Viking (rocket engine)

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Viking 5C rocketengine.jpg
Viking 5C rocket engine
Country of origin France
First flight 1979
Last flight 2003
Designer Société Européenne de Propulsion (SEP)
Predecessor none
Successor Vikas
Vulcain
Status retired
Liquid-fuel engine
Propellant Dinitrogen tetroxide / UDMH or UH 25
Mixture ratio 1.7-1.86
Cycle Gas-generator cycle
Pumps 3 coaxial pumps
Configuration
Chamber film-cooled, ablative throat insert
Nozzle ratio 10 (Viking 5C)
30.8 (Viking 4B)[1]
Performance
Thrust (vac.) 690–805 kN (155,000–181,000 lbf)
Thrust (SL) 611–678 kN (137,000–152,000 lbf)
Thrust-to-weight ratio 80-99
Chamber pressure 5.5 MPa (800 psi)
Isp (vac.) 281-301 sec
Isp (SL) 248-284 sec
Restarts unlimited
Gimbal range fixed, swiveled and gimbaled versions were made
Dimensions
Length 2.87–3.51 m (9.4–11.5 ft)
Diameter 0.95–1.7 m (3.1–5.6 ft)
Used in
Ariane 1 - Ariane 4
References
References [2]

The Viking rocket engines were members of a series of bipropellant engines for the first and second stages of the Ariane 1 through Ariane 4 commercial launch vehicles, using storable, hypergolic propellants, N2O4/UH 25 (mixture 75% UDMH and 25% Hydrazine.[3])

The earliest versions, developed in 1965, had a sea-level thrust of about 190 kN. By 1971, the thrust has improved to 540 kN, with resulting engine named Viking 1 and adopted for the Ariane program. The engine first flown on Ariane 1 rocket in 1979 was Viking 2, with the further improved thrust reaching 611 kN.

The version used on the Ariane 4 first stage, which clustered four together, had 667 kN thrust each. The second stage of Ariane used a single Viking. Over 1000 were built, and achieved a high level of reliability from early in the program.

The 144 Ariane 1 to 4 used a total of 958 Viking engines. Only 2 engines have led to a failure. The first failure (on second Ariane 1 flight 23 May 1980) was due to a chamber combustion instability.[4] The vehicle has lost an attitude control and broke up. Several injector changes were implemented in the aftermath of the failure, and fuel swapped from the UDMH to the UH 25.

The second failure is of human origin: a rag had been left in a water coolant pipe during installation, resulting in a loss of thrust and vehicle breakup due off-center thrust during launch 22 February 1990.[5]

Initially, all the engines were tested before being integrated on a launcher. Beginning in 1998, engineers, confident of the reliability of the engine, authorized the use of untested engines on launchers. One engine per year, randomly taken in the workshops of assembly, was tested.[6] This confidence is very rare in the world of space engines.

The unusual feature of the Viking engines is their water tank and water pump, used to cool the exhaust gasses of the gas generator. The hot exhaust of the gas generator is cooled by water injection to 620C before been used to drive the three coaxial turbopumps (for water, fuel and oxidizer) and to pressurize the fuel tanks. The water was also used as a hydraulic fluid to actuate the valves.[7]

Technical Data[edit]

Version Viking 2 Viking 2B Viking 4 Viking 4B Viking 5C Viking 6
Height 2.87 m 2.87 m 3.51 m 3.51 m 2.87 m 2.87 m
Diameter 0.95 m 0.99 m 1.70 m 1.70 m 0.99 m 0.99 m
Mass 776 kg[8] 776 kg[9] 826 kg 826 kg 826 kg 826 kg
Fuels Dinitrogen tetroxide and UDMH in Ratio 1.86:1 Dinitrogen tetroxide and UH 25 in Ratio 1.70:1 Dinitrogen tetroxide and UDMH in Ratio 1.86:1 Dinitrogen tetroxide and UH 25 in Ratio 1.70:1 Dinitrogen tetroxide and UH 25 in Ratio 1.70:1 Dinitrogen tetroxide and UH 25 in Ratio 1.71:1
Fuel Consumption 250 kg/s ca. 275 kg/s ca. 275 kg/s 273 kg/s 244 kg/s ca. 275 kg/s
Performance of the turbine 2500 kW/10,000 U/min. 2500 kW/10,000 U/min. 2500 kW/10,000 U/min. 2500 kW/10,000 U/min. 2500 kW/10,000 U/min. 2500 kW/10,000 U/min.
Vacuum thrust 690 kN ? 713 kN 805 kN[10] 758 kN 750 kN
SeaLevel thrust 611 kN 643 kN - - 678 kN ?
Use Ariane 1, Ariane 2, 3 Ariane 1 Ariane 2 - 4 Ariane 4 PAL (Ariane 4 liquid booster )

See also[edit]

References[edit]

  1. ^ George Paul Sutton, "History of Liquid Propellant Rocket Engines", p. 798
  2. ^ News Archive 2009 Viking engine
  3. ^ Souchier, A..Drakkar Ariane 1st stage - The concept and its originality , AA(Societe Europeenne de Propulsion, Vernon, Eure, France) International Astronautical Federation, International Astronautical Congress, 27th, Anaheim, Calif., Oct. 10-16, 1976, 4 p.
  4. ^ Guy Collins. "Europe in Space", p. 51
  5. ^ Launch failures: the “Oops!” factor
  6. ^ Qualification Over Ariane’s Lifetime
  7. ^ George Paul Sutton, "History of Liquid Propellant Rocket Engines", p. 799
  8. ^ "Archived copy". Archived from the original on 2015-08-24. Retrieved 2015-08-14.
  9. ^ "Archived copy". Archived from the original on 2015-08-24. Retrieved 2015-08-17.
  10. ^ Martin J. L. Turner, "Rocket and Spacecraft Propulsion: Principles, Practice and New Developments", p.90

External links[edit]

  • [1] Vernon, French manufacturer's history site.