# Fregat

Fregat (Russian: Фрегат, lit. 'frigate') is an upper stage developed by NPO Lavochkin in the 1990s. It has been used in some Soyuz and Zenit launch vehicles, but it is universal. It can be used as a part of any medium and heavy class launch vehicles. Fregat became operational in February 2000.
Its liquid propellant engine uses unsymmetrical dimethylhydrazine (UDMH) fuel and dinitrogen tetroxide (N$_2$O$_4$) oxidizer, two hypergolic propellants that spontaneously ignites on contact with each other. With a success rate of 97.3%—including two failures and one partial failure—the Fregat is among the most reliable upper stages worldwide. It has successfully deployed over 300 payloads into various orbits and is the only upper stage capable of placing payloads into three or more distinct orbits in a single launch.

## Description

The Fregat upper stage is a versatile and autonomous vehicle designed to inject large payloads into a range of orbits, including low, medium, and geosynchronous. Additionally, it serves as an escape stage for sending space probes on interplanetary missions, such as the Venus Express and Mars Express.
Developed by NPO Lavochkin in the 1990s, the Fregat features six spherical tanks—four for propellants and two for avionics—arranged in a circle. Its main engine is centrally positioned, allowing for a compact design with a diameter larger than its height. Structural support is provided by eight struts passing through the tanks, which also transfer thrust loads to the launcher. Fregat operates independently from the lower stages of its launch vehicle, with its own guidance, navigation, attitude control, tracking, and telemetry systems.
The Fregat’s design was largely based on the spacecraft bus used in the Soviet Phobos program of the late 1980s, itself based on the architecture used for the Soviet lunar probes developed at NPO Lavochkin in the 1960s. Fregat also integrated several flight-proven subsystems and components from previous spacecraft and rockets. This approach ensured high reliability and accelerated development. Fregat was flight-qualified in February 2000 and successfully completed four missions that same year.
Currently used as the fourth stage on Soyuz launch vehicles, the Fregat’s S5.92 engine is capable of up to 25 ignitions, with seven demonstrated during flight. This allows it to execute complex mission profiles that would be impossible for the launch vehicle alone. The stage provides both three-axis and spin stabilization for spacecraft payloads. Fregat uses storable, hypergolic propellants—unsymmetrical dimethylhydrazine (UDMH) as fuel and dinitrogen tetroxide (N$_2$O$_4$, also called NTO or amyl) as the oxidizer, which ignite spontaneously upon contact. To date, Fregat has successfully deployed over 300 payloads into various orbits and remains the only upper stage capable of placing payloads into three or more distinct orbits in a single launch.

