Soyuz 4 and 5 Spacecraft Dock in Orbit Summary

  • Last updated on November 10, 2022

By pioneering the manual docking and crew transfer of a two-person spacecraft, the Soyuz 4 and 5 mission revealed a key Soviet policy shift favoring orbital space stations.

Summary of Event

On January 16, 1969, two Soviet spacecraft, Soyuz 4 and Soyuz 5, docked in orbit. The ships named Soyuz (“union”) remained connected for four hours and thirty-five minutes, while two cosmonauts emerged from Soyuz 5, performed a limited number of exterior tasks, and entered Soyuz 4. After separation, both vehicles conducted additional experiments before returning safely to Earth. The Soyuz 4 and 5 mission achieved the first docking of two piloted ships and the first transfer of crew members to an already-occupied vessel. It also signaled a Soviet policy shift from lunar circumnavigation to orbital space stations. Space program, Soviet;Soyuz program Soyuz program Spacecraft docking Astronauts and cosmonauts [kw]Soyuz 4 and 5 Spacecraft Dock in Orbit (Jan. 16, 1969) [kw]Spacecraft Dock in Orbit, Soyuz 4 and 5 (Jan. 16, 1969) [kw]Soyuz 4 and 5 Spacecraft Dock in Orbit (Jan. 16, 1969) [kw]Orbit, Soyuz 4 and 5 Spacecraft Dock in (Jan. 16, 1969) Space program, Soviet;Soyuz program Soyuz program Spacecraft docking Astronauts and cosmonauts [g]Europe;Jan. 16, 1969: Soyuz 4 and 5 Spacecraft Dock in Orbit[10160] [g]Soviet Union;Jan. 16, 1969: Soyuz 4 and 5 Spacecraft Dock in Orbit[10160] [c]Space and aviation;Jan. 16, 1969: Soyuz 4 and 5 Spacecraft Dock in Orbit[10160] [c]Science and technology;Jan. 16, 1969: Soyuz 4 and 5 Spacecraft Dock in Orbit[10160] Shatalov, Vladimir A. Volynov, Boris V. Khrunov, Yevgeny V. Yeliseyev, Aleksei S.

The mission began at 10:39 a.m. (Moscow time) on January 14, when Soyuz 4 was launched from the Tyuratam missile complex near Leninsk, Soviet Union (now Baykonur, Kazakhstan). The A-2 launch vehicle, a modified intercontinental ballistic missile, placed the 6.6-metric-ton Soyuz spacecraft into an orbit that was 225 kilometers at its farthest point from Earth’s surface (the apogee) and 173 kilometers at its nearest point (the perigee). With Colonel Vladimir A. Shatalov, the command pilot, on board, Soyuz 4 circled the globe every 88.2 minutes, its orbit intersecting the equator at a 51.7 degree angle.

The spacecraft was an upgraded version of a type that had been in piloted use since 1967. Soyuz 4 was cylindrical at the rear (where the service and propulsion elements were housed) and rounded forward. Its front end was divided further into bell-shaped command and spherical work compartments connected by an air lock. Its work compartment contained an exit hatch and an active docking mechanism—that is, a metal probe that could be inserted and locked into the matching receptacle of a second spacecraft. The combined length of the compartments was about 5 meters, with a total volume of approximately 9 cubic meters. The ship’s electrical system was powered by two sets of solar panels mounted toward the back. The spacecraft was aerodynamically modified to allow some maneuvering at descent and had sufficient lift to reduce the force of gravity to three or four times normal from the eight or nine typical of ballistic reentries. It was also provided with duplicate 400-kilogram-thrust liquid rocket engines and multiple parachutes for soft-landing capability and had an enhanced capacity to land in water.

The Soviet news services reported the launch promptly; by 11:30 a.m., a video recording of the event was shown on Moscow television; live television coverage from Soyuz 4 accompanied by Shatalov’s commentary was aired by noon. Observers long accustomed to the operational security surrounding Soviet space activities knew immediately that a politically significant mission was under way. When Shatalov adjusted his orbit to between 207 and 237 kilometers, there was widespread speculation that a rendezvous with a second spacecraft would take place shortly. A television transmission that revealed two empty seats in Shatalov’s spacecraft stirred further conjectures that a transfer of personnel from one spacecraft to another might occur also.

The accuracy of those deductions was soon verified. At 9:46 a.m. on January 15, Soyuz 5 was launched on a matching orbital path with an almost identical apogee, perigee, and orbital period. The second Soyuz spacecraft—a twin of the first except for its recessed, or passive, docking mechanism—carried three crew members: Lieutenant Colonel Boris V. Volynov, the command pilot; Aleksei S. Yeliseyev, the technical scientist; and Lieutenant Colonel Yevgeny V. Khrunov, the engineer pilot. As soon as Soyuz 5 went into orbit, both ships’ automatic systems began a series of small positional corrections. By Soyuz 5’s eighteenth orbit and Soyuz 4’s thirty-fourth orbit, the sequence of automated adjustments brought the two spacecraft within 100 meters of each other. Shatalov, the commander of the active vessel and the overall mission commander, then manually aligned his ship with its partner and completed the docking exercise. At 11:20 a.m., on January 16, the two spacecraft were joined mechanically and electrically and were able to act as a single unit. Although the four crew members were unable to pass from one vessel to another through the docking apparatus, an 18-cubic-meter working area consisting of four compartments was established. The Soviet press described it as the world’s first experimental space station.

