Optical design of "MicroMED", an optical particle counter to characterize Martian airborne dust.

• MicroMED is the first OPC developed to monitor airborne dust on Mars. • MicroMED is characterized by low mass, size, and power consumption. • The optical design is simplified by using an optical fibre coupled to a laser source. • The optical system is designed to detect dust particles with diameters ≥ 0.4 µm. Airborne dust monitoring is crucial to characterize the thermal structure and evolution of the Martian atmosphere and climate. For this purpose, the MicroMED instrument has been selected within the ExoMars program to be deployed on Mars. It is an optical particle counter that measures the dust amount and size distribution of airborne dust close to the Martian surface. MicroMED is characterized by low mass, size and power consumption and is suitable to be accommodated on both rovers and landers. In this paper, the MicroMED optical design is described along with the analysis performed to prove compliance with all requirements needed for its nominal performance. [ABSTRACT FROM AUTHOR]