Follow along for live updates on the submersible that vanished while taking five people down to the wreck of the Titanic.

FRENCH DEEP SEA ROBOT JOINS INTERNATIONAL SEARCH FOR MISSING SUBMERSIBLE

A French deep sea robot that can dive to depths of 6,000 meters (19,685 feet) has joined the search for the missing Titan submersible and its five passengers.

France’s state-run ocean research institute said Thursday the Victor 6000 is fitted with cameras, lights and robotic arms that could, if Titan is found, assist in raising it to the surface.

“With all of its cameras and things, we’re capable of finding things really well in an area 20 to 30 meters (yards) around,” said Olivier Lefort, the fleet director at the French ocean research institute Ifremer. He added that if the Titan is found, Victor 6000 could help attach cables to the submersible in an effort to raise it.

The robot was aboard the French ocean research ship L’Atalante, which was working in the Atlantic, 48 hours away, when the Titan vanished Sunday on its way to the Titanic wreckage, which is at about 3,800 meters (12,467 feet) deep.

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What to know:

— What we know so far about the submersible, what may have gone wrong, and what’s being done to find it

— A look at the five passengers aboard the vessel

— A 2018 lawsuit warned that insufficient prototype testing could put passengers in danger

— The vessel is a submersible not a submarine, and there is a key difference

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‘DESPERATE SITUATION:’ SCIENTISTS, WHILE REALISTIC ABOUT SURVIVAL CHANCES, OFFER HOPE

Scientists, while remaining realistic about the chances of finding the Titan on the vast ocean floor, are still offering a glimmer of hope.

Rob Larter, a marine geophysicist with the British Antarctic Survey, said in London on Thursday that it’s incredibly difficult to find an object the size of the Titan in a totally dark environment. He says it’s not going to be found with active sonar from a surface ship, but rather with a towed or autonomous vehicle that’s near the seafloor. Even those vehicles can see just a matter of meters.

“I’ve been involved in searches for hydrothermal vent sites,” he said. “We’ve have the vehicles just a few tens of meters away and missed them and then come back and find them. So it really is, you know, literally it’s just a needle in a haystack situation unless you’ve got a pretty precise location”

Jamie Pringle, an expert in forensic geosciences at Keele University in the United Kingdom says the first 24 hours are critical in these kinds of rescue operations and that time period has long passed.

“So there’s always a chance. It’s never zero. But I think obviously the longer the time elapses, the lower the chance of success,” he said.

Larter called it a “desperate situation” buy says you try to stay optimistic as long as possible.

“It’s kind of unimaginable if people are alive, trapped in a submersible with oxygen supplies running down,” he said.

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THE SEARCH FOR THE SUBMERSIBLE IS NEARING THE CRITICAL 96-HOUR MARK

The search is nearing the critical 96-hour mark when breathable air is expected to run out, reaching a vital moment in the intense effort to save the five people aboard.

The Titan submersible was estimated to have a 96-hour supply of breathable air when it launched Sunday morning in the North Atlantic. That means the deadline to find and rescue the sub is roughly between 6 a.m. (1000 GMT) and 8 a.m. (1200 GMT) on Thursday based on estimates the U.S. Coast Guard and company behind the expedition have provided.

Experts say that the oxygen supply number is an imprecise estimate and could be extended if passengers have taken measures to conserve breathable air. And it’s not known if they survived since the sub disappeared Sunday morning.

Officials have expanded the coverage area to thousands of miles — twice the size of Connecticut and in waters 2 1/2 miles deep. Airplanes, ships, remote-operated underwater vehicles and a U.S. Navy-owned specialized salvage system have been deployed, concentrating where unidentified noises had been heard for two days. The noises raised hopes of a possible discovery.

TITAN SEARCHERS FACE UNDERWATER CHALLENGES TO FIND SUBMERSIBLE

Underwater mountains and valleys. Deep-sea water pressure. Weather conditions. And a search area twice the size of Connecticut – in waters 2 1/2 miles (4 kilometers) deep – with few clues about the Titan’s location.

The crews tasked with finding the Titan, which was reported overdue Sunday night, are facing all those challenges and more to locate the submersible amid the North Atlantic waters.

While undersea search efforts are nothing new – a 2019 expedition found two lost Japanese aircraft carriers that went down in World War II’s historic Battle of Midway around the Northwestern Hawaiian Islands – looking for the 22-foot-long (6.7-meter) carbon-fiber vessel amid the vast ocean is far more difficult than finding a needle in a haystack.

