This shift occurred after Site 1/5, also known as Gagarin's Start, failed to secure funding for upgrades to accommodate the slightly larger Soyuz-2 rocket.

The numbering of the sites reflected Baikonur’s role as a secondary ICBM base, with the primary being the Plesetsk Cosmodrome, which featured four launch complexes.

This included an assembly building, a processing facility for nuclear warheads, a diesel-powered energy plant, and a nearby residential complex.

The flame trench was scaled down, and assembly and support facilities were closer to the launch pad to improve efficiency and streamline operations.

[1] As the R-7's role as a nuclear delivery system diminished, Site 31 was repurposed to support orbital launches, including those carrying cosmonauts.