Rendezvous and docking of spacecraft followed by the transfer of crews are among the basic skills required for the maintenance of orbiting facilities such as today’s International Space Station (ISS). While today it is routine for the Russian Soyuz spacecraft to perform these functions in support of ISS operations, a half a century ago manned spacecraft had yet to dock and transfer crews. This was accomplished for the first time in January 1969 during the largely forgotten flights of Soyuz 4 and 5 as part of the testing program of this then-new spacecraft.

 

The Soyuz

The origins of the Soyuz spacecraft, including today’s updated Soyuz MS which ferries crews to the ISS, can be traced back to a series of design studies for a manned circum-lunar mission performed at OKB-1 (the Russian acronym for “Experimental Design Bureau – 1”) starting in December 1961 under the direction of the pioneering Soviet aerospace engineer, Chief Designer Sergei Korolev. While the original circumlunar mission was scrapped in 1964 in favor of simpler lunar mission architectures, these studies did lead to the development of a whole family of manned spacecraft based on the Soyuz 7K design for missions in Earth orbit as well as to the Moon beyond. The archetype of the family, designated 7K-OK (where OK is the Russian acronym for “orbital ship”), was officially approved for development by a Military-Industrial Commission (VPK) decree on August 18, 1965.

Chief Designer Sergei Korolev headed OKB-1 which was responsible for many of the Soviet Union’s early space spectaculars. (RKK Energia)

The standard Soyuz 7K design consisted of three modules. At the bottom was the roughly cylindrical service module (SM) with a diameter of 2.7 meters at the base a height of 2.5 meters. It carried the spacecraft’s redundant propulsion and attitude control systems as well as other equipment needed to support the crew and their mission while in orbit. The SM of the 7K-OK was fitted with a pair of wing-like solar panels to recharge batteries which provided power for the spacecraft. Next was the 2.2-meter in diameter, bell-shaped descent module (DM) where the crew would ride during the mission. It was fitted with a heat shield, parachutes and other recovery aids to bring the crew of up to three cosmonauts back to Earth at the end of their mission. On top of this was the roughly spherical orbital module (OM) which provided about five cubic meters of habitable space for the crew during their mission and would be jettisoned before the return to Earth. On top of the earliest versions of the orbital module was a probe-and-drogue type docking system but, with no provisions for an internal crew transfer at this point, the crew would need to perform an EVA to transfer from one ship to another with the OM serving as an airlock. This three-module arrangement maximizes the habitable volume of a spacecraft for a given mass and was even considered in some earlier American Apollo design proposals.

A cutaway drawing of the Soyuz 7K-OK which was the ancestor of the Soyuz MS which still flies today a half a century later. Click on image to enlarge. (RKK Energia)

The Soyuz 7K-OK, with a launch mass of about 6,600 kilograms, would start its ascent protected by a fairing topped with a launch escape system (LES) which would pull the crew to safety in case of an abort during the first 160 seconds of the ascent (see “A Brief History of Launch Aborts”). The launch vehicle for the Soyuz 7K-OK was the 11A511 which would later be known by the name “Soyuz” as well. This launch vehicle is the ancestor of the 14A14 “Soyuz-2” rocket used today. The 11A511, whose development started in 1963, was an improved version of the earlier 11A57 unified launcher which was used to orbit a number of Soviet spacecraft between 1963 and 1976 including the manned Voskhod, which gave this rocket its common name (see “The Mission of Voskhod 1”). Like the earlier Voskhod launch vehicle, the 11A511 was built to a set of strict reliability requirements known as the “3KA Regulations” so that the launch vehicle was man-rated from the start. The 11A511 with the Soyuz stacked on top was 50 meters tall and had a launch mass of 310 metric tons. With a liftoff thrust of 4,050 kilonewtons, it was capable of placing up to about seven metric tons in low Earth orbit.

