Salyut 6, launched on 29 September 1977, incorporated the best elements of all the previous stations. It combined Salyut 4’s power system (a trio of panels providing a peak of 4 kW), thermal regulation system, and navigational systems (Delta to depict the station’s orbit on the control panel, and Kaskad to control its orientation) with Salyut 3’s environmental systems and gyrodynes. The greater degree of automation would enable the crew to devote more time to experiments. The addition of the rear docking port required that the propulsion system be redesigned. Chelomei’s Almaz had its docking port in the rear because the crew’s capsule was on the front, and a twin-chamber engine had been designed to fit around the transfer tunnel. When it had been given the design and told to get it into service as soon as possible, the Korolev Bureau had replaced this untested engine with a Soyuz service module. Chelomei had continued to develop his own configuration and, after the loss of Salyut 2, the twin-chamber engine had flown on Salyuts 3 and 5. The Korolev Bureau now adopted this peripherally mounted engine in order to leave the axis free for the rear docking port, but instead of leaving the engine and its propellant tanks exposed, as on Almaz, the entire assembly, together with other apparatus, was encased in an unpressurised bay of the same diameter as the main section of the stepped-cylinder configuration. On earlier Korolev stations, the main engine had burned nitric acid and hydrazine fed by a hydrogen peroxide powered turbine, and the attitude-control thrusters had vented cold hydrogen peroxide. In this revised design, the orbital manoeuvring engines and the attitude control thrusters burned unsymmetrical dimethyl hydrazine in nitrogen tetroxide, which were drawn from a common set of tanks which were pressurised by bladders inflated by high-pressure nitrogen gas instead of a turbine.
KeywordsGravity Gradient Routine Operation Orbital Module Noctilucent Cloud Main Compartment
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