Abstract
Disturbances generated by reaction wheels on board the spacecraft are among the most substantial . Hence they play a crucial role when microvibration budget has to be assessed. This paper aims at characterising the effects of RW on the structure by focusing on the format of the disturbance input matrix of these components. In particular the case of single and multiple wheel accounted for. In the first one the responses are evaluated at some specific locations of the reaction wheel where their disturbance is amplified, i.e. harmonics. In the second case a more realistic scenario is considered with several wheels to be characterised and the effects of neglecting some terms of the disturbance input matrix are discussed. Finally a sensitivity analysis is carried out to quantify in which extent changes in the input matrix can alter the response. A preliminary methodology is then suggested to characterise a large num ber of wheels.