January 3, 2020

In-Situ Detectors

MOS Detector

CNES and ONERA have been developing passive and active detectors for several years. The principle of the active detectors (MOS) is to measure the discharge of a capacitor at the moment of impact of a micro-particle. This technique was already used on the LDEF (Long Duration Exposure Facility) by the Americans. It is used for real-time counting of particles (flux) and an estimation of the impact energy of the particles by comparison with ground-based calibration. As long as the impact does not generate a short-circuit, the detector can be recharged and continue its surveillance. A module consists of 4 detectors. One of them flew on the International Space Station (ISS) as part of the MEDET experiment.

Figure 1.- MEDET experiment and deployment in orbit Credits: STEEL Electronique

PVDF detectors

Detector improvement entails measuring more precise parameters for the particles (velocity, trajectory, chemical composition, etc.). The new generations of detectors will have several detection stages and CNES/ONERA are working on PVDF films which can detect penetration by a particle without an electrical power supply. Two films can be associated or a PVDF film can be combined with an MOS.