Kosmos 557

DOS-3 (Originally)

Mission Profile

Kosmos 557 (originally designated DOS-3) was a Soviet civilian space station launched on 11 May 1973 aboard a Proton-K as a potential Salyut follow-on, but the station suffered a propulsion system failure shortly after separation that caused it to consume all its attitude control fuel. Unable to maintain attitude or receive crew, it was given the classified Kosmos designation rather than being announced as a station, and reentered the atmosphere after only 11 days in orbit. Kosmos 557 represented a painful setback that occurred almost simultaneously with the American Skylab launch, compounding Soviet embarrassment in the space station competition. The failure led to improvements in the propulsion systems of subsequent Salyut stations.