A cutaway drawing of the 11A511 Soyuz launch vehicle. It is a distant ancestor of the Soyuz-2 rocket which still flies today. Click on image to enlarge. (RKK Energia)

 

Manned Mission Plans

Following Korolev’s death on January 14, 1966, his deputy, Vasili Mishin, took control of the design bureau which was renamed TsKBEM (the Russian acronym for “Central Construction Bureau of Experimental Machine Building” – the direct ancestor of today’s Russian aerospace giant, RKK Energia) in March 1966. Mishin pushed forward on an aggressive plan to fly a pair of spacecraft for the inaugural manned mission of the Soyuz for a docking mission. The first Soyuz launch would be of the active spacecraft followed by the passive rendezvous target a day later. If the target was inserted into orbit within about 20 kilometers of the active Soyuz, the latter would use its “Igla” (Russian for “needle”) rendezvous system to perform an automated docking during the first or second orbit. Otherwise, the docking would take place after 24 hours to allow the spacecraft to perform a less aggressive rendezvous profile while the spacecraft were largely out of direct contact with its network of Soviet tracking stations. The pair of spacecraft would remain docked for three days and return to Earth after each had spent four days in orbit.

Russian diagram illustrating the EVA crew transfer planned for the first manned Soyuz mission. Click on image to enlarge. (RKK Energia)

During the first pair of manned test flights, it was planned that one cosmonaut would be launched in the active Soyuz while three would follow in the Soyuz acting as the target. After rendezvousing and docking, two cosmonauts from the passive Soyuz would perform an EVA to transfer to the active spacecraft. A similar procedure would eventually be employed by a cosmonaut transferring between the Soyuz LOK and LK variants being developed for a manned lunar landing mission. This ambitious mission would allow the Soviet Union to catchup and (by some measures) surpass the accomplishments of the American Gemini missions (see this web site’s Gemini page).

The crews selected for the original Soyuz 1/2 mission: Gagarin, Khrunov, Komarov, Yeliseyev and Bykovsky.

By the autumn of 1966 the crews had been selected for the first manned Soyuz launches. Veteran cosmonaut Vladimir Komarov was the commander of “Soyuz 1” and would be launched solo as the active spacecraft. The famed Yuri Gagarin was assigned as his backup. “Soyuz 2”, which would act as the target, would be commanded by veteran cosmonaut Valery Bykovsky with Yevgeny Khrunov and Alexei Yeliseyev tasked with performing the crew transfer EVA after the two spacecraft had docked. Soyuz 1 was launched on April 23, 1967 but Komarov immediately encountered a series of system malfunctions which made a rendezvous and docking impossible. With the “Soyuz 2” launch cancelled, Soyuz 1 was brought back home with great difficulty the next day but a failure of the DM’s parachute system during descent resulted in a crash landing which instantly killed Komarov (see “The Avoidable Tragedy of Soyuz 1”).

Cosmonaut Vladimir Komarov shown during ground training inside of the Soyuz. (RKK Energia)

In the wake of the fatal Soyuz 1 mission, changes were made to the 7K-OK design to correct its deficiencies while a much more conservative test program was adopted. A pair of unmanned Soyuz spacecraft, Kosmos 186 and 188, were launched in October of 1967 to test the spacecraft and perform an automated docking using the untried Igla system. While largely successful, problems encountered during these flights led to a second pair of unmanned Soyuz launches, Kosmos 212 and 213, to repeat the mission in April 1968. With the final solo unmanned test flight of Kosmos 238 launched in August 1968, the 7K-OK was cleared for manned missions.

A television image of Kosmos 213 docked to Kosmos 212. The antenna for the Igla docking system is clearly visible on top of the spacecraft.

In keeping in the more conservative testing program adopted in the wake of the Soyuz 1 accident, this time the target craft, Soyuz 2, was launched unmanned on October 25, 1968. Only after the spacecraft systems were checked out did Soviet authorities launch Soyuz 3 the following day with a single cosmonaut on board, Georgi Beregovoi, who would perform a rendezvous and docking. The crew transfer exercise would be left for the next mission. Upon entering orbit, Beregovoi was only 11 kilometers from his target and immediately executed an automated rendezvous with a manual docking to take place during the first orbit while Soyuz 3 was in the dark and out of touch with ground controllers. Unfortunately, Beregovoi encountered problems during his attempts to approach Soyuz 2 resulting in the docking being scrubbed after he had consumed too much of his propellant supply. Despite the failure to dock, the mission otherwise met all its objectives and Beregovoi safely returned to Earth after almost four days in orbit – the longest Soviet manned spaceflight since Vostok 5 flown in June 1963 (see “Soyuz 3: Getting the Soviet Union Back Into the Moon Race”).

