Dynamic Identification of a Solid Rocket Motor From Firing Test Using Operational Modal Analysis

The firing test of the first stage of the solid rocket motor P80 of the VEGA launcher was run successfully in December 2007 at the guyanese Space Center in Kourou. This research activity demonstrates the capability of the developed operational modal analysis methods to identify the dynamic properties of the solid rocket motor, working under its actual operative conditions, by using response data only recorded during the firing test. The main objective was first to prove the applicability and then to evaluate the overall efficiency of different state-of-the-art approaches in operational modal analysis to track changes in the natural frequencies, damping ratios and mode shapes of the first stage of the VEGA launch vehicle undergoing significant mass variation due to the burning propeller. Additionally, a sensitivity of the considered approaches to deal with structures characterized by time-dependent parameters was numerically carried out.