(Corrects data on mission cost in 3rd from last paragraph)
By Jane Sutton
MIAMI (Reuters) - Third-generation oceanographer Fabien Cousteau will attempt to spend a record 31 days living and working underwater in a bus-sized laboratory submerged in the warm, turquoise Atlantic off the Florida Keys.
If he succeeds he will beat the 30-day underwater living record set 50 years ago in the Red Sea by his scuba-pioneering grandfather, Jacques-Yves Cousteau.
"We're doing something unprecedented," said the 45-year-old who grew up on the decks of his grandfather's ships, Calypso and Alcyone. "It's the risk of discovery, it's the curiosity, it's the adventure. It's going beyond that box that we always live in and are comfortable with, to learn something new."
While submerged, Cousteau and his five-person team plan to Skype with school children in classrooms around the world, make a 3D IMAX documentary, measure the effects of underwater living on their own bodies, count the fish and chart the pollution levels in the surrounding waters, experiment with coral-growing techniques and test the newest underwater motorcycles.
"It'll be a packed schedule," said the Paris-born Cousteau, who divides his time between France and New York. "This is a huge endeavor and we definitely need to take advantage as much as possible."
He and his Mission 31 team plan to take the plunge on September 30 and surface on Halloween at the Aquarius habitat in the Florida Keys National Marine Sanctuary. The cylindrical 43-foot (13-meter) laboratory sits on a patch of sand near some deep coral reefs about 9 miles (14.5 km) south of Key Largo.
It is owned by the U.S. National Oceanic and Atmospheric Administration (NOAA) and run by Florida International University. NASA has used it to train astronauts for the isolation and weightlessness of space.
LIKE A FISH
Aquarius is the last undersea laboratory still operating, "the best-kept secret in the oceans," Cousteau said. Dozens of others around the world have been mothballed due to high costs.
Aquarius is air-conditioned and has a shower, a bathroom and six bunks, and portholes that give the occupants a 24-hour view of the abundant marine life. The living space is at a depth of 50 to 60 feet (15 to 18 meters), where the atmospheric pressure is roughly 2.5 to three times that at the surface.
Aquarius visitors use a technique known as "saturation diving."
Undersea pressure causes divers' bodies to absorb more nitrogen, oxygen and other inert gases than they would at sea level. When surfacing, they must ascend slowly and stop at regular intervals to allow the extra gases to dissipate, or risk the formation of potentially deadly bubbles in the blood and tissue, known as decompression sickness or "the bends."
But research has shown that once their bodies are saturated with the maximum amount of gas it is possible to absorb at a particular depth, the length of time it takes to safely decompress stays the same no matter how long they stay.
Aquarius residents can dive around outside for six to nine hours a day without decompressing, compared with a limit of about an hour for divers working from the surface, because they stay underwater.
"We get to see things in the way you would if you were immersed like a fish," Cousteau said.
When the mission ends, the pressure inside Aquarius will be slowly lowered until it equals that on the surface, allowing the divers to decompress inside the lab for 24 hours and then swim to the surface.
Cousteau's grandfather, who died in 1997, first demonstrated that saturation diving could be done safely when he spent 30 days in an underwater habitat in the Red Sea off Sudan in 1963, an adventure chronicled in the Academy Award-winning documentary film "World Without Sun."
"We're going one day longer to make the point," Fabien Cousteau said. "We're doing it twice as deep and we're going farther in terms of our ocean walks."
The explorers will use underwater motorcycles that glide above the sea floor like hovercraft to get around efficiently while collecting data and "taking a pulse to the health of our oceans," Cousteau said.
Celebrity supporters are scheduled to drop by to bring attention to ocean conservation and science education.
On the VIP list are Richard Branson, the British magnate who runs a space tourism company; Sylvia Earle, the ocean explorer and former NOAA chief scientist known as "Her Deepness;" and tentatively Black Eyed Peas singer will.i.am, whose i.am.angel foundation is training a dozen young first-time divers for a visit the lab.
"This is going to be a mind-blowing experience for them, which is really cool," Cousteau said.
The Mission 31 team plans live broadcasts through Skype education, which allows teachers to arrange free group video calls to their classrooms. They'll check in periodically on the Weather Channel and hope to arrange a chat with astronauts living aboard the International Space Station.
"We're going to be reaching all seven continents and outer space," Cousteau said.
The previous longest stay at Aquarius was 18 days, and the mission won't be without risk. A diver working outside of Aquarius died in 2009 when his equipment malfunctioned. The adventure could be cut short if a hurricane hits near the Florida Keys.
The divers will live together in very tight quarters, regularly testing their oxygen levels, stress levels, blood pressure and other vital signs to measure the physical and emotional effects.
They'll sleep only five or six hours a night, and disconnect the Wifi for a half day once a week to have a little down-time.
"I'm planning on us making sure we don't get so exhausted, that we don't make silly mistakes which could be very, very costly down there," Cousteau said.
The team hopes to raise about $1.8 million, which would cover the $15,000 daily rent for Aquarius plus the cost of the technology, audio-visual production, the daily education program and a mission control team to monitor and assist from the surface. Funding will come from a mix of private donations and corporate sponsorships, Cousteau said.
Swiss watchmaker Doxa is offering a limited-edition titanium-cased Mission 31 dive watch for $2,890, with a quarter of the proceeds going to support the endeavor.
Throughout the month undersea, Cousteau will keep in touch with the world above in order to make the point that, "Social media connects many of us around the world but the oceans connect us all."
(Editing by Eric Walsh and Bill Trott)