March 1981:Salyut 6 Expedition 4, part 3

Progress 10 in Flight

Before the launch of the tenth Progress cargo spacecraft the Dniepers (Popov and Ryumin) carried out a repair to one of the two redundant “Kaskad" attitude control subsystems of the Salyut 6 station. The operation consumed a large amount of crew time.

When Progress 10 was launched from Baikonur, at 0441 (all times GMT) on 29 June 1980, 70% of the dry cargoes it carried had been requested by the cosmonauts. From the initial orbit of 191 x 281 km; period 88.9 minutes; inclination 51.6°, the cargo spacecraft was manoeuvred, over the next two days, to a successful automatic docking with Salyut 6/Soyuz 36 which occurred at 0553 on 1 July. As usual, after opening the internal hatches to the cargo spacecraft, the first item the Dniepers unloaded was a 3 kg package containing letters from their families and new periodicals.

The Dniepers made light work of unloading the dry cargoes the spacecraft delivered and routinely installed new equipment into the systems to replace ailing or worn-out units. Amongst the routine cargoes were several items new to the station including a US-made Polaroid instant camera and film, a new 25 cm colour TV for use on the Earth-Orbit TV link and cassettes of new pop music for the Elektrinika tape recorder.

Amongst the foodstuffs delivered were new specimens of onion, dill,peas, parsley, cucumber, radish and even some canned fish. The fresh foods, and also some new flower seeds, were planted in the hydroponic garden to mature and provide data for the biological experiments. For the continuation of their scientific experiments Progress 10 delivered new intensifies for the BST-1M and a device to rectify a fault in a Bulgarian-made instrument which was presenting an inversed image. Finally water and fuel were pumped into the Salyut's respective tanks.

At 2221 on 17 July Progress 10, its SKDU having been used earlier to put Salyut 6/Soyuz 36 into a 91.2 minute orbit with an altitude of 328 x 355 km (slightly lower than normal for a rendezvous with a ferry ship), was undocked. At 0147 on 19 July the SKDU was activated for the final time to send Progress 10 to reentry in the dense layers of the atmosphere away from the shipping lanes.

The Cosmic Olympians

After Soyuz T-2 cosmonaut Malyshev and Aksenov returned to Earth on 9 June they reported that the Dniepers were working enthusiastically and were seemingly gaining in their capacity for work. The cosmonauts might well have noted that Popov and Ryumin were also in very good spirits as they demonstrated during the 22nd Olympic Games which,accompanied with tremendous fanfare, were held in Moscow between 18 July and 3 August. During the opening ceremony the Dniepers formally read out, via TV, a pre-prepared statement to the Lenin Stadium in Moscow. Their serious official attitude contrasted sharply with their less public statements to FCC controlles. When asked what they would be doing during the games Popov commented: "Not competing! After all we are able to go once around the world in 90 minutes, no athlete could match that!" During the period of the games the Dniepers were able to see all the major events via the Earth-Orbit TV link. They were, of course, true patriots cheering on Soviet victories and at one stage expressing their “extreme dissatisfaction" with the Soviet basketball team who had been eliminated in the semi-finals of the event.

New International Crew

On 23 July the launch window opened for another 8 day Interkosmos flight and, as expected, the Soviets launched another crew to the station. There had been some debate before the flight by Salyut observers as to the nationality of the cosmonaut-researcher of the next Interkosmos flight. Next in line according to the Soviets in 1979 was a Cuban but by 1980 a Vietnamese cosmonaut was being tipped as the next Interkosmonaut. Expectations that the CR would be a Cuban were heightened in early July when the Cuban news agency announced that the Dniepers were preparing the station for a new crew to join them and-describing, in general terms, the experimental programme mapped out for the Soviet/Cuban crew. When the flight occurred, however, the companion to the Soviet commander was a citizen of the Socialist Republic of Vietnam (SRV).

The first notice that Vietnam was to have a cosmonaut came from an interview with Vladimir Lyakhov on Radio Moscow broadcast on the day of his launch, 25 February 1979. In his pre-flight interview Lyakhov stated that crews with representatives from Bulgaria,Hungary,Cuba,Mongolia,Vietnam and others were preparing for future flights. The first official statement that Vietnamese pilots were in training occurred on 18 May 1979 when TASS said that in accordance with their participation in the Interkosmos programme, of which it is a signatory,Vietnam had sent 2 pilots to Moscow for spaceflight training.

