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. 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.[6] The final flight of a Soyuz-U rocket took place on 22 February 2017, carrying Progress MS-05 to the International Space Station.

A Soyuz-U on the launchpad for the Soyuz 18 mission
FunctionOrbital carrier rocket
Country of originSoviet Union
  • Soyuz-U: 51.1 m (168 ft)
  • Soyuz-U/Ikar: 47.3 m (155 ft)
  • Soyuz-U/Fregat: 46.7 m (153 ft)
Diameter3 m (9.8 ft)[1]
  • Soyuz-U: 313,000 kg (690,000 lb)
  • Soyuz-U/Ikar: 308,000 kg (679,000 lb)
  • Soyuz-U/Fregat: 308,000 kg (679,000 lb)
  • Soyuz-U: 2
  • Soyuz-U/Ikar: 3
  • Soyuz-U/Fregat: 3
Payload to LEO
Associated rockets
FamilyR-7 (Soyuz)
Derivative workSoyuz-U2
Launch history
Launch sites
Total launches786[2][3][4]
First flight18 May 1973[6]
Last flight22 February 2017 (Progress MS-05)
Type of passengers/cargoSoyuz spacecraft
Progress spacecraft
Boosters – Blok-B,V,G,D[7]
No. boosters4
Height19.6 m (64 ft)
Diameter2.68 m (8.8 ft)
Empty massSoyuz: 3,800 kg (8,400 lb)
Gross mass43,400 kg (95,700 lb)
Powered byRD-117
Maximum thrustSea Level: 838.5 kN (188,500 lbf)
Vacuum: 1,021.3 kN (229,600 lbf)
Specific impulseSea Level: 262 s (2.57 km/s)
Vacuum: 319 s (3.13 km/s)
Burn time118 seconds
First stage – Blok-A[7]
Height27.10 m (88.9 ft)
Diameter2.95 m (9.7 ft)
Empty massSoyuz: 6,550 kg (14,440 lb)
Gross massSoyuz: 99,500 kg (219,400 lb)
Powered byRD-118
Maximum thrustSea Level: 792.5 kN (178,200 lbf)
Vacuum: 990.2 kN (222,600 lbf)
Specific impulseSea Level: 255 s (2.50 km/s)
Vacuum: 319 s (3.13 km/s)
Burn time290 seconds
Second stage – Blok-I[7]
Height6.70 m (22.0 ft)
Diameter2.66 m (8.7 ft)
Empty massSoyuz: 2,410 kg (5,310 lb)
Gross massSoyuz: 25,200 kg (55,600 lb)
Powered byRD-0110
Maximum thrust297.9 kilonewtons (67,000 lbf)
Specific impulse325 seconds
Burn time270 seconds
Upper stage (optional) – Fregat[8]
Height1.5 m (4.9 ft)
Diameter3.35 m (11.0 ft)
Empty mass930 kg (2,050 lb)
Propellant mass5,250 kg (11,570 lb)
Powered byS5.92
Maximum thrust19.85 kilonewtons (4,460 lbf)
Specific impulse333.2 seconds
Burn time1100 seconds
Upper stage (optional) – Ikar[9]
Height2.56 m (8.4 ft)
Diameter2.72 m (8.9 ft)
Empty mass820 kg (1,810 lb)
Gross mass3,164 kg (6,975 lb)
Powered byS5.144/17D61
Maximum thrust2.94 kN (660 lbf)
Specific impulse307 seconds

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 until this was beaten by SpaceX's Falcon 9 in 2022.[10][11] 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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