## Fregat upper stage launch statistics

| № | Date | Number | Modification | Mission | Launch vehicle | Payload | Result |
| 1 | 2000/02/09 | 1001 | Fregat | ST07 | Soyuz-U | Full-size satellite layout, Inflatable Braking Device | Success |
| 2 | 2000/03/20 | 1002 | Fregat | ST08 | Soyuz-U | Dumsat | Success |
| 3 | 2000/07/16 | 1003 | Fregat | ST09 | Soyuz-U | Cluster FM6, Cluster FM7 | Success |
| 4 | 2000/08/09 | 1004 | Fregat | ST10 | Soyuz-U | Cluster FM5, Cluster FM8 | Success |
| 5 | 2003/06/02 | 1005 | Fregat | ST11 | Soyuz-FG | Mars Express, Beagle 2 | Success |
| 6 | 2003/12/27 | 1006 | Fregat | ST12 | Soyuz-FG | AMOS-2 | Success |
| 7 | 2005/08/13 | 1007 | Fregat | ST13 | Soyuz-FG | Galaxy 14 | Success |
| 8 | 2005/11/09 | 1010 | Fregat | ST14 | Soyuz-FG | Venus Express | Success |
| 9 | 2005/12/28 | 1009 | Fregat | ST15 | Soyuz-FG | GIOVE-A | Success |
| 10 | 2006/10/19 | 1011 | Fregat | ST16 | Soyuz-2.1a | MetOp-A | Success |
| 11 | 2006/12/24 | 1012 | Fregat | – | Soyuz-2.1a | Meridian № 11L | Success |
| 12 | 2006/12/27 | 1013 | Fregat | ST17 | Soyuz-2.1b | CoRoT | Success |
| 13 | 2007/05/29 | 1016 | Fregat | ST18 | Soyuz-FG | Globalstar M065, Globalstar M069, Globalstar M071, Globalstar M072 | Success |
| 14 | 2007/10/20 | 1015 | Fregat | ST19 | Soyuz-FG | Globalstar M066, Globalstar M067, Globalstar M068, Globalstar M070 | Success |
| 15 | 2007/12/14 | 1015-2 | Fregat | ST20 | Soyuz-FG | RADARSAT-2 | Success |
| 16 | 2008/04/26 | 1008 | Fregat | ST21 | Soyuz-FG | GIOVE-B | Success |
| 17 | 2009/05/21 | 1018 | Fregat | – | Soyuz-2.1a | Meridian № 12L | Success |
| 18 | 2009/09/17 | 1014 | Fregat | – | Soyuz-2.1b | Meteor-M № 1, Sterkh, Universitetsky-Tatyana-2, UGATUSAT, BLITS, IRIS, Sumbandila | Success |
| 19 | 2010/10/19 | 1023 | Fregat-M | ST22 | Soyuz-2.1a | Globalstar M073, Globalstar M074, Globalstar M075, Globalstar M076, Globalstar M077, Globalstar M079 | Success |
| 20 | 2010/11/02 | 1022 | Fregat-M | – | Soyuz-2.1a | Meridian № 13L | Success |
| 21 | 2011/01/20 | 2001 | Fregat-SB | – | Zenith-3SLBF | Elektro-L No.1 | Success |
| 22 | 2011/02/26 | 1035 | Fregat-M | – | Soyuz-2.1b | Glonass-K № 11L | Success |
| 23 | 2011/07/13 | 1024 | Fregat-M | ST23 | Soyuz-2.1a | Globalstar M081, Globalstar M083, Globalstar M085, Globalstar M088, Globalstar M089, Globalstar M091 | Success |
| 24 | 2011/07/18 | 2002 | Fregat-SB | – | Zenith-3SLBF | Spektr-R | Success |
| 25 | 2011/10/02 | 1045 | Fregat-M | – | Soyuz-2.1b | Glonass-M № 742 | Success |
| 26 | 2011/10/21 | 1030 | Fregat-MT | VS01 | Soyuz-ST-B | Galileo 1, European Union Galileo 2 | Success |
| 27 | 2011/11/28 | 1046 | Fregat-M | – | Soyuz-2.1b | Glonass-M № 746 | Success |
| 28 | 2011/12/17 | 1021 | Fregat | VS02 | Soyuz-ST-A | Pleiades-1A, ELISA W11, ELISA E12, ELISA W23, ELISA E24, SSOT | Success |
| 29 | 2011/12/23 | 1042 | Fregat-M | – | Soyuz-2.1b | Meridian № 15L | Success |
| 30 | 2011/12/28 | 1027 | Fregat-M | ST24 | Soyuz-2.1a | Globalstar M080, Globalstar M082, Globalstar M084, Globalstar M086, Globalstar M090, Globalstar M092 | Success |
