Functional Cargo Block

The Functional Cargo Block or FGB (from the Russian "Функционально-грузовой блок", ФГБ, "Funktsionalno-gruzovoy blok", FGB, GRAU index 11F77) was part of the Soviet TKS spacecraft. The TKS spacecraft was intended to be used as a resupply craft for Almaz space stations and saw some test flights in the Salyut space station program. The TKS spacecraft was formed by mating a FGB with a VA spacecraft, with both the VA and the FGB being capable of independent operation.

Following the development of the FGB for the TKS spacecraft, the FGB (without VA spacecraft) formed the basis for space station modules in the Soviet and Russian space program – these space station modules are to some extent called Functional Cargo Block (FGB) as well, like the Zarya FGB module.^[1][2]

The FGB provides "functional" support in the form of electrical power, propulsion, guidance and docking; The support for "cargo" operations is supplied in the form of a pressurized habitable cargo storage section (accessible by the crew) and the externally mounted fuel tanks.