The two crews preparing for the Soviet/Vietnamese flight were: Prime crew of Viktor Gorbatko (USSR) and Lt-Col. Pham Tuan (SRV),a 33 year old pilot who was already a hero of the SRV for his feat of shooting down an American B-52 bomber in 1972, during the Vietnamese War, with his MiG fighter. The reserve crew consisted of Valeri Bykovsky (USSR) and Bui Thanh Liem (SRV).

Soyuz 37 in Orbit

Standing in the squares marked KK (Spaceship commander) and BI (Flight Engineer), as normal for all the pre-flight statements, facing the huge A-2 carrier rocket carrying Soyuz 37 under the shroud, the Soviet/Vietnamese cosmonauts Viktor Gorbatko and Pham Tuan made the usual round of thanks and dedications to all concerned with the flight at national and party level. It was about 2100 local time at Baikonur (1600 GMT) as the two men were taken to the Soyuz cabin. Pham Tuan carried with him a small engraving of Lenin carved by a Vietnamese artist and dedicated to the flight. At 1833:03 (GMT) on 23 July Soyuz 37 was launched into the night sky beginning the sixth Interkosmos manned flight.

In space Tuan reportedly suffered from headaches and loss of appetite during the first hours of the flight, symptoms not uncommon with rookie cosmonauts, but he soon recovered. Following the standard pattern Soyuz 37 rendezvoused with Salyut 6/Soyuz 36 the following night after about 24 hours of flight. In preparation for the docking approach Ryumin, watching via TV, asked the Tereks (Gorbatko and Tuan’s call sign) to activate their beacon lights on Soyuz 37 when 2 km from the station rather than at 100 m as planned. Ryumin required more data on their approach for the docking which would take place in darkness. The docking was accomplished without further incident at 2002 on 24 July. Three hours later the internal hatch was opened to the aft docking unit and the Tereks were welcomed aboard by the Dniepers with the usual warmth.

Following their celebration supper and an exchange of telegrams with the Soviet and SRV leadership the Tereks began the first of 30 planned experiments. This was about 1nhour after they had entered the station. Both crews retired shortly afterwards because it was early morning Moscow Time. The four men were allowed to sleep an hour longer than planned before FCC woke them all at 1100 (now 25 July) to begin the planned series of experiments in earnest.

SRV Experiments

During their 7 days aboard Salyut the Tereks devoted much attention to the programme of Earth observations which, for the first time ever, would yield maps of Vietnam’s geological,mineral, botanical and oceanographic features. From their height of 345 km the Tereks obtained photographs and spectral data of Vietnamese territory using the KATE-140 and MKF-6M cameras allowing specialists the opportunity to study:

• Tidal flooding and erosion ontheVietnamese coastal areas:

• Silting in the mouths of Vietnamese rivers to assess fish feeding habits and their effects:

• Hydrological features of the Mekong and Red River deltas and Central Plateau Region, and

• Effects on the Vietnamese countryside, plants and forests of the enormous amounts of defoliants and firebombs dropped during the Vietnam War.

In the BIOSPHERE V (for Vietnam) experiment the Spektr-15 instrument was used to obtain the spectral characteristics of certain regions of the Vietnamese countryside to assess their biological productivity. Studying the planet visually Pham Tuan noted that the countries of South-East Asia, notably Laos,Thailand and Kampuchea, appeared very green and he was able to distinguish rivers and roads. Atmospheric observations were conducted under the POLARIZATION, REFRACTION and related experiments using the small GDR-made Pentakon 6M and Praktika EE2 hand-held SLR cameras.

Medical experiments saw the Tereks assess their own biomedical parameters with the instruments on board the station including the Czechoslovak Oxymeter, GDR Pneumotest, and the USSR Chibis suit with which the visitors also conducted detailed examinations of the Dniepers’ cardiovascular state. Pham Tuan’s breathing rate was measured during exercise on the veloergometer and his cerebral blood flow was also assessed.

In the HALONG experiment (named for a Vietnamese gulf) the Tereks obtained a gallium phosphide semiconductor crystal and a bismuth-antimony-telluride compound from the Kristall unit.