Khrunov and Yeliseyev then put on spacesuits and life packs, depressurized the work compartment of Soyuz 5, and passed through the external hatch. The two cosmonauts remained outside the combined spacecraft for about thirty-five minutes, attached to safety cords and using handrails to move about. Observed by the television cameras installed for the benefit of Moscow viewers, they took photographs of Earth and celestial bodies, checked their spacesuits and regenerating life packs, and mimicked the assembly of components that would be required in a permanent orbital space station. Khrunov and Yeliseyev then entered the depressurized work compartment of Soyuz 4 through its external hatch, repressurized it, and joined Shatalov in the command compartment. The entire transfer operation, including the release and replenishment of air in the two work compartments, took about one hour. Soyuz 4, which had left Earth with one crew member on board, now had three. Soyuz 5, which had lifted off with a crew of three, now had one. At 3:55 p.m., after four hours and thirty-five minutes of docking, the two spacecraft uncoupled and continued their flight paths in tandem.

The remainder of the Soyuz 4 and 5 mission was occupied with rest periods alternating with system checks, medical experiments, and terrestrial and celestial observations. Shortly before 9:00 a.m., on January 17, Shatalov began the descent sequence for Soyuz 4; within the hour, the three cosmonauts landed safely in the Kazakh uplands. Shatalov described the landing as exceptionally soft and trouble-free. Soyuz 4 returned to Earth on its forty-eighth orbit after a flight time of seventy-one hours and fifteen minutes.

Volynov, left in sole occupation of Soyuz 5, remained in space about twenty-six hours after the descent of Soyuz 4. Throughout the afternoon of January 17, he conducted television interviews, carried out additional medical tests and observations of Earth and heavenly bodies, and adjusted his spacecraft’s orbit to 229 kilometers by 201 kilometers. Following a shortened rest period, Volynov then began the reentry process. At 11:00 a.m. on January 18, he landed safely at the edge of the Kazakh uplands. Soyuz 5 ended its mission on its forty-ninth orbit, after a voyage lasting seventy-two hours and fifty-four minutes.

On January 19 the Soviet press summarized the major characteristics of the Soyuz 4 and 5 mission. These features included the successful completion of detection, maneuvers, rendezvous, and docking of the two spacecraft; creation of an inhabited experimental space station in orbit; transfer of two cosmonauts from one spacecraft to another; checking and testing of spacecraft systems and components; and conducting of scientific observations and experiments. Spokespersons for the Soviet Academy of Sciences laid particular emphasis upon the value of the crew transfer, stating that it had important implications for the supply, maintenance, replacement, or rescue of the crews of future piloted orbital stations.


The success of the Soyuz 4 and 5 mission gave the Soviet cosmonaut program a much-needed morale boost. Soviet-piloted space exploration had been in disarray since the death of Colonel Vladimir Komarov in the Soyuz 1 mission on April 24, 1967, and the only piloted attempt since then (the Soyuz 2 and 3 mission in October, 1968) had been an operational disappointment. The Soyuz 4 and 5 mission promised to inaugurate a new, dynamic phase of the Soviet space program. The uncharacteristic winter launch and the prompt, thorough media coverage indicated that the Soviet leadership had gained complete confidence in the redesigned Soyuz spacecraft and its support mechanisms. The mission was also a significant event in the strenuous Soviet-American space rivalry of the 1960’s, for it upstaged a manual docking and crew transfer by Apollo 9 astronauts in March of 1969.

While the Soyuz 4 and 5 mission was an obvious success, the magnitude of its technological achievements was unclear. Some Western analysts asserted that the linkup was not a true orbital space station. They pointed out that its orbit would have decayed in about ten days, that no part of a Soyuz craft could be left behind for future visits, and that linked compartments of a space station should have an internal docking tunnel. Others noted that docking maneuvers were not new: Two unpiloted Soyuz spacecraft, Kosmos 186 and 188, had performed automatic docking in October, 1967; and in April, 1968, another unpiloted Soyuz spacecraft, Kosmos 212, docked automatically with an unpiloted craft. Furthermore, an American docking of a piloted spacecraft with a satellite had been accomplished in March, 1966, by the Gemini VIII mission, and a Gemini X crew member had performed a ship-to-ship spacewalk while inspecting a connected Agena satellite.

