French novelist Jules Verne's 1869 novel "Twenty Thousand Leagues Under the Sea" is regarded as having thrillingly portrayed the underwater world. It has been 140 years since this novel was published, and while humanity is on the verge of constructing a lunar base, our knowledge of the deep sea has not significantly advanced from what Jules Verne understood. The ocean covers 71% of the Earth's surface, yet only a tiny fraction has been precisely mapped. This is because entering the deep sea is considered more technically challenging and difficult than exploring outer space.
The same is true for an underwater "base." To study the deep sea, humans need to enter it directly, but the high pressure makes this difficult. Although it is most desirable for researchers to stay underwater through a base, there have been very few cases of constructing and operating underwater bases. The only existing underwater base is the Aquarius coral base in the United States. Established by the National Oceanic and Atmospheric Administration (NOAA) in 1986, it is located 18 meters underwater off the coast of Florida. French oceanographer Fabien Cousteau lived there for 31 days in 2014, setting the record for the longest duration anyone has ever spent in an underwater base.
◇British startup "Deep" aims to become the SpaceX of the ocean
After 40 years of inactivity in underwater base development following Aquarius, a new wave is emerging. The British startup "Deep" is at the forefront of this. Deep is working on a project to construct an underwater base where scientists can stay for several weeks, months, or even years at depths of up to 200 meters. Deep aims to be the SpaceX of the ocean. Just as SpaceX created a new history in space development with its groundbreaking technology of reusable rockets, Deep hopes to open a new chapter in deep-sea exploration through the construction of underwater bases.
Deep is pushing forward with the construction of a new underwater base by integrating cutting-edge marine science and engineering technologies. They are developing a modular underwater base known as Vanguard. This module can accommodate three divers for up to one week, and Deep plans to conduct tests in a disused quarry in Chepstow, Wales, during the first quarter of this year.
Kirk Krack, who leads the human diving performance sector at Deep, noted in Spectrum, published by the Institute of Electrical and Electronics Engineers (IEEE), that "when diving at depths of 150 to 200 meters, a diver's actual working time is only 10 minutes, and it takes six hours just for decompression." He added, "Utilizing the underwater base can shorten the time needed for decompression, allowing for significantly longer working hours during the 30 days spent at the base." Krack explained that if scientists can stay longer in the deep sea, it will enhance our understanding of the mysterious marine ecosystem and marine environment, potentially offering clues to solve the climate crisis.
Currently, deep-sea operations are conducted using a method called saturation diving. Divers' bodies are pre-adapted to the underwater pressure using a pressure chamber installed on a surface vessel before descending via underwater transport equipment. Because divers must withstand the high pressure underwater, their working time is inherently limited. After the diving operations, divers must undergo decompression to match surface atmospheric pressure, which can also take several hours. When performing deep-sea diving, a mixed gas of helium and oxygen is used instead of nitrogen, as nitrogen can cause decompression sickness at high pressures. Although this complex procedure is followed, the working time available in the deep sea remains very short, leading to low efficiency.
Deep plans to enable divers to work underwater for a week without needing to surface by utilizing a module called Vanguard. Unlike the Aquarius base, Vanguard is designed as a modular form that can be installed in necessary locations and retrieved later. When installed close to shore, it can receive power through cables from the land; when placed farther out to sea, it can generate its energy using floating renewable energy generation facilities and fuel cells. A mixed gas of oxygen and helium is stored in tanks on the ocean floor, allowing divers to use it at any time.
Deep also employed advanced manufacturing technologies to withstand the high pressure of the deep sea. They developed a new process called Wire Arc Additive Manufacturing (WAAM), which combines metal additive manufacturing and welding by using robots. In this method, metal layers are stacked in a 3D printing manner, while each layer is fused using a Metal-Inert Gas (MIG) torch. Deep is also developing another underwater base called Sentinel, which connects multiple Vanguards. Krack stated that "the goal is to establish a base by the ocean where humans can permanently reside by 2030."
◇An underwater base is also emerging in front of Ulsan
The underwater base is not just a project of distant countries. South Korea is also making progress in constructing an underwater base. The Korea Institute of Ocean Science and Technology (KIOST) is pursuing underwater base construction off the coast of Ulsan. This large project is led by KIOST and involves 23 institutions, including Lotte Engineering & Construction, Hyundai Engineering & Construction, Ocean Space, Korea Aerospace Research Institute (KARI), Shipbuilding and Marine Plant Research Institute, SK Telecom, and Soonchunhyang University Hospital.
Han Taek-hee, the project leader and a senior researcher at KIOST, said, "The underwater space platform is a culmination of various advanced marine science technologies intertwined together, similar to a space station." He noted that, "We completed the design for the underwater base construction by last year and plan to place the order in the second half of this year, aiming for construction to begin next year and completion by 2027."
The underwater base that KIOST is promoting differs from Deep's concept. Deep's model involves scientists or divers acclimating to the pressure of the underwater base, whereas KIOST designed its underwater base to maintain an internal pressure equivalent to one atmosphere, similar to that at the surface, removing the need for separate depressurization.
Han stated that in the first phase, scheduled for completion in 2027, they have designed the underwater base to allow three researchers to stay for a maximum of 28 days at a depth of 30 meters. If the project expands in phases two and three, the base's capacity will increase to accommodate 30 to 70 researchers at a depth of 100 meters.
The underwater base can be utilized not only for marine scientific research but also for operating data centers, health monitoring, and a variety of other fields. KIOST plans to operate one module of the underwater base as a data center. Ground-based data centers consume substantial energy for cooling to dissipate heat, but constructing a data center underwater, where temperatures are inherently lower, can save energy required for cooling. Han noted, "It's also important to monitor whether the underwater base data center module is functioning properly and whether cooling efficiency meets expectations."