Spacecraft Coatings Optimizing LiDAR Debris Tracking and Light Pollution Impacts

Abstract: Space safety and astronomy are at odds. The problem posed by space debris and derelict satellites in the low Earth orbit is an existential threat to all space operations. These dangerous objects in space are more easily tracked with ground-based LiDAR if they are highly reflective, especially in the near-infrared (NIR) range. At the same time, reflective objects in orbit are the bane of ground-based astronomers, causing light pollution and marring images with bright streaks. How can this tension be resolved? The hypothesis tested is that a near-infrared-transparent (NIRT) coating which is opaque in the visible light range and transparent in the NIR range is a promising candidate for use in satellite construction. This experiment tests whether typical spacecraft surfaces such as anodized aluminum or multi-layer insulation (MLI) with a NIRT coating applied will absorb visible light and reflect NIR. The findings confirm the efficacy of the NIRT coating for this purpose, reducing visible light reflection by 47% (+/-3%) and increasing reflection in the NIR by 7% (+/-2%). This promising novel NIRT coating may help provide a path forward to resolve the tension between astronomy and the space industry.