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MIR-1 and MIR-2 Submersibles Mark 25 Years of History MIRs Show Versatility in Public and Private Operations By Dr. Anatoly M. Sagalevich T he MIR-1 and MIR-2 submersibles were built by RaumaRepola in Finland from 1985 to 1987, and they have since advanced scientifc and historical understanding among researchers, government and the public. The vehicles were designed by scientists from the P.P. Shirshov Institute of Oceanology of the Russian Academy of Sciences (RAS) and Rauma's engineers. Deepocean trials for the 6,000-meterrated MIRs were conducted in the Atlantic in December 1987, with MIR-1 at 6,170 meters and MIR-2 at 6,120 meters depth. The MIRs have important advantages compared to other submersibles of the same class, including high battery capacity (100 kilowatt-hours), high speed underwater (up to 5 knots) and a ballast system using only seawater. The average time of a MIR dive is 15.2 hours, almost double the duration of other 6,000-meter submersibles. For 25 years, spanning 39 MIRs expeditions and 1,095 dives, the Deep Manned Submersibles Laboratory of P.P. Shirshov Institute of Oceanology RAS has been providing safety, maintenance, repair and piloting for the MIRs. Scientifc Research Deep-ocean research has been conducted with the MIR submersibles at more than 50 sites around the world, including hydrothermal felds in the Atlantic and Pacifc oceans. The MIRs performed dives on 23 sites with benthic hydrothermal vents. Trans-Atlantic Geotraverse Hydrothermal Field. The Trans-Atlantic Geotraverse hydrothermal feld was investigated during four expeditions from 1988 to 2002. A chain of relict hydrothermal hills was found at 3,600 meters depth, The RV Akademik Mstislav Keldysh with the MIRs on board. formed by polymetallic sulfde deposits with high contents of copper, zinc, nickel, cobalt, iron, manganese, gold, silver and other metals. The largest hydrothermal geological formation on the ocean bottom, with about 10 million tonnes of sulfde ores, was discovered there in 1991 and named the MIR underwater mount. Logachev Hydrothermal Field. In 1995, the MIRs discovered deep hydrothermal circulation while diving to the Logachev hydrothermal feld on the Mid-Atlantic Ridge. In the frst dive, the sub crew observed a high-temperature black smoker, where fuid was fowing to the bottom from small craters and spreading along the bottom without rising, as in classical smokers. Analyses of fuid samples showed a high density and high concentration of heavy metals and other chemical elements. On the bottom were found ultrabasic rocks, serpentinites, samples of which were lifted to the surface. www.sea-technology.com DECEMBER 2012 / st 45