Tags: Space Station.
DOS-2 designation given to a space station launched as part of the Salyut programme which was lost in a launch failure on 29 July 1972 when the failure of the second stage of its Proton-K launch vehicle prevented the station from achieving orbit it instead fell into the Pacific Ocean. The station which would have been given the designation Salyut 2 had it reached orbit was structurally identical to Salyut 1 as it had been assembled as a backup unit for that station.
