Soyuz-B (Russian: Союз-Б meaning Union-B) or Soyuz 9K (Russian: Союз 9К) 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. Following the cancellation of both the Soyuz 7K and P programmes; the former in favour of the LK-1 spacecraft, and the latter in favour of uncrewed anti-satellite programmes, the Soyuz 9K was no longer required, and it too was cancelled.