The Soyuz-FG was an improved variant of the

Soyuz-U Soyuz-U ( GRAU index: 11A511U) was a Soviet and later Russian expendable medium-lift launch vehicle designed by the TsSKB design bureau and constructed at the Progress factory in Samara, Russia. The ''U'' designation stands for ''unified' ...

launch vehicle from the R-7 rocket family, developed by the

Progress Rocket Space Centre Rocket and Space Centre "Progress" (), commonly known as RKTs Progress (), is a Russian joint-stock company under Roscosmos. It is responsible for building and operating the Soyuz (rocket family), Soyuz family of rockets, which serve as the pri ...

in Samara, Russia. It featured upgraded first and second stage engines, RD-107A and RD-108A, respectively, with enhanced injector heads that improved combustion efficiency and specific impulse. The designation "FG" refers to ''forsunochnaya golovka'' (''injector head'') in Russian. Soyuz-FG made its maiden flight on 20 May 2001, delivering a

Progress Progress is movement towards a perceived refined, improved, or otherwise desired state. It is central to the philosophy of progressivism, which interprets progress as the set of advancements in technology, science, and social organization effic ...

cargo spacecraft to the

International Space Station The International Space Station (ISS) is a large space station that was Assembly of the International Space Station, assembled and is maintained in low Earth orbit by a collaboration of five space agencies and their contractors: NASA (United ...

(ISS). It became the primary vehicle for launching crewed Soyuz TMA, Soyuz TMA-M, and

Soyuz MS The Soyuz MS (; GRAU: 11F732A48) is the latest version of the Russian Soyuz (spacecraft), Soyuz spacecraft series, first launched in 2016. The "MS" stands for "modernized systems," reflecting upgrades primarily focused on the communications and ...

spacecraft from 2002 until its retirement in 2019. Launches occurred from the

Baikonur Cosmodrome The Baikonur Cosmodrome is a spaceport operated by Russia within Kazakhstan. Located in the Kazakh city of Baikonur, it is the largest operational space launch facility in terms of area. All Russian Human spaceflight, crewed spaceflights are l ...

in Kazakhstan: crewed missions from

Gagarin's Start Gagarin's Start (, ''Gagarinskiy start''), also known as Baikonur Site 1 or Site 1/5 was a launch site at the Baikonur Cosmodrome in Kazakhstan that was used by the Soviet space program and Roscosmos. History 20th century The launchpad f ...

(Site 1/5) and satellite launches from Site 31/6.

Design

Soyuz-FG was introduced in May 2001 as a transitional solution while the more advanced

Soyuz-2 Soyuz2 (; GRAU index: 14A14) is a Russian expendable medium-lift launch vehicle and the seventh major iteration of the Soyuz rocket family. Compared to its predecessors, Soyuz-2 features significant upgrades, including improved engines and ...

was still in development. Development of the upgraded RD-107A (boosters) and RD-108A (core) engines outpaced the rest of the Soyuz-2 rocket. The availability of the upgraded engines allowed their early use on Soyuz-FG, while Soyuz-U continued using existing engine stockpiles. The RD-107A and RD-108A engines, replaced the older RD-107 and RD-108 units, switching from 260 two-component centrifugal injectors to over 1,000 one-component injectors. This refinement enabled more complete propellant combustion, reduced high-frequency vibrations in combustion chambers, and improved

specific impulse Specific impulse (usually abbreviated ) is a measure of how efficiently a reaction mass engine, such as a rocket engine, rocket using propellant or a jet engine using fuel, generates thrust. In general, this is a ratio of the ''Impulse (physics), ...

by , a five percent improvement, which allowed for a payload increase of . For uncrewed missions, Soyuz-FG could fly with a

Fregat Fregat () is an upper stage developed by NPO Lavochkin for universal compatibility with a wide range of medium- and heavy-lift launch vehicles. Fregat has been used primarily with Soyuz and Zenit rockets, and entered operational service in ...

upper stage, built by Lavochkin in Khimki. The first flight of this configuration took place on 2 June 2003, with a total of ten such launches marketed by the European-Russian company Starsem. Soyuz-FG flew 70 times, with one failure on 11 October 2018 during the launch of Soyuz MS-10. A faulty sensor led to a booster collision with the core stage shortly after liftoff, triggering an emergency abort. The crew—NASA astronaut Nick Hague and Russian cosmonaut Aleksey Ovchinin—safely returned to Earth. Following the MS-15 launch on 25 September 2019, Soyuz-FG was retired in favor of the fully digital Soyuz-2, which offers more precise guidance and greater mission flexibility.

Launch history

Notes

References

* *

External links

Russian Federal Space Agency about Soyuz-FG

LV's manufacturer TsSKB-Progress about Soyuz-FG
{{R-7 rockets Soyuz program R-7 (rocket family) Space launch vehicles of Russia Vehicles introduced in 2001

Design

Launch history

See also

Notes

References

External links