Polarimetric backscattered Mueller matrix bidirectional reflectance distribution function (MmBRDF) for remote inspection of spacecrafts

Thermal insulation of space satellites and space probes often consists of Multi-layer insulation (MLI), composed of multiple layers of Mylar or Kapton coated on one side with a thin layer of metal, typically silver or aluminum. The purpose of this paper is to investigate the optical characteristics of several materials used as integral part in the design of spacecrafts. In this study, preliminary results on the remote interrogation of Mylar layers, using backscattered polarimetric imaging, at different aspect angles, are reported. Specifically, the Mueller matrix of the Bidirectional Reflectance Distribution function (MmBRDF) for Mylar was constructed, based on the estimation of the Mueller matrix (MM) elements, at different aspect angles of the target, under quasi-monostatic geometry. Measurements were performed using an in-house-built, auto calibrated, scalable imaging polarimetric system. The calibration results demonstrate the high quality of the acquired measurements, characterized by stability, and accuracy. The outcome of the study indicates that polarimetric backscattered Mueller matrix enhances significantly the intrinsic merit of our system to monitor, inspect and characterize materials commonly used in space.