This paper discusses the early phase of the ignition transient of the VEGA Launcher's third stage solid rocket motor, Zefiro 9A. During the first two firing tests of the Z9A SRM (QM2 and VT1) a peculiar unexpected negative force peak and a significant pressure unbalance in the motor chamber were measured during the very first phase of the ignition transient.

The high temporal resolution of data acquisition by geostationary satellites and their capability to resolve the diurnal cycle allows for the retrieval of a valuable source of information about geophysical parameters.