By Marie Jackson & Matthew Davis
BBC News
British adventurer Hamish Harding and a UK-based businessman and his son are on the missing submersible diving to the Titanic’s wreck, their families say.
Mr Harding, 58, chairman of aircraft firm Action Aviation, is a renowned explorer who has flown to space and holds three Guinness World Records.
The family of Pakistani businessman Shahzada Dawood and his son, Suleman, have asked people to pray for them.
Submersible operator OceanGate said its entire focus was on the crew’s return.
French explorer Paul-Henry Nargeolet is also thought to be on board, according to a Facebook post by Mr Harding before the dive started
Stockton Rush, chief executive of OceanGate, is also widely reported to be on the vessel.
Contact with the small sub was lost about an hour and 45 minutes into its dive in the mid-Atlantic on Sunday.
Now search teams are in a race against time but so far there has been no sign of the vessel.
For Mr Harding, a billionaire private jet dealer, the trip to Titanic’s wreckage was the latest in a string of adventures.
He has visited the South Pole multiple times, flew into space in 2022 on board Blue Origin’s fifth human-crewed flight, and set three world records – including the longest time spent at full ocean depth during a dive to the deepest part of the Mariana Trench.
Over the weekend, Mr Harding said on social media that a ship had set off from the city of St John’s, in Newfoundland, Canada, for the destination of the Titanic wreck.
From there, he and the crew were planning to start diving operations in the submersible down to the wreck at around 04:00 local time (08:00 GMT) on Sunday morning.
He wrote on Facebook that he was “proud to finally announce” that he would be aboard the mission to the wreck of the Titanic.
Due to the “worst winter in Newfoundland in 40 years,” he said “this mission is likely to be the first and only manned mission to the Titanic in 2023”.
He continued: “A weather window has just opened up and we are going to attempt a dive tomorrow.”
Action Aviation said on Sunday that the sub had had a successful launch and Mr Harding was “currently diving“.
Later, his stepson Brian Szasz said in a now-deleted post on Facebook: He “has gone missing on (the) submarine.”
In a statement released on Tuesday, the Dawood family said: “Our son Shahzada Dawood and his son, Suleman, had embarked on a journey to visit the remnants of the Titanic in the Atlantic Ocean.
“As of now, contact has been lost with their submersible craft and there is limited information available.”
Shahzada Dawood, from one of Pakistan’s richest families, is a trustee of the Seti Institute, a research organisation in California, according to its website.
It says he lives in the UK with his wife, Christine, and his children Suleman and Alina, and is in the Founder’s Circle of the British Asian Trust.
He is also vice chairman of Dawood Hercules Corporation, part of the Dawood Group, a conglomerate of various businesses owned by the family.
In their statement, his parents said: “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.”
It went on to say the family was well looked after and were praying for the safe return of their family members.
Military planes, a submarine and sonar buoys have so far been used in the search for the vessel.
Titanic’s wreck lies some 435 miles (700km) south of St John’s, Newfoundland, though the rescue mission is being run from Boston, Massachusetts.
The US Coast Guard said a research ship called the Polar Prince had conducted a surface search for the sub on Monday evening.
It is used to transport submersibles to the wreckage site and was the support ship on Sunday’s tourist expedition.
In relation to an inquiry about Mr Harding, a spokesperson from the UK’s Foreign Office said it was “in contact with the family of a British man following reports of a missing submarine off the coast of North America.”
The eight-day trip involving a journey to the wreck of the Titanic – run by OceanGate Expeditions – costs $250,000 (£195,600) per person and starts in St John’s.
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.
The Titan is designed to carry five people and has “life support” for 96 hours for the crew, according to the firm’s website.
The Titanic sits 3,800m (12,500ft) beneath the surface at the bottom of the Atlantic. It is about 600km (370 miles) off the coast of Newfoundland.
The passenger liner, which was the largest ship of its time, hit an iceberg on its maiden voyage from Southampton to New York in 1912. Of the 2,200 passengers and crew onboard, more than 1,500 died.