Feature ArticleMIR-1 and MIR-2 Submersibles Mark 25 Years of History
By Dr. Anatoly M. Sagalevich
The RV Akademik Mstislav Keldysh with the MIRs on board.
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. Deep-ocean trials for the 6,000-meter-rated 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.
Deep-ocean research has been conducted with the MIR submersibles at more than 50 sites around the world, including hydrothermal fields in the Atlantic and Pacific oceans. The MIRs performed dives on 23 sites with benthic hydrothermal vents.
Trans-Atlantic Geotraverse Hydrothermal Field. The Trans-Atlantic Geotraverse hydrothermal field was investigated during four expeditions from 1988 to 2002. A chain of relict hydrothermal hills was found at 3,600 meters depth, formed by polymetallic sulfide 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 sulfide 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 field on the Mid-Atlantic Ridge. In the first dive, the sub crew observed a high-temperature black smoker, where fluid was flowing to the bottom from small craters and spreading along the bottom without rising, as in classical smokers.
Analyses of fluid 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.
On the basis of these data, it was concluded that the present hydrothermal area is located within serpentinized ultrabasic rocks that outcrop on the seafloor, which confirmed that the fluids originate from the upper layers of the mantle. Similar processes were discovered at the Rainbow and Lost City hydrothermal fields in the Atlantic, where the formation of fluids is also based on deep hydrothermal circulation.
Underwater Volcanoes. On the Piipa volcano in the Bering Sea, the MIRs discovered wide fields with methane seeps on the bottom and white chimneys created by ocean crust with deep layers of fluid containing 81 percent methane. Large areas of the bottom, up to 100 square meters, are covered by bacteria. The presence of methane explains the large community of the Caliptogenia clams observed by the MIRs on the Piipa volcano, which is the northern-most location of these species yet known.
New species. The MIRs also discovered new species of marine hydrothermal animals, including Mirocaris keldyshi and Lorania concordia in the Atlantic, Vestimentifera arcovestiidae in the Manus Basin in the Pacific and Caliptogenia Ectenagena extenta in Monterey Bay, California.
The MIRs conducted investigations of the nuclear submarine wrecks Komsomolets, which sunk in the Norwegian Sea at 1,700 meters in April 1989, and Kursk, which sunk in the Barents Sea at 108 meters in August 2000.
Komsomolets. The MIRs arrived at the Komsomolets site one month after the accident. After three dives, the reason for the accident was established and radiation levels were measured around the submarine and inside the bow (torpedo) compartment. To continue this article please click here.
Dr. Anatoly M. Sagalevich is the head of the Deep Manned Submersibles Laboratory at the P.P. Shirshov Institute of Oceanology of the Russian Academy of Sciences in Moscow, Russia. He worked on vehicle design for the MIR-1 and MIR-2 submersibles with Dr. Igor Mikhaltsev and a group of Finnish engineers headed by Sauli Ruohonen.