Georgi Beregovoi shown onboard Soyuz 3 in orbit in October 1968.

A post-flight investigation into the failure of Soyuz 3 to dock placed the blame on pilot error. However, there were a number of factors which contributed to the situation. With the aggressive rendezvous profile which had been adopted, Beregovoi had no chance to adapt to his new environment after reaching orbit. And flying solo resulted in a heavy workload to configure Soyuz 3 for orbital flight and an immediate rendezvous with no help from a copilot or ground controllers when unforeseen problems were encountered during a fast-paced timeline. Most importantly, Beregovoi’s training seemed to have played a central role in the failure. The simulators used in docking training were apparently not accurate representations of the Soyuz and Beregovoi was never briefed about the actual appearance of the 7K-OK in orbit which would have provided vital cues about the relative attitudes of the two craft. While he had aligned his spacecraft so that the solar wings of Soyuz 2 were oriented properly in his periscope during his approach, Beregovoi inadvertently had the roll angle of Soyuz 3 with respect to Soyuz 2 off by 180° – in other words, he was approaching Soyuz 2 upside down compared to the orientation required for docking. When he gave inputs to align the attitudes of the two spacecraft, the Igla system automatically sent signals to Soyuz 2 which resulted in its attitude changing in the direction opposite from that expected. Changes in training and procedures would be required to avoid a repeat of the problems experienced by Soyuz 3.

 

The Next Soyuz Mission

With most of the objectives of the Soyuz 2/3 mission met, it was decided to move ahead with the next Soyuz mission which would include the docking of a pair of manned spacecraft followed by a crew transfer. At a meeting of the VPK on December 23, 1968, it was decided that the pair of Soyuz spacecraft would be launched on January 11 and 12, 1969 – the first manned launches from the Baikonur Cosmodrome in Soviet Kazakhstan in the depths of the harsh central Asian winter.

7K-OK No. 13 shown being prepared for the “Soyuz 5” flight. (RKK Energia)

At this same meeting, the composition of the all-rookie crews for what would be known as the “Soyuz 4” and “Soyuz 5” flights was also finalized. Commanding the active 7K-OK No. 12 spacecraft which would become “Soyuz 4” was Soviet Air Force Lt. Colonel Vladimir Shatalov. An honors graduate of the Red Banner Air Force Academy, the 41-year old Shatalov joined the cosmonaut corps in January 1963 as part of a new generation of military officers who were accomplished test pilots and engineers with graduate degrees. Shatalov had most recently served as the backup to Beregovoi for the Soyuz 3 flight. Shatalov’s backup was Georgi Shonin with Georgi Dobrovolsky serving as the reserve crew member.

Lt. Col. Vladimir Shatalov was the commander of the Soyuz 4 flight.

The commander of the 7K-OK No. 13 spacecraft, which would be designated “Soyuz 5” after launch, was Soviet Air Force Lt. Colonel Boris Volynov. The 34-year old Volynov was part of the original group of cosmonauts chosen in 1960 and had served in support roles in many earlier missions. The flight engineer and research engineers flying into orbit with Volynov who would perform the crew transfer EVA were the same men who were to serve that role for the original “Soyuz 2” mission. The flight engineer, Alexei Yeliseyev, was 34 years old and entered the cosmonaut corps in May 1966 as a civilian. The research engineer was 35-year old Soviet Air Force Lt. Colonel Yevgeny Khrunov who had served as a military pilot before being selected as part of the first group of cosmonauts along with Volynov. The backup crew for Soyuz 5 was Anatoli Filipchenko, Viktor Gorbatko and Valeri Kubasov with the reserve crew consisting of Anatoli Kuklin, Vladislav Volkov and Pyotr Kolodin.

