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Soyuz-FG's long road to retirement

The 21st century version of the legendary Russian Soyuz rocket family, which carries cosmonauts into orbit, has the designation Soyuz-FG, where "FG" stands for "forsunochnaya golovka" -- Russian for the injector head. It was the main component which had gotten a makeover when the Soyuz-FG variant was introduced in 2001. Despite much more significant improvements in the works, the Soyuz-FG's working career then span over nearly two decades.

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General architecture of the Soyuz-FG rocket

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Soyuz-FG: A small step forward

The Soyuz-FG represented the fifth round of gradual upgrades since the end of the 1950s in what is known today as the Soyuz rocket family. The focus of the FG program were the main engines on the four boosters of the first stage and on the core booster of the second stage.

In development since around 1993, the new injector heads were designed to improve the mixing of fuel and oxidizer sprayed inside the combustion chambers of the modified RD-107A (14D22) and RD-108A (14D21) engines which propel the first and second stage, respectively. The older RD-107 (11D512) and RD-108 (11D511) engines used 260 two-component centrifugal injectors, while the new engines received more than 1,000 one-component injectors. They allowed finer aeration of propellant for more thorough burning of its components while also reducing the probability of high-frequency vibrations inside the combustion chambers. (813)

Because RD-107 and RD-108A were successfully tested and ready for flight ahead of other upgrades planned for the Soyuz-2 series of rockets, the developers decided to introduce an intermediate version of the rocket designated Soyuz-FG (11A511U-FG), which would feature the modified engines on the first and second stage. (814)

This relatively small upgrade increased the specific impulse of the engine by around five seconds or by 1.3 percent. As a result, Soyuz-FG could carry from 250 to 300 kilograms of extra payload to a 200-kilometer orbit when compared to that of the Soyuz-U variant. When launched with the manned Soyuz transport spacecraft (its main payload), Soyuz-FG could deliver up to 7,200 kilograms in the low Earth's orbit. The Soyuz-FG could also carry the 7,400-kilogram Progress cargo ship.

All other components of the Soyuz-FG were borrowed largely unchanged from the Soyuz-U variant, which also remained in operation.

A typical flight profile

launch

A typical launch sequence and a ground track for a Soyuz-FG launch with a Soyuz-MS spacecraft.

According to a generic flight profile, the Soyuz-FG drops its four boosters of the first stage 118 seconds after liftoff, while the second stage continues firing until 287 seconds in flight. Depending on the mission, the third stage inserts its payload into an initial Earth's orbit from 520 to 540 seconds after launch.

The payload fairing protecting the satellites during the ascent through the atmosphere can be dropped from 127 to 207 seconds into the flight at an altitude from 70 to 100 kilometers above the Earth's surface, when the rocket has a velocity from 1,800 to 2,200 meters per second. The exact parameters of the ascent timeline depend on the available drop zones for a given ascent trajectory. (120)

Long road to retirement

Like all previous launchers assigned to carry crews, the Soyuz-FG would have to be "man-rated" during test launches with unmanned satellites, before it could be entrusted with the life of cosmonauts. In the case of Soyuz-FG, its introduction was timed to precede the first mission of the Soyuz TMA spacecraft variant, which could take advantage of the launcher's extra cargo capacity.

On May 21, 2001, the first Soyuz-FG successfully launched the Progress M1-6 cargo ship, followed by another flawless launch on Nov. 26 of the same year with Progress M1-7. In October 2002, Soyuz-FG carried its first crew riding to orbit in the Soyuz TMA-1 spacecraft. The rocket has remained the sole carrier of manned vehicles ever since. By 2016, after 15 years in service, Soyuz-FG had made 48 launches with the manned Soyuz spacecraft and two missions with the Progress cargo ships within the ISS program and eight missions with commercial payloads.

family

The Soyuz rocket family as of 2002.

