Zvezda, Salyut DOS-8, also known as the Zvezda Service Module, is a module of the International Space Station (ISS). It was the third module launched to the station, and provided all of the station's life support systems, some of which are supplemented in the US Orbital Segment (USOS), as well as living quarters for two crew members. It is the structural and functional center of the Russian Orbital Segment (ROS), which is the Russian part of the ISS. Crew assemble here to deal with emergencies on the station.

The Salyut programme was the first space station programme, undertaken by the Soviet Union. It involved a series of four crewed scientific research space stations and two crewed military reconnaissance space stations over a period of 15 years, from 1971 to 1986. Two other Salyut launches failed. In one respect, Salyut had the task of carrying out long-term research into the problems of living in space and a variety of astronomical, biological and Earth-resources experiments, and on the other hand the USSR used this civilian programme as a cover for the highly secretive military Almaz stations, which flew under the Salyut designation. Salyut 1, the first station in the programme, became the world's first crewed space station.