The Soyuz-U launch vehicle was an improved version of the original Soyuz rocket. Soyuz-U was part of the R-7 family of rockets based on the R-7 Semyorka missile.

Quick Facts About the Soyuz-U:

- Type : Orbital carrier rocket.

- Origin : Soviet Union.

- In service : 18 May 1973 - 22 February 2017.

- Mass : 313,000 kg (690,000 lb).

- Length/Height : 51.1 m (168 ft).

- Diameter : 3 m (9.8 ft).

- Payload to LEO : 6,900 kg (15,200 lb).

- Propellant: LOX/RG-1.

- Engines: Boosters: 4 RD-117 with thrust of 838.5 kN (188,500 lbf), First stage: 1 RD-118 with thrust of 792.5 kN (178,200 lbf), Second stage: 1 RD-0110 with thrust of 297.9 kilonewtons (67,000 lbf).

Members of this rocket family were designed by the TsSKB design bureau and constructed at the Progress factory in Samara, Russia (now a united company, TsSKB-Progress). The first Soyuz-U flight took place on 18 May 1973, carrying as its payload Kosmos 559, a Zenit military surveillance satellite. The final flight of a Soyuz-U rocket took place on 22 February 2017, carrying Progress MS-05 to the International Space Station.

Soyuz-U was in use continuously for almost 44 years. Production of R-7 derived launch vehicles peaked in the late 1970s-early 1980s at 55–60 a year. Soyuz-U held the world record of highest launch rate in a year in 1979 with 47 flights. Over its operational lifetime, the Soyuz-U variant flew a total of 786 missions, another world record. Soyuz-U has also been one of the most reliable launchers, with a success rate of 97.3%. The rocket had a streak of 112 consecutive successful launches between 11 July 1990 and 5 May 1996.

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