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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

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.

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 earlier Soyuz 11A511 was the first attempt at creating a standardized R-7 core in place of the numerous variations that had been used up to 1966. Starting that year, the 11A511 Blok I and strap-on boosters were added to the Voskhod (11A57), Vostok-2 (8A92), and Molniya-M (8K78M) vehicles as well as minor R-7 variants flown once or twice for specialized payloads.

The uprated 11A511U core was introduced to the R-7 family in 1973, yielding the carrier rocket variant named Soyuz-U, although adoption across the board was not complete until 1977 when the existing stock of 11A511-derived boosters was used up.



Two versions of Soyuz-U were fitted with an additional upper stage:

  • Soyuz-U/Ikar with the Ikar third stage, produced by the Progress State Research and Production Rocket Space Center, TsSKB-Progress. Ikar is used to deliver various payloads with masses of 750 to 3,920 kg (1,650 to 8,640 lb) to heights of 250 to 1,400 km (160 to 870 mi). The performance of the Ikar upper stage is lower than that of the Fregat upper stage, but it is more precise in maneuvering and it can operate autonomously longer. This version was launched 6 times in 1999, carrying four GlobalStar satellites on each mission.[3]
  • Soyuz-U/Fregat with the Fregat third stage, developed and produced by Lavochkin Association in Khimki. This version only flew 4 times in 2000;[4] the Fregat upper stage was subsequently flown regularly atop Soyuz-FG and Soyuz-2 boosters.

An older variant of Soyuz-U, the Soyuz-U2 launcher, first flown in 1982, had the same hardware as the basic Soyuz-U. Instead of standard RP-1, it used a high energy, synthetic version, Syntin, as the first stage fuel. This variant, mainly used to transport crew and cargo to the Mir space station, last flew in 1995, after production of Syntin ended due to cost reasons.

Soyuz-U was the basic platform for the development of the Soyuz-FG variant, which used an all-new first stage and took over crew transport to the ISS in 2002. Since 2013, both Soyuz-U and Soyuz-FG are gradually being replaced by the modernized Soyuz-2 launch vehicle.

Human spaceflight


The first use of a Soyuz-U to launch a crewed mission took place 2 December 1974, when the Soyuz 16 crew was launched in preparation for the Apollo–Soyuz Test Project (ASTP). Soyuz 19, which as part of the ASTP docked with the last Apollo spacecraft ever flown, was also launched by a Soyuz-U rocket.[6]

On 6 July 1976, a Soyuz-U launched Soyuz 21, which took a crew of two to the Salyut 5 space station. Many subsequent space station crews were launched on Soyuz-U launchers. The final crewed mission to use the Soyuz-U was Soyuz TM-34, a Soyuz ferry flight to the International Space Station.

A spectacular accident occurred on 26 September 1983, when the launcher for the Soyuz T-10a mission was destroyed by fire on the launch pad. The crew was saved by activation of the launch escape system a few seconds before the explosion.

Missions after 2000


From 2000 until its retirement in 2017, Soyuz-U vehicles were used by the Russian Federal Space Agency primarily to launch Progress-M robotic cargo spacecraft on resupply missions to the International Space Station (ISS).

Although the Soyuz-U was generally very reliable, occasional failures occurred, such as the October 2002 launch of a Foton satellite which crashed near the pad at Plesetsk after the Blok D strap-on booster suffered an engine malfunction. One person on the ground was killed.

A Soyuz-U mission failed to launch Progress M-12M to the ISS on 24 August 2011, when the upper stage experienced a problem and broke up over Siberia. It was the first time a Progress spacecraft had failed to reach orbit. Another cargo ship, Progress MS-04, was lost on 1 December 2016 shortly after launch, likely due to a problem with the third stage of the Soyuz-U.

In April 2015, Soyuz-U was declared obsolete. Its production was stopped and the rocket was scheduled for retirement after launching the remaining vehicles with Progress cargo ships.[12] The final flight was Progress MS-05, which launched from the Baikonur Cosmodrome on 22 February 2017, 05:58:33 UTC.[13]


  1. ^ "Soyuz-U". Archived from the original on 11 December 2016. Retrieved 19 March 2022. Astronautix.com
  2. ^ a b Krebs, Gunter. "Soyuz-U (11A511U)". Gunter's Space Page. Retrieved 22 February 2017.
  3. ^ a b Krebs, Gunter. "Soyuz-U Ikar (11A511U)". Gunter's space page. Retrieved 7 May 2016.
  4. ^ a b Krebs, Gunter. "Soyuz-U Fregat (11A511U)". Gunter's space page. Retrieved 7 May 2016.
  5. ^ a b In 1983, flight Soyuz T-10a took fire on the launch pad before the end of the countdown, so it is not counted in the list of launches; this is why adding successes and failures yields 787 launches instead of 786.
  6. ^ a b c Mark Wade (26 March 2001). "Soyuz 11A511U". Friends and Partners. Archived from the original on 4 March 2016. Retrieved 7 January 2009.
  7. ^ a b c "Soyuz-U User's Manual" (PDF). Starsem. Retrieved 11 March 2016.
  8. ^ "Конструкция разгонного блока "Фрегат"". NPO Lavochkin (in Russian). Archived from the original on 26 December 2015. Retrieved 10 March 2016.
  9. ^ "IKAR Upper Stage". TsSKB-Progress. Retrieved 21 December 2015.
  10. ^ @elonmusk (20 October 2022). "Congrats to @SpaceX team on 48th launch this year! Falcon 9 now holds record for most launches of a single vehicle type in a year" (Tweet) – via Twitter.
  11. ^ "Soyuz-FG on penultimate flight delivers three new crewmembers for ISS". NASASpaceFlight.com. 20 July 2019. Retrieved 21 October 2022.
  12. ^ Nowakowski, Tomasz (30 June 2015). "All eyes on Progress: Russian spacecraft to deliver supplies to ISS". Spaceflight Insider. Archived from the original on 21 April 2016. Retrieved 6 May 2016.
  13. ^ Chris Gebhardt (21 February 2017). "Longest-serving rocket in history bids farewell with Progress MS-05 launch". NasaSpaceFlight.com.