Hamish Harding, the billionaire on board the Titanic submersible, is a serial explorer who also went to space on a Blue Origin flight

• A British billionaire on board the missing Titanic submersible is a noted explorer.
• Hamish Harding previously flew to space on a Blue Origin flight and has broken several records.

June 26, 2023: This story was originally published June 20. Since then, the search-and-rescue team seeking the Titan has concluded the passengers on board, including Hamish Harding, most likely died after a catastrophic implosion of the submersible.

A British billionaire on board a missing submersible that was headed to the Titanic wreckage was a noted explorer who flew to space last year on a Blue Origin flight.

Hamish Harding is one of five passengers on the Titan submersible that was visiting the Titanic wreckage when it lost communication with its mother ship on Sunday.

On Thursday, OceanGate — the company behind the Titanic submersible — confirmed that Harding and the four other passengers were believed to be dead. Debris of the submersible was found near the Titanic wreck, and the Coast Guard said it was "consistent with the catastrophic loss of the pressure chamber."

A search mission was underway to recover the lost ship. During the rescue operation, it was believed that the crew in the submersible could run out of oxygen by Thursday afternoon if the vessel is still intact.

Harding, 58, is no stranger to tourism of the extreme. He's part of a select group of space tourists who have paid privately to join missions in orbit.

Last year, he flew 66.5 miles above Earth on Blue Origin's New Shepherd rocket during a 10-minute suborbital flight.

You can see Harding's journey to space here:

Harding also holds three Guinness World Records for achievements including the longest time spent navigating the Mariana Trench, the deepest part of the ocean, and the fastest flight going all the way around the globe, crossing both poles.

He was also part of two record-breaking missions to the South Pole, the first joining astronaut Buzz Aldrin who became the oldest person to reach the pole in 2016, and one where his 12-year-old son, Giles Harding, became the youngest to reach the pole, per Forbes.

He is also a skydiver and is a trustee of the Explorers Club, per The Guardian.

"Can't believe it's been that long already but absolutely can't wait for our next mission/journey/adventure! #OneMoreRecord," said Harding in a tweet five months after his deep dive in the Mariana Trench in August 2021.

Harding, a plane pilot who made his money in aircraft sales, announced on Instagram Sunday he would be joining the OceanGate expedition onboard the Titan submersible as their mission specialist.

He added that due to "the worst winter in Newfoundland in 40 years," this mission would likely be the only one to the Titanic in 2023.

Harding has been widely reported to be a billionaire, though his exact net worth is unknown, per Forbes.

Harding's stepson, Brian Szasz, confirmed his disappearance via posts on his Facebook and Twitter accounts.

"Hamish my stepdad is lost in a submarine thoughts and prayers that the rescue mission will be successful," Szasz said in his Facebook post on Monday.

Correction: June 26, 2023 — An earlier version of this story misstated the number of Guinness World Records held by Hamish Harding. Harding held three Guinness World Records, not "at least four."