Kosmos 557 was the third civilian space station (DOS 3) the Soviet Union.
The space station was launched on 11 May 1973, 12:20 UTC from Baikonur on a Proton rocket into orbit. The orbital altitude was 218-266 kilometers at an inclination of 51.6 degrees. However, Cosmos 557 could not be stabilized in orbit because the command transmission was unsuccessful. So they burnt up after eleven days on 22 May 1973 over the Pacific. She therefore received only a code name of the Cosmos series. In the case of a successful start, the station had received a Salyut - designation.