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Planning joint mission of Soyuz-4 and -5

At the beginning of November 1968, Soviet officials overseeing the Soyuz 7K-OK project finally gave the official green light to the second attempt to dock two spacecraft and transfer part of the crew from one ship to the other. Despite the fact that the previous rehearsal mission of the Soyuz-3 spacecraft in October 1968 had not resulted in a successful docking, the leaders of the program were now confident in the original flight scenario, which had remained unfulfilled since the Soyuz-1 tragedy in April 1967.

Previous chapter: Aftermath of the Soyuz-3 mission


A simplified scale model illustrating transfer between the two Soyuz spacecraft.

Exactly as it was planned in the original attempt in 1967, the first Soyuz was to carry a single pilot, followed 24 hours later by a second spacecraft with three cosmonauts aboard. The first spacecraft, production number 12, which would become Soyuz-4, was equipped with an active docking mechanism and it was charged with all the maneuvering during the rendezvous. In the meantime, the second spacecraft (Vehicle No. 13 or Soyuz-5) — would be carrying the passive half of the docking system and be responsible for maintaining the correct orientation during berthing.

Following their docking in orbit, two cosmonauts on Vehicle No. 13 would don their spacesuits, exit the ship and transfer to Vehicle No. 12, which would then carry them back to Earth. The second Soyuz (No. 13) would land with the remaining single pilot onboard. At the end of 1968, the joint Soyuz flight was still considered to be a rehearsal for the L3 lunar expeditionary project, because its flight scenario required the two-way transfer of a pilot from the Lunar Orbital Spacecraft to the Lunar Lander.


Crew transfer scenario during the joint Soyuz mission.

Taking lessons from the troubled Soyuz-3 flight, mission planners wanted to avoid docking on the first day of the flight to give both crews some time to adapt to weightlessness. This time, the active rendezvous operations were planned on the third day of the mission for active Vehicle No. 12 and on the second day for the crew of Vehicle No. 13.

In another lesson from Soyuz-3, the most crucial rendezvous maneuvers were timed to take place on the sunlit side of the Earth and over the Soviet territory within range of ground stations so that mission control could advise the crew in real time. The pilots were now instructed to pay attention to the position of the main antenna on the target vehicle during the rendezvous and report to the ground its position as "umbrella up" or "umbrella down," which would give mission control an immediate understanding about the mutual attitude of the two ships.

Last but not least, after the initial automated rendezvous, the switch to the manual docking maneuvers was now allowed only at a distance of 100 meters, instead of 200 meters as during the rendezvous between Soyuz-2 and -3. At 100 meters, the ships were expected to be fully leveled relative to each other by the automated system. (849)

On. Dec. 23, 1968, the Military Industrial Commission within the Soviet of Ministers formally appointed Vladimir Shatalov to pilot the active Vehicle No. 12 (Soyuz-4) and Boris Volynov, Aleksei Yeliseev and Evgeny Khrunov to fly aboard the passive Vehicle No. 13, (Soyuz-5). Yeliseev and Khrunov were also training for a spacewalk to perform the transfer from Vehicle No. 13 to Vehicle No. 12.

The backup team was comprised of Georgy Shonin, Anatoly Filipchenko, Viktor Gorbatko and Viktor Kubasov.

Because in previous test flights mission controllers had identified active and passive ships as "A" and "B," the pilots of the upcoming missions were assigned call signs starting with corresponding letters. To the chagrin of Shatalov, the pilot of Vehicle No. 12 was given the call sign "Amur," and Volynov piloting Vehicle No. 13, would have the call sign "Baikal." At some point, Shatalov managed to trade "Amur" for "Granit" (granite), but, apparently, not after his first mission. (231)

The launches of Vehicles No. 12 and 13 were initially scheduled for Jan. 12 and Jan. 13, 1969.


Next chapter: Preparing joint mission of Soyuz-4 and -5

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The article and illustrations by Anatoly Zak; Last update: January 15, 2019

Page editor: Alain Chabot; Last edit: January 14, 2018

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A Soviet-period visuals illustrating transfer between Soyuz 7K-OK spacecraft.


Yeliseev and Khrunov in their spacewalk suits during training.


Volynov (left) and Khrunov apparently training in use of photo and video equipment during preparation for Soyuz-4 and -5 mission.