Energia Buran OS-120

11K25 OS-120

Mission Profile

Energia Buran OS-120 (11K25) was a Soviet concept for a smaller, lighter variant of the Buran orbiter, studied under the Buran program in the late 1980s to reduce development costs and expand the range of missions the reusable orbiter could support. Sharing the Energia's baseline 58.8 m height, 7.7 m diameter, and 2,400 tonne liftoff mass configuration generating 34,840 kN of thrust, the OS-120 would have carried fewer crew and a smaller payload than the full Buran. The concept never advanced beyond preliminary design as the collapse of Soviet funding brought the entire Energia-Buran program to an end by the early 1990s.