September-December 1980:Salyut 6 Expedition 4, part 1

By 29 November 1979 Salyut 6 had sunk to an orbit of 352x372 km altitude; period 91.5 minutes, approaching an ideal launch/landing window opportunity between about December 18 to 30. Earlier the Soviets had said that Salyut 6 was to be re-used and that manned flights would resume in 1980. The December window was used to test fly an unmanned version of the new Soyuz ferry.

The test vehicle, dubbed Soyuz-T, was a much improved version of the two-man Soyuz 12 type ferry used for flights to the Salyut 3 to 6 stations. The failures of Soyuz 15, 23, 25 and 33 to dock with Salyuts 3, 5 and 6 and their subsequent emergency return to Earth validated the Soviet planners' desire to have a vehicle with far more reliability and versatility. While most western observers were anticipating imminent test flights of the much publicised “Kosmolyot” space plane,the Soviets were quietly perfecting an improved Soyuz utilising the latest advances in Soviet electronics and hardware. It must be recalled that most of the systems of the Soyuz in use were first flown as long ago as 1966. The improved Soyuz was test flown under the label of Cosmos 1001 and 1074. The latter vehicle was in space for 60 days qualifying it for extended flight.

Soyuz-T exhibited several significant design modifications including:

• Introduction of an Autonomous Onboard Computing Complex (ABKK) capable of flying the mission profile without human assistance.

• Improved telemetry rates. The ABKK provides onboard and FCC digital cathode displays of specific systems in a processed form, an impovement on the previous analogue sequencers.

• Re-introduction of solar panels for the generation of electricity enabling Soyuz-T to remain in space longer than the two days allowed to the Soyuz 12 type ferry in the event of docking difficulties. Extra power for the station also can be gained from the panels.

• Introduction, for the turbine driven Soyuz motor (SKDU),of a Salyut 6 type combined engine installation (ODU). On Soyuz-T the main engine and 4 attitude control thrusters use the same fuel supply. The attitude control engines also act as reserve to the main engine. The ODU exhibits higher thrust and manoeuvring capacity than the SKDU. Unification of the engines makes more propellant available for further docking attempts should the initial one fail.

Also,Soyuz-T is provided with a colour TV camera (previously only a B/W one was carried); improved radio communication, orientation and descent systems. In addition significant modifications have been made to the internal layout suggesting that Soyuz-T has accommodation for 3 men. Vladimir Shatalov once called Soyuz "the spaceship of the future”; clearly the Soviets intend to use them for the foreseeable future in their civilian space programme.

Soyuz-T in Flight

Soyuz-T was launched from Baikonur at 1230 (all times GMT) on 16 December 1979 into an initial orbit of 201 x 232 km, 51.6° inclination, and period 88.6 minutes. A Washington source noted that launch had occurred 73 minutes after Salyut’s pass over the cosmodrome. This was later than normal Soyuz (no later than 30 minutes) and Progress (45 to 60 minutes) launches, indicating that some time was to elapse before the announced intention to dock with Salyut 6. That period was three days during which time the craft was manoeuvred and checked out. Soyuz-T performed impeccably, Soviet engineers announced.

At 1405 on 19 December Soyuz-T made an apparently flawless docking with the front docking unit of Salyut 6. The docking, performed entirely with Soyuz’s ABKK, exhibited differences to earlier dockings in that Soyuz-T flew an approach path that was both above and in front of Salyut, losing altitude to meet the station, as opposed to catching up with the station from behind, the normal practice. The Salyut 6/Soyuz-T complex was in an orbit at a height of 342 x 362 km; period 91.3 minutes after the docking. On 25 December the Soyuz-T ODU was used to raise the orbit to one with a 91.9 minute period; height was 370 x 382 km. The complex was then allowed to sink by atmospheric drag with Soyuz-T powered down.

