Performance reconstruction of VEGA solid rocket motors: VERTA flights experience

Vega is the ESA launch vehicle designed to inject small satellites into Low Earth Orbit. It is a 3 m-diameter single-body vehicle, standing 30 m tall with a lift-off mass of 137metric tonnes. It has three solid-propellant stages and a liquid-propellant upper module for attitude and orbit control, and satellite release. Following Vega maiden flight on 13 February 2012, ESAs Verta (Vega Research and Technology Accompaniment) programme was set up with the main objective of providing a framework for the smooth transition of Vega launch system from development to exploitation. In this work, the analysis and performance reconstruction of the solid rocket motors of the Vega launch vehicle for the qualification flight and the five Verta flights is carried out with a post-firing 0D quasi-steady performance reconstruction model, developed for the purpose and already used in the past for the analysis of the static firing tests. The aim is to use the firing and flight measures available in order to evaluate the behavior of the motor, through the reconstruction of the non-ideal parameters: combustion efficiency, thrust efficiency, hump curve, scale factor and nozzle throat area evolution. The final goal is to increase the understanding of VEGA’s solid rocket motors behavior in terms of non-ideal parameters in order to assess the overall motor performance, to enrich the knowledge of the motor behavior, to characterize motor dispersion and scattering, and to consolidate the methodology used for the performance reconstruction.