The crew of the Soyuz 5 flight: (l to r) Lt. Col. Yevgeny Khronov, Alexei Yeliseyev and Lt. Col. Boris Volynov.

As was planned for the original Soyuz 1/2 mission, the active Soyuz would be launched first followed by the passive Soyuz the next day. Unlike the earlier plans where the active spacecraft would immediately start a fast-paced rendezvous and docking before the passive spacecraft had finished its first orbit, a less aggressive rendezvous profile would be flown instead with docking coming the day after the launch of the passive spacecraft. This extra day would allow Volynov, Yeliseyev and Khrunov an opportunity to acclimate to the weightless environment as well as provide more time to prepare for docking and the EVA to follow. The change would also allow the docking to take place while the ships were in daylight and within range of the Soviet tracking network so that ground controllers could monitor progress in real time and assist where needed.

After much debate, it was decided that Shatalov would rely on an automatic rendezvous to close the gap between the ships followed by taking manual control for the final approach and docking. After the issues encountered by Soyuz 3, there had been some who advocated a totally automatic rendezvous and docking as had been successfully performed during the unmanned Kosmos 186/188 and 212/213 test flights but Mishin and others argued for and got a manual docking instead. Shatalov was instructed to revert to the automatic procedure only if problems were encountered during the manual docking attempt.

Once docked, Yeliseyev and Khrunov would immediately start preparations for the crew transfer EVA which would be performed during daylight on the following orbit. The pair of cosmonauts had been training for over two years for this task. Much like their American counterparts who performed EVAs during the Gemini program, this training included sessions in a vacuum chamber and zero-g training in a modified Tu-104 airliner which could produce short periods of weightlessness by flying repeated parabolic arcs.

A Soviet diagram of the Yastreb spacesuit. The components are 1) telemetry line, 2) hose connections, 3) manometer, 4) oxygen feed connection, 5) safety line, 6) pack suspension system, 7) visor closing bracket, 8) visor filter, 9) spacesuit window, 10) helmet connecting ring, 11) pack suspension lock, 12) operating mode selection valve, 13) mirror, 14) pressure regulator valve, 15) life support system control panel, 16) air tight helmet, 17) life support system pack and 18) emergency oxygen supply cut-in valve lever. Click on image to enlarge.

While Yeliseyev and Khrunov would wear simple flight suits like the rest of the crew members during launch and other phases of the mission, for the EVA they would don new Yastreb (Russian for “Hawk”) spacesuits developed by the Zvezda Design Bureau. Stored in the OM until needed, these multi-layered suits were based on the Berkut (“Golden Eagle”) spacesuit worn by Alexei Leonov for his historic, first-ever EVA during the Voskhod 2 mission of March 1965 (see “The Mission of Voskhod 2”) and included improvements suggested by him. Like the earlier Berkut, Yastreb originally included a life support backpack capable of supporting a cosmonaut for two hours. Unfortunately, the cosmonauts frequently encountered difficulties during Tu-104 zero-g training as they attempted to squeeze through the 66-centimeter hatch of the Soyuz OM. Since the installation of a larger 70-centimeter hatch would cause a six to eight month mission delay, it was decided to reposition a modified life support unit onto the cosmonaut’s leg instead in order to provide the needed clearance.

Soviet diagram of docked Soyuz spacecraft. The components are 1) solar panels, 2) service module (SM), 3) orbital module (OM), 4) OM hatch, 5) Igla rendezvous antenna, 6) docking apparatus and 7) portholes. Click on image to enlarge.

Once Yeliseyev and Khrunov donned their spacesuits, Volynov would seal the hatch between the OM and DM and the OM would be depressurized. After opening the OM hatch, the pair cosmonauts would wear tethers to keep themselves secured to the spacecraft during EVA as well as pass telemetry and voice communications back to the ship. Handrails were placed on the OM exteriors to aid the cosmonauts as they moved from one spacecraft to the next. Because of overheating issues encountered during testing and training with the Yastreb suits, the cosmonauts were trained to move slowly and take frequent short rest breaks after exerting themselves much as Gemini astronauts had learned to do. Once Yeliseyev and Khrunov had transferred to Soyuz 4, the OM would be repressurized and the cosmonauts would remove their suits. Soyuz 4, now with three on board, would return to Earth the next day followed by Volynov now flying solo in Soyuz 5 the day after.

