Envision Mission to Venus: Subsurface Radar Sounding

This paper presents the Subsurface Radar Sounder (SRS) instrument onboard European Space Agency's (ESA) EnVision mission. EnVision is one of the three candidates selected for the Cosmic Vision 2015-2025 M5 medium-class missions. It is aimed at exploring the activity, the geologic history and the atmosphere of Venus. SRS is an orbital ground-penetrating radar with the unique science objectives of understanding the evolution of Venus' surface by searching for subsurface dielectric interfaces in the top hundreds of metres of the crust. In the paper, we describe the main science objectives of SRS, the performance evaluation under expected target conditions, the instrument design and the acquisition strategy that maximize the scientific returns.