Zefiro 9A – VEGA Third Stage Solid Rocket Motor - Development Activities and Lessons Learnt
- Paper number
IAC-10.C4.2.3
- Author
Mr. Stefano Bianchi, European Space Agency (ESA), Italy
- Coauthor
Mr. Michel Bonnet, European Space Agency (ESA), Italy
- Coauthor
Dr. Ferruccio Serraglia, European Space Agency (ESA), Italy
- Year
2010
- Abstract
Zefiro 9 is the third stage of the new VEGA Launcher of the European Space Agency, currently in its final qualification phase. Zefiro 9 is a Solid Rocket Motor developed by AVIO Group, derived from Zefiro 16 SRM demonstrator, designed in order to comply with the VEGA Launcher’s requirements using advanced concept and technologies such as Carbon Fibre case with integrated skirts obtained by filament wounding, low density (internal) thermal protection, igniter with consumable case, low torque flexible joint, and thrust vector control with electromechanical actuators. The geometry of the propellant grain is a finocyl configuration. The Development and Qualification Plan of Zefiro 9 has been strongly influenced by the experience earned during the Zefiro 16 tons development and qualification phase. As first consequence, the firing test campaign has been constituted by only two tests at motor level: • a development firing test during the Development Phase; • a qualification firing test during the Ground Qualification Phase. During its development, Zefiro 9 went through several modifications of its original configuration in order to solve specific issues and improve the overall performance of the motor. The major one was implemented after the first qualification firing test. The qualification firing test of the Zefiro 9 SRM took place in March 2007, but failed with the ejection of the nozzle after 35 seconds of operating time. An inquiry board was put in place, and pointed some weaknesses in the design of the nozzle and in manufacturing quality on some of its components. An intense work was made by AVIO teams in order to recover the situation, with a complete material characterization campaign, a full re-design of the nozzle, and a strong improvement in the manufacturing process and quality of the C-Ph insulators. Taking advantage of the schedule shift because of the redesign of the Z9 nozzle, the project decided to increase the Z9 performance with an overloading of propellant (+560 Kg), allowing to improve the launcher payload capability of more than 60 Kg. Because of these significant changes in the 3rd stage motor configuration (now named Z9-A), two firing tests were planned to demonstrate the qualification. The first one was successfully performed in October 2008 and the second one in April 2009. This paper will discuss the new Zefiro 9A configuration, the main performance improvements achieved as well as the lessons learnt during the development and the qualification activities.
- Abstract document
- Manuscript document
IAC-10.C4.2.3.pdf (🔒 authorized access only).
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