Soyuz-FG

Soyuz FG

The launch of Soyuz TMA-3 atop a Soyuz-FG rocket.
Function	Medium-lift launch vehicle
Manufacturer	Progress
Country of origin	Russia
Cost per launch	773,600,000 ₽ (2012)[1]
Size
Height	51 m (167 ft)[1]
Diameter	2.7–3.715 m (8.86–12.19 ft)[1]
Mass	310,000–313,000 kg (683,000–690,000 lb)[1]
Stages	FG: 3 FG/Fregat: 4
Capacity
Payload to LEO[1][2]
Altitude	200 km (120 mi)
Orbital inclination	51.8°
Mass	FG: 6,900 kg (15,200 lb) FG/Fregat: 7,800 kg (17,200 lb)[citation needed]
Associated rockets
Family	R-7 (Soyuz)
Based on	Soyuz-U
Derivative work	Soyuz 2
Launch history
Status	Retired
Launch sites	Baikonur, LC-1/5 and LC-31/6
Total launches	70     FG: 60[3]     FG/Fregat: 10[4]
Success(es)	69
Failure(s)	1 (Soyuz MS-10)
First flight	20 May 2001 (Progress M1-6)
Last flight	25 September 2019 (Soyuz MS-15)
Type of passengers/cargo	Soyuz-TMA Soyuz-MS Progress Venus Express
Boosters (First stage) – Blok-B,V,G,D[a]
Height	19.6 m (64 ft)
Diameter	2.68 m (8 ft 10 in)
Empty mass	3,800 kg (8,400 lb)
Gross mass	43,400 kg (95,700 lb)
Propellant mass	40,350 kg (88,960 lb)[1]
Powered by	1 × RD-107A
Maximum thrust	SL: 838.5 kN (188,500 lbf) vac: 1,021.3 kN (229,600 lbf)
Specific impulse	SL: 263.3 s (2.582 km/s) vac: 320.2 s (3.140 km/s)
Burn time	118 seconds
Propellant	LOX / RG-1
Second stage (core) – Blok-A[5]
Height	27.1 m (89 ft)
Diameter	2.95 m (9 ft 8 in)
Empty mass	6,550 kg (14,440 lb)
Gross mass	99,500 kg (219,400 lb)
Propellant mass	92,600 kg (204,100 lb)[1]
Powered by	1 × RD-108A
Maximum thrust	SL: 792.41 kN (178,140 lbf) vac: 921.86 kN (207,240 lbf)
Specific impulse	SL: 257.7 s (2.527 km/s) vac: 320.6 s (3.144 km/s)
Burn time	286 seconds
Propellant	LOX / RG-1
Third stage – Blok-I[5]
Height	6.7 m (22 ft)
Diameter	2.66 m (8 ft 9 in)
Empty mass	2,410 kg (5,310 lb)
Gross mass	25,300 kg (55,800 lb)
Propellant mass	22,800 kg (50,300 lb)[1]
Powered by	1 × RD-0110
Maximum thrust	297.93 kN (66,980 lbf)
Specific impulse	326 s (3.20 km/s)
Burn time	230 seconds
Propellant	LOX / RG-1
Fourth stage (optional) – Fregat[6]
Height	1.5 m (4 ft 11 in)
Diameter	3.35 m (11.0 ft)
Empty mass	930 kg (2,050 lb)
Propellant mass	5,250 kg (11,570 lb)
Powered by	1 × S5.92
Maximum thrust	19.85 kN (4,460 lbf)
Specific impulse	333.2 s (3.268 km/s)
Burn time	Up to 1,100 seconds (up to 20 starts)
Propellant	N2O4 / UDMH
[edit on Wikidata]

The Soyuz-FG launch vehicle was an improved version of the Soyuz-U from the R-7 family of rockets, designed and constructed by Progress in Samara, Russia. The rocket's guidance, navigation, and control system was developed and manufactured by the Polisvit Special Design Bureau in Kharkiv, Ukraine.^[7]

Soyuz-FG made its maiden flight on 20 May 2001, carrying a Progress cargo spacecraft to the International Space Station (ISS). It was retired after the 25 September 2019 launch of Soyuz MS-15 to the ISS; the analog control system significantly limited its capabilities and prompted its replacement by the Soyuz 2.^[8] From 30 October 2002 to 25 September 2019, the Soyuz-FG was the only vehicle used by the Russian Federal Space Agency to launch Soyuz TMA, Soyuz TMA-M and Soyuz MS crewed spacecraft to the ISS.

For uncrewed flights, Soyuz-FG optionally flew with a Fregat upper stage, developed and produced by Lavochkin Association in Khimki. The maiden flight of this configuration occurred on 2 June 2003, the first of ten such launches.^[4] Launches of the Soyuz-FG/Fregat configuration were marketed by a European-Russian company called Starsem.

Soyuz-FG was launched from the Baikonur Cosmodrome in Kazakhstan, from Gagarin's Start (Site 1/5) for crewed missions, and from Site 31/6 for satellite launches with the Fregat upper stage.

The Soyuz-FG performed 64 successful launches until its first failure on 11 October 2018 with the Soyuz MS-10 mission. A video recording of the spaceflight released several weeks later suggested a faulty sensor, resulted in the destruction of the rocket. The crew, NASA astronaut Nick Hague and Russian cosmonaut Aleksey Ovchinin, escaped safely.^[9]

The FG designation stands for forsunochnaya golovka, Russian for injector head, the main component which received significant improvements. The previous RD-107 and RD-108 engines on the first and second stages, respectively, used 260 two-component centrifugal injectors. The improved RD-107A and RD-108A engines each had more than a thousand one-component injectors. These new injectors allowed finer aeration of propellant for more thorough burning and reduced the probability of high-frequency vibrations inside the combustion chambers. The result was increase in specific impulse by about 5 seconds (0.049 km/s), or about five percent, which allowed the rocket to list another 250 to 300 kilograms (550 to 660 lb) of payload to orbit.^[1]

While Progress was already developing the heavily modernized Soyuz 2 rocket, beacuse the RD-107A and RD-108A engines were already tested and ready for flight, the company decided to introduce the Soyuz-FG as an intermediate upgrade between the Soyuz U, which would remain in use to expend the remaining stock of older engines, and until the Soyuz 2 could be readied for flight.^[1]

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