James Cameron launches mission to the bottom of the Mariana Trench

The Avatar director wants to be the third person to go 11km down the world's deepest hole.

The filmmaker James Cameron emerges from the Deepsea Challenger in which he plans to become the third person to dive 11km to the bottom of the Mariana Trench in the Pacific.

The earth's last frontier is about to be explored first-hand after more than half a century. It is a mission to the deepest part of the ocean, so deep that the pressure is the equivalent of three SUVs sitting on your toe.

And it is being launched by the rich and famous.

In the coming days, James Cameron, the director of Titanic, Avatar and The Abyss, plans to dive nearly 11km down into the Mariana Trench in the western Pacific, in a one-man lime-green submarine that he helped design.

The British airline and telecoms entrepreneur Richard Branson is not far behind. And the former Google chief executive Eric Schmidt is funding another deep-water submarine project that is still on the drawing board.

More people have been to the moon than to this underwater valley, roughly 320km south-west of Guam, which has been visited by only two people, the Swiss engineer Jacques Piccard and the US Navy captain Don Walsh. And they spent only 20 minutes there. Their vessel disturbed so much of the sea floor that all they could see through the window was a murky fog.

That dive was in 1960 and no one has been back since. Unmanned submarines have ventured that deep, but there is a difference between seeing something remotely on a computer monitor and being there, seeing it up close.

"It's the last frontier for science and exploration on this planet," Cameron said in a ship-to-shore interview. "It's to draw public attention to the oceans and continued need for exploration as well as stewardship. It would be a good thing if we understand the oceans before we destroy the life that's in them."

Cameron plans to spend at least six hours on the bottom in his cramped, almost form-fitting submersible, Deepsea Challenger. He plans to film an undersea documentary with his partner National Geographic, including 3D footage.

Craig McLean, the chief of research for the US National Oceanic and Atmospheric Administration, calls Cameron a hero.

"This is an awakening for the public on how little we know about our planet," McLean said. "We don't have to look up in the sky to find what's out there. We've got it in our oceans."

Andy Bowen, the director of the deep-sea sub lab at the Woods Hole Oceanographic Institution in Massachusetts, remotely guided the unmanned Nereus to the same sea floor for 13 hours in 2009. He describes the pitch-dark, ice-cold place as "the most hostile, most remote environment on the face of the planet".

McLean said the 7,500kg-per-square inch pressure was not bone-crushing, "it's obliterating". Cameron said if there were a leak, the pressure would crush him so fast he couldn't even cry out.

But getting to that dangerous place, Bowen said, "is frankly intoxicating".

Cameron already feels the majesty and he hasn't been quite that deep yet. Last week, on a test dive for his 12-tonne, 7.6-metre vertical submersible, Cameron went to a different trench 8.2km down. That set a record for the deepest solo submarine dive and Cameron was mesmerised by deep sea anemones that looked like hanging gardens, tube worms and jellyfish that would pulse by.

There was a moment when Cameron was photographing a jellyfish that swam right in front of his viewport, backlit by special lighting techniques.

"I just saw this very ancient and very simple animal," Cameron recalled. "The thought that popped through my head was that God must have been proud the day that he created the jellyfish."

Visit the Deepsea Challenge website at deepseachallenge.com

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