| 31 | 2012/07/22 | 1019 | Fregat | – | Soyuz-FG | Kanopus-V № 1, Zond-PP, BKA, exactView-1, TET-1 | Success |
| 32 | 2012/09/17 | 1037 | Fregat-M | ST25 | Soyuz-2.1a | MetOp-B | Success |
| 33 | 2012/10/12 | 1031 | Fregat-MT | VS03 | Soyuz-ST-B | Galileo 3, Galileo 4 | Success |
| 34 | 2012/11/14 | 1034 | Fregat-M | – | Soyuz-2.1a | Meridian № 16L | Success |
| 35 | 2012/12/02 | 1020 | Fregat | VS04 | Soyuz-ST-A | Pléiades-1B | Success |
| 36 | 2013/02/06 | 1029 | Fregat-M | ST26 | Soyuz-2.1a | Globalstar M078, Globalstar M093, Globalstar M094, Globalstar M095, Globalstar M096, Globalstar M097 | Success |
| 37 | 2013/04/26 | 1047 | Fregat-M | – | Soyuz-2.1b | Glonass-K № 747 | Success |
| 38 | 2013/06/25 | 1041 | Fregat-MT | VS05 | Soyuz-ST-B | O3b FM1, O3b FM2, O3b FM4, O3b FM5 | Success |
| 39 | 2013/12/19 | 1040 | Fregat-MT | VS06 | Soyuz-ST-B | Gaia | Success |
| 40 | 2014/03/23 | 112-01 | Fregat-M | – | Soyuz-2.1b | Glonass-M № 754 | Success |
| 41 | 2014/04/03 | 1038 | Fregat-M | VS07 | Soyuz-ST-A | Sentinel-1A | Success |
| 42 | 2014/06/14 | 112-02 | Fregat-M | – | Soyuz-2.1b | Glonass-M № 755 | Success |
| 43 | 2014/07/08 | 1025 | Fregat-M | – | Soyuz-2.1b | Meteor-M №2, Vernov, DX1 [ru], UKube-1, TechDemoSat-1, SkySat-2, AISSat-2 | Success |
| 44 | 2014/07/10 | 1032 | Fregat-MT | VS08 | Soyuz-ST-B | O3b FM3, O3b FM6, O3b FM7, O3b FM8 | Success |
| 45 | 2014/08/22 | 1039 | Fregat-MT | VS09 | Soyuz-ST-B | Galileo 5, Galileo 6 | Failure |
| 46 | 2014/10/30 | 1026 | Fregat-M | – | Soyuz-2.1a | Meridian № 17L | Success |
| 47 | 2014/11/30 | 1044 | Fregat-M | – | Soyuz-2.1b | Glonass-K № 12L | Success |
| 48 | 2014/12/18 | 133-01 | Fregat-MT | VS10 | Soyuz-ST-B | O3b FM9, O3b FM10, O3b FM11, O3b FM12 | Success |
| 49 | 2015/03/27 | 133-02 | Fregat-MT | VS11 | Soyuz-ST-B | Galileo 7, Galileo 8 | Success |
| 50 | 2015/09/11 | 133-03 | Fregat-MT | VS12 | Soyuz-ST-B | Galileo 9, Galileo 10 | Success |
| 51 | 2015/11/17 | 1033 | Fregat-M | – | Soyuz-2.1b | EKS № 1 | Success |
| 52 | 2015/12/11 | 2004 | Fregat-SB | – | Zenith-3SLBF | Elektro-L No.2 № 2 | Success |
| 53 | 2015/12/17 | 133-04 | Fregat-MT | VS13 | Soyuz-ST-B | Galileo 11, Galileo 12 | Success |
| 54 | 2016/02/07 | 112-03 | Fregat-MT | – | Soyuz-2.1b | Glonass-M № 751 | Success |
| 55 | 2016/04/25 | 133-08 | Fregat-M | VS14 | Soyuz-ST-A | Sentinel-1B | Success |
| 56 | 2016/05/24 | 133-05 | Fregat-MT | VS15 | Soyuz-ST-B | Galileo 13, Galileo 14 | Success |
| 57 | 2016/05/29 | 112-04 | Fregat-M | – | Soyuz-2.1b | Glonass-M № 753 | Success |
| 58 | 2017/01/28 | 133-07 | Fregat-MT | VS16 | Soyuz-ST-B | Hispasat 36W-1 | Success |
| 59 | 2017/05/18 | 133-09 | Fregat-M | VS17 | Soyuz-ST-A | SES-15 | Success |
| 60 | 2017/05/25 | 111–301 | Fregat-M | – | Soyuz-2.1b | Tundra № 2 | Success |
| 61 | 2017/07/14 | 122-02 | Fregat-M | – | Soyuz-2.1a | Kanopus-V-IK, MKA-N № 1, MKA-N № 2, Mayak, Iskra-MAI-85, Ecuador UTE-YUZGU», Flying Laptop, TechnoSat, WNISAT-1R, NorSat-1, NorSat-2, Flock-2k 1...48, CICERO 1...3, Corvus-BC 1...2, Lemur-2 42...49, NanoACE | Partial failure |
| 62 | 2017/09/22 | 112-05 | Fregat-M | – | Soyuz-2.1b | Glonass-M № 752 | Success |
