Molniya (rocket)
Molniya (Russian Молния for flash, English Molniya ) is a four-stage, Soviet rocket that is specially designed to launch high-flying satellites and interplanetary space probes.
History
The development of the rocket goes back to the R-7 rocket, which was extended for interplanetary missions or high earth orbit on four stages. These signed Sergei Korolyov on January 15, 1960 a corresponding development order and in May 1960, the first draft was present. The first launch of a Molniya was already on October 10, 1960 held in Baikonur since been launched Moon, Mars and Venus probes with her until the end of the 1960s. Very many early Molniya - offs ended up that the payload remained in a low Earth orbit. This was due to the error-prone techniques of the fourth stage of the rocket. Molniya is no longer in use and was from 1964 frequently ( the Molniya communications satellites ) and military early warning satellites of the type Oko used until the end of 2010 on the launch of its namesake. It was built by the TsSKB -Progress (Samara Space Center ), the propulsion system for Motorostroitjel (Samara ) and the sixth was from the design office Lavochkin ( Khimki Moscow ). The Molniya was later regarded as one of the most reliable rockets of Russia, on 21 June 2005 she suffered due to a fault in the engine of the second stage, the first false start since 1990. Commercially it was only used once in 1995 when she the Indian earth observation satellites, IRS -1C and the American military satellites skipper brought into orbit. Since the technique of Molniya already outdated and is not flexible enough in use, it was gradually replaced by the more modern Soyuz - Fregat. The last launch of a ( built in 2005 ) Molniya -M took place on September 30, 2010, providing them in 2469 ( an early warning satellite of the type Oko ) into a highly elliptical (see Molniya orbit ) brought the cosmos satellite orbit. A total of 320 rockets from Baikonur and Plesetsk from were launched into space. There were a total of 21 false starts, of which 7 in the first 15 starts.
Technology
The first two stages of the Molniya ( GRAU index 8K78 ) correspond to the Vostok rocket, based on which it was based. But not the Blok E Vostok taken, but a stronger rocket stage called Blok I was developed for the third stage, the later in the Voskhod and Soyuz was used. Blok I was powered by a four-chamber RD -108 engine ( which was originally developed for the R -9 ICBM ), which used the Kerosinart RP -1 and liquid oxygen (LOX ) as fuel. In contrast to only half as long Blok E this spherical fuel tank received triple fuel capacity.
The fourth stage of the Molniya ( Blok L) was based on the third stage of the Vostok rocket, also burned RP -1 with liquid oxygen and was powered by a developed by the engine specialists Michael Melnikov S1.5400 main turbofan engine with 66.7 kN of thrust. The stage had 1160 kg empty weight and could carry about 3,700 kg of fuel. Blok L could be fired only once and must therefore be ignited at a precise time, in order to achieve the necessary for the satellite orbit. In addition, this resulted in the need for a separate orientation and stabilization system and a heat insulation for the tanks which increased the empty weight. The ignition of the engines in weightlessness prepared some additional problems. So a droppable solid APU BOZ was started before the ignition of the actual engines at apogee of the transfer orbit, which took care of his thrust, the fuel collected in the tanks on the ground and thus simulated the engine ignition under the conditions of Earth's gravity. This Blok L was complicated, error-prone and inflexible, often, in particular, resulted in the early start to a suspension of the payload in an unusable orbit.
From 1964 Molniya -M ( GREY index 8K78M ) was introduced, which had minor modifications to the first two stages and a Blok L with the improved S1.5400A engine. Later, three variants of the Blok L ( Blok 2BL Blok Blok -ML and SO -L), which differed only in the matched to the respective payload flight profile emerged.