Soyuz-B

Soyuz-B ( meaning Union-B) or Soyuz 9K () was a proposed Soviet spacecraft, which was designed for use as an orbital tug. A number of applications were proposed for it, including use as part of the Soyuz A-B-V complex for crewed circumlunar spaceflight.

The Soyuz 9K was intended to have been launched into low Earth orbit by the Soyuz 11A511 carrier rocket. Following launch, it would have been refuelled by up to three Soyuz-V tankers, before commencing its mission. It was primarily intended for use in boosting crewed Soyuz 7K and Soyuz-P spacecraft into higher orbits; the Soyuz-A onto a circumlunar trajectory for human Lunar exploration, and the Soyuz-P into a higher orbit to intercept and destroy another spacecraft.