The US coast guard said Thursday that a multinational search for a lost submarine near the Titanic site is still focused on rescuing the five-member crew, despite concerns that the vessel's oxygen may have ran out
As the mammoth search for the Titan, lost somewhere in the North Atlantic between the ocean's surface and more than two miles (almost four kilometres) deep, entered its crucial stage, two more unmanned submarines were deployed Thursday.
Rescuers calculated that the sub's 96-hour emergency air supply would run out by Thursday afternoon. After that probable deadline, US Coast Guard Rear Admiral John Mauger claimed rescuers were "fully committed."
People's will to live must be considered. "We're searching and rescuing," he told NBC's Today show.
The operation has gained assets and professionals in the past day, and sonar has detected strange undersea noises.
US and Canadian military planes, coast guard ships, and teleguided robots are responding to sonar-detected underwater noises in the North Atlantic.
The Coast Guard announced Thursday that the French research ship Atalante launched an unmanned robot that can search up to 6,000 metres (almost 20,000 feet) below water. Experts call the Victor 6000 "the main hope" for underwater rescue.
The Coast Guard also tweeted that a robot from the Canadian vessel Horizon Arctic has reached the ocean floor and begun searching.
Mauger also stated that medical personnel and a decompression chamber are on their way.
Though specialists cannot authenticate their source, the sounds prompted optimism that the passengers on the small tourist ship are alive.
"We don't know," stated US Coast Guard Captain Jamie Frederick.
"We need optimism and hope."
According to the US Coast Guard, Titan, the submersible, descended around 8:00 am Sunday and was scheduled to resurface seven hours later.
The 21-foot (6.5-meter) tourist vessel lost contact with its mothership less than two hours into its mission to see the Titanic, which lies over four kilometres below the North Atlantic.
Titan carried British billionaire Hamish Harding and Pakistani entrepreneur Shahzada Dawood and his son Suleman, both British nationals.
OceanGate Expeditions costs $250,000 per sub seat.
Stockton Rush, the company's CEO, and "Mr Titanic" Paul-Henri Nargeolet, a French submarine operator, are both on board.
Ships and planes have searched 10,000 square miles (20,000 square kilometres) of surface water—roughly the size of Massachusetts—for the vessel, which attempted to dive 400 miles off Newfoundland, Canada.
After a Canadian P-3 plane spotted the noises, rescuers moved two underwater ROVs and one surface vessel using sonar.
The ROV searches failed, but US Navy acoustics experts have analysed Canadian aircraft data.
The Pentagon provided three C-130s and three C-17s, while the Navy contributed a winch system for lifting huge things from deep depths and other equipment and troops.
In 1912, the Titanic hit an iceberg and sank on its maiden trip from England to New York with 2,224 passengers and crew. 1,500+ died.
It was discovered in 1985 and still attracts divers.
That depth has 400 atmospheres of pressure.
In 2018, OceanGate Expeditions' former head of marine operations David Lochridge filed a lawsuit alleging that he was fired for criticising the craft's "experimental and untested design."
Tom Zaller, who oversees "Titanic: The Exhibition," examined the wreck 23 years ago in a submersible like the one that disappeared Sunday.
"You're sending a very small vessel two and a half miles down, which is incredibly complicated and technical," he remarked.
"It's just this very seemingly unsophisticated sphere."
Zaller has known Nargeolet for decades and contacted Rush before Sunday's tour.
"I was in that sub for 12 hours with everything working fine," Zaller added. "Almost four days. I'm inconceivable."
