Flexible Mode Modelling of the InSight Lander and Consequences for the SEIS Instrument

Naomi Murdoch (1) , Daniel Alazard (2) , B. Knapmeyer-Endrun (3) , N. A. Teanby (4) , R. Myhill (4)

1 DEOS - Département Electronique, Optronique et Signal
2 DCAS - Département Conception et conduite des véhicules Aéronautiques et Spatiaux
3 MPS - Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research
4 University of Bristol [Bristol]

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.

Mots clés: Mars; Seismology; Atmosphere; Regolith; Geophysics; Structural dynamics

Domaines: Optique / photonique

Naomi Murdoch, Daniel Alazard, B. Knapmeyer-Endrun, N. A. Teanby, R. Myhill. Flexible Mode Modelling of the InSight Lander and Consequences for the SEIS Instrument. Space Science Reviews, 2018, 214 (117), pp.1-24. ⟨10.1007/s11214-018-0553-y⟩. ⟨hal-01915826⟩