Technological Development of Dust Sensor for CMDM to be aboard MMX

Abstract

We are developing an instrument called Circum-Mars Dust Monitor (CMDM), which will be installed on the Mars Moon Explorer (MMX) being developed by JAXA, to observe dust particles in orbit around Mars. CMDM aims at in-situ observation of dust particles orbiting around Mars which has been theoretically predicted to exist ranging between tens of μ m and hundreds of μ m in size with impact speed ranging between about 0.2 km/s and about 0.8 km/s. The instrument must be a real-time dust instrument with high reliability to distinguish actual dust events from noise-induced trigger signals. In addition, a sensitive area of at least 1 m² is required to study the undiscovered Martian dust ring particles to the background flux level of interplanetary dust particles. However, the resources required for the spacecraft system must be kept to a minimum. The sensor unit of the CMDM consists only of a polyimide film and a piezoelectric ceramic element. Therefore, the sensor has a sensitive area of 1 m² but a mass of only a few hundred grams. In this paper, we describe the results of solving the technical problems in sensor development identified during the conceptual design and the results of sensitivity measurements using a sensor BBM made from materials actually used in-flight products.