Fabien Cousteau, Proteus and the race to live under the sea

With the ocean a vastly unexplored frontier, two new enterprises are racing to go where no man has gone before and live and work beneath its depths. Renowned aquanaut Fabien Cousteau and UK-based DEEP are building state-of-the-art underwater space stations which could help scientists finally unlock the secrets of the deep. Lucy Dunn investigates.

Our oceans cover more than 70 per cent of the Earth’s surface, but 80 per cent of them are unexplored. In fact, we know more about the surface of Mars than we do about the ocean floor. Some 90 per cent of ocean species are yet to be discovered – we have identified around a quarter of a million of them, but some scientists estimate that there could be millions more.

All this could be about to change. While Elon Musk et al have been busy looking up into space, several projects have been looking down, planning underwater habitats – like international space stations but in the deep sea – for scientists to live and work and accelerate our understanding of the ocean; a new kind of space race, but one much, much closer to home.

The two frontrunners are Proteus and DEEP, a UK-based company designing a deep-sea base called Sentinel. Potentially to be based in the Mediterranean in 2027, the modular habitat will be “recoverable, reconfigurable and redeployable”, says DEEP.

Across the Atlantic, with a similar timescale for launch, Proteus will be situated in Curaçao, an island in a marine-protected park north  of Venezuela. The project is the brainchild of Fabien Cousteau, grandson of diver and film-making pioneer Jacques Cousteau.

“The ocean is the great barometer of this planet. It is the provider of almost everything that we depend on,” says Fabien. “It is the reason we breathe – 60 per cent of our oxygen comes from the ocean or more. It is the mitigator of weather patterns, why we have rain. It is why we can grow things on land…” Plugging this knowledge gap is key, he says. “How can we make decisions, whether it’s for business or economics, for environmentalism, for conservation,  if we don’t even know what we’re starting with?”

Susan Casey, The New York Times bestseller and author of new book The Underworld, agrees. “I call the deep ocean the motherboard of the planet; without understanding the workings of it, we really don’t have a clue about anything else. All the models we have that are used for climate, that are used for understanding various ecosystems within it, they’re only as good as the information we can put into them, and that information is not going to be very good if we’ve never been there and don’t know anything about it.”

If building underwater habitats sounds like the stuff of science fiction, it isn’t; dwellings like these have been around for a long time. In 1963 Cousteau’s grandfather famously built and lived for 10 days in Conshelf II, a 10-metre deep “village” at the bottom of the Red Sea. It was the first time human beings had spent any length of time underwater and, since then, over 60 habitats have been constructed, although most have been abandoned or fallen into disrepair, funding lost and ploughed into the space race.

One of the last standing is the small, ageing underwater lab Aquarius in the Florida Keys, which is still used to host research missions. Astronaut Tim Peake visited there while learning how to cope with confined spaces in extreme environments. In 2014 Cousteau set a new world record there, spending 31 days underwater – which is where his idea for Proteus was born. “The only way I could see learning more about the ocean is to spend more time there; to go out eight, 10, 12 hours a day to explore that final frontier on our planet. With Mission 31 we were able to do over three years’ worth of scientific experiments in 31 days, which is mind blowing,” he says.

The sea is full of amazing things that could help humankind, he says, such as the “solar snail”, a particular favourite of his. “It lives in the deep-sea hydrothermal vents in the Indian Ocean and is the only animal in the world to secrete iron armour. It has these iron scales on its foot and, it turns out, these scales have photovoltaic properties and are now being looked at as a solar energy-gathering device.” He says marine animals could have almost endless applications in terms of biotechnology, biomimicry and new ideas about engineering. “The ocean is this reservoir of four billion years of evolution. I feel that the future of humankind, in terms of engineering, is very much a biological future.”

The pharma industry is also turning its attention to the deep with its potential to unlock new antibiotics: several marine-sourced anti-cancer drugs are already in circulation. And, while not your typical mushrooms growing under trees, recent research has proved that the ocean is full of fungi. Like penicillin, an antibiotic that originally came from the fungus Penicillium, these organisms could have huge potential not only for drugs, but Fabio Favoretto, a postdoctoral researcher at the Scripps Institution of Oceanography, points out, they could “create other components that we can use for our own good”.

Alex Rogers, science director of Ocean Census, a global initiative to accelerate the discovery and protection of ocean life, believes that an underwater habitat where scientists could live means they could tackle a much larger volume of work. “At the moment, even if you’re diving with technical dive equipment, your time on the ocean floor is very limited because you have to decompress for many hours on the way up,” says Rogers. “These habitats would completely free you up in terms of time.” Scientists could also work on samples in the onboard laboratory – materials that are brought back to the surface can have a tendency to decompose.

He is excited at the prospect of what these might mean for science. “At the moment discovery rates are somewhere between 1,000 and 2,500 species a year, a rate that’s not changed for the last 150 years. We really need to accelerate that rate. Because, as everyone knows, the ocean is under increasing human impact.”