| 63 | 2017/11/28 | | Fregat-M | – | Soyuz-2.1b | Meteor-M №2, Baumanets-2, LEO Vantage 2, Helios-Wire BIU, IDEA-OSG 1, AISSat-3, D-Star One, SEAM, Corvus-BC 3, Lemur-2 58...67 | Failure |
| 64 | 2017/12/26 | 2006 | Fregat-SB | – | Zenith-3SLBF | Angosat-1 | Success |
| 65 | 2018/02/01 | 122-03 | Fregat-M | – | Soyuz-2.1a | Kanopus-V № 3, Kanopus-V № 4, Lemur-2 74, Lemur-2 75, Lemur-2 76, Lemur-2 77, S-Net A, S-Net B, S-Net C, S-Net D, D-Star One | Success |
| 66 | 2018/03/09 | 133-06 | Fregat-MT | VS18 | Soyuz-ST-B | O3b FM13, O3b FM14, O3b FM15, O3b FM16 | Success |
| 67 | 2018/06/16 | 112-06 | Fregat-M | – | Soyuz-2.1b | Glonass-M № 756 | Success |
| 68 | 2018/11/03 | 112-08 | Fregat-M | – | Soyuz-2.1b | Glonass-M № 757 | Success |
| 69 | 2018/11/07 | 133-14 | Fregat-M | VS19 | Soyuz-ST-B | MetOp-C | Success |
| 70 | 2018/12/19 | 133-10 | Fregat-M | VS20 | Soyuz-ST-B | Composante Spatiale Optique | Success |
| 71 | 2018/12/27 | 122-06 | Fregat-M | – | Soyuz-2.1a | Kanopus-V № 5, Kanopus-V № 6, GRUS-1, ZACube-2, Lume-1, Flock-3k 1...12, Lemur-2 88...95, D-Star One iSat, D-Star One Sparrow, UWE-4, ICEYE-Dummy, SAMSON-Dummy 1...3 | Success |
| 72 | 2019/02/21 | 112-07 | Fregat-M | – | Soyuz-2.1b | EgyptSat-A | Success |
| 73 | 2019/02/27 | 133-15 | Fregat-M | VS21 | Soyuz-ST-B | OneWeb-0006, OneWeb-0007, OneWeb-0008, OneWeb-0010, OneWeb-0011, OneWeb-0012 | Success |
| 74 | 2019/04/04 | 133-17 | Fregat-MT | VS22 | Soyuz-ST-B | O3b FM17, O3b FM18, O3b FM19, O3b FM20 | Success |
| 75 | 2019/05/27 | 112-09 | Fregat-M | – | Soyuz-2.1b | Glonass-M № 758 | Success |
| 76 | 2019/07/05 | 122-04 | Fregat-M | – | Soyuz-2.1b | Meteor-M No.2 Sokrat VDNH-80 AmurSat SEAM-2.0 MTCube SONATE Beesat 9...13 MOVE-IIb TTU-101 Ecuador-UTE El Camino Real Lemur-2 100...107 NSLSat-1 JAISAT-1 EXOCONNECT LightSat Lucky-7 ICEYE X4 ICEYE X5 CarboNIX DoT 1 | Success |
| 77 | 2019/07/30 | | Fregat-M | – | Soyuz-2.1a | Meridian № 18L | Success |
| 78 | 2019/09/26 | | Fregat-M | – | Soyuz-2.1b | Tundra № 3 | Success |
| 79 | 2019/12/11 | 112-10 | Fregat-M | – | Soyuz-2.1b | Glonass-M № 759 | Success |
| 80 | 2019/12/18 | | Fregat-M | VS23 | Soyuz-ST-A | COSMO-SkyMed CHEOPS EyeSat ANGELS OPS-SAT | Success |
| 81 | 2020/02/07 | | Fregat-M | ST27 | Soyuz-2.1b | OneWeb (34 units) | Success |
| 82 | 2020/02/20 | | Fregat-M | – | Soyuz-2.1a | Meridian № 19L | Success |
| 83 | 2020/03/17 | | Fregat-M | – | Soyuz-2.1b | Glonass-M №760 | Success |
| 84 | 2020/03/21 | | Fregat-M | ST28 | Soyuz-2.1b | OneWeb (34 units) | Success |
| 85 | 2020/12/29 | | Fregat | VS24 | Soyuz ST-A | Falcon Eye 2 | Success |
| 86 | 2021/02/28 | 122-07 | Fregat-M | – | Soyuz-2.1b | Arktika-M №1 | Success |
| 87 | 2021/03/22 | 122-05 | Fregat-M | – | Soyuz-2.1a | CAS500-1 ELSA-d Target, Chaser DMSAT-1 Fukui Prefectural Satellite GRUS-1 × 3 ADELIS-SAMSON x 3 BeeSat × 4 Challenge One CubeSX-HSE CubeSX-Sirius-HSE GRBAlpha Hiber-3 Kepler-6,7 KMSL KSU_Cubesat LacunaSat-2b Shaheen Sat 17 NANOSATC-BR2 OrbiCraft-Zorkiy Pumbaa, Timon WildTrackCube-SIMBA 3B5GSAT UNISAT-7 BCCSAT-1 FEES DIY SMOG-1 STECCO | Success |
| 88 | 2021/03/25 | 123-05 | Fregat | ST30 | Soyuz-2.1b | OneWeb (36 units) | Success |