By 29 February 1980 the orbit was 343x369-km; period 91.5 minutes. On 23 March, at 2104, Soyuz-T was undocked from Salyut 6 leaving the station in a 344 x 363 km orbit; period 91.4 minutes. Following two days of autonomous tests Soyuz-T made a nighttime landing in Kazakhstan at 2150 on 25 March. Soyuz-T had been in flight 100 days 9 hours and 20 minutes.

Progress 8 in Orbit

No sooner had the excitement over the return of Soyuz-T abated than the first act of the fourth long term expedition to Salyut 6 was played out with the launch of Progress 8 at 1853 on 27 March. Progress was commanded over the next two days to a docking with the rear docking unit of Salyut 6 at 2001 on 29 March. The next day Progress 8’s SKDU was used to trim the Salyut’s orbit in readiness for the launch of the new all Soviet crew. Following the trim Salyut 6/Progress 8 was in a 348 x 360 km orbit; period 91.4 minutes, perfect for a manned launch.

Soyuz 35

Preparations for the launch of the fourth main crew of the Salyut 6 space station had not gone as planned. Cosmonauts Leonid Popov and Valentin Lebedev, who had been the reserve crew of the Soyuz 32 flight (Popov was also reserve to Valery Bykovsky on Soyuz 22, Lebedev may have been reserve Flight Engineer for that flight), had almost completed their training when, in early March, Lebedev seriously injured his knee during trampoline exercises. The injury required an immediate operation. The Soviets chose not to fly their reserve crew but to put an experienced FE with the rookie Popov. All of the experienced FEs offered their services and Valery Ryumin was chosen.

During the medical preparations for the flight Popov had spent many nights sleeping with his feet above the level of his head. He spent many hours on a special revolving table with a chair on it. The table, capable of moving in two axes with the chair spinning at the same time, is a relatively new device with which the Soviets are trying to avoid vestibular problems.

So it was than on 9 April, just over 7 months after returning from Salyut 6, Valery Ryumin found himself atop an A-2 booster in the Soyuz 35 cabin awaiting the launch. Both he and Popov looked relaxed. The launch occurred at 1338. Some 9 minutes after the start Popov (call sign Dneiper) and Ryumin were gazing down on the Earth from orbit.

Following a normal manned rendezvous lasting 24 hours the navigation system of Soyuz 35 was activated when the spacecraft was only 10 km from Salyut 6. FCC was able to watch the docking via Soyuz's TV camera after it was switched on some 600 m away from the station. Docking occurred at 1516 on 10 April at a point over the Caspian Sea.

Onboard Salyut 6

After equalising air pressure between Soyuz and Salyut, at 1826:11, the Dneipers (as the crew was known) opened the hatch between the vehicles and entered the station. In an amusing sidelight Ryumin opened a letter he had left for the next crew after vacating the station on 19 August 1979, never dreaming that he would be the recipient of his own note. Ryumin confided that he was not in the habit of writing letters to himself! In another humorous aside Ryumin showed the FCC specialists, watching via TV, a cucumber which he said had grown in the station’s hydroponic installation without any human assistance, such as watering; after stunning the biologists he admitted the cucumber was plastic. These incidents showed that the crew w>ere reacting quitenormally to the spaceflight. Popov’s pulse (normal average 62 beats/min) had reached 125-133 before launch and 114 during launch. Ryumin, surprisingly for the space veteran he is, had a maximum pulse rate of 178 during launch. Popov was initially a little hasty in his movements around the station but, with Ryumin’s advice, soon learned to pace himself. The Dneipers suffered the usual congestion in their cranial arteries and slight vestibular disorders. But in spite of these “normal” spaceflight complaints they were in good health. Their programme of medical and physical exercises was initiated as soon as they had settled in.

The Dneipers’ first work task was to activate the station’s systems and "demothball” the life-support systems. Within the first day of boarding Salyut 6 these urgent tasks had been completed. Pressure was stabilised at 730 mm on the mercury column; temperature was 20° C. The hatch to Progress 8 was opened on 11 April and the Dneipers began the unloading operation. The cargo craft carried the usual supplies of propellant, food, clothes, LSS regenerators, water, hygiene facilities, etc., as well as some new equipment.

