Fregat

Fregat

Model of Fregat at MAKS Airshow, 2013
Manufacturer	NPO Lavochkin
Country of origin	Russia
Used on	Current: Soyuz-2 Retired: Soyuz-FG, Soyuz-ST, Soyuz-U, Zenit-3F
Launch history
Status	Active
Total launches	113
Successes (stage only)	110
Failed	2
Other	1 (partial failure)
First flight	2 February 2000
General characteristics[1]
Height	Fregat: 1.875 m (6 ft 1.8 in) Fregat-MT: 1.945 m (6 ft 4.6 in) Fregat-SB: 2.435 m (7 ft 11.9 in)
Diameter	Fregat: 3.44 m (11.3 ft) Fregat-MT: 3.8 m (12 ft) Fregat-SB: 3.875 m (12.71 ft)
Empty mass	Fregat: 945 kg (2,083 lb) Fregat-MT: 1,035 kg (2,282 lb) Fregat-SB: 1,080 kg (2,380 lb)
Gross mass	Fregat: 6,235 kg (13,746 lb) Fregat-MT: 7,640 kg (16,840 lb) Fregat-SB: 11,680 kg (25,750 lb)
Propellant mass	Fregat: 5,307 kg (11,700 lb) Fregat-MT: 6,650 kg (14,660 lb) Fregat-SB: 10,330 kg (22,770 lb)
Powered by	1 × S5.92
Maximum thrust	19.85 kN (4,460 lbf) (high) 13.93 kN (3,130 lbf) (low)
Specific impulse	333.2 s (3.268 km/s) (high) 320 s (3.1 km/s) (low)
Burn time	Up to 1,350 seconds (up to 7 starts)
Propellant	N2O4/UDMH

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 (N₂O₄) 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.