Finally, the experiments and observations conducted by the Soyuz 4 and 5 mission were difficult to evaluate on their own merits, for they were part of a systematic, long-range research program. It was apparent, however, that the four Soviet cosmonauts performed their difficult sequential tasks with great competence and that the manual docking and transfer of crew members between two occupied spacecraft were important and original achievements.

The mission also signaled a long-term shift in the goals of the Soviet space program. Until the Soyuz 4 and 5 docking, Westerners assumed that the Soviet Union was preparing to send cosmonauts around the Moon. Soviet actions seemed to confirm that view: In September, 1968, Zond (“probe”) 5, an unpiloted Soyuz-like spacecraft, was dispatched on a lunar voyage; and in November, Zond 6 repeated the exercise with a reentry speed that could be tolerated by cosmonauts.

The intent of the Soyuz 4 and 5 mission, however, was unmistakable. The Soviets had decided to concentrate on piloted orbital space stations, with their undeniable scientific, military, and industrial attractions, and leave the first piloted circumlunar flights to the United States. A well-established and well-funded set of priorities connects the Soyuz 4 and 5 mission to the increasingly significant and technologically sophisticated Salyut (“salute”) and Mir (“world” or “peace”) space stations of the 1970’s and 1980’s. Space program, Soviet;Soyuz program Soyuz program Spacecraft docking Astronauts and cosmonauts

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Bond, Peter R. Heroes in Space: From Gagarin to Challenger. New York: Basil Blackwell, 1987. An excellent, detailed treatment of the piloted space missions of both the United States and the Soviet Union. Bond’s work, which covers the Soyuz 4 and 5 mission in detail, is an excellent general treatment. Contains diagrams, maps, notes, illustrations, an appendix of Soviet and American piloted spaceflights, and an index.
  • citation-type="booksimple"

    xlink:type="simple">Hall, Rex D., and David J. Shayler. Soyuz: A Universal Spacecraft. New York: Springer, 2003. The first comprehensive work in English on the Soyuz program. Traces the history of the Soyuz spacecraft’s development since 1967. Details design modifications, and includes many photographs and illustrations. Appropriate for all reading levels.
  • citation-type="booksimple"

    xlink:type="simple">Johnson, Nicholas L. Handbook of Soviet Manned Space Flight. San Diego, Calif.: Univelt, 1980. Volume 48 in the American Astronautical Society’s Science and Technology series is an excellent introduction to Soviet piloted space missions from their beginnings through 1979. Johnson provides an in-depth treatment of the Soyuz 4 and 5 docking. Contains illustrations, charts, diagrams, notes, appendixes listing launches and launch facilities, and an index.
  • citation-type="booksimple"

    xlink:type="simple">Lewis, John S. Space Resources: Breaking the Bonds of Earth. New York: Columbia University Press, 1987. This well-written popular work is a survey of space exploration to 1986, an overview of the technological factors affecting American and Soviet space policies, and an extended argument in favor of the exploitation of space. It places the Soyuz flights in the context of all space missions. Contains an appendix of human-related launchings and an index.
  • citation-type="booksimple"

    xlink:type="simple">Oberg, James E. Red Star in Orbit. New York: Random House, 1981. An unflattering treatment of the Soviet space program by an American space authority. Coverage of the Soyuz 4 and 5 mission is dismissive in tone. Includes illustrations, short biographies of cosmonauts, a list of Soviet-piloted missions, an annotated bibliography, and an index.
  • citation-type="booksimple"

    xlink:type="simple">Riabchikov, Evgeny. Russians in Space. Translated by Gay Daniels. Garden City, N.Y.: Doubleday, 1971. Presents the official viewpoint of the Soviet government regarding space exploration. While unabashedly partisan in orientation and argumentative in tone, it is well written and provides interesting anecdotes of the Soyuz 4 and 5 mission. The work contains some inaccuracies, however, and should be read with care. Some illustrations are included.
  • citation-type="booksimple"

    xlink:type="simple">Smith, Marcia S. “The Evolving Role of Man in Space.” In The Space Station: An Idea Whose Time Has Come, edited by Theodore R. Simpson. New York: Institute of Electrical and Electronics Engineers, 1985. An excellent overview of American and Soviet piloted space missions by a noted American authority. Reviews the competitive aspects of the space race without resorting to controversy. Smith emphasizes the development and uses of orbital space stations, thoroughly discussing the evolution of Soyuz spacecraft. Includes illustrations, charts, a bibliography, and an index.
  • citation-type="booksimple"

    xlink:type="simple">Smolders, Peter L. Soviets in Space: The Story of the Salyut and the Soviet Approach to Present and Future Space Travel. Translated by Marian Powell. New York: Taplinger, 1974. A laudatory treatment of the Soviet space program from its inception to the establishment of the Salyut space station. Somewhat polemical in tone but very detailed; it has a good treatment of the Soyuz 4 and 5 mission. Contains numerous illustrations and diagrams, and an index.

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