The cosmonauts were scheduled to carry out a great deal of repair and maintenance work before the formal experiment programme could begin in earnest. Much of the equipment aboard Salyut had been working for 2.5 years, about double the planned lifetime of the station. A new 80 kg buffer battery was connected as was a replacement battery in the steering unit. The batteries were replaced within one orbital nighttime period as opposed to the two periods budgeted for pre-flight. The radio communications system was checked; new command and warning systems were installed and checked; conditioning units in the water regeneration system were replaced; scientific equipment, such as the Elena-F gamma ray detector, was checked; air was pumped into the station’s compartments from Progress 8 and. finally, the clocks were synchronised with those at the FCC. The repair and maintenance work, completed ahead of schedule, took about two weeks. In addition the cosmonauts watched the Earth, conducted medical and biological tests, obtained semiconductors from the Splav 01 and Kristall furnaces and worked to the now established routine with weekends off.

At 1751:30 on 24 April the Progress 8 SKDU was fired for exactly 81 seconds to raise the station’s orbit from a near circular 349x353 km to one with a height of 340x368 km, period 91.4 minutes. The station’s oxidiser tanks were then topped up. At 0804 on 25 April Progress 8 undocked and the next day at 0654 its SKDU was fired for the last time to send the cargo craft, loaded with used equipment to an atmospheric entry above the Pacific Ocean.

Progress 9

Just one day after the demise of Progress 8, on 27 April, the ninth Progress cargo spacecraft was launched from Baikonur at 0624. The ship successfully docked with Salyut 6/Soyuz 35 at 0809 on 29 April, ‘It’s becoming like a rail schedule," a Soviet journalist commented.

Along with the usual supplies of mail, food, clothes, etc.,Progress 9 carried a new motor for the Biogravistat centrifuge which the crew installed. There were also replacement gas analyser filters, new VCR parts, the Lotos device for moulding parts from polyurethene, including small Olympic symbols to be presented to “favoured" guests to the Soviet capital during the Summer Olympic games (these were to be brought to Earth aboard the Soyuz 35 ship when the Soviet/Hungarian crew, who flew in late May returned).

The main unloading operations were left until after the cosmonauts and FCC staff had celebrated the May Day holiday. During the two-day rest the Dneipers watched the May 1st Red Square parade and spoke to their relatives via the Earth-Orbit TV link and also conducted sporadic Earth observations tasks.

In a major innovation to the system of water supply Progress 9 delivered the Rodnik system by means of which 180 kg of water was pumped directly into a tank aboard Salyut. Before this system was adopted water was carried to the station in individual 5 kg bottles,each of which had to be manhandled by the crewmen into the supply section of the station.

The unloading of Progress 9 went smoothly and the cosmonauts work with it was soon completed and on 16 May the cargo ship’s SKDU was used to trim the orbit of the complex to 349x369 km, period 91.5 minutes. At 1851 on 20 May Progress 9 was commanded to undock from the complex and two days later the ship's SKDU was fired to send it to its destructive reentry.

Soyuz 36 Preparations

Even as the Progress 9 was being manoeuvred out of orbit the carrier rocket for the next flight was being rolled out at Baikonur. The A-2 rocket was scheduled to carry into orbit, for a rendezvous with Salyut 6, the long-delayed Soviet/Hungarian crew who had had their flight cancelled before their scheduled take-off on 5 June 1979.

For the Soyuz 36 flight, as usual for all Interkosmos flights,two crews were trained. The first comprised Valeri Kubasov (USSR) and Bertalan Farkas (pronounced Farkash), a 30-year-old captain in the Hungarian Air Force, and Vladimir Dzhanibekov (USSR) and his companion Bela Magyari, also 30 and a captain in the HAF.

The selection board eventually approved Valery Kubasov and Bertalan Farkas as the prime crew of the flight with Dzhanibekov and Magyari serving as their reserves. The flight was scheduled for launch on 26 May - the first launching opportunity of what was to become a busy landing window.