Those Japanese aircraft carriers were exponentially larger than the Titan – and still they were lost for decades after the June 1942 air and sea battle.

“I’ve seen large vessels hiding within extreme geology so searching for smaller objects requires more detailed scrutiny as opposed to searching for a sunken (cruiser) or aircraft carrier,” wrote Robert Kraft, a deep-sea explorer who was part of the 2019 expedition, in an email to The Associated Press from aboard his latest voyage.

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SOUND MAY HELP, OR HINDER, SEARCH FOR MISSING SUBMERSIBLE

Teams racing to find the missing Titan submersible have detected underwater noises in the search area. But it won’t be easy to find the source of that sound in the “noisy” ocean.

There are many other potential sources of sound underwater, including from fish, other animals and of course human-made instruments, according to Matt Dzieciuch, an ocean acoustics expert at the Scripps Institution of Oceanography.

While the Coast Guard said search teams heard banging noises at 30-minute intervals, it’s still unclear whether the banging noises were a true signal of life.

Usually, an underwater vehicle will have a device called a pinger that can correspond with the surface and make it easier to locate, Dzieciuch said. But it’s unclear whether the Titan submersible was using one.

The search team is facing additional challenges because sound gets bent as it travels underwater, due to how pressure and temperature change at different depths, Dzieciuch said. That can create echo-like effects and make it hard to locate the source of a particular sound.

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TITAN FACED PROBLEMS DURING PREVIOUS VOYAGES

Since its first expedition to the Titanic shipwreck in the summer of 2021, the Titan’s crews encountered problems aboard the submersible, including issues with its electrical system and battery, according to documents filed in a federal court in Virginia that oversees matters involving the Titanic shipwreck.

The issues during the first expedition were mostly electrical problems that were “solved as they came up,” according to the documents filed by OceanGate Expeditions, the undersea exploration company that commanded the Titan’s missions.

Ultimately, 18 of the submersible’s crew members explored the wreck site for the first time in 2021, the filing stated. Others, such as Paul-Henry Nargeolet, had already traveled to the site.

Nargeolet co-piloted four dives in 2021 and is one of the five people missing since the submersible vanished Sunday on its latest dive to the Titanic wreck.

The 2022 expedition brought more problems to the Titan.

“On the first dive to the Titanic, the submersible encountered a battery issue and had to be manually attached to its lifting platform,” the company wrote in another filing. “In the high sea state, the submersible sustained modest damage to its external components and OceanGate decided to cancel the second mission for “repairs and operational enhancements.”

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TITAN EXPEDITION FEATURED MULTIPLE MISSIONS TO SHIPWRECK

The Titan’s voyage this month was one of several missions the submersible took to the Titanic’s wreck site in recent weeks.

The entire expedition began in early May in St. John’s, Newfoundland in Canada and was expected to last until the end of June, according to documents filed in a federal court in Virginia that oversees matters involving the Titanic shipwreck.

Each mission lasted eight days, but it was not clear how many missions had taken place before the fateful trip – or how many were scheduled to occur afterward. Eighteen total dives were planned.

An Instagram photo posted by OceanGate Expeditions, the undersea exploration company that commanded the Titan’s missions, showed a group of smiling people labeled as “our Mission 3 and Mission 4 crew” at sea just days before the Titan vanished on Sunday – the first day of its latest voyage.

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UNDERSEA EXPLORATION ROBOTS CRITICAL IN SEARCH FOR MISSING SUBMERSIBLE

Remote-operated robots that are typically used for undersea exploration will instead be critical to any hope of finding the Titan.

There were two such remotely operated vehicles — or ROVs – in North Atlantic waters on Wednesday, with more on the way.

Designed to scan the sea floor in real time, the ROVs are outfitted with cameras and travel to depths many other vessels cannot.

ROVs have been used for undersea exploration since at least the mid-1980s, according to deep-sea explorer Katy Croff Bell, who is president of Ocean Discovery League.

The vessels are expensive to use and their method of data collection can be slow and painstaking, which is partly why scientists know so little about the ocean floor even after years of exploration.

But the ROVs might be the only way to find the Titan after the submersible vanished Sunday on a dive to the wreckage of the Titanic.

“ROVs are essential to the search and rescue mission,” Bell said. “Really the only way you’re going to be able to recover anything from the deep sea floor in real time.”

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SIMPLE VIDEO GAME CONTROLLER USED TO STEER TITAN

The Titan is steered by a simple, off-the-shelf video game controller – to the shock of gamers worldwide.

