- Businessman Hamish Harding was aboard the Titanic tourist submersible that went missing on Sunday.
- Harding wrote on Instagram that there was bad weather but a "window" had opened up for a dive.
- Harding has been on several adventures, including a trip on Blue Origin's spaceflight in June 2022.
British billionaire Hamish Harding was aboard the Titanic tourist submersible when it went missing on Sunday.
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.
Harding, the founder and chairman of an aircraft brokerage company Action Aviation, is a prominent adventurer and thrill seeker.
The businessman made an Instagram post on Saturday, the day before the five-person crew made their fateful dive.
"Due to the worst winter in Newfoundland in 40 years, this mission is likely to be the first and only manned mission to the Titanic in 2023. A weather window has just opened up and we are going to attempt a dive tomorrow," Harding wrote on Instagram.
Harding holds three Guinness World Records, including one for spending the "longest time traversing the deepest part of the ocean on a single dive."
The 58-year-old was one of the passengers on Jeff Bezos' rocket company Blue Origin's fifth human spaceflight in June 2022.
Mark Butler, Action Aviation's managing director, told the AP that he thinks there is "still plenty of time to facilitate a rescue mission" and that the submersible has "equipment on board for survival in this event."
"We're all hoping and praying he comes back safe and sound," he added.
Five passengers, including Harding, are aboard the submersible. Search efforts by the US Coast Guard are currently ongoing.
But time is running short, and the crew in the submersible could run out of oxygen by Thursday afternoon — that is, if the vessel is still intact.
Representatives for Harding at Action Aviation did not immediately respond to a request for comment from Insider sent outside regular business hours.