Soyuz 23 was a 1976 Soviet crewed space flight, the second to the Salyut 5 space station. Cosmonauts Vyacheslav Zudov and Valery Rozhdestvensky arrived at the station, but an equipment malfunction did not allow docking and the mission had to be aborted.

The crew returned to Earth, but landed on partially frozen Lake Tengiz, the first splashdown in the Soviet space program. While there was no concern about any immediate threat to the crew, the capsule sank under the surface of the frozen lake, and recovery took nine hours owing to fog and other adverse conditions. The landing marked the only example of an unintentional splashdown of a crewed spacecraft to date.

This is Soyuz's 38th flight, and 22th crewed flight.

The Soyuz is a Soviet crewed spaceship, developed to made manned lunar missions. This version called 7K will fly 4 times on the giant launcher N1, and several tens of times on Proton to fly over the Moon, which will be successful during the mission Zond 4. Soyuz will become the first spacecraft to transport living beings to the Moon during the flight of Zond 5, with two turtles. Subsequently, it is adapted to low orbit and will fly on the Soyuz launcher to serve the Salyut and Mir stations and the ISS.