While there have been approximately 70 habitats built in 17 different countries, only Jules Undersea Lodge and Aquarius are currently operating. Clearly, there are problems with ambient pressure habitats, making a one-atmosphere habitat critical to the future of undersea living.
Problems with Ambient Pressure Habitats
Virtually all of the habitats developed to date have been ambient pressure habitats where the occupants are exposed to the pressure induced physiological effects of living at depth. The major physiological problem is the saturation of tissues with nitrogen when the occupants of habitats situated at a depth of more than 10 meters remain on-site for more than several hours. Once tissue saturation occurs the diver must gradually decompress. With habitats as shallow as 15 meters this decompression procedure takes up to 20 hours. In deeper habitats decompression can take several days. Insufficient decompression or premature or accidental surfacing will lead to decompression sickness (e.g. "the bends"), a condition that often results in crippling injuries or death.
Occupants of habitats deeper than 15 meters can no longer breath normal air due to the possibility of oxygen toxicity, and so expensive mixed gas mixtures must be supplied. Other problems such as bone necrosis, inert gas narcosis, high pressure nervous syndrome, carbon dioxide poisoning, thermal problems and chronic ear infections increase the risk of living in ambient pressure conditions.
In addition to the potential physical risks, the cost of ambient pressure habitat development, placement, operations, support and maintenance is quite high, and as a consequence few habitats have functioned on a long term basis.
The One-Atmosphere Habitat Solution
The solution to the problems associated with ambient pressure habitats is simply to develop a one-atmosphere habitat system. In a one-atmosphere habitat, the occupants remain at surface pressure regardless of the habitat's depth. Life in a submerged one-atmosphere habitat is no more stressful than life on the surface.
A one-atmosphere habitat is composed of one or more pressure hulls capable of resisting the external hydrostatic pressure of the sea, just as in a submarine or manned submersible. However, a stationary habitat does not require the complex systems that provide a submarine with autonomy. Typically, a one-atmosphere habitat would have normal air supplied from the surface through a pressure resistant pipe. Likewise, power and water is easily routed to the habitat from the surface. And, most importantly, access to the habitat can be through a cylindrical access tunnel. Visitors to the habitat simply walk there, down a series of ramps and steps.
The purpose of a habitat is observation, and with contemporary materials a one-atmosphere habitat for water of shallow to moderate depth can now be built with a large component of transparent acrylic. The capability of habitat visitors to observe the seafloor and the myriad forms of marine life, in both daylight and night, is remarkable.
Habitat occupants who are trained divers can also "lock-out" of the habitat through a lock out chamber that isolates the ambient pressure exit area from the surface pressure habitat. A diver can then explore the local area, in keeping with conventional no-decompression limits, returning later to the habitat and locking back in.
A further possibility is to include a dry-transfer lock so that people and equipment could transfer from the habitat to a submarine.
H2OME - The World's First Sea Floor Residence
Based on the millions of dollars we have spent on the development of the engineering for the Poseidon Undersea Resort, the engineers at U.S. Submarine Engineering LLC have developed the world's first sea floor residence. The structure is circular in plan view with viewports through 360 degrees. The structure contains two levels and is 335 square meters (3600 sq. ft.) in size. Access is by elevator.
Download a brochure on the H2OME.