A light dust shield, including aerogel, for DISC instrument on board ESA's Comet Interceptor mission: numerical simulations and Ballistic Limit Equation

The Dust Impact Sensor and Counter (DISC), part of the payload of Comet Interceptor mission, will determine the coma dust features of the mission target comet. DISC sensing plate will be exposed to cometary dust hypervelocity impacts (HVI), because of the high flyby speed (10– 60 km/s) foreseen for the space probe. For this measurement configuration, an efficient dust shield is mandatory, to protect the electronics of the detector and the housing S/C. Aiming at withstanding the predicted HVI without affecting DISC measurements and significantly increasing the payload mass, we designed a light aerogel-stuffed Whipple shield. In this work, we present an analysis of the dust-shield performances by computing the related Ballistic Limit Equations (BLEs) with the support of laboratory tests and numerical simulations. Our results reveal that the DISC dust shield exhibits resilience against particles up to 7 mm in size impacting DISC at 20 km/s—resulting in a momentum 100 times larger than impact predicted during the Comet Interceptor flyby. In addition, we find that the DISC dust shield withstands, for fixed impact velocity, critical particle diameters about four times larger than those stopped by a classic Whipple shield, with a Bumper and Rear wall configuration of equal areal density.