Mir (Russian: Мир, lit. 'world, peace') was a class of two self-propelled deep-submergence vehicles. The project was initially developed by the USSR Academy of Sciences (now the Russian Academy of Sciences) along with Lazurit Central Design Bureau, and two vehicles were ordered from Finland. The Mir-1 and Mir-2, delivered in 1987, were designed and built by the Finnish company Rauma-Repola's Oceanics subsidiary. The project was carried out under the supervision of constructors and engineers of the Shirshov Institute of Oceanology.
Characteristics The vessels are designed to be used for scientific research. They might also be used to assist in submarine rescue operations, although they do not have the capacity to take anybody aboard when underwater. The carrier and command centre of both Mir submersibles is the R/V Akademik Mstislav Keldysh. The two Mir units are operated by the Russian Academy of Sciences. Their military counterparts are the Konsul-class submersibles. The Mir submersibles can dive to a maximum depth of 6,000 metres (19,685 ft). Traditionally, the personnel sphere of a deep sea submersible is manufactured of titanium plates that are welded together. On Mir, the personnel sphere is made of a maraging steel alloy that has ten percent better strength/weight ratio than titanium. This alloy contains about 30% cobalt and smaller amounts of nickel, chrome and titanium. Two hemispheres were made by casting and machining, and then bolted together, thus avoiding welded joints. The resulting construction is close to the density of water, thus making it easier to move in different depths. Additional buoyancy is provided by 8 cubic metres (280 cu ft) of syntactic foam. Unlike other deep submergence vehicles that use iron ballast to reach the ocean floor, the buoyancy and depth is adjusted by ballast tanks.
The Mir submersibles are 7.8 m long, 3.6 m wide, 3.0 m high, and weigh 18,600 kg (maximum payload is 290 kg). The personnel sphere's walls are 5 cm thick, and the inside diameter of the working area is 2.1 m. Three viewports are provided (viewport material is 18 cm thick): the forward-facing port is 20 cm diameter; the two side-facing ports are 12 cm diameter each. Power is provided by NiCad batteries of 100 kWh capacity. Electric motors drive hydraulic pumps to actuate hydraulic manipulators and three propulsors. The aft hydraulic propulsor is rated at 9 kW and 2 side propulsors are rated at 2.5 kW each. Maximum underwater speed is 5 knots. Longitudinal trim is controlled using two spherical water ballast tanks, fore and aft. Water can be forced out of these tanks as required by using compressed air. Air pressure inside the cabin remains at a constant one atmosphere: the air is recycled in a manner similar to that used on board spacecraft, with lithium hydroxide scrubbers removing accumulated carbon dioxide. VHF radio is used to maintain communication with the surface. The units contain imaging sonar units of 250 metre range, so nearby objects can be visualized and their distance measured. The distance to the seabed can also be accurately measured when nearing touchdown. The units' life-support systems have 246 man-hour capacity, or 3.42 days for a three-person crew. The units are designed for pressure at 6,000 metre depth, and have been tested to 125% of that pressure. In field testing, Mir-1 descended to 6,170 m and Mir-2 descended to 6,120 m. Originally the hydraulic manipulators were covered by a helmet-like retractable see-through visor, but these were removed in a major overhaul in 1994. The submersibles change depth at a maximum vertical speed of 40 metres per minute, so several hours are required to travel to and from deep sites.
Finnish-Soviet co-operation
Production of the two Mir units was a prime example of Finnish-Soviet economic and technical co-operation during the Cold War. The technical specification for the creation of the devices was prepared by the head of the Department of Deep-sea Habitable Vehicles of the Institute of Oceanology of the USSR Academy of Sciences, project manager Igor Mikhaltsev. The main ideas on the design of the submarines, the arrangement of its individual systems, nodes, elements, and the acquisition of scientific and navigation equipment belong to I. E. Mikhaltsev, his deputy A.M. Sagalevich and the chief engineer of the project from the Finnish shipbuilding company Sauli Ruohonen, who headed a group of Finnish engineers and technicians who participated in the construction of the submarines. Bids from Canada, France and Sweden to construct the submarines had been retracted most likely due to political pressure. In a later interview with STT the then Rauma-Repola department head Peter Laxell said he believed that "Finland got the permit to deliver the crafts to the Soviets on the basis that the CoCom officials in the USA believed the project would be a failure ... Once it became clear to them we actually had accomplished the engineering feat there was a huge uproar about how such technology could be sold to the Soviets, enough for many visits to the Pentagon." Because of the CoCom restrictions, most of the technology used had to be developed in Finland. The electronics was developed by Hollming. The syntactic foam was produced in Finland by Exel Oyj, as 3M, the leading producer, refused to supply their product. The construction, including casting, was done by Lokomo (a Rauma-Repola subsidiary) in Tampere, Finland. The level of technology flowing into the Soviet Union raised concern in the US and Rauma-Repola was privately threatened with economic sanctions. For example, one concern of the Pentagon was the possibility that the Soviet Union would manufacture a pioneer submarine fleet that could clear the ocean floor of US deep sea listening equipment. With the possibility of losing its lucrative offshore oil platforms market Rauma-Repola yielded, and submarine development ceased in Finland. One project that was abandoned was the development of a fuel cell based air-independent propulsion system. The 122 m length support vessel R/V Akademik Mstislav Keldysh was also built in Finland, at the Hollming shipyard in Rauma in 1980 (later operated by STX Finland, closed in 2014).
Expeditions
… excerpt ends here. Continue reading the full article.
