Underwater research submarine (MIR)

Mir is a pair of crewed deep-submergence research submersibles, Mir-1 and Mir-2, built in 1987 by Rauma-Repola’s Oceanics subsidiary in Finland for the USSR Academy of Sciences. Each carries three people to a test depth of 6,000 meters, reaching about 98 percent of the world ocean floor; the pressure sphere is a maraging-steel alloy and buoyancy comes from syntactic foam. A unit displaces 18.6 tons on 7.8 meters length, runs a 9 kW electric drive at about 5 knots, and works from the mother ship R/V Akademik Mstislav Keldysh. The two Mirs filmed the Titanic wreck and in 2007 dived under the North Pole ice.