Model of the subsoil conditions
Model of the subsoil conditions
The ground at the InSight landing site consists of three different layers and materials with different properties. A model of the soil properties has been developed using the propagation times of marsquake waves and the signals generated by the 'Mole' when it was hammering into the ground with the Heat Flow and Physical Properties Package (HP 3 ) geothermal measurement system, as well as the many measurements performed with the Auxiliary Payload Sensor Suite (APSS) – consisting of a barometer, an anemometer, a magnetometer and two cameras), the HP 3 radiometer and the Rotation and Interior Structure Experiment (RISE). Beneath what is referred to as the 'duricrust' (from Latin 'durus', meaning hard, and 'crusta', meaning shell or crust), there is a comparatively firm crust consisting of a kind of 'cemented' sand and roughly comparable to the firm, caramelised sugar crust of a crème brûlée. Further down, there is a several-metre-thick regolith of finely fragmented crustal rock and finally fragmented bedrock reaching deep underground.