Ironically, the Soyuz-FG was initially seen only as a stop-gap variant on the road to the Soyuz-2 series, which would incorporate the newest features of the Soyuz-FG, in addition to much more radical upgrades, including a new-generation flight control system.

However, the plans to switch human missions from the Soyuz-FG to the Soyuz-2, initiated as early as 2005, took years longer than planned.

As of 2012, the production of Soyuz-U-PVB and Soyuz-FG variants was expected to cease by the beginning of 2016. In 2014, the conflict with Ukraine, which supplied flight control avionics for Soyuz-U and Soyuz-FG, made the switch even more urgent. With the two former Soviet republics at a virtual state of war, NASA had to ask the US State Department to plead with the Ukrainian government to supply necessary hardware for Soyuz-FG and Soyuz-U-PVB. To make matters worse, in April 2015, the second attempt to launch a Progress cargo ship on a Soyuz-2-1a rocket resulted in a dangerous accident, which could have doomed a crew had it been onboard.

The final plan to retire Soyuz-FG is in the works

The Soyuz-2-1a test flight program resumed in December 2015, but the actual switch of human missions to Soyuz-2.1a was put off as far as 2019. According to NASA sources, soon after the Progress M-27M accident, top Roskosmos officials assured the head of the NASA Space Station Program Office Manager Michael T. Suffredini that they would not retire the old reliable Soyuz-FG for as long as the US space agency continues booking seats on the Soyuz spacecraft for its astronauts heading to the ISS. As of 2017, the most recent iteration of the NASA contract for Soyuz flights would end in 2019.

Not surprisingly, in March 2017, the official Russian press announced that human missions would be switched from Soyuz-FG to the Soyuz-2-1a rocket in 2019 or 2020. As of September 2017, the plan was to switch human missions to Soyuz by the beginning of 2019.

On Aug. 11, 2017, RKK Energia submitted an integrated schedule to Roskosmos to use the two remaining Soyuz-FG rockets for the launches of the Progress MS-10 (No. 440) cargo ship on Oct. 11, 2018, and that of the Progress MS-11 (No. 441) scheduled for Feb. 6, 2019.

These rockets were originally manufactured for the launches of the Soyuz MS-12 (No. 742) spacecraft in March 2019 and Soyuz MS-13 (No. 743) in September 2019.

On Aug. 30, 2017, Roskosmos gave a contract to RKTs Progress in Samara to conduct minor rework on the two Soyuz-FG rockets to adapt them for the Progress MS vehicles.

As of September 2017, the two final Soyuz-FG rockets had been scheduled to fly in April and September 2020. However the Roskosmos leadership was pressing the industry to retire the FG variant as early as 2019 to cut costs and avoid problems with Russian security services, which put serious obstacles in obtaining avionics and associated technical assistance from Ukraine's Kommunar plant. As a result, at least one of previously planned launches of Soyuz-FG in 2020 could be performed in 2019, industry sources said.

(To be continued)

Specifications of the Soyuz-FG rocket:

Number of stages 3
Liftoff mass 310-313 tons
Maximum length 51 meters
Payload fairing diameters 2.7, 3.0, 3.3, 3.715 meters
Price 773,600,000 rubles (around 2012)
Official reliability factor 0.985
STAGE I
Stage I propulsion system Four RD-107A engines
Stage I total propellant load 161.4 tons
Stage I oxidizer load (liquid oxygen) 111.6 tons
Stage I fuel load (kerosene) 45.0 tons
Stage I hydrogen peroxide load 4.8 tons
Stage I thrust at Earth's surface 4,146.4 kilonewtons
Stage I Thrust in vacuum 5,075.3 kilonewtons
STAGE II
Stage II propulsion system One RD-108A engine
Stage II total propellant load 92.6 tons
Stage II oxidizer load (liquid oxygen) 63.8 tons
Stage II fuel load (kerosene) 26.3 tons
Stage II hydrogen peroxide load 2.5 tons
Stage II thrust at Earth's surface 792.48 kilonewtons
Stage II thrust in vacuum 990.18 kilonewtons
STAGE III
Stage III propulsion system One RD-0110 engine
Stage III total propellant load 22.8 tons
Stage III oxidizer load (liquid oxygen) 15.7 tons
Stage III fuel load (kerosene) 7.1 tons
Stage III thrust in vacuum 297.93 kilonewtons

