Long duration orbital station of the third generation Salyut-6
As the service life of any LDOS which is rather limited is defined mainly by the fuel reserves and consumables of the life – support system accommodated on it during the injection the question arose with regard to the creation of the constant logistics support system of orbital stations to make their operating life independent of the initial stock of onboard resources. For this purpose the station must have at least, two docking assemblies.
This project was implemented already at NPO Energia established on the base of TsKBEM in May 1974, which was headed by V.P. Glushko. Yu.P. Semenov was appointed Chief Designer in charge of this direction of development. The new instrument compartment was developed with the propulsion system having bellows diaphragms in tanks allowing to refuel it in flight. The second docking assembly made it possible not only to refuel the station but make the crew rotation with a constant stay of the crew onboard the station. It was indeed a new word in space technology and not all believed that it was possible to implement such a decision but an aspiration to really making a long duration station with the capability of constant renewal of its resources overcame doubts. The new stations were equipped with an additional transfer chamber with the second docking assembly that allowed a simultaneous stay of the Soyuz vehicle and the Progress cargo vehicle on the station when refueling and during the cargo delivery or two Soyuz vehicles could stay simultaneously during the crew rotation. There was a capability of extravehicular activity, in this case the transfer compartment became the airlock where spacesuits and all the equipment were accommodated. They were required for extravehicular activity on the external surface of the station using special handrail for the cosmonaut movement and restraint during EVA. Some onboard systems were upgraded, color television was introduced and a folding shower cabin was installed in the working compartment for the crew needs. The station service life was increased to three years.
It should be emphasized that developers of this Manned Space Complex were so bold as to trust in this highly reliable automatic equipment of the Progress vehicles which had to dock repeatedly to the station with the crew onboard. And only today we see that this decision was correct. The Progress vehicles allowed not only to deliver the expendable equipment, but to enhance the station capabilities to conduct research at the expense of the delivery of the required science hardware. During the station operation in the Progress vehicle autonomous flight upon completion of the docked flight phase as a part of MSC a number of important technical and applied experiments was carried out.
On September 29, 1977 the first long duration orbital station of the third generation LDOS No. 5 – Salyut-6 was injected into orbit; five prime crews and 11 visiting crews worked on this station till July 29, 1982. Let’s note that the first expedition to the station did not take place. The Soyuz-25 spacecraft launched on October 9, 1977 with cosmonauts V.V. Kovalenok and V.V. Ryumin did not dock with the station because of the admitted deviations in the berthing and docking phase and also because of the propellant excessive consumption and it had to return to Earth. The first cosmonauts who visited the Salyut-6 station by the Soyuz 26 spacecraft were cosmonauts Yu.V. Romanenko and G.M. Grechko who had worked in orbit for more than 96 days, from December 10, 1977 to March 16, 1978.
The Salyut-6 Orbital Station with the Sloyuz-31 vehicle docked in flight
During the first expedition a significant event occurred. On January 20, 1978 for the first time in the world the Progress-1 automatic cargo (tanker) vehicle was launched to the Salyut-6 station. It delivered the required cargo and refueled its propulsion system.
The second expedition – cosmonauts V.V. Kovalenok and A.S. Ivanchenkov worked in orbit from June 15 to November 2, 1978, i.e. 139 days. This duration was a record again. Word “record” was often used during operation of orbital stations, however not the ambition to establish records induced the developers of space technology to pursue research. In particular regular research of a human body in the space flight conditions was conducted. A man found a new habitat and the process of its development became irreversible. It was very important to study all features of a long-term orbital flight and reveal all those hazards which wait for cosmonauts in such a flight. The third expedition – cosmonauts V.V. Lyakhov and V.V. Ryumin – worked from February 25 to August 19, 1979, i. e. 175 days. The fourth expedition – cosmonauts L.I. Popov and V.V. Ryumin – worked from April 9 to October 11, 1980. The crew spent in orbit already 185 days. The fifth expedition – cosmonauts V.V. Kovalenok and V.P. Savinykh – worked from March 12 to May 26, 1981, i.e. 74 days.
Work on the manned expedition to Mars had been performed at NPO/RSC Energia for a long time. The research results of long-term flights were very important for such a work and this research could be carried out on orbital stations only.
During the Salyut-6 OS operation when implementing a scientific program more than 1 550 different experiments were performed, more than 150 names of scientific devices and tools of the total mass more than 2 200 kg were used. Using a capability of the cargo delivery to the station, more than 750 kg of scientific devices were delivered to the station. Work was performed in the sphere of astrophysics (onboard submillimetre telescope OST-1M, radio telescope SRT-10, etc.), materials processing (processing plants Splav and Kristall), geophysics (photographic apparatus KATE-140, Pentakon, multi-zone camera MSC), biology, medicine, etc.
On July 29, 1982 the Salyut-6 orbital station with transport logistics vehicle (TLV) Kosmos1267 which operated as a part of MSC was de-orbited and ceased its existence over the Pacific Ocean.