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Successful First Test Firing of P120C SRB for Ariane 6 and Vega-C

By Doug Messier
Parabolic Arc
July 16, 2018
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P120C awaits first hot firing. (Credit: ESA)

  • A successful test firing of 135 seconds conducted on the BEAP test bench in Kourou, French Guiana
  • P120C – the largest monolithic carbon-fiber solid rocket motor (SRM) in the world – is loaded with 142 tons of propellant
  • P120C will equip the boosters of both Ariane 62 and Ariane 64 and the Vega-C first stage ; 35 motors to be produced annually

KOUROU, French Guiana (Avio PR) — The P120C was successfully tested on 13 July in Kourou, French Guiana, on the BEAP test bench for solid rocket motors, operated by the French space agency CNES. This successful test of the first P120C ever produced is a major step in the development of the future European launchers, Ariane 6 and Vega-C.

The P120C, co-developed by ArianeGroup and Avio, on behalf of their 50/50 joint venture Europropulsion, is the world’s largest monolithic carbon fiber SRM. The program for the development of Ariane 6 and Vega-C was decided on at the European Space Agency (ESA) Ministerial Council in 2014.

Two further test stand firings will follow to qualify this motor before the first flight of Vega-C in 2019 and that of Ariane 6 in 2020.

With major investments required for producing solid-propellant motors, the P120C is a perfect example of rationalization, since it will equip both Ariane 6 (in both its two-booster Ariane 62 and its four-booster Ariane 64 versions) and the first stage of Vega-C. This will allow up to 35 motors to be produced every year, making optimal use of industrial infrastructures on the European continent and in French Guiana, thus meeting the goals of the Ariane 6 and Vega-C programs: optimized costs, shorter cycles owing to a simplified design, and the application of innovative technologies and processes.

The P120C consists of two principal parts. The first is the structural casing, built by Avio and made of carbon fiber (filament-wound, automated fabric layup pre-impregnated epoxy sheets). The second part is the nozzle, built by ArianeGroup and made of various composite materials, including carbon/carbon; it allows very high speed ejection of the extremely hot gases (3,000°C) generated by the motor, thus creating thrust by transforming the combustion gas energy into kinetic energy. The latter can also pivot, which enables the launcher to be piloted.

The P120C in figures:

  • Motor length: 13.5 m Average thrust: 4,500 kN
  • Diameter: 3.4 m Specific impulse: 278.5 s
  • Propellant mass: 142 t Combustion time: 135 s
  • Motor dry mass: 11t
  • Motor case mass: 8.3 t