 

Payload capabilities of the Soyuz-FG rocket as compared to Soyuz-U*:

Launch site Inclination Orbital altitude Soyuz-U payload Soyuz-FG payload
Plesetsk 62.8 degrees 220 kilometers 6,150 kilograms N/A
Plesetsk 67.1 degrees 190 kilometers 6,090 kilograms N/A
Plesetsk 81.4 degrees 200 kilometers 5,800 kilograms N/A
Baikonur 51.8 degrees 200 kilometers 6,650 kilograms 6,900 kilograms
Baikonur 64.9 degrees 190 kilometers 6,450 kilograms 6,700 kilograms
Baikonur 51.6 degrees - - 7,200 kilograms (Soyuz)
Baikonur 51.6 degrees - - 7,400 kilograms (Progress)

*All payload parameters, when the rocket uses a payload fairing with a diameter of 3.715 meters

 

Chronology of Soyuz-FG missions:

No
Year
Date
Time
Payload
Payload type
Launch site
Complex
Pad
Status
1
2001
May 21
02:32 Moscow Time
Manned / cargo supply
5
Success
2
2002
March 21
23:13 Moscow Time
Manned / cargo supply
5
Success
3
2002
Oct. 30
06:11:11 Moscow Time
Manned
5
Success
4
2003
April 26
07:53:52 Moscow Time
Manned
5
Success
5
2003 June 2
17:45:26 GMT
Planetary / Mars
6
Success
6
2003
Oct. 18
09:38:03 Moscow Time
Manned
5
Success
7
2003
Dec. 29
00:30 Moscow Time
Application / communications
6
Success
8
2004
April 19
07:19 Moscow Time
Manned
5
Success
9
2004
Oct. 14
07:06 Moscow Time
Manned
5
Success
10
2005
April 15
04:46 Moscow Time
Manned
5
Success
11
2005
Aug. 14
03:28:28 Moscow Time
Application / communications
6
Success
12
2005
Oct. 1
07:54:53 Moscow Time
Manned
5
Success
13
2005 Nov. 9
03:33:34 GMT
Venus Express
Planetary / Venus
6
Success
14
2005
Dec. 28
08:19 Moscow Time
Application / navigation
5
Success
15
2006
March 30
06:30:20 Moscow Time
Manned
5
Success
16
2006
Sept. 18
08:08:40 Moscow Time
Manned
5
Success
17
2007
April 7
21:31:14 Moscow Time
Manned
1
5
Success
18
2007
May 30
00:31 Moscow Time

Globalstar, Globalstar, Globalstar,
Globalstar

Application / communications
6
Success
19
2007
Oct. 10
17:22 Moscow Time
Manned
1
5
Success
20
2007
Oct. 21
00:12 Moscow Time

Globalstar, Globalstar, Globalstar,
Globalstar

Application / communications
6
Success
21
2007
Dec. 14
16:17 Moscow Time
Application / remote-sensing
6
Success
22
2008
April 8
15:16 Moscow Time

Soyuz TMA-12

1
5
Success
23
2008
April 27
02:16 Moscow Time

GIOVE-B

Application / navigation
6
Success
24
2008
Oct. 12
11:01 Moscow Time

Soyuz TMA-13

Manned
1
5
Success
25
2009
March 26
14:49 Moscow Time

Soyuz TMA-14

Manned
1
5
Success
26
2009
May 27
14:34:49 Moscow Time

Soyuz TMA-15

Manned
1
5
Success
27
2009
Sept. 30
11:14:45 Moscow Summer Time

Soyuz TMA-16

Manned
1
5
Success
28
2009
Dec. 21
00:52 Moscow Time

Soyuz TMA-17

Manned
1
5
Success
29
2010
April 2
08:04:34 Moscow Summer Time

Soyuz TMA-18

1
5
Success
30
2010
June 16
01:35:19 Moscow Summer Time
5
Success
31
2010
Oct. 8
03:10:55 Moscow Summer Time
1
Success
32
2010
Dec. 15
22:09:25 Moscow Time
5
Success
33
2011
April 5
02:18:20 Moscow Summer Time

