Final hot firing proves P120C booster for Ariane 6

Advanced features make this new motor a pivotal achievement of European industry. It is an example of innovative thinking and optimisation that allows Europe to equip two very different launch vehicles with the same solid rocket motor.

Depending on the configuration, two or four P120C boosters will be strapped onto the sides of the future Ariane 6 heavy-lift rocket, the P120C will also serve as the first stage of the smaller Vega-C launch vehicle.

This huge P120C motor was filled with 142 tonnes of solid propellant inside its 13.5 m long and 3.4 m diameter casing and was moved from the integration building to the dedicated stand used for testing solid propulsion stages.

After ignition it burned for 130 seconds, delivering a maximum thrust of about 4500 kN simulating liftoff and the first phase of flight. No anomalies were seen and, according to initial recorded data, the performance met expectations. A full analysis of these test results and inspection of all components will confirm readiness of this motor for the debut launch of Ariane 6.

“This firing of the P120C motor paves the way for its use on Ariane 6. It is proof of the hard work and dedication of all the teams involved who have made this test possible despite the COVID-19 crisis. This accomplishes an important milestone towards flight,” commented Stefano Bianchi, Head of Space Transportation Development at ESA.

Avio in Italy built this motor case in one piece by winding carbon-fibre composite for a strong and rigid lightweight shell casing. ArianeGroup in France developed the advanced P120C nozzle, while Nammo in Norway provided the igniter. The propellant was cast by Regulus in French Guiana. Advanced manufacturing techniques have been incorporated by Europropulsion in horizontal robotic integration of the nozzle too. Efficient production methods have shortened production cycles and optimised costs. 

Europropulsion built three models of the P120C for testing: a development model (DM) configured for Vega-C; a first qualification model (QM1) also configured for Vega-C; and a second qualification model (QM2) configured for Ariane 6.

This hot firing of QM2 is the third and final test of the P120C. It follows the test of the development model in July 2018 and the first qualification model in January 2019.

The test stand was modified with some specific mechanical and avionics adaptations for the Ariane 6 configuration. This test aimed to observe increased performance characterised by a higher burning rate in a shorter combustion time than in the DM and QM1 motors.

The environmental impacts of every P120C test are measured in a similar way to any launch. Air quality and water pollution are checked in real time around the test bench, in the cities of Kourou and Sinnamary, and at launch observation sites. The measurements are then analysed by the Institut Pasteur.

All measurements on this test so far, indicate an extremely low impact on the ecosystem. This is also thanks to the strict meteorological constraints on wind speed at sea level and at certain altitudes, and the required absence of rain.

Completion of this test is an important achievement and maintains the development schedule for Ariane 6 and Vega-C. The ‘Ground Qualification Review 2’ of all the data collected will finally confirm this motor is qualified for use on Ariane 6.

Ariane 6 will extend Europe’s capabilities to independently access space and offer more opportunities for the commercial and institutional market worldwide while reducing costs.

ESA, France’s CNES space agency, and Europropulsion which is jointly owned by Avio and ArianeGroup, collaborated on this test.