 

Getting into Orbit

On January 3, 1969, the crews for the Soyuz 4/5 mission arrived at the Baikonur Cosmodrome to begin final preparations for their flights including familiarization training in the spacecraft they would actually fly. More time than anticipated was required to prepare for launch with the first spacecraft, 7K-OK No. 12, not starting the journey to its pad at Area 31 (which had previously been used to launch Soyuz 3) until 07:30 Moscow Time on January 11. Later that evening, the Soyuz State Commission met and formerly approved the crew selection and set January 13 and 14 as the new launch dates. The following morning, 7K-OK No. 13 was rolled out and erected at the pad at Area 1 where all previous Soviet manned missions had started, save for Soyuz 3.

The crew of the Soyuz 4/5 mission shown at the Soyuz State Commission meeting on January 11, 1969 certifying their assignment and launch date. (RKK Energia)

On January 13, 1969, Shatalov boarded 7K-OK No. 12 with a launch planned for 13:00 Moscow Time in order to maximize the amount of daylight available in the planned recovery zones. A number of problems plagued the launch vehicle during the countdown which was ultimately stopped at the T-9 minute mark due to a problem with the rocket’s gyroscope caused by high humidity and the low temperatures. Some in the West had speculated about the inability to launch under conditions as cold as -30° C but relatives of the Soyuz launch vehicle had been routinely launched on unmanned missions during the cold winter months. This included Venera 5 and 6 which were successfully sent to Venus using the four-stage Molniya launch vehicle on January 5 and 10, respectively, from the pad at Area 1 (see “Venera 5 & 6: Diving Towards the Surface of Venus“). When it became clear that a problem with the booster’s hydraulic system would not be resolved within the tight launch window, the launch was scrubbed – reportedly the first time this had happened during a Soviet manned mission with the cosmonaut already on board.

The launch of Soyuz 4 on January 14, 1969 from the pad at Area 31 at the Baikonur Cosmodrome. (Sovfoto)

The problems with the 11A511 were fixed and the countdown recycled for launch on January 14. Once again, a problem arose with the rocket during the second launch attempt in a system which would normally only be accessible during horizontal processing back in the assembly building. Instead of delaying the mission for several days, a young pad worker voluntarily stripped down to his waist in the sub-zero conditions and squeezed through a small access hatch to correct the problem. The countdown continued and at 10:32 Moscow Time, Soyuz 4 successfully lifted off from the pad at Area 31. After just over nine minutes of powered flight, the 6,626-kilogram Soyuz 4 was now in a 173.0 by 225.3 kilometer orbit with an inclination of 51.72° with the callsign Amur.

During his first day in orbit, Shatalov hosted a telecast which was later shown on Soviet television.

Upon reaching orbit, Shatalov remarked “I like it up here!” and then proceeded to get his ship configured for orbital flight. As had been done during the Soyuz 3 mission, Shatalov hosted a television broadcast from orbit which was later replayed nationwide on Soviet television. At 16:35 Moscow Time during the fifth orbit, Shatalov manually fired Soyuz’s engines to raise his orbit to a more circular 207 by 237 kilometers in preparation for the launch of Soyuz 5 scheduled for the next day. From 18:16 on launch day to 04:12 Moscow Time on January 15, Shatalov rested while the orbit of his spacecraft was outside of Soviet territory preventing direct contact with ground controllers.

The launch of Soyuz 5 on January 15, 1969 from the pad at Area 1 at the Baikonur Cosmodrome.

