Korolev was always interested in application of artificial gravity for large space stations and interplanetary craft. He sought to test this in orbit from the early days of the Vostok program. Two Soyuz versions were considered:

• Soyuz 7K-OK, tethered to Block I

• Two Soyuz 7K-OK, which would rendezvous and dock in orbit and then undock, pulling the tether out between them.

Separation of the two components with a rotation of 0.5 degrees/second would produce 0.03 G of artificial gravity. The components would then close to 300 m, reaching 7 degrees/second and 1/6 G. The Voskhod would need additional liquid fuel rocket thrusters fitted to put the components into rotation. The Soyuz would need no special equipment. The two Soyuz scheme was attractive because nose-to nose tethering meant that the BO living module would have the correct vertical orientation for sustained experiments. However he Soyuz would be limited to a maximum of three days of experiments because the batteries would run down since the solar cells could not be kept oriented to the sun during the experiment. After Korolev's death, the project was closed by Mishin on 28 March 1966 and not pursued further.

Mass: 6,400 kg (14,100 lb). Main Engine: KTDU-35.

• 1966 March 28 - Korolev tether projects cancelled - Flight: Voskhod 3, Voskhod 4.
  Korolev was always interested in application of artificial gravity for large space stations and interplanetary craft. After Korolev’s death, the projects to develop tether experiments to be flown aboard Voskhod and Soyuz spacecraft were closed by Mishin and not pursued further.