More details about the Titan submersible catastrophe are coming to light.

Eight months after the OceanGate submersible imploded, a new documentary is highlighting the harrowing search and knocking sounds rescuers heard at the time, which ultimately fostered hope of finding its five passengers alive.

"The symmetry between those knockings is very unusual," former Navy submarine Captain Ryan Ramsey said during ITN's The Titan Sub Disaster: Minute by Minute trailer. "It's rhythmic, it's like somebody is making that sound, and the fact that it is repeated is really unusual."

The documentary, which is set to air March 6 and 7 on Britain's Channel 5, chronicles the disappearance of the submersible in the North Atlantic Ocean, as well as the rescue mission and reflections from experts, according to ITN Productions. It will also examine exclusive audio from the Canadian Air Force, including the infamous banging sounds heard during the massive search.

On June 18, the Titan was headed to the wreckage of the RMS Titanic—which tragically sunk to the bottom of the Atlantic Ocean in April 1912—when it lost signal.

Two days later, U.S. Coast Guard officials shared that the Canadian Air Force had directed efforts to a specific part of the ocean after it detected underwater banging noises. The optimistic update came just hours after officials revealed an estimated 40 hours of oxygen was left in the submersible.

However, as news of its missing five passengers—company CEO Stockton Rush as well as passengers Hamish Harding, Paul-Henri Nargeolet, Shahzada Dawood and his 19-year-old son Suleman Dawood—captivated the world, the search concluded when the Coast Guard confirmed on June 22 that all passengers were presumed dead after finding debris from an external part of the sub.

After the heartbreaking news, the company operating the submersible addressed the fate of the men onboard.

"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 the June statement. "Our hearts are with these five souls and every member of their families during this tragic time. We grieve the loss of life and joy they brought to everyone they knew."

On June 18, 2023, a deep-sea submersible Titan, operated by the U.S.-based company OceanGate Expeditions and carrying five people on a voyage to the wreck of the Titanic, was declared missing. Following a five-day search, the U.S. Coast Guard announced at a June 22 press conference that the vessel suffered a "catastrophic implosion" that killed all five passengers on board.

Pakistani-born businessman Shahzada Dawood and his 19-year-old son Suleman Dawood, both British citizens, were also among the victims.

Their family is one of the wealthiest in Pakistan, with Shahzada Dawood serving as the vice chairman of Engro Corporation, per The New York Times. His son was studying at the University of Strathclyde in Glasgow, Scotland.

Shahzada's sister Azmeh Dawood told NBC News that Suleman had expressed reluctance about going on the voyage, informing a relative that he "wasn't very up for it" and felt "terrified" about the trip to explore the wreckage of the Titanic, but ultimately went to please his father, a Titanic fan, for Father's Day.

The Dawood Foundation mourned their deaths in a statement to the website, saying, "It is with profound grief that we announce the passing of Shahzada and Suleman Dawood. Our beloved sons were aboard OceanGagte's Titan submersible that perished underwater. Please continue to keep the departed souls and our family in your prayers during this difficult period of mourning."

OceanGate CEO Stockton Rush was the pilot of the Titan. The entrepreneur—who founded the research company in 2009 in Everett, Wash.—had long been interested in exploration. Rush, 61, previously said he dreamed of becoming the first person on Mars and once said that he'd "like to be remembered as an innovator."

In addition to leading voyages to see the remnants of the Titanic, Rush had another surprising connection to the historic 1912 event: His wife Wendy Rush is the great-great-granddaughter of a couple who died on the Titanic, Ida and Isidor Straus.

British billionaire Hamish Harding confirmed he was a part of the mission in a June 17 Instagram post, a day before the submersible went into the water and disappeared.

"I am proud to finally announce that I joined @oceangateexped for their RMS TITANIC Mission as a mission specialist on the sub going down to the Titanic," he wrote. "Due to the worst winter in Newfoundland in 40 years, this mission is likely to be the first and only manned mission to the Titanic in 2023. A weather window has just opened up and we are going to attempt a dive tomorrow."

Harding—the chairman of aircraft company Action Aviation—said the group had started steaming from St. Johns, Newfoundland, Canada and was planning to start dive operations around 4 a.m. on June 18. The 58-year-old added, "Until then we have a lot of preparations and briefings to do."

His past explorations included traveling to the deepest part of the ocean in the Mariana Trench, telling Gulf News in 2021, "It was an incredibly hostile environment. To travel to parts of the Challenger Deep where no human had ever been before was truly remarkable."

The Dubai-based businessman also circumnavigated the Earth by plane with the One More Orbit project and, last year, took a trip to space on Amazon founder Jeff Bezos' Blue Origin New Shepard rocket. Harding shared his love for adventure with his son Giles, described as a "teen explorer" on his Instagram.

As for the fifth member, a representative for French explorer Paul-Henri Nargeolet told the New York Times that he was a passenger on the Titan, with Harding also referencing him on Instagram as a member of the team. 

The Times described him as a maritime expert who was previously part of the French Navy. The 71-year-old was a bonafide Titanic specialist and has traveled to the wreckage 35 times before. Nargeolet served as the director of RMS Titanic, Inc., a company that researches, salvages and displays artifacts from the famed ship, per the outlet. 

Alongside fellow passenger Hamish Harding, he was a member of The Explorers Club, founded in 1904.

As Harding noted in his post, the submersible—named Titan—was a part of an OceanGate Expeditions tour that explores the wreckage of the RMS Titanic, which infamously sank in 1912.

The company expressed its sympathies to the families of the victims. "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. "Our hearts are with these five souls and every member of their families during this tragic time. We grieve the loss of life and joy they brought to everyone they knew."