The five billionaires who were on board the submersible

All five passengers on board the missing Titan submersible are believed to have died, the company that operates the vessel says.

The CEO of the submersible company, a British billionaire explorer, a French diver and a father and son were all on board.

Here is what we know about them.

Hamish Harding, 58

The British adventurer ran Action Aviation, a Dubai-based private jet dealership, and completed several exploration feats.

He visited the South Pole multiple times - once with former astronaut Buzz Aldrin - and flew into space in 2022 on board Blue Origin's fifth human-crewed flight.

He held three Guinness World Records, including longest time spent at full ocean depth during a dive to the deepest part of the Mariana Trench.

In summer 2022, he told Business Aviation Magazine that he grew up in Hong Kong, qualified as a pilot in the mid-1980s while studying at Cambridge, and set up his aircraft firm after making money in banking software.

He said the Titanic dive had been meant to take place in June 2022 but was delayed because "the submersible was unfortunately damaged on its previous dive". He said no-one was injured in the incident.

Asked about his appetite for exploration, he said: "My view is that these are all calculated risks and are well understood before we start."

Last weekend, he said on Facebook that the mission was "likely to be the first and only in 2023" because of poor weather conditions in Newfoundland, Canada, where the missions set off from.

Later, his stepson Brian Szasz said in a now-deleted post on Facebook that his stepfather "has gone missing on (the) submarine".

Friend David Mearns, a marine scientist and expedition leader, described Mr Harding as a "very charming guy" who was attracted to extreme adventures.

Patrick Woodhead, founder of British tour operator White Desert Antarctica, said Mr Harding was an "incredible" aviation explorer, and that his thoughts and prayers were with Mr Harding's wife, Linda, and his sons.

Terry Virts, a retired Nasa astronaut, said his friend was the "quintessential British explorer" who loved adventure and exploring, but was not an adrenaline junkie.

"Some people watch Netflix, some people play golf, and Hamish goes to the bottom of the ocean, or into space, and he's set world records flying around the planet," he told BBC Radio 4 Today's programme.

Mr Harding - along with Paul-Henry Nargeolet who was also on board - was a member of the Explorers Club, a little known century-old exploration group whose members have included Sir Edmund Hillary and Amelia Earhart.

Its president, Richard Garriott de Cayeux, said Mr Harding's excitement over the expedition had been palpable during a meeting at last week's Global Exploration Summit.

Shahzada Dawood, 48, and Suleman Dawood, 19

British businessman Shahzada Dawood was from one of Pakistan's richest families. He was travelling on the sub with his son Suleman, a student.

Mr Dawood lived with his wife, Christine, and other child, Alina, in Surbiton, south-west London. The family were spending a month in Canada prior to the dive.

Shahzada was vice-chairman of Pakistani conglomerate Engro Corporation, which is a large fertiliser firm.

He worked with his family's Dawood Foundation, as well as the SETI Institute, a California-based research organisation which searches for extra-terrestrial life.

Shahzada was also a supporter of two charities founded by King Charles III - the British Asian Trust and the Prince's Trust International.

A Palace spokesperson previously said the King's "thoughts and prayers" were with all those onboard.

Shahzada's family said he was interested in "exploring different natural habitats", and had previously spoken at both the United Nations and Oxford Union.

He studied in Philadelphia, in the US, and the University of Buckingham in England, where he graduated in 1998.

Suleman was a student at the University of Strathclyde in Glasgow, where he had just completed his first year at the university's Business School.

A family statement described the teenager as a "big fan of science fiction literature and learning new things", and having an interest in Rubik's cubes and playing volleyball.

He recently graduated from ACS International School Cobham in Surrey, according to local media reports.

Paul-Henry Nargeolet, 77

Also on board was Mr Nargeolet, a former French Navy diver.

Nicknamed Mr Titanic, he reportedly spent more time at the wreck than any other explorer and was part of the first expedition to visit it in 1987, just two years after it was found.

He was director of underwater research at a company that owns the rights to the Titanic wreck.

According to a company profile, Mr Nargeolet supervised the recovery of thousands of Titanic artefacts, including the "big piece", a 20-tonne section of the boat's hull.

Family spokesman Mathieu Johann described Mr Nargeolet as a "super-hero for us in France".

"He is the world specialist on the Titanic, its conception, the shipwreck, he has dived in four corners of the world," he told Reuters.

Shortly before boarding the sub, Mr Nargeolet said he had been looking forward to an expedition next year to recover objects from the wreck, he added.

Mr Nargeolet's wife, Anne, who is French, lives in Connecticut, while his children live outside of France, according to Reuters.

Stockton Rush, 61

Stockton Rush was the chief executive of OceanGate, the firm which runs the Titanic voyages, and the company confirmed he was on board.

He was an experienced engineer who has previously designed an experimental aircraft and worked on other small submersible vessels.

Mr Rush founded the company in 2009, offering customers a chance to experience deep sea travel, and made global headlines in 2021 when it began offering trips to the site of the Titanic wreck.

For $250,000 (£195,600), his company offers passengers the opportunity to get an up-close glimpse of what remains of the famous ship.

Participants travel some 370 miles (595km) on a larger ship to the area above the wreck site, then do an eight-hour dive to the Titanic on a truck-sized submersible known as Titan.

Speaking to the New York Times in 2022, he defended the business model, and said the ticket price was a "fraction of the cost of going to space and it's very expensive for us to get these ships and go out there".

A 2017 feature written for the website of Princeton University, where he studied, reported that Mr Rush goes on every OceanGate dive.

Mr Rush was married to Wendy Rush, who is the great-great-granddaughter of Isidor and Ida Straus, who died in the Titanic wreck after letting women and children escape before them.