Soyuz TMA-21

1
5
Success
34
2011
May 8
00:12:45 Moscow Summer Time

Soyuz TMA-02M

1
5
Success
35
2011
Nov. 14
08:14:03 Moscow Time
5
Success
36
2011
Dec. 21
17:16:14 Moscow Summer Time
5
Success
37
2012
May 15
07:01:23 Moscow Summer Time
5
Success
38
2012
July 15
06:40:03.91 Moscow Time
5
Success
39
2012
July 22
10:41:39 Moscow Time
Kanopus-V No. 1, BKA, MKA-FKI-PN1, exactView-1, TET-1
Application / remote sensing
6
Success
40
2012
Oct. 23
14:51:10 Moscow Time
6
Success
41
2012
Dec. 19
16:12: 35 Moscow Time
5
Success
42
2013
March 29
00:43:20 Moscow Time

Soyuz TMA-08M

1
5
Success
43
2013
May 29
00:31:24 Moscow Summer Time

Manned

5
Success
44
2013
Sept. 26
00:58:50 Moscow Time
5
Success
45
2013
Nov. 7
08:14:15 Moscow Time
5
Success
46
2014
March 26
01:17:23 Moscow Time
5
Success
47
2014
May 28
23:57:41 Moscow Time
5
Success
48
2014
Sept. 26
00:25 Moscow Time
5
Success
49
2014
Nov. 24
00:01:14 Moscow Time
6
Success
50
2015
March 27
22:42:57 Moscow Time
5
Success
51
2015
July 23
00:02:44 Moscow Time
5
Success
52
2015
Sept. 2
07:37:43 Moscow Time
5
Success
53
2015
Dec. 15
14:03:09.328 Moscow Time
5
Success
54
2016
March 19
00:26:38.355 Moscow Time
5
Success
55
2016
July 7
04:36:40.208 Moscow Time
5
Success
56
2016
Oct. 19
11:05:14.378 Moscow Time
6
Success
57
2016
Nov. 17
23:20:13.099 Moscow Time
5
Success
58
2017
April 20
10:13:43 Moscow Time
5
Success
59
2017
July 28
18:41:12.285 Moscow Time
5
Success
60
2017
Sept. 13
00:17:02.407 Moscow Time
5
Success

 

Read much more about the history of the Russian space program in a richly illustrated, large-format glossy edition:

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The article and graphics by Anatoly Zak; Last update: November 6, 2017

Page editor: Alain Chabot; Last edit: October 23, 2017

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rollout

A Soyuz-FG rocket with the Soyuz TMA-17M spacecraft leaves assembly building at Site 112 on July 20, 2015. Click to enlarge. Credit: Roskosmos


stage1

Liftoff of Soyuz rocket. Click to enlarge. Credit: RKTs Progress


rd107a

A demo version of the RD-107A engine. Click to enlarge. Copyright © 2010 Anatoly Zak


adapter

An adapter connecting Soyuz spacecraft to its Soyuz FG launch vehicle. Click to enlarge. Credit: Roskosmos


pad

A Soyuz-FG rocket with the Soyuz-TMA-17 spacecraft shortly after its rollout to the launch pad in Baikonur on July 20, 2015. Click to enlarge. Credit: Roskosmos


lift

A Soyuz-FG rocket lifts off with the Soyuz MS-05 spacecraft on July 28, 2017. Click to enlarge. Credit: NASA


RD-0110