At 10:05 Moscow Time on January 15, the 6,585-kilogram Soyuz 5 with Volynov, Yeliseyev and Khrunov on board lifted off from the pad at Area 1 to begin the next phase of the mission. Shatalov high above in orbit aboard Soyuz 4 spotted the ascending spacecraft, assigned the callsign Baikal, as it was placed into a 198.7 by 230.2 kilometer orbit with an inclination of 51.69°. For the first time, Soyuz was flying with a full complement of three cosmonauts on board. During the fifth orbit, Volynov manually maneuvered Soyuz 5 into a higher 211 by 253 kilometer orbit as part of the slower paced rendezvous profile which had been adopted for this mission. The Soyuz 5 crew proceeded with medical, observation and navigation tasks for the balance of the day. In order to align the crew schedules for the pair of spacecraft, the crews rested between 20:00 Moscow Time on January 15 to 04:00 Moscow Time the following day in preparation for the next day’s busy schedule.

 

Docking & The EVA

At 09:00 Moscow Time on January 16, Shatalov manually maneuvered Soyuz 4 into a 201 by 253 kilometer orbit as he continued to slowly close in on Soyuz 5. At 10:37 Moscow Time, Shatalov and Volynov activated the automated Igla rendezvous systems on their respective craft after the gap between them had shrunk to a few kilometers. Over the next half hour, Soyuz 4 closed the gap with Soyuz 5 and the commanders switched to manual control at a distance of 100 meters. Shatalov slowly maneuver Soyuz 4 until he was about 40 meters from his target as the pair of ships crossed the African coast. Once in touch with Soviet ground controllers, Shatalov started closing in once again.

Television image of Soyuz 4 approaching Soyuz 5 prior to their historic docking.

During the final approach, Shatalov encountered some issues with erroneous signals from docking system resulting from the spurious activation of the control and diagnostic system on board Soyuz 4. With ground controllers watching via television, the probe of the Soyuz 4 docking system entered the drogue of Soyuz 5 at a speed of just 25 centimeters per second as the crew of the latter ship made (by today’s standards) a vulgar sexual remark. At 11:20 Moscow Time, the two spacecraft were hard docked with Volynov exclaiming “Welcome!”. The first docking between two manned spacecraft was successful. There were some initial issues with excessive rolling of the docked spacecraft probably due to the diagnostic system issue on Soyuz 4, but the attitude was quickly stabilized.

Once the final connections between Soyuz 4 and 5 were made, the two craft were essentially operating as a single unit sharing control, communications and power. The Soviet press rightly hailed the achievement but stretched the situation a bit by claiming that the first “experimental space station” with a total internal volume of 18 cubic meters had been created. But with a mass of 12,924 kilograms, the combined Soyuz 4/5 was still almost 1.8 metric tons lighter than the single American Apollo 7 spacecraft launched three months earlier into low Earth orbit for the initial manned test of the Apollo spacecraft (see “Apollo 7: Rise of the Phoenix”). And with no means of transferring crews internally, this was not a very practical “space station”.

Depiction of a pair of docked 7K-OK spacecraft. (RKK Energia)

With the docking completed, preparations were started for the EVA during the next orbit. Yeliseyev and Khrunov moved into the OM of Soyuz 5 to retrieve their Yastreb spacesuits from storage. With Volynov’s help, Yeliseyev and Khrunov struggled to don their spacesuits in the tight confines of the OM. Eventually the suits were pressurized and tested with Volynov retreating to the DM closing the hatches behind him. The OM with Yeliseyev and Khrunov inside was depressurized and the external hatch opened allowing sunlight to stream into the module. Since the pair of cosmonauts were already 11 minutes behind schedule and with the EVA end time fixed by when the spacecraft entered orbital darkness, the total allowable EVA time was now shorter forcing some minor EVA tasks to be cut to save time.

After receiving the final permission from Volynov, Khrunov was the first to exit Soyuz 5 briefly becoming entangled with his tether in the process. After he remarked about the amazing view as he looked around while the ships were crossing over South America, Khrunov used the handrails to move himself towards Soyuz 4 which was now completing its 35th orbit since being launched two days earlier. Yeliseyev exited next and followed Khrunov’s lead making this the first two-person EVA in history. Khrunov’s first task was to remove the external television camera from Soyuz 5 and move it to Soyuz 4 so that it could record Yeliseyev’s transfer. Unfortunately, the film camera that was to provide high quality photographs of the EVA was accidentally lost as it floated out of the Soyuz 5 OM hatch which Volynov would remotely close only after Yeliseyev and Khrunov were safely inside Soyuz 4.

