Volkswacht Bodensee - The five people on board missing sub near Titanic

Among the missing is the tour operator's boss, a French submarine operator known as "Mr Titanic", a British aviation tycoon and a wealthy Pakistani businessman and his son.

- Stockton Rush -

Stockton Rush is the chief executive of OceanGate Expeditions, a company based in Washington state which operates the tourist dives and was founded in 2009.

According to his company website, Rush began his career in 1981 as the youngest jet transport rated pilot in the world, aged 19.

In 1984, Rush became a flight test engineer on the F-15 fighter jet program for the McDonnell Douglas company.

But over the last two decades, he threw himself into several ocean-related tech ventures including Seattle's BlueView Technologies, which makes small, high-frequency sonar systems.

After a long period when trips were postponed after Rush failed to get the proper permits for the project's support vessel, OceanGate Expeditions started taking paying customers to the Titanic's wreck in 2021.

- Paul-Henri Nargeolet -

Nicknamed "Mr Titanic", French submarine operator Paul-Henri Nargeolet was one of the vessel's crew.

The 77-year-old, who served in the French navy for 25 years, has dived all over the world and spoken openly about the risks of his exploits in the most inaccessible waters of the world's oceans.

Connecticut-based Nargeolet had already undertaken more than 30 dives to explore the Titanic and had supervised the recovery of around 5,500 objects, including a fragment weighing 20 tonnes that is displayed in Los Angeles.

His research produced a 2022 book where he questioned the findings of British and American enquiries into the 1912 disaster, arguing that five smaller holes were to blame rather than a 100-metre gash that followed Titanic's collision with an iceberg.

- Hamish Harding -

Harding, 58, is a British aviation tycoon who holds three Guinness world records and has a history of thrill-seeking adventures.

A year ago, he became a space tourist through Amazon founder Jeff Bezos's Blue Origin company.

He founded Action Aviation, a company that buys and sells aircraft with offices in Dubai and London's Stansted airport, with UK media reporting that the UAE-based businessman is a billionaire.

He was based in the Indian city of Bengaluru for five years, as managing director of a logistics company, before establishing Action Aviation in 2004.

His Guinness records are for longest duration and distance traversed at full ocean depth by a crewed vessel, and the fastest circumnavigation via both Poles by plane.

- Shahzada and Suleman Dawood -

Prominent Pakistani businessman Shahzada Dawood, 48, is the vice-chairman of Karachi-headquartered conglomerate Engro.

His son Suleman, 19, is a university student, and both hold British citizenship.

A statement by the family-run holding group Dawood Hercules described Shahzada as a "loving father" to two children with a keen interest in "photography, especially wildlife photography, and exploring different natural habitats".

Engro has an array of investments in energy, agriculture, petrochemicals and telecommunications. At the end of 2022, the firm announced revenue of 350 billion rupees ($1.2 billion).

Shahzada's father Hussain Dawood is regularly listed among Pakistan's richest men by the domestic press.

Shahzada's profile on Engro's website said he also serves as a trustee on the board of The Dawood Foundation -- a high-profile family education charity founded in 1960.

He was educated in the United States and Britain, the profile said.

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C.Meier--BTB