• Schibler, Patrick
• Anglade, André
• Gabsi, Taoufik
• Lognonné, Philippe
• Pot, Olivier

Abstract

Introduction In the framework of Mars exploration programs (with ESA, NASA and ISAS/JAXA), our team is most involved in the development of geophysical instruments. We are using mainly seismic methods that are planed to operate in conjunction with low frequency radars to characterize the Martian subsurface down to few kilometers deep. In order to achieve the optimal performance tests for the seismic experiment and provide a coherent physical relation between the ground mechanical and electromagnetic properties, we developed a "Mars Environmental and Soil Simulating Facility". This facility will allow to study the environmental effect on the instrument performances as well as to study the physical variation in the soil acoustic and electromagnetic properties as a function of temperature, UV, dust ionization and gas inclusions. This facility located at the IPGP campus in Saint-Maur (France) comes to support the performance studies for ESA planetary geophysical instruments and is open to cooperation for NASA Martian missions. Scientific objective The performances of subsurface exploration systems can be summarized to be mainly a function of the following: - The instrument ability to operate properly under constraining Martian surface conditions (thermal noise level, sensitivity variation etc.), - The ground geophysical parameters (acoustical and electromagnetic properties) and their evolution as a function of the Martian environmental conditions (temperature, pressure, density, UV. . . ), In order to address those two issues, our "Environmental and Soil Simulating Facility" will, (1) test the geophysical instrument in Martian-like environmental conditions (2) allow measurements for the environmental dependency of acoustic and electromagnetic properties in Mars-like environment. Facility description Our facility is composed by two general types of equipments, a Martian environmental chamber and specific instrumentation dedicated to dielectric characterization of Martian soil simulant. Martian environmental chamber On IPGP campus, we are already using these existing facilities: - clean-room including a laminar flux tent for integrations of space instrumentation, - seismic vault (including seismic pillar) for functional testing of space seismometers, - Martian environmental chamber (pressure 6 hPa of CO2 gas, temperature from +20 to -120° C) As this facility must be representative of Martian environment, it will be completed by a seismic pillar and a magnetic field compensation (a-magnetic room). Dielectric characterization of Martian soil stimulant We measure complex permittivity of different Martian surface sediments simulating the variety and complexity of the upper crust composition in order to study potential discharge effects on the instruments and to understand the intrinsic electromagnetic properties of such sediments under different environmental parameters....

Topics

• density
• impedance spectroscopy
• surface
• inclusion
• experiment