Only ghostly television images are available of the crew transfer EVA like this still of Yeliseyev shown moving towards Soyuz 4.

On board Soyuz 4, Shatalov remotely opened the external hatch of his depressurized OM as he monitored the cosmonaut’s progress on television. Khrunov entered the Soyuz 4 OM followed by Yeliseyev whose progress was recorded by the exterior television camera as the ships passed over Soviet territory. After Yeliseyev and Khrunov were safely inside Soyuz 4, the external hatch was secured and the OM repressurized. Yeliseyev and Khrunov had performed the first crew transfer during what turned out to be a 37-minute EVA. Shatalov warmly greeted Yeliseyev and Khrunov who ceremonially presented the commander with recent newspapers as well as letters and telegrams from family and various Soviet officials including Chief Designer Mishin congratulating them on their feat.

Shatalov greets Yeliseyev and Khrunov in the Soyuz 4 OM following the crew transfer and receives recent newspapers as well as letters and telegrams from family and Soviet officials.

 

Coming Home

With their joint mission tasks now completed, Shatalov and Volynov began preparations to undock. The two spacecraft separated at 15:54 Moscow Time after being joined for a total of four hours and 34 minutes over three orbits. The two spacecraft would now continue on independent missions. By 18:30 Moscow Time, Shatalov, Yeliseyev and Khrunov had returned to the Soyuz 4 OM for some much deserved rest while Volynov, now flying solo on board Soyuz 5, slept in the DM.

A view of the departing Soyuz 4 after it undocked from Soyuz 5 following 4 hours and 34 minutes of joint operations.

After waking up the morning of January 17, the expanded crew of Soyuz 4 wrapped up medical and other experiments they had been performing and began stowing their gear for the return home. While completing their final circuit of the Earth, Shatalov manually reoriented Soyuz 4 and initiated the retro sequence. Afterwards, the three modules of the Soyuz separated from each other leaving the DM to make a guided reentry. At 09:53 Moscow Time, Soyuz 4 softly landed under clear skies some 40 kilometers northwest of the city of Karaganda in Kazakhstan about 40 kilometers from its intended target. Soyuz 4 had been aloft for 71 hours, 20 minutes and 47 seconds. Having transferred from Soyuz 5 which was launched the day after Soyuz 4, Yeliseyev and Khrunov logged just 12 minutes shy of two days in flight.

Volynov shown performing measurements through an OM porthole after the departure of Soyuz 5.

Meanwhile, Volynov continued his mission in orbit on board Soyuz 5 as he waited for his turn to return home the next day. Volynov continued his experiments photographing the Earth and making astronomical observations. He also used the “RSS-1” spectrograph to perform geophysical observations in the 400 to 650 nanometer wavelength range. During his 36th orbit, Volynov maneuvered Soyuz 5 into a lower 201 by 229 kilometer orbit in preparation for his return home.

Among the experiments performed during the Soyuz 4 and 5 flights was Earth photography.

Volynov woke up at 01:30 Moscow Time on January 18 after retiring early the previous evening. While his spacecraft was apparently doing fine, Volynov encountered problems trying to orient his spacecraft for the retro sequence and waving off descent to the following orbit using automated systems was considered. At 10:20 Moscow Time as Soyuz 5 was crossing the Gulf of Guinea near Africa, Volynov was able to initiate the retro sequence. Six minutes later, he heard the charges fire which were to separate the three Soyuz modules. To his horror, Volynov noticed he could still see the antennas mounted on the ends of the SM’s solar panels – the SM was still attached as reentry approached. Volynov sent a coded message to ground controllers and braced himself for a potentially fatal reentry.