| 89 | 2021/04/25 | 123-11 | Fregat | ST31 | Soyuz-2.1b | OneWeb (36 units) | Success |
| 90 | 2021/05/28 | 123-10 | Fregat | ST32 | Soyuz-2.1b | OneWeb (36 units) | Success |
| 91 | 2021/07/01 | 112-15 | Fregat | ST33 | Soyuz-2.1b | OneWeb (36 units) | Success |
| 92 | 2021/08/21 | 123-03 | Fregat | ST34 | Soyuz-2.1b | OneWeb (34 units) | Success |
| 93 | 2021/09/14 | 123-05 | Fregat | ST35 | Soyuz-2.1b | OneWeb (34 units) | Success |
| 94 | 2021/10/14 | 123-14 | Fregat | ST36 | Soyuz-2.1b | OneWeb (36 units) | Success |
| 95 | 2021/11/25 | 111–305 | Fregat | – | Soyuz-2.1b | EKS-5 | Success |
| 96 | 2021/12/05 | 133-13 | Fregat-MT | VS26 | Soyuz ST-B | Galileo FOC FM23 Galileo FOC FM24 | Success |
| 97 | 2021/12/27 | 123-04 | Fregat | ST37 | Soyuz-2.1b | OneWeb (36 units) | Success |
| 98 | 2022/02/05 | 111–401 | Fregat | – | Soyuz-2.1a | Neitron №1 | Success |
| 99 | 2022/02/10 | 133-19 | Fregat-MT | VS27 | Soyuz ST-B | OneWeb (34 units) | Success |
| 100 | 2022/03/22 | 111-? | Fregat | – | Soyuz-2.1a | Meridian-M 10 (20L) | Success |
| 101 | 2022/07/07 | 112-13 | Fregat | – | Soyuz-2.1b | GLONASS-K 16 | Success |
| 102 | 2022/08/09 | 123-06 | Fregat | – | Soyuz-2.1b | Khayyam CubeXS-HSE-2 CYCLOPS Geoscan-Edelweiss ISOI KAI-1 KODIZ Kuzbass-300 MIET-AIS Polytech Universe-1, 2 ReshUCube-1 Siren Skoltech B1, B2 UTMN VIZARD-SS1 | Success |
| 103 | 2022/10/10 | 112-16 | Fregat | – | Soyuz-2.1b | GLONASS-K 17 | Success |
| 104 | 2022/10/22 | 142-503 | Fregat | – | Soyuz-2.1b | Gonets-M 23, 24, 25 Skif-D | Success |
| 105 | 2022/11/02 | 111-306 | Fregat | – | Soyuz-2.1b | EKS-6 | Success |
| 106 | 2022/11/28 | 112-?? | Fregat | – | Soyuz-2.1b | GLONASS-M 761 | Success |
| 107 | 2023/05/26 | 142-01 | Fregat | – | Soyuz-2.1a | Kondor-FKA №1 | Success |
| 108 | 2023/06/27 | 142-02 | Fregat | – | Soyuz-2.1b | Meteor-M №2-3 Ahmat-1 ArcCube-01 A-SEANSAT-PG1 Avion BSUSat-2 CSTP-1.1, 1.2 Cube-SX-HSE-3 Impuls-1 Khors-1, 2 KuzGTU-1 Monitor-2, 3, 4 Nanosond-1 NORBI 2 PHI-Demo Polytech Universe-3 Rassvet-1 × 3 ReshUCube-2 SamSat-ION Saturn Sirius-SINP-3U SITRO-AIS × 8 StratoSat TK-1 Svyatobor-1 UmKa-1 UTMN-2 Vizard-meteo Yarilo-3, 4 Zorkiy-2M | Success |
| 109 | 2023/08/07 | 112-23 | Fregat | – | Soyuz-2.1b | GLONASS-K2 13L | Success |
| 110 | 2023/08/10 | 122-10 | Fregat | – | Soyuz-2.1b | Luna 25 | Success |
| 111 | 2023/12/16 | 122-11 | Fregat | – | Soyuz-2.1b | Arktika-M No. 2 | Success |
| 112 | 2024/02/29 | 142-03 | Fregat-M | – | Soyuz-2.1b | Meteor-M No.2-4 MARAFON-D-GVM Pars 1 SITRO-AIS × 16 Zorkiy-2M-2 | Success |
| 113 | 2024/05/16 | ? | Fregat-M | – | Soyuz-2.1b | Nivelir-L №4 (Kosmos 2576) Rassvet-2 × 3 SITRO-AIS × 4 Zorkiy-2M-4 Zorkiy-2M-6 | Success |
| 114 | 2024/11/04 | 142-601 | Fregat-M | – | Soyuz-2.1b | Ionosfera-M №1 Ionosfera-M №2 Altair ArcticSat-1 ASRTU-2 CSTP-2.1, 2.11, 2.2 Gorizont Hod-Hod 1A HyperView-1G Khors 3, 4 Kolibri-S Kowsar Mordovia-IoT MTUCI-1 Nokhcho Norbi-3 Polytech Universe-4, 5 RTU MIREA 1 Ruzaevka-390 SamSat-ION 2 SIT-2086 SIT-HSE SITRO-AIS × 24 TUSUR-GO Vizard-ion Vladivostok-1 YUZGU-60 ZimSat-2 | Success |

