“MicroMED” Optical Particle Counter: From Design to Flight Model

Abstract

MicroMED (Micro Martian Environmental Dust Systematic Analyzer (MEDUSA)) instrument was selected for the ExoMars 2020 mission to study the airborne dust on the red planet through in situ measurements of the size distribution and concentration. This characterization has never been done before and would have a strong impact on the understanding of Martian climate and Aeolian processes on Mars. The MicroMED is an optical particle counter that exploits the measured intensity of light scattered by dust particles when crossing a collimated laser beam. The measurement technique is well established for laboratory and ground applications but in order to be mounted on the Dust Suite payload within the framework of ExoMars 2020 mission, the instrument must be compatible with harsh mechanical and thermal environments and the tight mass budget of the mission payload. This work summarizes the thermo-mechanical design of the instrument, the manufacturing of the flight model and its successful qualification in expected thermal and mechanical environments.

A Semi-Linear Elliptic Model for a Circular Membrane MEMS Device Considering the Effect of the Fringing Field

“…Since the aforementioned analytical solutions are unobtainable, suitable numerical procedures have to be selected, and it becomes imperative to evidence the pros and cons of each method [ 25 , 26 , 30 , 31 , 32 ]. MEMS is a rampant technology employed for realizing thermo-elastic systems [ 1 , 33 , 34 , 35 , 36 , 37 ], and it has a wide variety of applications ranging from biomedical engineering to microfluidics [ 38 , 39 , 40 , 41 , 42 ]. Moreover, many researchers are actively engaged in the development of important experimental research works for the development and prototyping of special MEMS such as, for example, circular graphene membrane MEMS devices [ 43 , 44 ], SiN circular membrane MEMS devices [ 45 , 46 ], and CMOS MEMS-based membrane-bridge devices [ 47 ] particularly useful for industrial applications.…”

Optimized Design and Implementation of Digital Lock-In for Planetary Exploration Sensors

“…It requires a pump to drag the dust inside a chamber and a laser diode as an active device, with a group of detectors, as well as a micro-balanced quartz crystal; also, Peltier temperature control for the sensing of water vapor is included [42], [43]. 4) MicroMED is a miniaturized version of MEDUSA, which has been designed and prototyped for the Humboldt payload in the EXOMARS mission [42], [44] (ESA), by a consortium of Spanish National Institute of Aerospace Techniques and Italian research institutes taking into the base the MEDUSA heritage [42], [43], [45]. UC3M Dust Sensor, whose physical principle was presented in [13] and outlined in Section I, presents some differences with these previously detailed instruments, which can make it interesting for monitoring large areas on the planet's surface with low cost, low power consumption, and acceptable data budget for telemetries.…”

Structural Optimization of MicroMED Dust Analyzer

“…The instrument is an amplitude-dependent single Optical Particle Counter (OPC) designed and qualified for the ESA ExoMars 2022 mission towards Mars [14][15][16]. The instrument includes several subassemblies and hardware components arranged in a compact and lightweight design, whose locations are depicted in Figure 1 and was intended to infer the airborne dust size and size distribution in situ at the lowest troposphere of the Red Planet [17][18][19]. This would be a groundbreaking achievement because, at present, data about dust on Mars were exclusively acquired using remote sensing (e.g., thermal IR instruments, near-IR spectrometers, and Terrestrial ground-based telescopes).…”