Estimation and mitigation of micro-vibrations in spacecraft applications

Abstract

The motion of any spacecraft is divided into two stages – the launch and the in-orbit motion. Consequently, the loads acting on the spacecraft are also of different nature in both these motions. Both these loads propagate through the spacecraft structure, which is primarily made of honeycomb sandwich panels. These sandwich panels are made of outer face sheet and inner honeycomb core. Both these components are made of aluminium of different grades. The loads acting on the spacecraft propagate through this structure and are critical for the subsystems mounted on these structures. The launch loads are characterized by high amplitude (reaching up to 10 g’s) and low frequency. These loads are further amplified by the low inherent damping characteristics of the sandwich panels. The in-orbit loads are extremely low amplitude and low frequency vibrations, known as micro-vibrations. These micro-vibrations are critically responsible for the pointing accuracy of the satellites. These have been discussed in detail in the upcoming chapter.