Return to Earth

On 28 July both crews participated in the customary press conference. Gorbatko noted that he was impressed by the size of Salyut when compared to the small Soyuz ferry. Part of the time during the Tereks final two days on the station was taken up transferring their seats from Soyuz 37 to Soyuz 36 in which they were to return. As usual the fresher Soyuz was to be left for the resident crew. On 30 July the results of their work on Salyut were stored in the Soyuz 36 descent cabin in preparation for the return to Earth the next day.

At 0700 on 31 July the crews checked the Salyut and Soyuz systems in preparation for the undocking. At 0852, following the farewell speeches seen on TV. the internal hatches were closed,sealing Gorbatko and Tuan in Soyuz 36. At 1155 Soyuz 36 unlatched from Salyut's front docking unit and performed the separation burn.

During their final orbit before retrofire the Tereks were addressed by Granit (Vladimir Shatalov) via radio from FCC who informed them of the weather conditions at the landing site. He told them that there were few clouds, visibility was over 10 km and there was a slight south-westerly wind. At 1425,on command from the tracking ship Borovichi in the South Atlantic, the Soyuz 36 SKDU was ignited for over 200 s to bring the spacecraft out of orbit. The Tereks made a soft landing at 1515 some 180 km SE of Dzhezkazgan.

Newsmen were quickly on the scene to record the cosmonauts' traditional impromptu news conference next to the descent capsule. The Tereks thanked the workers, both in space and on the ground, who had helped make the flight such a success. Gorbatko and Tuan were pronounced to be in good health by the medical team and were flown from the landing site to Dzhezkazgan and then to Baikonur for their debriefing reports.

On 4 August the cosmonauts arrived in Zvezdny Gorodok for the first of their many press conferences. Finally, before departing for their tour of Vietnam, they were awarded medals for their flight in the Kremlin on 16 August.

Experimental Work in Orbit

On 1 August, just over 24 hours after the Soyuz 36 touchdown, the Dniepers redocked Soyuz 37 to the front docking port of Salyut 6. The spaceship, with the cosmonauts aboard, was undocked from the rear docking unit at 1643 and backed away to an unspecified distance (probably about 180 m) while Salyut rotated 180° and then redocked with the front unit at 1715.

Despite the speed of the redocking, suggesting that another manned flight was imminent, no more Soyuz or Progress spacecraft were launched throughout the August window. The reason was apparently to allow the cosmonauts to concentrate upon the series of important Earth observations and smelting experiments planned for completion before the launch of the next Interkosmos crew at the next window and their subsequent return to Earth during the same window (mid-October). The Soviets had earlier announced that the flight would not greatly exceed the 175 day flight in terms of length of time spent in space although the flight did allow for three Interkosmos flights to take place. The reason for the lack of a Progress tanker became clear in mid-September when the Soviets said that Salyut 6 still had about 2.5 tonnes of cargo aboard (more than when the Dniepers were launched). To have launched another Progress ship would have meant bringing more cargoes to a station already full to the brim with equipment. Refuelling was not a significant factor in the decision because the cosmonauts were leaving Salyut 6 in a gravity gradient stabilised mode most of the time with the attitude thrusters deactivated to allow them to conduct a broad range of Earth observations and smelting experiments. The only times the thrusters were activated were during the sessions of photography with the MKF-6M and other cameras.

Birthday Celebrations

During August both cosmonauts celebrated birthdays. Valery Ryumin's was the first, on 16 August. Unlike the year before, when he had expected to celebrate it on the Earth but had to celebrate in space following the unscheduled EVA to free the KRT-10 antenna and their subsequent delayed return to Earth,Ryumin had expected to be in space for this birthday from the start of the flight. To mark the occasion FCC staff arranged for a special TV broadcast on the Earth-Orbit link from Ryumin's apartment. The “show”' was hosted by cosmonauts Kovalenok and Sevastyanov and featured a birthday cake with 41 candles baked by his wife. Actors Yuri Vizbor and Sergei Nikitin sang a specially composed song in which the families and friends present joined.

Popov’s 35th birthday was celebrated on 31 August with another Earth-Orbit TV linkup. The events provided the cosmonauts with a break from their strenuous work 340 km above the Earth.

Preparations for Another Start

On 4 September the orbit of the station was corrected raising the period from 91.14 to 91.3 minutes. The height after the burn was 343 x 355 km in the standard 51.6° inclination. A further refinement to the orbit on 16 September left the Salyut 6/Soyuz 37 complex in a 91.4 minute period track in readiness for the next Interkosmos launch.