InSight Mars Mission: SEIS Instrument Thermal Design, Testing, and Support to In-Flight Operations and Performances
The Interior exploration using Seismic Investigations, Geodesy, and Heat Transport (InSIGHT) mission goals are the investigation of the internal structure and processes of Mars, relating them to the evolution of other telluric planets, and the determination of the present level of tectonic activity and meteorite impacts on Mars surface. The Seismic Experiment for Interior Structure (SEIS) is the main instrument onboard the lander. A robotic arm places SEIS on the Mars surface. SEIS is a very sensitive seismometer built by Centre National d’Etudes Spatiales (CNES) and its partners (DLR, ETHZ, ICL/OXF, IPGP, JPL). SEIS monitors seismic activity and tidal displacements. Over the course of one Martian year (~24 Earth months), SEIS endorses a very changing thermal environment with air temperature varying between -105°C and +25°C. SEIS sensors are very sensitive to any temperature variation. SEIS Thermal Control System (TCS) has to filter these variations in the 7 mbar Mars atmosphere thanks to an efficient thermal insulation system. This paper presents the SEIS TCS development and first in-flight performances (launch in May 2018 and landing on Mars in November 2018). In sequence, this paper contents are: thermal design, thermal tests driven by a high thermal time constant, thermal behavior during cruise and first Mars surface operations and actual temperature variations in relation to SEIS scientific performances.