Volynov ripped the pages from his log book, rolled them up and stuffed them into his seat hoping that they would survive. Volynov kept calm during the ordeal and, instead of saying goodbye to friends and family, he used a tape recorder as he made observations from his tumbling spacecraft hoping that a record of his reentry might survive and tell investigators what had happened. As the unprotected front hatch and lightly insulated sides of the DM took the brunt of the reentry heat, Volynov could smell smoke inside the cabin as he endured a 9g ballistic reentry. After a sharp bang probably caused by the explosion of the SM propellant tanks, the DM was at last free and assumed the intended blunt-end-forward attitude so the heat shield could absorb the heat of reentry. Unfortunately, the DM’s attitude control propellant was already exhausted as the system had struggled in vain to orient the spacecraft, but the natural stability of the DM design kept it oriented properly for the rest of the reentry. Volynov then realized he would survive after all.

While there was a moment after the main parachute was deployed when the lines wound up because of the uncontrolled spin of the DM, the canopy quickly opened fully. The Soyuz 5 DM landed at 11:00 Moscow Time some 600 kilometers off course 200 kilometer southwest of Kostanay in northern Kazakhstan. The rough landing threw Volynov out of his harness and across the DM cabin breaking several teeth in the process but at least he was alive after his flight of 72 hours, 52 minutes and 15 seconds. Far from his intended landing site and with outside temperature at -36° C, Volynov knew that he could not wait inside the quickly cooling DM for rescuers to arrive. According to one account, after exiting the DM, Volynov saw a column of smoke in the distance and hiked several kilometers to a peasant hut where the occupants kept him warm and comfortable until the rescue team arrived.

The crew of the Soyuz 4 and 5 flights at a post-mission celebration.

Despite Volynov’s close call, the Soyuz 4/5 mission was a resounding success. The first docking of two manned spacecraft, the first two-person EVA and the first crew transfer in orbit were new “firsts” the Soviets could add to their list of space achievements and exploit for their propaganda value. Unfortunately, these achievements had already been overshadowed by NASA’s Apollo 8 mission to the Moon completed just three weeks earlier (see “Apollo 8: Where No One Has Gone Before”). And while the Soyuz flights to date allowed the Soviets to gain valuable experience in various aspects of spaceflight operations, they did not test hardware that would be needed for the planned Soviet Moon landing mission which would employ different rendezvous and docking systems, different spacesuits and so on. And with the failure of the first test of the Soviet N-1 Moon rocket on February 21, 1969, it was becoming clear that the Americans were on the verge of winning the race to the Moon barring another Apollo mishap.

A view of the launch of N-1 no. 3L on February 21, 1969. Unfortunately this first unmanned test of the Soviet’s Moon rocket was terminated after only 68 seconds of flight. (Russian Space Web)

After the mission, Vladimir Shatalov was tapped to command Soyuz 8 in October 1969 then the Soyuz 10 mission in April 1971 in a failed attempt to dock with the Salyut 1 space station. Later that year, Shatalov became the Commander of Cosmonaut Training. Badly shaken from his rough reentry and landing, Boris Volynov was removed from flight status for two years but went on to command the Soyuz 21 mission which spent 49 days on the Salyut 5 space station in the summer of 1976. Alexei Yeliseyev would next fly as Shatalov’s flight engineer on the Soyuz 8 and 10 missions while Yevgeny Khrunov served as the backup commander for the Soyuz 38 mission to the Salyut 6 space station in 1980 before moving on to work at the 30th Central Scientific Research Institute at the Ministry of Defense. With the objectives of the original Soyuz 1/2 mission finally met but with American plans to land on the Moon surging ahead of Soviet efforts, Soviet authorities were now faced with the decision of how to proceed with the maturing Soyuz program.

 

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Related Video

Here is an excellent Russian language documentary about the Soyuz 4 and 5 mission:

 

 

Related Reading

“Soyuz 3: Getting the Soviet Union Back Into the Moon Race”, Drew Ex Machina, November 2, 2018 [Post]

“The Avoidable Tragedy of Soyuz 1”, Drew Ex Machina, April 23, 2017 [Post]

 

General References

Rex D. Hall and David J. Shayler, Soyuz: A Universal Spacecraft, Springer-Praxis, 2003

Nicholas Johnson, Handbook of Soviet Manned Space Flight, Univelt, 1980

Asif A. Siddiqi, The Soviet Space Race with Apollo, University Press of Florida, 2003