It’s not the only commercially available equipment onboard the submersible, according to OceanGate Expeditions’ website.

“The use (of) off-the-shelf components helped to streamline the construction, and makes it simple to operate and replace parts in the field,” the company said on its website.

The undersea exploration company, based in Everett, Washington, oversaw the Titan’s mission and has been making yearly voyages to the Titanic since 2021.

OceanGate chief executive Stockton Rush, in an interview with the CBC last year, said the video game controller is “super durable.” There are spare controllers kept onboard, but is not clear whether the submersible also had manual controls or other redundancies.

“It’s meant for a 16 year old to throw it around,” said Rush, who is the Titan’s pilot and among the five people missing.

Documents show the company was repeatedly warned that there might be catastrophic safety problems posed by the way the submersible was developed.

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SPECIALIZED UNDERWATER VESSEL FLOWN FOR SEA FLOOR SEARCH

The daunting search and rescue effort for the Titan is rushing experts and specialized underwater equipment together by land, by air and by sea to find the submersible before its oxygen runs out.

A remotely operated vehicle that can scan the sea floor, known as an ROV, was flown to Canada on Tuesday and is expected to arrive at the Titanic site on Thursday morning.

“The equipment that is onsite and coming is the most sophisticated in the world and certainly capable of reaching those depths,” said Sean Leet, chief executive of Canadian Horizon Maritime company.

The company and the Mi’kmaq band co-own the Polar Prince, which is the research vessel that launched the Titan.

“We are praying for our friends onboard the Titan submersible,” said Miawpukek First Nation Chief Mi’sel Joe. “We want them to come home safely. We ask everyone across Canada and the world to pray with us that we can find and rescue the Titan.”

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US NAVY SENDING EQUIPMENT FOR POSSIBLE SALVAGE

The U.S. Navy is sending a specialized salvage system that’s capable of hoisting “large, bulky and heavy undersea objects such as aircraft or small vessels” in the hopes that the Titan will be found in the waters of the North Atlantic.

The Titan weighs 20,000 pounds (more than 9,000 kilograms). The U.S. Navy’s Flyaway Deep Ocean Salvage System is designed to lift up to 60,000 pounds (27,215 kilograms), the Navy said on its website.

The Flyaway has a traction winch as well as a system that prevents “high-snap tension” from occurring in the lift line.

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PASSENGER ON 2021 DIVE TO TITANIC DESCRIBES RISKS

Looking back on his own 2021 dive to the Titanic, an early OceanGate passenger says one must be “a little bit crazy.”

Arthur Loibl, a retired businessman and adventurer from Germany, told The Associated Press on Wednesday that he conceived the idea to see the Titanic while on a 2016 trip to the South Pole. He paid $110,000 for a dive in 2019, but the first submersible didn’t survive testing. Loibl went two years later.

“Imagine a metal tube, a few meters long with a sheet of metal for a floor. You can’t stand, you can’t kneel. Everyone is sitting close to or on top of each other,” Loibl said. “You can’t be claustrophobic.”

The dive, which was repeatedly delayed to fix problems, took 10 1/2 hours, he said.

Lost aboard the vessel are pilot Stockton Rush, the CEO of the company leading the expedition. His passengers are a British adventurer, two members of a Pakistani business family and a Titanic expert.

“I was a bit naive, looking back now,” said Loibl.

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COAST GUARD BRINGS IN MORE SHIPS FOR SEARCH

The Coast Guard says it is bringing in more ships and underwater vessels to search for a submersible missing in the North Atlantic after underwater sounds were detected, providing a glimmer of hope three days after the Titan disappeared while taking five people down to the wreck of the Titanic.

Although the exact location and source of the sounds were not yet determined, they allowed searchers to focus on a more narrowly defined area. The full scope of the search was twice the size of Connecticut and 2 1/2 miles (4 kilometers) deep, said Capt. Jamie Frederick of the First Coast Guard District.

“This is a search and rescue mission, 100%,” Frederick said. “When you’re in the middle of a search and rescue case, you always have hope.”

But even those who expressed some optimism warned that many obstacles remain: from pinpointing the vessel’s location, to reaching it with rescue equipment, to bringing it to the surface — assuming it’s still intact — before the passengers’ oxygen supply runs out.

The U.S. Coast Guard did not elaborate on what rescuers believe the noises could be. The vessel hasn’t been heard from since Sunday. The passengers are estimated to have as little as a day’s worth of oxygen left.

The Associated Press

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