Story highlights Jacques Cousteau's grandson, Fabien, to live in underwater lab 31 days

Team of aquanauts will plunge 20 meters underwater, living in lab the size of a school bus

50 years since Cousteau elder lived in ocean habitat, made Oscar winning documentary

Modern day mission captured in 24/7 TV coverage, Skype chats, social media updates

Speaking to Fabien Cousteau is like plunging into dreamlike darkness. The sunlight falls away as you dive deeper and deeper underwater with him, and you can't help but hold your breath a little as he describes the alien creatures hovering at the edge of vision.

I needn't fear. Fabien is a master aquanaut -- and the grandson of legendary diver Jacques Cousteau.

His American accent, with soft French undertones, guides me 20 meters below the surface of the water until we rest our imaginary flippers at a very special spot on the ocean floor -- 14 kilometers off the coast of Florida Keys.

It's cold down here, around 35 degrees Fahrenheit. The enormous water pressure -- three times the atmosphere on land -- bears down on us, filling our veins with nitrogen and creating the feeling of being ever so slightly drunk.

As our eyes adjust to the gloom, twinkling yellow lights reveal a steel capsule the size of a school bus, with small portholes providing a glimpse of the scientists working inside.

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Welcome to " Aquarius ", the only underwater laboratory in the world, and Fabien's home for a record-breaking 31 days.

Cousteau's legacy

Fifty years after his famous grandfather, Jacques Cousteau, spent 30 days living in an underwater village at the bottom of the Red Sea, Fabien will follow in his footsteps with a similar project twice as deep and one day longer.

In 1963, Cousteau elder turned science fiction into reality when he and a team of five divers lived in an underwater habitat -- named "Conshelf II" -- researching the effects of deep sea living.

The pioneering experiment found cuts and grazes healed quicker and hair grew slower. New species of animals were discovered and Cousteau's haunting video diary was turned into an Oscar winning documentary, "World Without Sun."

"I hope we recapture the magic, mystery and beauty of the ocean which my grandfather was able to offer the world for so many decades," said Fabien, who takes the plunge on September 30.

Mission 31

This will be a new era of ocean exploration as the team of six aquanauts -- dubbed "Mission 31" -- examine not just the physical and psychological effects of underwater living, but the impact of climate change.

They will use space-age motorcycles to cruise the ocean floor nine hours a day, examining marine life, coral reefs, and ocean acidity -- which is linked to carbon emissions in the air.

"It's very much in the same spirit of adventure and exploration as in my grandfather's day," said 45-year-old Cousteau. "But by default we're living in a time where human impact is directly related to the ocean's health."

"The ocean contains 99% of the planet's total living space. That said, we know so little about it -- just 5% has been explored."

Photos: Futuristic underwater hotel Photos: Futuristic underwater hotel Deep space – It might look like a spaceship, but this remarkable design is in fact a luxury underwater hotel. Hide Caption 1 of 9 Photos: Futuristic underwater hotel Surreal seascape – The brainchild of Polish designers Deep Ocean Technology (DOT), the futuristic building features saucer-like lounges connected to 21 underwater bedrooms. Hide Caption 2 of 9 Photos: Futuristic underwater hotel Magnificent Maldives – The sleek design, which can cost up to $50 million, is now set to be built on the remote tropical island of Kuredhivaru in the Maldives. Hide Caption 3 of 9 Photos: Futuristic underwater hotel Water world – "The biggest challenge is to sink the hotel," said designer Pawel Podwojewski. "In this case, we'll take care of the construction, which means the underwater hotel will be completed in Poland and shipped to Maldives." Hide Caption 4 of 9 Photos: Futuristic underwater hotel Sky-high opulence – The unique structure may plunge 30-meters below the water, but its luxury facilities are sky-high, including a helicopter landing pad, opulent restaurant and rooftop swimming pool. Hide Caption 5 of 9 Photos: Futuristic underwater hotel Room with a view – Guests can enjoy views of vibrant coral reefs and sea creatures, all from the comfort of their bedroom. Hide Caption 6 of 9 Photos: Futuristic underwater hotel New depths – More adventurous guests can dive straight into the water from a special airlock compartment, including its own decompression chamber. Hide Caption 7 of 9 Photos: Futuristic underwater hotel Stairway to heaven? – The lounges are connected by a glass tunnel. In an emergency, the doughnut-shaped underwater room can slide to the surface of the ocean. Hide Caption 8 of 9 Photos: Futuristic underwater hotel Next stop...Dubai? – The unique hotel may soon be built in the United Arab Emirates, with Dubai construction company Drydocks now in negotiations with designers. Hide Caption 9 of 9