## Failures
### August 2014 failure

The Arianespace-operated flight of a Fregat MT ended in failure on 22 August 2014 after the vehicle deposited two EU/ESA Galileo navigation satellites into the wrong orbit. The lift off at 12:27:11 UTC from the Sinnamary launch site near Kourou, French Guiana, appeared to go well. However, a failure was only apparent later when, after the second firing of the Fregat MT upper stage had taken place, the satellites were detected as being in the wrong orbit.
The Independent Inquiry Board formed to analyze the causes of the "anomaly" announced its definitive conclusions on 7 October 2014 following a meeting at Arianespace headquarters in Évry, near Paris. The failure occurred during the flight of the Fregat fourth stage. It occurred about 35 minutes after liftoff, at the beginning of the ballistic phase preceding the second ignition of this stage. The scenario that led to an error in the orbital injection of the satellites was precisely reconstructed, as follows:
* The orbital error resulted from an error in the thrust orientation of the main engine on the Fregat stage during its second powered phase.
* This orientation error was the result of the loss of inertial reference for the stage.
* This loss occurred when the stage's inertial system operated outside its authorized operating envelope, an excursion that was caused by the failure of two of Fregat's attitude control thrusters during the preceding ballistic phase.
* This failure was due to a temporary interruption of the joint hydrazine propellant supply to these thrusters.
* The interruption in the flow was caused by freezing of the hydrazine.
* The freezing resulted from the proximity of hydrazine and cold helium feed lines, these lines being connected by the same support structure, which acted as a thermal bridge.
* Ambiguities in the design documents allowed the installation of this type of thermal "bridge" between the two lines. In fact, such bridges have also been seen on other Fregat stages now under production at NPO Lavochkin.
* The design ambiguity is the result of not taking into account the relevant thermal transfers during the thermal analyses of the stage system design.
The root cause of the failure of flight VS09 is therefore a shortcoming in the system thermal analysis performed during stage design, and not an operator error during stage assembly.
Since 22 August 2014, Soyuz ST-B launch vehicles with Fregat-MT upper stages have performed three successful launches, six Galileo navigation satellites have been inserted into their target orbits in frame of Soyuz at the Guiana Space Centre ongoing ESA programme.

### July 2017 partial failure

In July 2017, a Russian-operated rideshare flight of a Fregat upper stage ended with 9 of 72 small satellites dead-on-orbit.

