Technical data supports the version that the oxygen on the Titan submersible runs out in 96 hours, which theoretically means that this deadline is fulfilled between 14:00 and 15:00 on Thursday. However, the exact moment cannot be precisely determined, experts say. But one thing is clear, the rescue is a race against time.

Breathing air is about to run out, but 96 hours with five people on board can actually mean more. This is if passengers took measures to save oxygen, say experts cited by the Guardian. It also depends on how many people are still alive aboard the missing submarine as of Sunday morning.

Frank Owen, an expert in submarine search and recovery, said the duration of oxygen supply is a useful “target” for searches, but is based only on a “nominal amount of consumption”. Owen did not rule out that the passengers were advised to “do everything to lower their metabolic rate so they can extend the period”.

So far, many obstacles remain in the way of rescuers, from determining the exact location of the Titan to the equipment to recover it and raise it to the surface. And all this must happen before the supply of oxygen runs out.

Robot Victor 6000, the last hope

As a long-awaited addition to the search efforts, the French research vessel Atalante has been dispatched to deploy a robotic underwater vehicle capable of diving deeper than the wreckage of the Titanic, the Coast Guard said.

A French underwater robot called the Victor 6000 was deployed at the request of the US Navy, which sent its own special rescue system designed to lift large and heavy underwater objects such as airplanes or small sunken ships.

• On the same topic: What is hypercapnia, the greatest danger that threatens the crew of the submarine “Titan” before the oxygen runs out

The wreckage of the Titanic, the British liner that collided with an iceberg and sank on its maiden voyage in 1912, killing more than 1,500 people, lies on the seabed at a depth of about 3,810 meters. It is approximately 1,450 km east of Cape Cod, Massachusetts, and 400 km south of St. Pete. Jones, Newfoundland.

Among those aboard the submersible for the $250,000-a-person sightseeing adventure are British billionaire and adventurer Hamish Harding, 58, and Pakistani-born businessman Shahzada Dawood, 48, along with their 19-year-old son Suleman, both citizens of Great Britain.

French oceanographer and leading Titanic expert Paul-Henri Narjolet, 77, and Stockton Rush, founder and chief executive of OceanGate, are also on board.

• VIDEO What is and what does the Titan look like, a small submarine with tourists that disappeared during the expedition to the wreck of the Titanic

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