygen, similar to diving systems.

Aquanaut health: The aquanauts must be physically fit to conduct the missions well and handle any emergencies. They also tend not to eat or drink a lot before and during their mission as they cannot access washrooms. During the nine-hour-long dive undertaken by Cdr Singh, he limited his diet to some dry fruits that he carried.

Acoustic communication: Communication is a major challenge for deep-sea missions. Radio waves, the basis of day-to-day communications, cannot penetrate deep water, necessitating the use of acoustic telephones. Here, sound waves carry information to a receiver placed just underneath the surface of the water.

Given other countries’ reticence to share the technology, India has developed its own acoustic telephone. An initial test at a harbour failed because factors such as the temperature and salinity of the water also impact its efficacy. Later, it worked in the open ocean.