### November 2017 failure

The Russian-operated flight of a Fregat upper stage ended in failure after the vehicle deposited the upper stage, a Meteor MS-1 weather satellite, and 18 secondary cubesats back into Earth's atmosphere due to the first Fregat burn being ignited with the stage in the wrong orientation. The guidance computer on the Soyuz rocket's Fregat upper stage was mis-programmed, causing it to begin an unnecessary turn that left it in the wrong orientation for a critical engine burn required to enter orbit.

## Debris

The Fregats did not have enough impulse capability to de-orbit themselves after placing their payload into orbit and so several have remained in orbit as space debris.
The Fregat-SB upper stage rocket used to launch the Russian Spektr-R satellite into orbit in 2011, broke into multiple pieces on May 8, 2020 creating even more debris than normal.

## Versions
### Fregat-M/Fregat-MT

Fregat-M/Fregat-MT tanks have ball-shaped additions on the tops of the tanks. These additions increase the load capability of the propellant from 5,350 kilograms (11,790 lb) to 6,640 kilograms (14,640 lb), without causing any other changes to the physical dimensions of the vehicle.

### Fregat-SB

A version called Fregat-SB can be used with Zenit-2SB launch vehicle. This version is a variation of Fregat-M with a block of drop-off tanks ("SBB" or Сбрасываемый Блок Баков in Russian) which makes increased payload capability possible. The torus-shaped SBB weighs 360 kg (790 lb) and contains up to 3,050 kg (6,720 lb) of propellant. The total dry weight of the Fregat-SB (including SBB) is 1,410 kg (3,110 lb) and the maximum propellant carrying capacity is 10,150 kg (22,380 lb).
Fregat-SB was launched for the first time on 20 January 2011, when it lifted the Elektro-L weather satellite into geosynchronous orbit.

### All versions data

Fregat Upper Stage Family :
| Stage | Fregat | Fregat-M | Fregat-MT | Fregat-SB | Fregat-SBU | Fregat-2 |
| Engine | S5.92 | S5.92 LN (Long Nozzle) | S5.92 LN (Long Nozzle) | S5.92 LN (Long Nozzle) | S5.92 LN (Long Nozzle) | S5.92 LN (Long Nozzle) |
| Total Launches | 44 | 49 | 17 | 4 | – | – |
| Thrust (Low) | 13.73 kN (3,090 lb$_f$) | 13.96 kN (3,140 lb$_f$) | 13.96 kN (3,140 lb$_f$) | 13.96 kN (3,140 lb$_f$) | 13.96 kN (3,140 lb$_f$) | 13.96 kN (3,140 lb$_f$) |
| Thrust (High) | 19.61 kN (4,410 lb$_f$) | 20.01 kN (4,500 lb$_f$) | 20.01 kN (4,500 lb$_f$) | 20.01 kN (4,500 lb$_f$) | 20.01 kN (4,500 lb$_f$) | 20.01 kN (4,500 lb$_f$) |
| Specific Impulse (Low) | 3,168 N*s/kg | 3,222 N*s/kg | 3,222 N*s/kg | 3,222 N*s/kg | 3,222 N*s/kg | 3,222 N*s/kg |
| Specific Impulse (High) | 3,207 N*s/kg | 3,268 N*s/kg | 3,268 N*s/kg | 3,268 N*s/kg | 3,268 N*s/kg | 3,268 N*s/kg |
| Propellant (Max) | 5,350 kg (11,790 lb) | 6,640 kg (14,640 lb) | 7,100 kg (15,700 lb) | 10,000 kg (22,000 lb) | 10,710 kg (23,610 lb) | 12,240 kg (26,980 lb) |
| Burn Time | 1235...874 seconds | 1535...1085 seconds | 1640...1160 seconds | 2310...1635 seconds | 2475...1750 seconds | 2830...2000 seconds |
| Flow Rate | 4.3...6.1 kg/s | 4.3...6.1 kg/s | 4.3...6.1 kg/s | 4.3...6.1 kg/s | 4.3...6.1 kg/s | 4.3...6.1 kg/s |
| Total Impulse | 16.9...17.2 MN*s | 21.4...21.7 MN*s | 22.9...23.2 MN*s | 32.2...32.7 MN*s | 34.5...35.0 MN*s | 39.4...40.0 MN*s |