Under the name of Cosmos 1686 the fourth soviet spaceship TKS series was launched on 27 September 1985. Originally, with around 20 tons of quite large TKS ships planned as a space shuttle for transporting people in the military Almaz- program (for comparison: the Soyuz spacecraft to transport two to three people weigh less than eight tons). Manned flights were never realized with TKS. So the ferry TKS -4 was rebuilt and unmanned started as Cosmos 1686, to supply the Space Station Salyut 7 with supplies and fuel. As already apparent in the two previous missions Cosmos 1267 and Cosmos 1443 that the TKS - ships are suitable as extension modules for enlargement of space stations and passenger transport could be cheaper performed with Soyuz spacecraft was at TKS 4 the thought of manned flights entirely discarded. In order to save weight seats and onboard instruments were removed for the crew. Furthermore, for the first time the brake and landing system was expanded at the front end of the return capsule. This room was sufficiently available to provide the ferry with scientific and military equipment. Cosmos 1686 was thus the first full-fledged module to extend a Salyut station and with it the construction of a modular space station.
After six days of flight Cosmos 1686 docked automatically on October 2, 1985 at the front, narrow end of Salyut 7. Ten days earlier, started a crew to the space station on Soyuz T-14 and it was the first time that a remote-controlled module docked with a manned space station. For safety, the crew held at the time of the coupling maneuver on the Soyuz spacecraft to return to Earth in an emergency. The main task of the crew was to take the new module into operation and conduct military experiments. However, this was only partially successful, as the commander Vladimir Vasyutin seriously ill and carried a premature return to Earth had. The complex Salyut 7/Kosmos 1686 was then used by the crew of Soyuz T-15 on 6 May 1985, which carried out the unprecedented flight between two space stations ( from the space station Mir to Salyut 7 and back again). During the 50 -day stay, the main task was to continue the military experiments and then to dismantle valuable materials and equipment and to transfer to the new space station Mir. This mission was manned Salyut 7 for the last time.
During the docked state cosmos took over in 1686 among other things, the supply of the complex with energy via the own solar cells and led its own thrusters to maneuver height and position check. In August 1986 Cosmos 1686 brought the complex into a higher orbit in order for future missions, including the Space Shuttle Buran to stand by. Strong solar winds, however, led to the fact that the complex fell faster than expected. In December 1989, the orientation system of the cosmos failed in 1686 what the plans for further manned flights also deteriorated. A repair was not carried out for reasons of cost in favor of the new space station Mir. Salyut 7 flew another year unmanned and crashed on February 7, 1991 along with Cosmos 1686 over the Pacific from.
On the basis of TKS ferry modules have been developed (eg Sarja ) to the permanent disposition of the space stations Mir ( eg Kwant 2) and International Space Station.
- Supply ship
- Soviet and Russian space
- Space mission in 1985