A senior U.S. Navy official confirmed to ABC News that an underwater acoustic detection system heard on Sunday what was likely the implosion of the Titan submersible. The information was immediately shared with the U.S. Coast Guard on Sunday and analysis continued afterwards.

"The U.S. Navy conducted an analysis of acoustic data and detected an anomaly consistent with an implosion or explosion in the general vicinity of where the Titan submersible was operating when communications were lost," the senior official told ABC News in a statement. "While not definitive, this information was immediately shared with the Incident Commander to assist with the ongoing search and rescue mission."

According to the official, "This information was considered with the compilation of additional acoustic data provided by other partners and the decision was made to continue our mission as a search and rescue and make every effort to save the lives on board.”

Separately, a U.S. defense official said an analysis of the “banging” noises picked up by sonar buoys were not from the missing submersible but were either natural ocean sounds, biological noises or noises associated with the surface response vessels.

-ABC News' Luis Martinez

Hamish Harding, a British businessman who was among the five people killed in the Titan implosion, was remembered as a "passionate explorer" by his loved ones.

"Hamish Harding was a loving husband to his wife and a dedicated father to his two sons, whom he loved deeply," a statement sent on behalf of his family and Action Aviation, the company he chaired, said. "To his team in Action Aviation, he was a guide, an inspiration, a support, and a Living Legend."

"He was one of a kind and we adored him. He was a passionate explorer -- whatever the terrain -- who lived his life for his family, his business and for the next adventure," the statement continued. "What he achieved in his lifetime was truly remarkable and if we can take any small consolation from this tragedy, it's that we lost him doing what he loved."

-ABC News' Mark Guarino

Explorer Robert Ballard, who was on the 1985 expedition that discovered the Titanic wreckage and has made many dives since, reacted to news of the implosion with ABC News on Thursday.

"It's very tragic what happened, I know the people that passed away," he said, adding that he's known OceanGate CEO Stockton Rush, who was piloting the vessel, for 20 years. "I know this was his dream, so my heart goes out to him and his family and the families of all the people who lost loved ones."

Ballard surmised the crew likely experienced difficulties and began to drop weights to ascend to the surface but "never made it."

"If you're on your way up and you're buoyant and you don't make it, it's a catastrophic implosion," he said.

"I don't think people can appreciate the amazing energy involved in the destructive process of an implosion," Ballard continued. "It just takes and literally shreds everything. So it's extremely powerful."

The Explorers Club reacted to news of the submersible's implosion, saying in a letter to members on Thursday: "Our hearts are broken."

President Richard Garriott de Cayeux noted that two of the passengers lost in the implosion -- Hamish Harding and Paul-Henri Nargeolet -- were members of the Explorers Club, while OceanGate CEO Stockton Rush was a friend of the society who had conducted lectures at its headquarters.

"Hamish Harding is a dear friend to me personally and to The Explorers Club," Garriott de Cayeux said. "He holds several world records and has continued to push dragons off maps both in person and through supporting expeditions and worthy causes."

Nargeolet was "one of the foremost experts on submersible expeditions to the Titanic," Garriott de Cayeux said.

"They were both drawn to explore, like so many of us, and did so in the name of meaningful science for the betterment of mankind," he continued. "They pushed themselves in their entrepreneurial pursuits as they did in exploration."

The United States Coast Guard commander leading the search for a missing submersible off the coast of Newfoundland, Canada, said Tuesday morning that crews in multiple aircraft have flown over an area of the Atlantic Ocean "roughly about the size of Connecticut" while "looking for any signs of surfacing."

"As we continue on with the search, we're expanding our capabilities to be able to search under the water as well," Rear Adm. John Mauger, commander of the First Coast Guard District, told ABC News' Robin Roberts during an interview on "Good Morning America."

A commercial vessel with remotely operated vehicles is now on scene that will allow rescuers to search underwater, according to Mauger.

"This is a complex case," he added. "The Coast Guard doesn't have all the resources to be able to affect this kind of rescue, although this is an area that's within our search zone."

In many cases, Mauger said, the Coast Guard's role is to coordinate all of the assets and technical expertise that can be used in a search, in addition to operating aircraft or ships when necessary.

"In this particular case, we've established a unified command with the United States Navy, with the Canadian Armed Forces, with the Canadian Coast Guard and with the private operator OceanGate Expeditions to make sure that we understand what's needed and deploy all available equipment to the scene that could be used to locate this submersible, whether it's on the surface or down beneath the surface," he said.

Crews have been working "around the clock" to locate the deep-sea vessel since it lost contact with its operator on Sunday morning, according to Mauger.

In the last 24 hours, a Canadian aircraft has been dropping sonar buoys into the water that can pick up sound the submersible may be emitting. Vessels that have the capability to listen with their own sonar equipment are also on scene, according to Mauger.

"If they are making sound, that's certainly one of the ways that we're going to use to locate them," he said.