The Design of a Global Oceanic Plastic Debris Monitoring System Using Imaging Spectroscopy Onboard Low-Flying Satellites

Abstract

The distribution and behavior of the vast accumulation of plastic waste in the oceans, often referred to as the 'plastic soup’, are heavily influenced by plastic debris coming from rivers and coastal areas. Currently, the location and dynamics of the oceanic ‘plastic soup’ is already well understood. However, the exact process behind the formation of this plastic soup remains incompletely comprehended. This knowledge gap can be linked, in part, to the absence of worldwide detailed spatiotemporal data collected from ground and space. This is specifically due to the lack of detection and imaging techniques with a high spatial and temporal resolution. To address this gap, an innovative concept is proposed based on
imaging spectroscopy. The goal is to address and further improve the observed spectral signatures of different plastics by imaging the observed scenery. In order to distinguish between these different kinds of plastics, a dedicated optical filtering system with a high resolution and revisit time has to be designed. Therefore, the concept is based on an Acousto-Optic Tunable Filter (AOTF), specifically designed for remote sensing and imaging. In order to achieve a high temporal resolution, being able to capture the evolution and movement of plastic in the oceans, a constellation of satellites are foreseen. Therefore, a low flying platform and deployable optics are introduced. Flying at 300 km altitude instead of a typical > 600 km for Earth observation satellites, reduces the required imaging aperture.