Flexible Mode Modelling of the InSight Lander and Consequences for the SEIS Instrument
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We present an updated model for estimating the lander mechanical noise on the InSight seismometer SEIS, taking into account the flexible modes of the InSight lander. This new flexible mode model uses the Satellite Dynamics Toolbox to compute the direct and the inverse dynamic model of a satellite composed of a main body fitted with one or several dynamic appendages. Through a detailed study of the sensitivity of our results to key environment parameters we find that the frequencies of the six dominant lander resonant modes increase logarithmically with increasing ground stiffness. On the other hand, the wind strength and the incoming wind angle modify only the signal amplitude but not the frequencies of the resonances. For the baseline parameters chosen for this study, the lander mechanical noise on the SEIS instrument is not expected to exceed the instrument total noise requirements. However, in the case that the lander mechanical noise is observable in the seismic data acquired by SEIS, this may provide a complementary method for studying the ground and wind properties on Mars.
KeywordsMars Seismology Atmosphere Regolith Geophysics Structural dynamics
NAT and RM acknowledge support from the UK Space Agency. We acknowledge the following students from ISAE-SUPAERO who helped to prepare the flexible mode model: Alexandre Acerra-Gil, Aurelio de Aguiar-Rodrigues and Mouadh Bouayad. We would also like to thank an anonymous reviewer for their very constructive comments. This paper is InSight Contribution Number 61.
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