When we left the Soviet Union they had somewhat successfully landed a probe on Venus and they had completed the automatic docking of two Soyuz 7K-OK spacecrafts. However they did not reach their goal of a circumlunar flight in time for the 50th anniversary of the glorious revolution.
With the success of Kosmos 146 and in spite of the failures of the first three 7K-Ok’s it was now time to plan for a Soyuz manned mission. The planned involved the launch and docking of two piloted Soyuzes. Soyuz 7K-OK production model number 4 was assigned the role of the active vehicle. The active vehicle was supposed to carry one cosmonaut into earth orbit. Twenty-four hours later, vehicle No. 5 (the passive vehicle) carrying three cosmonauts would be inserted in orbit. After rendezvouing, two cosmonauts from vehicle No. 5 would transfer through open space to vehicle No. 4.