Blok-D

Blok -D (Russian Блок Д ) is a rocket upper stage, which is used in some types of the former Soviet and present Russian launchers. The different variants of the Blok -D upper stage have already been used over 250 times in rocket launches. Blok -D is manufactured by RKK Energia.

The upper stage was derived from the fifth stage of the manned lunar expedition complex L3 within the stopped Soviet manned lunar program. The first flight of the Blok -D upper stage took place in 1967.

Later it was used as a fourth stage of the Proton rocket and brought Soviet space probes to the Moon, Mars and Venus. The Blok -D was separated from the upper stage Briz- M as the fourth stage of the modernized Proton-M. Since 1999, Blok -D is also used in the Zenit- 3SL launched from the lake missiles private satellite launch company Sea Launch.

Variants

Blok -D

This was the original version. It was used in the Proton-K rocket as high school. The description in GREY index is 11S824. This stage was equipped with a main engine of the RD -58, which produced a thrust of 84 kN. Blok -D had an empty weight of 1,800 kg.

The first launch of this original version on 10 March 1967. The last time she flew on 16 October 1975. Overall, this variant was not very reliable. Often stranded by their failure destined for the moon or other planets in an Earth orbit spacecraft.

Blok -D1

The problems with Blok -D led to the development of Blok D1. The description in GREY index is 11S824M. It was the modified RD- 58M engine used. In all eleven running start, the satellite reached their destination. Therefore, this stage has a background of 100 percent.

The first launch of this version took place on 9 August 1975. The last time she flew on 1 December 1989.

Blok -D2

This variant with the GREY index 11S824F was used three times, namely for the start of the probes Phobos 1 and 2 and Mars 96 Mars.

Blok -DM

Blok -D ( GRAU index 11S86 ) was modified in 1974 to the launch of satellites in geosynchronous orbits and other Earth orbit for Blok -DM. 2002, Blok -DM a success rate of 97 % in 218 flights since 1974 and 43 successful missions in a row between 1997 and 2002.

Blok - DM2

This variant of Blok -DM was used in 1982 for the first time.

Blok - DM3

Another variant Blok - DM3 flew in 1996.

Blok -DM -SL

This is a variant of Blok - DM3 and is used as the upper stage of the Zenit 3SL used in Sea Launch.