The Salyut-7 was the last space station of the Soviet Salyut Program and was used as a testbed for the modular Mir space station.
Originally the station was the backup of the Salyut-6 space station. But that mission went as planned and so the station was launched in 1982.
In orbit Salyut-7 suffered from technical failiures and had to be repaired several times.
Despite that the station also hosted several non-Russian cosmonauts as part of the Interkosmos program. Some of these countries were India, France, Syria and Afghanistan.
The model uses the same core model as the Salyut-6. Only extra additions are the supplemental solar panels and some minor details. Overall the model has a medium difficulty.