Development status and performances of a Seismometer for future Martian missions

摘要

A new seismometer intended to the next missions to Mars has been developed by SODERN as the industrial partner of IPGP (Institut de Physique du Globe de Paris) and CNES (French Space Agency). This seismometer is a Very Broad Band seismometer (VBB) to measure the Martian seismic activity. It is based on the principle of an inverted mechanical pendulum, the movement of which being detected thanks to very accurate capacitive sensors, a short term differential capacitive sensor, for accurate measurement of seismic motions, and a long term capacitive sensor dedicated to gravity outputs. Two similar seismometers axes are incorporated in the same package to provide two-axes measurement (the third axis being provided by a short term MEMS seismometer from Imperial College). The package is under vacuum to allow the best quality factor of the pendulum. Severe constraints of mass as far as hard environmental conditions have led to a very detailed optimisation of the design. Breadboards have been manufactured and tested. They allow demonstrating the capability of this seismometer to be embarked in the next ESA ExoMars mission, onboard the GEP(Geophysical Payload). This paper describes the architecture of the seismometer and gives the achieved performances as measured on ground and expected on Mars. It will also give the development status and how the critical points have been mitigated.