Investigation of martian soil properties by complementary instruments ADRON-EM and RM instruments of ExoMars 2022 mission

The ExoMars landing mission, which is currently scheduled to launch in 2022, will carry the active gamma ray and neutron spectrometer ADRON-EM and compact passive neutron spectrometer ADRON-RM to the equatorial region of Mars as part of the mission's science payload. The main science objective of the ExoMars mission is dedicated to understanding the evolution and habitability of Mars. ADRON-EM instrument is developed in Space Research Institute (IKI) for active neutron sensing of the soil from the stationary landing platform. The main goal of this experiment is study of elemental composition of the martian subsurface down to 1 m. The instrument consists of two units, the block of detectors and electronics (DE) and the pulse neutron generator (PNG). Measuring post-pulse neutron and gamma ray emission from the soil, one can detect layering stratification of hydrogen and other major elements of the soil. The second complementary instrument ADRON-RM (IKI) is installed on the Rover. It will measure the spatial variability of neutron flux emitted from the martian surface along the traverse. The data processing will convert the raw data into an estimation of bulk water distribution and abundance of neutron absorbing elements, mainly chlorine and iron. The instrument will also provide continuous monitoring of the neutron component of the radiation background on the surface which is necessary to know for planning future human missions to the planet. In the beginning of the surface mission after landing, there is the unique possibility to perform the measurement of subsurface density by both instruments operating together. The data for this analysis will be obtained from different distances between rover and landing platform. Description of ADRON-EM and RM instruments and expected results will be presented.