Sir Richard Branson says he plans to travel to the deepest parts of the world's oceans in a single-person submarine.
The billionaire adventurer announced that he and fellow explorer Chris Welsh plan to make at least two dives over the next two years.
They and other pilots will take turns travelling to the bottom of the Mariana Trench in the Pacific, the Atlantic's Puerto Rico Trench and South Sandwich Trench, Diamantina Trench in the Indian Ocean and the Molloy Deep in the Arctic Ocean.
Sir Richard will take the first dive later this year to the Mariana Trench, which at 36,000ft is deeper than Mount Everest is high.
Speaking at a launch in Newport Beach, California, he showed off the 18ft carbon fibre and titanium sub, a blue-and-white plane-like craft with stubby wings and a cockpit that will be able to travel for miles over the ocean floor, and can stay down unaided for 24 hours.
"Man has not explored our ocean," Sir Richard said in an interview at Newport Harbour Yacht Club. "If someone says something is impossible we like to prove it's possible," he added. "I love learning and I'm just very fortunate to participate in these kinds of adventures."
Sir Richard said his Virgin Oceanic adventure will have a scientific purpose as well and he is working with various ocean research groups.
The founder of Virgin Airlines plans to make a larger sub that can hold more people and offer trips to tourists - for a sizeable fee.
Last year Branson unveiled a three-person submarine called the Necker Nymph, which is available for 2,500 US dollars a day for guests of his private resort in the Caribbean. The submarine, created by San Francisco-based Hawkes Ocean Technologies, is capable of going almost 100ft deep. In a subsequent interview with Popular Mechanics, Hawkes officials said they were also working with Sir Richard on submersibles capable of high-speed deep sea travel.
He has also been working on a space tourism venture with the construction of a 209 million US dollar spaceport in New Mexico. The British businessman has said he expects to launch the first suborbital flights from Spaceport America between mid-summer 2011 and spring 2012.