The main aim of this project is to develop a methodology to fully characterise sources of microvibration on board satellites.
Microvibrations are low amplitude dynamic disturbances occurring at frequencies upto several hundred Hertz and produced by the functioning of on board equipment such as reaction wheel assemblies, cryo coolers etc. These vibrations propagate through the satellite structure, and although they do not pose risks for the spacecrafts mechanical integrity, they can seriously degrade the performance of accurately targeted optical payloads, such as high resolution cameras or telescopes.
In order to predict the level of stability of the payload it is necessary to have a high quality mathematical model of the microvibration sources. Measurements of blocked reactions obtained with the equipment mounted on a dynamometric table are insufficient to correctly reproduce the effect of the microvibration source on the satellite, and measurements of the dynamic mass of the sources to include the effect of the coupling between source and satellite structure, are complicated and time consuming.
The development of an efficient semi-empirical methodology to characterise existing sources, and modelling technique to integrate them with a satellite structural model will be the core research activity. In addition to theoretical and computational work the project is expected to include some experimental activity to validate the methodology, and it will be carried out in cooperation with Industry.