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In the recent years, driven by the increasingly stringent stability requirements imposed by some satellites' payloads (e.g. the new generation of optical instruments), the issue of accurate on-board spacecraft microvibration modelling has attracted signicant interest from engineers and scientists. This paper investigates the microvibrationinduced phenomenon on a cantilever congured reaction wheel assembly including sub and higher harmonic amplications due to modal resonances and broadband noise. A mathematical model of the reaction wheel assembly is developed and validated against experimental test results. The model is capable to represent each conguration in which the reaction wheel assembly will operate whether it is hard-mounted on a dynamometric platform or suspended free-free. The outcomes of this analysis are used to establish a novel methodology to retrieve the dynamic mass of the reaction wheel assembly in its operative range of speeds. An alternative measurement procedure has been developed for this purpose, showing to produce good estimates over a wide range of frequency using a less complex test campaign compared to typical dynamic mass setups. Furthermore, the gyroscopic eect inuence in the reaction wheel assembly response is thoroughly examined both analytically and experimentally. Finally, to what extent the noise aects the convergence of the novel approach is investigated.

In this paper, a full methodology to deal with microvibration predictions onboard satellites is described. Two important aspects are tackled: 1) the characterization of the sources with a pragmatic procedure that allows integrating into the algorithm the full effect of the sources, including their dynamic coupling with the satellite structure; 2) the modeling of the transfer function source receivers with a technique named in this paper as the Craig-Bampton stochastic method, which allows prediction of a nominal response and variations due to structural uncertainties as accurate as full Monte Carlo simulations but at a fraction of the computational effort. The paper then includes a statistical study of the data from the structural dynamic testing of the five identical craft of the Rapid-Eye constellation to set the magnitude of the uncertainties that should be applied in the analysis. Finally, the computational procedure is applied to the new high-resolution satellite SSTL-300-S1 and the predictions compared with the experimental results retrieved during the physical microvibration testing of the satellite, which was carried out at the Surrey Satellite Technology Limited facilities in the United Kingdom

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