Aquanaut

An aquanaut is any person who remains underwater, breathing at the ambient pressure for long enough for the concentration of the inert components of the breathing gas dissolved in the body tissues to reach equilibrium, in a state known as saturation. Usually this is done in an underwater habitat on the seafloor for a period equal to or greater than 24 continuous hours without returning to the surface. The term is often restricted to scientists and academics, though there were a group of military aquanauts during the SEALAB program. Commercial divers in similar circumstances are referred to as saturation divers. An aquanaut is distinct from a submariner, in that a submariner is confined to a moving underwater vehicle such as a submarine that holds the water pressure out. Aquanaut derives from the Latin word aqua ("water") plus the Greek nautes ("sailor"), by analogy to the similar construction "astronaut". The first human aquanaut was Robert Sténuit, who spent 24 hours on board a tiny one-man cylinder at 200 feet (61 m) in September 1962 off Villefranche-sur-Mer on the French Riviera. ^[1][2][3]

Military aquanauts include Robert Sheats, author Robin Cook, and astronauts Scott Carpenter and Alan Shepard. Civilian aquanaut Berry L. Cannon died in 1969 of carbon dioxide poisoning during the U.S. Navy's SEALAB III project.^[4][5][6]

Scientific aquanauts include Sylvia Earle, Jonathan Helfgott, Joseph B. MacInnis,^[7] Dick Rutkowski, Phil Nuytten, and about 700 others, including the crew members (many of them astronauts) of NASA's NEEMO missions at the Aquarius underwater laboratory.

A unit of the Russian Navy has developed an aquanaut program that has deployed divers more than 300 metres (980 ft) deep. An ocean vessel has been developed and is based in Vladivostok that is specialized for submarine and other deep sea rescue and that is equipped with a diving complex and a 120-seat deep sea diving craft.^[8]

A Nigerian ship's cook, Harrison Odjegba Okene, survived for 60 hours in a sunken tugboat, the Jascon-4. The vessel, which capsized on 26 May 2013 due to strong ocean swells, had been performing tension tow operations and stabilising an oil tanker at a Chevron platform in the Gulf of Guinea^[9] (in the Atlantic Ocean), about 32 km (20 mi) off the Nigerian coast.

After sinking, the boat came to rest, upside-down, on the sea floor at a depth of 30 m (98 ft). Eleven crew members died. However, in total darkness, Okene felt his way into the engineer's office, where an air pocket about 1.2 m (3 ft 11 in) in height contained enough oxygen to keep him alive. There, he fabricated a platform from a mattress and other floating objects, keeping his upper body above the water to help reduce heat loss.^{[10][11][12][13]}

Three days after the accident Okene was discovered by South African divers Nicolaas van Heerden, Darryl Oosthuizen and Andre Erasmus from the Lewek Toucan, a saturation diving support vessel, employed to investigate the scene and recover bodies. Upon entering the engineer’s office, van Heerden saw a hand, which he assumed to be a corpse. As he pulled on the hand, van Heerden realised the hand was grasping onto his. Immediately, the diver surfaced within the air space to speak with and devise a rescue plan with his supervisor and Okene. The rescuers realised the only practicable option was to provide Okene with a diving helmet so he could breathe during the transit to the diving bell. After swimming out of the shipwreck, Okene was locked into a closed diving bell and returned to the surface for decompression from saturation Okune lost consciousness during the transit to the bell but recovered and was successfully decompressed, which took about two and a half days. Experts estimated that given the volume of trapped air Okene was living in underwater, the increased partial pressure of oxygen due to the depth, and some carbon dioxide absorption by the water surface, he possibly had two or three days’ worth of oxygen remaining.^[9][14]

After his ordeal underwater he faced and overcame his nightly terrors by becoming a commercial diver himself, earning a International Marine Contractors Association recognised Class 2 certificate.^[15]

• Continental Shelf Station Two – Undersea research habitat in the Red Sea
• Jacques Cousteau – French naval officer, oceanographer, filmmaker and author (1910-1997)
• World Without Sun – 1964 film by Jacques Cousteau
• La Chalupa Research Laboratory – Primary platform for the Scott Carpenter Man in the Sea Program
• Astronaut

• Arctic IV (1975), documentary about Joseph MacInnis' Arctic dive
• Information article from Tass about Soviet aquanautic program