Photos: Deep sea robots Photos: Deep sea robots Deep-sea robots – "What happens in the vast, deep ocean, out of sight and beyond the reach of sunlight and satellites?" asks chief scientist Chris German. He is on a mission, with his team at the Woods Hole Oceanographic Institution, to find out. They developed Sentry, a robotic underwater vehicle used for exploring the deep ocean. Hide Caption 1 of 11 Photos: Deep sea robots Mid-Cayman Rise in the Caribbean – The development of new technology is crucial to our understanding of this vastly unexplored realm. Researchers use Remotely Operated Vehicles (ROVs) to examine hydrothermal vents up to 5km below the surface. Hide Caption 2 of 11 Photos: Deep sea robots Mid-Cayman Rise, Caribbean Sea – At the scene of German's latest explorations, newly-discovered vents on the Mid-Cayman Rise, the dominant fauna is a new species of blind shrimp that feed on microbes fuelled by the chemical energy released from Earth's interior. The shrimp, in turn, are devoured by shrimp-eating anemones. Hide Caption 3 of 11 Photos: Deep sea robots ROV Jason – Fueled by chemical energy released from the earth's interior, lush ecosystems thrive at hydrothermal vents. Here, the suction-tube sampler of the Institution's ROV collects a sample of tiny snails. Hide Caption 4 of 11 Photos: Deep sea robots 'Alvin' in Miami, Florida 1967 – In 1977, the development of new technology allowed the human-occupied vehicle, "Alvin" to explore a volcanic ridge 2500 meters below sea-level. "This discovery changed our understanding of how life can function here on Earth and opened entirely new fields of research," says German. Hide Caption 5 of 11 Photos: Deep sea robots Alvin with two support swimmers – We still have more than 75% of the 55,000 kilometer-long volcanic ridge system to explore. These vents could shed light on how life first originated and are home to minerals that could be essential resources for us in the future. Hide Caption 6 of 11 Photos: Deep sea robots Deep-sea angler fish – This deep-sea angler fish was collected by a submersible. Just three inches long but fierce-looking, it has a long spine tipped with bioluminescent tissue that it can dangle in front of its mouth. Hide Caption 7 of 11 Photos: Deep sea robots Deep-sea octopus – Alvin pilot Bruce Strickrott encountered a docile deep-sea octopus 2,300 meters down in the Gulf of Mexico. Instead of swimming away, it grabbed the submersible's robotic arm, normally used for picking up samples of seafloor rocks and organisms. Hide Caption 8 of 11 Photos: Deep sea robots Swiss oceanographer Jacques Piccard – The deepest known point of Earth's seafloor is Challenger Deep. Jacques Piccard and Don Walsh were the first humans to venture to these parts in 1960 in their underwater vehicle the Trieste. This was only achieved again last year by director James Cameron in Deepsea Challenger. Hide Caption 9 of 11 Photos: Deep sea robots Preparing Alvin and Sentry for descent – For scientists to truly examine ocean trenches such as Challenger Deep we need to develop increasingly autonomous deep-sea vehicles that return with useful samples of life below. According to German, the resultant knowledge could help us cope with global challenges such as climate change, resource depletion and pollution. Hide Caption 10 of 11 Photos: Deep sea robots Hybrid remotely operated vehicle Nereus – Woods Hole Oceanograhic Institution's Nereus is a one-of-a-kind vehicle that operates as a free-swimming robot to conduct surveys and close-up investigations of seafloor organisms. It reached Challenger Deep in 2009 and in 2014 will be used to conduct the first systematic study of life in ocean trenches. Hide Caption 11 of 11

Underwater "Truman Show"

While audiences in the 1960s had to wait for Jacques Cousteau's groundbreaking documentary to hit cinemas, this time round we'll be able to follow Fabien every step of the way, thanks to rolling coverage on the Weather Channel, Skype video calls to classrooms around the world, Twitter and Facebook updates, and ultimately an IMAX film.

This isn't just a new age of environmental frontiers, but media management, as "Aquarius" also welcomes celebrities on board, including Virgin business magnate Richard Branson and pop singer will.i.am.

"We'll have millions of eyeballs looking at us -- a bit like an underwater Truman Show," said Cousteau.

"Inside, it looks much like a submarine, with bunk beds, a kitchenette and a laboratory. It actually gets very warm in the habitat -- almost as humid as the Amazon River."

Risky business

This will be the longest stint researchers have spent on Aquarius -- the previous record was 18 days -- and the ambitious mission will not be without risk. Diver Dewey Smith died after his equipment malfunctioned outside the lab in 2009.

The team will spend 15 days in extreme training, including diving 20 meters underwater, taking off their masks, being spun around to lose their bearings and then swimming back to the habitat.

"The point of training is to make sure we're prepared for every situation," said Cousteau, who has been diving since he was four.

"Once your veins are fully saturated in nitrogen you won't be able to go back to the surface because of the decompression sickness -- we'll have to slowly come back up over 24 hours."

Magic realm

For Cousteau, who grew up playing on the salt-stained deck of his grandfather's boat, the ocean is a bewitching realm -- and one he wants to share with a world which has seen more people travel into deep space than deep sea.

"Being in the water is a dream, it's part fantasy," he says. "It still holds so much magic and mystery and I can only imagine what kind of sea creatures will be coming up to us during those experiments in the dark."

"My grandfather said people protect what they love. But how can you protect what you don't understand?"