Soyuz 8 was part of a joint mission with Soyuz 6 and Soyuz 7 that saw three Soyuz spacecraft in orbit together at the same time, carrying seven cosmonauts.

The crew consisted of commander Vladimir Shatalov and flight-engineer Aleksei Yeliseyev, whose mission was to dock with Soyuz 7 and transfer crew, as the Soyuz 4 and 5 missions did. Soyuz 6 was to film the operation from nearby.

However, this objective was not achieved due to equipment failures. Soviet sources were later to claim that no docking had been intended, but this seems unlikely, given the docking adapters carried by the spacecraft, and the fact that both Shatalov and Yeliseyev were veterans of the previous successful docking mission. This was the last time that the Soviet crewed Moon landing hardware was tested in orbit, and the failure seems to have been one of the final nails in the coffin of the programme.

The radio call sign of the spacecraft was Granit, meaning 'Granite'. This word is apparently used as the name of a reactive or defensive squadron in Soviet military training, and, just like the Soyuz 5, it was constructed and its crew was trained to be the responsive (not entirely passive) or female spacecraft in its docking. Giving military names to the spacecraft was probably a response to an outcry that the commander of the Soyuz 5 made. Further, the word was probably chosen as it begins with a letter following that which starts the call sign of the Soyuz 7; it is the third letter at least of the Greek alphabet, though neither the Russian or Latin alphabets.

Crew

• Vladimir Shatalov (2)
• Aleksei Yeliseyev (2)

Mission Parameters

• Mass: 6646 kg
• Perigee: 201 km
• Apogee: 227 km
• Inclination: 51.7°
• Period: 88.7 min