- Family: Soyuz
- Length: 46.3 m
- Diameter: 2.95 m
- Launch Mass: 310 T
- Low Earth Orbit Capacity: 8200 kg
The Soyuz STB Fregat-MT was manufactured by Progress Rocket Space Center with the first launch on 2012-10-12. Soyuz STB Fregat-MT has 5 successful launches and 0 failed launches with a total of 5 launches. The 2.1b version adds an upgraded engine (RD-0124) with improved performance to the second stage. First launch took place from Plesetsk Cosmodrome Site 43 on 26 July 2008 with a classified military payload.
The 2.1b/ST version is sometimes called Soyuz ST-B.