Calibration of the Heat Flow and Physical Properties Package (HP 3) for the InSight Mars Mission

Abstract

The (HP3) of the InSight Mars mission is an instrument package to measure the Martian geothermal heat flow. The instrument's platinum resistance temperature sensors have been calibrated between -75 and +55 °C, and the absolute temperature uncertainty of the calibration is 10 mK. Temperature differences can be measured with an uncertainty of better than 5 mK. HP3 determines regolith thermal conductivity by using the HP3 mole as a modified line heat source, and thermal conductivity can be measured with an uncertainty of better than 4%. Tilt sensors used to determine the attitude of the mole during penetration measure tilt with an uncertainty of better than 0.25°.