Encyclopedia Astronautica
Soyuz 11A511U / Fregat


Russian orbital launch vehicle. Standard Soyuz universal booster with the Fregat upper stage, derived from the propulsion system for Lavochkin interplanetary probes.

The Fregat upper stage has a flight-proved propulsion subsystem that is based on a single-chamber Lavochkin engine. Four clusters of three 50-N hydrazine thrusters provide attitude control. The Fregat propulsion system powered the Fobos probe to Mars, and the main engine was fitted on nearly 30 interplanetary spacecraft. During its numerous missions, the engine demonstrated the highest reliability under extreme conditions, exceeding technical specifications. This application of proven, in-production hardware ensures high reliability and lower cost for the Fregat upper stage. Fregat operates on UDMH fuel and N2O4 oxidizer, and has a liftoff mass of up to 6,535 kg. The weight at burnout is 950-1,100 kg.. Vacuum thrust is 19.6 kN., and burn time is up to 877 sec. The engine can be restarted as many as 20 times.

LEO Payload: 5,000 kg (11,000 lb) to a 450 km orbit at 51.80 degrees. Payload: 2,700 kg (5,900 lb) to a 800 km SSO. Launch Price $: 50.000 million in 1999 dollars.

Stage Data - Soyuz 11A511U / Fregat

  • Stage 0. 4 x Soyuz 11A511U-0. Gross Mass: 44,500 kg (98,100 lb). Empty Mass: 3,784 kg (8,342 lb). Thrust (vac): 994.300 kN (223,528 lbf). Isp: 310 sec. Burn time: 120 sec. Isp(sl): 264 sec. Diameter: 2.68 m (8.79 ft). Span: 2.68 m (8.79 ft). Length: 19.60 m (64.30 ft). Propellants: Lox/Kerosene. No Engines: 1. Engine: RD-107-11D511. Status: In Production. Comments: Gross mass includes 1190 kg of hydrogen peroxide and 280 kg of liquid nitrogen expended during ascent but not contributing to propulsion.
  • Stage 1. 1 x Soyuz 11A511U-1. Gross Mass: 105,400 kg (232,300 lb). Empty Mass: 6,875 kg (15,156 lb). Thrust (vac): 997.091 kN (224,155 lbf). Isp: 311 sec. Burn time: 286 sec. Isp(sl): 245 sec. Diameter: 2.95 m (9.67 ft). Span: 2.95 m (9.67 ft). Length: 27.80 m (91.20 ft). Propellants: Lox/Kerosene. No Engines: 1. Engine: RD-108-11D512. Status: In Production. Comments: Gross mass includes 2600 kg of hydrogen peroxide and 520 kg of liquid nitrogen expended during ascent but not contributing to propulsion.
  • Stage 2. 1 x Soyuz 11A511U-2. Gross Mass: 25,200 kg (55,500 lb). Empty Mass: 2,355 kg (5,191 lb). Thrust (vac): 298.100 kN (67,016 lbf). Isp: 330 sec. Burn time: 250 sec. Diameter: 2.66 m (8.72 ft). Span: 2.66 m (8.72 ft). Length: 6.74 m (22.11 ft). Propellants: Lox/Kerosene. No Engines: 1. Engine: RD-0110. Status: In Production.
  • Stage 3. 1 x Fregat. Gross Mass: 6,535 kg (14,407 lb). Empty Mass: 1,100 kg (2,400 lb). Thrust (vac): 19.600 kN (4,406 lbf). Isp: 327 sec. Burn time: 877 sec. Diameter: 3.35 m (10.99 ft). Span: 3.35 m (10.99 ft). Length: 1.50 m (4.90 ft). Propellants: N2O4/UDMH. No Engines: 1. Engine: S5.92. Status: Out of Production. Comments: Upper stage developed from propulsion bus for Lavochkin lunar and planetary probes (Luna Ye-8, Mars M1, Fobos 1F). 20 restarts.

Status: Design 2000.
Gross mass: 305,000 kg (672,000 lb).
Payload: 5,000 kg (11,000 lb).
Height: 46.10 m (151.20 ft).
Diameter: 2.95 m (9.67 ft).
Thrust: 4,030.00 kN (905,980 lbf).
Apogee: 450 km (270 mi).

More... - Chronology...


Associated Countries
Associated Engines
  • S5.92 Isayev N2O4/UDMH rocket engine. 19.6 kN. Phobos propulsion module, later adapted as Fregat upper stage. In production. Isp=327s. Gas generator cycle. Nominal and low-thrust thrust levels. More...

See also
  • R-7 The world's first ICBM became the most often used and most reliable launch vehicle in history. The original core+four strap-on booster missile had a small third stage added to produce the Vostok launch vehicle, with a payload of 5 metric tons. Addition of a larger third stage produced the Voskhod/Soyuz vehicle, with a payload over 6 metric tons. Using this with a fourth stage, the resulting Molniya booster placed communications satellites and early lunar and planetary probes in higher energy trajectories. By the year 2000 over 1,628 had been launched with an unmatched success rate of 97.5% for production models. Improved models providing commercial launch services for international customers entered service in the new millenium, and a new launch pad at Kourou was to be inaugurated in 2011. It appeared that the R-7 could easily still be in service 70 years after its first launch. More...

Associated Manufacturers and Agencies
  • Korolev Russian manufacturer of rockets, spacecraft, and rocket engines. Korolev Design Bureau, Kaliningrad, Russia. More...

Associated Stages
  • Fregat N2O4/UDMH propellant rocket stage. Loaded/empty mass 6,535/1,100 kg. Thrust 19.60 kN. Vacuum specific impulse 327 seconds. Upper stage developed from propulsion bus for Lavochkin lunar and planetary probes (Luna Ye-8, Mars M1, Fobos 1F). 20 restarts. More...
  • Soyuz 11A511U-0 Lox/Kerosene propellant rocket stage. Loaded/empty mass 44,500/3,784 kg. Thrust 994.30 kN. Vacuum specific impulse 310 seconds. Gross mass includes 1190 kg of hydrogen peroxide and 280 kg of liquid nitrogen expended during ascent but not contributing to propulsion. More...
  • Soyuz 11A511U-1 Lox/Kerosene propellant rocket stage. Loaded/empty mass 105,400/6,875 kg. Thrust 997.09 kN. Vacuum specific impulse 311 seconds. Current version. Gross mass includes 2600 kg of hydrogen peroxide and 520 kg of liquid nitrogen expended during ascent but not contributing to propulsion. More...
  • Soyuz 11A511U-2 Lox/Kerosene propellant rocket stage. Loaded/empty mass 25,200/2,355 kg. Thrust 298.10 kN. Vacuum specific impulse 330 seconds. More...

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