Ocean Gate / Handout/Anadolu Agency via Getty Images

Update 2: The search and rescue operation for the missing Titan submersible has turned into a salvage operation as the 5 occupants are feared dead.

The Titan sub went missing about an hour and a half after it began its descent toward the sunken wreckage of the Titanic around 1 p.m. EST Sunday. The 2.4 mile descent to the ocean floor should have taken 2 and a half hours.

The sub sent a distress call at 3:45 p.m. before losing all contact with the mothership.

OceanGate staff on the mothership reportedly waited until after 9 p.m. EST Sunday to contact the Coast Guard for help.

Ocean Gate / Handout/Anadolu Agency via Getty Images

The Titan sub was estimated to have 96 hours of oxygen supply on board. That estimate includes small portable oxygen tanks. The Coast Guard said the sub’s oxygen supply ran out around 7 a.m. EST Thursday.

The batteries that operated the lights and heated the walls of the sub probably drained on the first day, leaving the occupants in full darkness and frigid cold.

The pilot of the sub, OceanGate CEO and founder Stockton Rush, and his 4 wealthy passengers are feared dead from hypoxia (lack of oxygen) and/or hypothermia (exposure to cold temperature).

It is unknown whether they had enough food and water rations to last 5 days. The sub had one “toilet” – a black box containing pee bottles and Ziplock bags for solid waste.

The passengers who paid $250,000 a head were instructed to limit their intake of food and beverages before boarding the sub.

The Coast Guard denied reports that banging sounds picked up on sonar came from the depths near the Titanic. The Coast Guard dismissed the sounds as the normal banging of Titanic wreckage debris.

A group of explorers who have been following the rescue operation closely say rescuers pinpointed the location of the sub on Wednesday. The explorers said the Coast Guard refused to announce the sub’s location because they couldn’t bring the sub to the surface from 13,000 feet in time to save the Titanic tourists.

The Boston Coast Guard has denied the allegations that the sub was found.

Update 1: Canadian rescuers reported hearing “banging” noises on sonar in the area of the Atlantic Ocean where a tiny tourist submarine went missing on Sunday.

Early Sunday, the sub descended 2.4 miles to the ocean floor to view the sunken wreckage of the Titanic. They were near the Titanic when they lost communication with the mothership.

The crew on a Canadian P-3 aircraft reported hearing banging noises in 30 minute intervals in the search area on Tuesday.

Rescuers reported the noises in emails to the Department of Homeland Security, which were viewed by Rolling Stone magazine.

An email from Explorers Society read: “It is being reported that at 2 a.m. local time on site that sonar detected potential ‘tapping sounds’ at the location, implying crew may be alive and signaling.”

The reports give families hope that their loved ones may still be alive.

Multiple countries have joined in the frantic search for the sub in an area of ocean the size of Connecticut.

The five people inside the OceanGate Titan submersible have less than 24 hours of emergency oxygen left. The oxygen supply is expected to run out by Thursday morning.

Even if the submarine floated to the surface of the ocean, the passengers and pilot can’t escape. They are sealed inside the sub by 17 bolts that can only be removed from the outside.

Additionally, rescuers fear the Titanic Five may have run out of food and water by now.

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Stockton Rush, the CEO for OceanGate Expeditions which owns the submarine, is the pilot of the sub. OceanGate employees waited until Tuesday to reveal Rush’s identity.

They also waited nearly 11 hours before reporting the sub missing on Sunday.

Critics warned Rush that the experimental submarine wasn’t safe. The sub uses a modified Playstation controller to steer through the water. The U.S. Navy uses XBox controllers to steer their submarine drones.
 

The Titanic wreckage is about 12,500 feet below the surface of the water. The tiny submarine named the Titan is carrying four wealthy passengers who paid $250,000 each.

The passengers include a British billionaire businessman, a French explorer, and a Pakistani businessman and his 19-year-old son.

The sub had a 96-hour oxygen supply when it set out to view the sunken wreckage around 6 a.m. Sunday. It lost contact with the mother ship hours later.

Rescuers fear the five-person submarine may be trapped within the wreckage of the Titanic.

5,800 pounds per square inch of ocean pushing down on the submarine means a tiny crack in the sub’s carbon fiber shell will crush the sub like a soda can and kill everyone inside instantly.

Rescuers include Coast Guard crews from Boston and submersibles flown in from England and California.

The Titanic sank after hitting an iceberg on April 15, 1912. The Titanic was on its maiden voyage from England to New York City when it sank with about 2,200 passengers and crew members on board. More than 1,500 people died.

At the time, Titanic was the largest cruise ship on Earth.