Model of the Fregat-SB
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Manufacturer | NPO Lavochkin |
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Country of origin | Russia |
Used on | Soyuz, Zenit-3F |
General characteristics | |
Diameter |
Fregat/Fregat-M: 3.35 m (11.0 ft) |
Length | 1.5 m (4.9 ft) |
Propellant mass |
Fregat: 5,250 kg (11,570 lb) |
Empty mass |
Fregat: 930 kg (2,050 lb) |
Engine details | |
Engines | S5.92 |
Thrust | 19.85 kilonewtons (4,460 lbf) |
Specific impulse | 333.2 seconds |
Burn time | 1,350 seconds |
Fuel | N2O4/UDMH |
Fregat/Fregat-M: 3.35 m (11.0 ft)
Fregat: 5,250 kg (11,570 lb)
Fregat-M: 5,600 kg (12,300 lb)
Fregat: 930 kg (2,050 lb)
Fregat-M: 980 kg (2,160 lb)
Fregat (Russian: Фрегат, frigate) is an upper stage developed by NPO Lavochkin in the 1990s, which is used in some Soyuz and Zenit rockets. Its liquid propellant engine uses UDMH and N2O4.
Fregat upper stage is designed for injecting large payloads into a low, medium-height or high geosynchronous orbit. Fregat is a versatile upper stage, in addition to orbital insertion, it can be used as an escape stage to send modern space probes into interplanetary trajectories (e.g. Venus Express and Mars Express). Fregat stages are currently used as the fourth stage of some Soyuz launch vehicles. The stage can be restarted up to 25 times,
NPO Lavochkin has built many interplanetary probes, and the Fregat stage follows their design traditions. The main part of the stage is six intersecting spheres placed on a single plane, four of which contain propellants. The remaining two contain the control equipment. The main engine is placed between the spheres, so Fregat is a tightly-packed stage with a diameter much larger than its height.
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 1227 GMT 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.