Surgeon Aleksandr Khaes entered the Ikhtiandr-66 habitat off Cape Tarkhankut on August 23, 1966, becoming the first Soviet aquanaut to live on the seabed.
The experiment by the Donetsk-based Ikhtiandr diving club proved that humans could survive underwater. It launched a decade of Soviet seabed habitats despite early storms, bureaucratic friction, and police interrogations.
Cape Tarkhankut in Crimea, a coastal steppe ending in steep cliffs above an ancient ship graveyard, served as the launch site. The initial attempt to lower the 1.5-tonne underwater house on August 19 failed when a severe storm scattered its ballast blocks across the bay. Only 30 of the original 100 expedition members remained in the tent camp by late August. Project participant Georgiy Tunin noted that harsh weather could destroy a team just as easily as equipment. Divers working in the ice-cold sea could spend no more than 20 minutes in the water before returning to shore to warm up.
By August 22, the sea calmed, allowing the team to reassemble the habitat. Khaes moved inside the next day under medical supervision led by team doctor Sergey Gulyar, who warned of underwater risks including nitrogen narcosis, high-pressure oxygen, and nitrogen oxide poisoning. Inside the humid habitat, Khaes rested on a bunk, established radio contact, and reported good health. At night, bioluminescent organisms glowed outside the portholes. Khaes later recalled waking up repeatedly in terror after losing spatial orientation, fearing that the securing cables would snap and leave him unable to find the emergency scuba gear on the nearby underwater rock.
Soviet diving enthusiasm in the 1950s
The drive to build underwater habitats began ten years earlier, following the 1956 publication of Jacques-Yves Cousteau and Frederic Dumas's book The Silent World in the magazine Yunost. Historian Natalya Lebina noted that Soviet citizens learned about scuba diving around the same time as the denunciation of Josef Stalin's cult of personality. The subsequent release of Cousteau's documentary film in Soviet cinemas and the production of the AVM-1 Podvodnik-1 breathing apparatus by the Respirator factory sparked widespread interest in diving.
Prominent figures soon joined the movement. Physicist Sergey Kapitsa, later the host of the television programme Evident, Yet Incredible, built homemade scuba gear in the mid-1950s alongside fellow physicist Arkadiy Migdal. Inspired by an Italian breathing set brought to Dubna by physicist Bruno Pontecorvo, they constructed two diving units at the Institute of Atomic Energy, using a compressor fitted to Migdal's Pobeda car to fill the air tanks. Kapitsa conducted his first dive in Koktebel in the summer of 1956, while his mother, Anna Kapitsa, noted in writings that her son was constantly drawing scuba apparatuses and seeking a patent. The two physicists joined an Academy of Sciences expedition to the Far East in 1957 to conduct underwater filming.
Amateur engineers of Donetsk
Cultural interest in the sea grew throughout the early 1960s, reflected in the poetry of Bella Akhmadulina and popular films such as the 1961 adaptation of Amphibian Man and the 1963 comedy Three Plus Two. In Donetsk, members of the Ikhtiandr diving club at the medical institute decided to construct a habitat, jokingly listing author Aleksandr Belyaev and explorer Jacques-Yves Cousteau as the project parents. Khaes, the club leader, conceived the plan after returning from Crimea with ancient amphora fragments recovered from the seabed.
Engineers and staff from the Fedorov Institute of Mining Mechanics and Technical Cybernetics formed the core of the team. The institute director granted permission to use scrap metal and build the structure under the official cover name of a special breathing process training chamber. Club members hand-cut steel plates, built wooden bunks, and assembled electrical wiring. Transported to Cape Tarkhankut on two railway flatcars in July 1966, the completed habitat contained two bunks and a small table.
Official pressure and state backing
After Khaes spent his first 24 hours alone, engineer Dmitriy Galaktionov joined him for two days. Miner Yuriy Sovetov replaced Khaes on August 26, but a rising storm on August 27 forced team leaders to abort the experiment and evacuate Galaktionov and Sovetov to the surface.
Upon returning to Donetsk, the team faced a reprimand because the Underwater Sports Federation had prohibited the trial. Moscow Criminal Investigation Department officers and state investigators questioned several young participants. Club member Yuriy Kiklevich stated that despite intense pressure and interrogations, no team member backed down. News reports by the TASS news agency soon brought positive attention from scientists, the military, and the Ministry of Coal Industry, which viewed the habitat as a model for sealed industrial laboratories.
In 1967, the club deployed the larger, multi-room Ikhtiandr-67 in Laspi Bay near Sevastopol, housing five aquanauts, including Boris Pesok, Yevgeniy Spinov, Georgiy Tunin, Anatoliy Kardash, and Nikolay Garkusha. In September 1967, doctor Mariya Barats and engineer Galina Guseva joined the crew, becoming the first Soviet female aquanauts. The club completed its final habitat project, Ikhtiandr-68, the following year.
The Leningrad Sadko project
Concurrently in 1966, the Leningrad Hydrometeorological Institute created the Sadko habitat. Arriving in Sukhum Bay in late August, the Leningrad team discovered that the Donetsk group had beaten them to the seabed by several days. On September 1, Sadko was placed at a depth of 10 metres. Tests with animals began on September 2, but a storm pushed the habitat down to 45 metres; a dog named Nochka and one rabbit were rescued, while a second rabbit perished.
Human trials ran from September 9 to 11 at a depth of 12.5 metres, involving 16 aquanauts working in pairs for six-hour shifts. In 1967, the team deployed Sadko-2, consisting of two three-metre steel spheres joined together at a depth of 25 metres. Journalist Leonid Repin described the habitat in Komsomolskaya Pravda as resembling a Martian spacecraft on a deserted shore. Aquanauts Veniamin Merlin and Nikolay Nemtsev lived inside for a week. In 1969, Sadko-3, built in a rocket shape, operated for two weeks alongside the Soyuz-6 space mission, housing three men and a stowaway kitten named Kessonka before a storm snapped its mooring cable and sank the empty structure to 40 metres.
The Chernomor underwater laboratory
The Soviet Academy of Sciences Shirshov Institute of Oceanology developed the 100,000-ruble Chernomor laboratory, which replaced the Sadko program. Unlike earlier habitats, Chernomor could submerge and surface autonomously, using retractable hydraulic legs repurposed from Il-18 aircraft landing gear. Researchers tested space rations packaged in tubes under water to study cosmonaut nutrition regimens.
In 1971 and 1972, the upgraded Chernomor-2M set a Soviet record by remaining submerged at a depth of 15 metres for 52 days. Commander Igor Sudarkin recorded in his diary that he missed his family, the colours of land, green grass, and riding a motorcycle through the forest. A severe storm forced an emergency evacuation by tugboats one week short of the planned 70-day goal, leaving the crew to suffer decompression headaches and fatigue during their rapid ascent.
Inflatable habitats and the end of an era
In Moscow, the Delfin diving club, led by Aleksandr Korolyov, developed the inflatable Sprut habitat series between 1967 and 1969. Official supervisors initially resisted the concept, remarking that they did not need a system where 100 people on the surface supported two underwater, preferring instead a ratio of 100 underwater to two on the surface. Sprut-U served as an emergency escape shelter during the Chernomor operations, and subsequent models from Sprut-4 to Sprut-10 conducted under-ice diving trials between 1982 and 1991.
Advancements in automated underwater probes and uncrewed submersibles eventually rendered human-crewed habitats obsolete. Following the dissolution of the Soviet Union in 1991, funding ended, closing the era of Soviet seabed habitation that began with Ikhtiandr-66.
