Film director James Cameron could dive as early as this weekend to the deepest place on Earth, further than any other human has on a solo mission, so long as the weather cooperates.
The Canadian filmmaker left the tiny Pacific atoll of Ulithi on Saturday headed for the Mariana Trench's Challenger Deep, which plummets 11 kilometres down in the Pacific Ocean, according to mission partner the National Geographic scientific institution.
His goal is to become the first human to visit the ocean's deepest point in more than 50 years, and to bring back data and specimens.
"If seas remain calm, a big if, the team may proceed with Cameron's submersible mission to the trench's Challenger Deep this weekend," a National Geographic News report said.
It said the submersible that Cameron designed - a "vertical torpedo" of sorts - had already successfully completed an unpiloted dive on Friday.
The sub is expected to allow the director to spend around six hours on the sea floor during which he plans to collect samples and film his journey with several 3D, high-definition cameras and a 2.4-metre-tall array of LED lights.
In 1960, a two-person crew aboard the US Navy submersible Trieste - the only humans to have reached Challenger Deep - spent just 20 minutes on the bottom, but their view was obscured by silt stirred up when they landed.
Cameron, 57, has been running several miles a day, practising yoga to increase his flexibility for the dive in the sub's cramped quarters and studying deep-ocean science, physician Joe MacInnis told National Geographic.
MacInnis is a member of the Deepsea Challenge project, a partnership with the National Geographic Society and Rolex.
Cameron already has 72 dives under his belt, including 12 to film Titanic.