(This story originally appeared in on Aug 04, 2017)

CHENNAI: At a time when India has successfully launched its heaviest rocket-GSLV-Mk3- capable of carrying humans to space, work has begun on building a vehicle to take man deep into the ocean.A team of scientists at ESSO-National Institute of Ocean Technology (NIOT) is ready with a preliminary design for the country's first manned submersible that can accommodate a three-member crew. Expected to be ready in five years at a cost of Rs 500 crore, it will be able to take scientists about six kilometres deep into the ocean to look for precious metals and lesser known life forms.Once the vehicle is ready, India will join an elite group of nations sending man underwater in a craft. At present, only China , US, Russia France and Japan have conducted manned deep-sea expeditions.NIOT director Satheesh Shenoi said the organisation submitted a proposal to the government and was awaiting approval. "Once we get the nod, an expert committee with members from scientific institutions like ISRO, DRDO and IIT will review and fine tune the design," said Shenoi.According to the design, the craft will be lowered into the sea from a ship. The crew, lying prostrate, in a 3.2 diameter titanium sphere, will be able to perform their task underwater for eight to 10 hours. A robotic arm will help them collect samples from the seafloor while they get a clear view through a glass pane.At present, India is conducting explorations for polymetallic nodules and polymetallic sulphides in certain regions of Indian Ocean on contract with the International Seabed Authority as part of the Deep Sea Mission launched by the Union ministry.The submersible is also part of the mission. "It is difficult to remotely operate unmanned vehicles to collect samples from small chimneys venting sulphides deep in the ocean. Manned submersibles will make the exploration less complex," Shenoi said.But before a bigger mission is executed, scientists are planning to make a similar looking spherical submersible in the next three years and send people about 500 m deep into the Indian Ocean.The smaller vessel will give scientists confidence and the required experience to get the final model ready. "Bharat Heavy Electricals Limited in Trichy has experience in making stainless steel vessels but not of the dimension we have planned. We are still debating on the material to be used and are looking for companies that can fabricate it here. We may also get from abroad. Once the sphere is ready, we are planning to make other components indigenously," Shenoi said.Indigenously making a submersible out of titanium — a metal that can withstand high water pressure —is a challenge. "We are in discussions with ISRO too as many aspects of the vessel are similar to a spacecraft," he added.