Favoretto sees the advantages of these habitats, but cautions that building will not be easy: both projects, still in planning stages, will require significant funding. “It is really expensive to go underwater. That is why we have been to the moon first. Even if we said it was hard to go to the moon, it was harder to go to the deep sea.”

Whereas Proteus will sit at a depth of about 20 metres – with a deeper satellite module at 70 metres – DEEP says Sentinel will be designed to sit anywhere on the ocean’s continental shelf down to 200 metres. Both habitats will sit in an area called the Sunlit Zone where 90 per cent of marine species are found; too deep for most divers, but too shallow to justify the cost of deep-water robots, meaning it is very understudied.

Like Sentinel, Cousteau’s station will also be modular, expanding to accommodate up to 18 people, or “aquanauts”, as Cousteau calls them.

As well as an on-site observatory and research lab, it will feature living quarters and a medical bay. An umbilical will connect the station to a mission control on land. There will be windows and a front door in the form of a moon pool, an entrance open to the water outside. Curaçao was chosen as a site because it is near one of the only actively growing coral reefs in  the Caribbean and the hope is it will provide insights on how to preserve and protect coral reefs.

Both companies say the habitats will be hired out to scientific institutions as well as wealthy private individuals. Deep-sea mining companies are only interested in more extreme depths where only robots can visit, so are unlikely to want to use them. Unlike a pressurised sub, both Proteus and Sentinel will be ambient, meaning they will be the same pressure as the pressure outside; Cousteau likens it to a “submerged cup with air trapped inside”. 

Aquanauts won’t need to spend time in a decompression chamber every time they pop out to dive and will be in a state of saturation – their bodies adjusting to the pressure. When they are ready to come up to the surface, they will need to decompress before returning to sea level. Habitats deeper than 20 metres, however, will need to be a mix of helium and oxygen. Divers will require special training for those conditions, as well as diving equipment and heating systems to combat the cold.

For Susan Casey, the jury’s out whether the habitats will be good for science. “My basic opinion is that anything that gets people into the ocean, and particularly into the deep ocean, I’m all for it.” However, she wonders about the efficacy of having a tethered habitat, compared with an unattended deep-sea observatory with robots and cameras streaming to the surface 24/7. “Is there something different or more valuable that would come from us sitting down there or witnessing this for a week here, a week there?” she wonders.

Against the backdrop of the Titan tragedy – the submersible that imploded in June 2023, killing all five people on board – there’s no doubt these structures will need to overcome significant challenges, from ensuring robust life-support systems to building structures in extreme environments to withstanding corrosion and pressure. And that’s before the physiological effects of people spending time at the bottom of the ocean are taken into account.

Dr Joseph Dituri has first-hand experience of this. Last year, the assistant vice-president at University of South Florida and former US Navy diver spent 100 days underwater at a facility in Key Largo as part of a research project looking at the effects that hyperbaric pressure has on the body; data that will ironically be as important for medicine as well as space explorers.

“It’s important to our civilisation for the future,” he says. “Elon Musk says we’re going to Mars. And I’m like, I have a question: what happens to the person when you stick them in a tube for 100 or 200 days?”

Dituri set out to discover if the increased pressure has the potential to help humans live longer and prevent ageing-related diseases. Undergoing rigorous medical tests each day, he and his team discovered that his telomeres – structures on chromosomes linked to extending life – got longer. “I went in with the extrinsic age of 44 and came out as a 34-year-old,” he says. He also found that the pressure caused him to shrink three-quarters of an inch, and noted a drastic improvement in his sleep, cholesterol levels and inflammation levels.

One of his most important findings was that the body has physiological time limits under saturation. “We’re approaching human tolerance for living underwater at 100 days,” he says. “The gas that I was breathing was air, but because you have to compress it so many times to get to the depth that you’re at, you have a higher partial pressure of oxygen. That increased partial pressure of oxygen leads you to something called pulmonary oxygen toxicity.”

Despite the challenges, both projects are marching on at pace. Plans are afoot for a Sentinel prototype and Proteus has already laid the groundwork, scoping out a site and installing sonar sensors in the area. “There’s underwater weather, just as there’s weather on the surface, but we often don’t record that,” explains Brian Helmuth, chief scientific officer at Proteus. “And so we’re putting out the capability to record those environmental conditions and the biological responses to get ready for the research that we do once Proteus is up and running.”

Helmuth, who worked with Cousteau on his Mission 31 project, can’t wait to get back down there. “After you’ve been living underwater for about three days, you feel like you’re part of the ocean ecosystem, it’s as close to feeling like an ocean animal as you can get. You get to know all the fish around you. You name them. They get used to you and come up to you. We had one mission where a pod of dolphins followed us around on every dive. A moray eel would sit under my legs while I was doing work.”

He believes Proteus will be a huge step change from anything done before. “Previously we’ve survived on the bottom, but what we’re planning is to actually thrive and live for extended periods of time. I really can’t wait to be down there for a long period of time and to be able to share that with the rest of the world.”

First published in the October 2024 issue of BOAT International. Get this magazine sent straight to your door, or subscribe and never miss an issue.