Who is on the OceanGate Titanic sub?

A search for the missing OceanGate Titan submersible craft, which disappeared on Sunday, June 18 during a dive to the wreckage of the Titanic in the Atlantic Ocean, has yet to yield results.  

More details are emerging about those onboard the vessel and of the Titan itself. 

Who is on the submarine? 

The five passengers on board the missing submarine have been identified as OceanGate CEO Stockton Rush, French mariner Paul-Henry Nargeolet, British businessman and explorer Hamish Harding, Pakistani businessman Shahzada Dawood, and Dawood's son Sulaiman Dawood. 

LIVE UPDATES: SEARCH FOR MISSING OCEANGATE TITAN SUBMARINE 

Who is Stockton Rush? 

Rush, who founded the company in 2009, is one of the five people on board the missing Titan submarine. 

"Rush oversees OceanGate’s financial and engineering strategies and provides a clear vision for development of 4,000 meter (13,123 feet) and 6,000 meter (19,685 feet) capable crewed submersibles and their partner launch and recovery platforms which make OceanGate Inc the leading provider of crewed submersibles for charter and scientific research," OceanGate’s website says. 

"In 1989, Rush personally built a Glasair III experimental aircraft, which he still owns and flies," the website also says. "He obtained his BSE in Aerospace Engineering from Princeton University in 1984, and his MBA from the U.C. Berkeley Haas School of Business in 1989." 

An OceanGate spokesperson told Fox News on Tuesday that it "can confirm" the 61-year-old Rush "is aboard the submersible as a member of the crew."  

Who is Paul-Henry Nargeolet?  

Nargeolet, 77, is described by OceanGate Expeditions as a "renowned Titanic expert, having led six expeditions to the Titanic wreck site and lectured at numerous Titanic exhibitions around the world." 

Nargeolet reportedly has completed dozens of dives to the wreckage in submersibles himself and supervised the recovery of thousands of artifacts, including a 20-ton section of the Titanic’s hull. 

Born in Chamonix, France, Nargeolet is considered a "leading authority" on the Titanic. He is listed as the Director of Underwater Research for E/M Group and RMS Titanic, Inc. 

Nargeolet spent more than two decades in the French navy, rising to the rank of Commander. He retired in 1986 and joined the French Institute for Research and Exploitation of Sea, leading deep submersibles. In this role, he led the first recovery expedition of the Titanic in 1987. 

Who is Hamish Harding? 

Harding, a 58-year-old adventurer and businessman from the United Kingdom, is the chairman of aircraft sales company Action Aviation. 

Action Aviation describes Harding as a "licensed Air Transport Pilot, a Living Legend of Aviation, inducted in 2022, a three Guinness World Records holder, an Explorer and an Entrepreneur." 

Harding, it added, "is an extraordinarily accomplished individual who has successfully undertaken challenging expeditions, including but not limited to One More Orbit project (the record-breaking circumnavigation of the world), a flight to Space with Blue Origin’s New Shepard rocket as a Commercial Astronaut (NS-21 Mission) and the reintroduction of Cheetahs from Namibia to India."  

"He has travelled on a submersible to the Challenger Deep in the Mariana Trench and has been to the South Pole a number of times," Action Aviation also said.  

'UNDERWATER NOISES' IN SEARCH FOR MISSING TITANIC SUBMARINE A 'BEACON OF HOPE' FOR FRIENDS OF PASSENGERS 

Who are Shahzada Dawood and Sulaiman Dawood? 

Shahzada Dawood, 48, and his son Sulaiman Dawood, 19, round out the missing passengers on board the Titan. 

Shahzada Dawood is among the richest men in Pakistan, with the majority of his family's wealth arising from the Dawood Hercules Corporation Limited, an investment company. One of its subsidiaries, Engro Corporation, confirmed that Dawood was missing aboard the craft early Tuesday. 

"We are very grateful for the concern being shown by our colleagues and friends and would like to request everyone to pray for their safety while granting the family privacy at this time," his family also said in a statement to The Associated Press. "The family is well looked after and are praying to Allah for the safe return of their family members." 

How many remaining hours of breathable air does the submarine have? 

The submarine began its journey to the Titanic on Sunday morning with 96 hours of oxygen on board, according to OceanGate’s website. 

Operators then lost contact with the vessel about 1 hour and 45 minutes into its descent. 

On Tuesday, around 1 p.m. ET, the U.S. Coast Guard estimated that there were about 40 to 41 hours of "breathable air" still available inside the vessel.  

By the Coast Guard’s estimate, that means oxygen would run out inside the Titan sometime Thursday morning.

How long was the submarine supposed to be gone? 

OceanGate Expeditions lists an 8-day round trip itinerary for its "Titanic Expedition." 

"Follow in Jacques Cousteau’s footsteps and become an underwater explorer -- beginning with a dive to the wreck of the RMS Titanic," it says. "This is your chance to step outside of everyday life and discover something truly extraordinary." 

The itinerary says the trips depart from St. Johns, Newfoundland, before spending a day in the North Atlantic and five days at the Titanic dive site.  

OceanGate says it takes about two hours for Titan to descend to the remains of the Titanic. 

"Once the submersible is launched you will begin to see alienlike lifeforms whizz by the viewport as you sink deeper and deeper into the ocean," the website says. "The descent takes approximately two hours but it feels like the blink of an eye." 

Then, once Titan reaches the Titanic, "Enjoy hours of exploring the wreck and debris field before making the two-hour ascent to the surface," the website adds. 

How many times has OceanGate been to the Titanic? 

OceanGate, on its website, says this year was its third-annual crewed expedition to the Titanic wreckage site. 

"After the successful expeditions to the wreck in 2021 and 2022, OceanGate Expeditions will continue to return annually to further document the Titanic and its rate of decay," the website says. 

OceanGate says there are currently 18 planned dives to the Titanic. 

A spokesman for the company did not immediately respond to a request for comment from Fox News Digital regarding the number of past dives Titan itself has completed to the Titanic site. 

What is an implosion and how might it happen?

A career scientist in the submersible vehicle industry indicated in an interview with Fox News Digital on Monday that he fears the worst -- a catastrophic implosion -- regarding the fate of the OceanGate Titan.

CLICK HERE TO GET THE FOX NEWS APP 

"The pressure down there at 4,000 meters is pretty high. About 5,800 PSI at Titanic depth," said Steve Somlyody, a Florida-based senior research scientist who has 20 years of experience in submersible design and operation. "If they had any kind of leak, it would lead to an implosion and it would happen in an instant, very immediately. You wouldn’t even know it happened." 

An implosion would mean pressure exerted on the outside of the Titan would cause it to collapse inward on itself.  

Fox News’ Tamara Gitt, Anders Hagstrom, Bradford Betz and Kerry Byrne contributed to this report.