Titanic submarine investigation: What's next in the recovery efforts

The desperate search to find the missing Titan submersible turned into a recovery effort Thursday after officials announced that the vessel imploded sometime this week, killing all five aboard, near the Titanic shipwreck. Now authorities are turning their focus to determining why the "catastrophic implosion" happened.

Deep-sea robots will continue to search the sea floor for clues about what occured deep in the North Atlantic. 

"I know there are also a lot of questions about how, why and when did this happen. Those are questions we will collect as much information as we can about now," Coast Guard rear Adm. John Mauger said, adding that it was a "complex case" that happened in a remote part of the ocean and involved people from several different countries.  

The Titan, owned by undersea exploration company OceanGate Expeditions, had been chronicling the Titanic's decay and the underwater ecosystem around the sunken ocean liner in yearly voyages since 2021.

Many questions about what occurred underwater remain: Exactly when and why did the implosion occur? Will the victims' bodies ever be found? How could this tragedy have been prevented?

Here's what we do know so far:

WHEN AND WHERE DID THE TITAN GO MISSING?

The craft submerged Sunday morning, and its support vessel lost contact with it about an hour and 45 minutes later, according to the Coast Guard.

The vessel was reported overdue about 435 miles south of St. John's, Newfoundland, according to Canada's Joint Rescue Coordination Centre in Halifax, Nova Scotia.

The Titan was launched from an icebreaker that was hired by OceanGate and formerly operated by the Canadian Coast Guard. The ship has ferried dozens of people and the submersible craft to the North Atlantic wreck site, where the Titan has made multiple dives.

WHAT HAPPENED ABOARD THE TITAN?

The vessel suffered a catastrophic implosion, killing all five aboard, sometime this week after it submerged Sunday morning. It's not clear exactly when or where the implosion occurred. But a senior military official said Thursday that a U.S. Navy acoustic system detected an "anomaly" Sunday that was likely the Titan's fatal implosion.

The Coast Guard announced that debris from the submersible had been found and the end of rescue efforts Thursday, bringing a tragic close to a saga that included an urgent around-the-clock search and a worldwide vigil for the missing vessel.

"The debris is consistent with the catastrophic loss of the pressure chamber," Mauger said in a news conference Thursday.

A deep-sea robot discovered the debris, near the Titanic shipwreck, that authorities say came from the submersible.

A U.S. Navy official said the Navy detected "an acoustic anomaly consistent with an implosion" shortly after the sub, named Titan, lost contact with the surface Sunday, CBS News national security correspondent David Martin reported. The information was relayed to the Coast Guard, which used it to narrow the radius of the search area, the official said.

Meanwhile, banging noises that were detected during the week were assessed to have been noise from other ships in the area, Martin reported.

WHAT'S NEXT AND WHO WAS KILLED?

The Coast Guard will continue searching near the Titanic for more clues about what happened to the Titan.

Officials say there isn't a timeframe for when they will call off the massive international search. Mauger said that the prospect of finding or recovering remains was unknown.

"This is an incredibly unforgiving environment down there on the seafloor, and the debris is consistent with a catastrophic implosion of the vessel," he said. "We'll continue to work and search the area down there."

Rescue teams will remain on scene with the underwater robots mapping the debris field, but there's no indication if or when remains will be brought to the surface.

"We're going to continue to investigate the site of the debris field and then there will be a lot of questions about how, why and when did this happen," Mauger said.

The victims are: Oceangate chief executive and Titan pilot Stockton Rush; two members of a prominent Pakistani family, Shahzada Dawood and his son Suleman Dawood; British adventurer Hamish Harding; and Titanic expert Paul-Henri Nargeolet.

"These men were true explorers who shared a distinct spirit of adventure, and a deep passion for exploring and protecting the world's oceans," OceanGate said in a statement. "We grieve the loss of life and joy they brought to everyone they knew."