Hyperspectral innovation on instruments and technologies at the European Space Agency

Abstract

Emerging spaceborne hyperspectral technologies answer a growing need to comprehend the Earth and its atmosphere. These technologies constitute a reliable source of information about Earth’s environment. The near real-time distribution of Earth Observation (EO) information can be a requirement for certain applications, such as early warning and disaster management systems. The last few decades have shown an increasing interest in hyperspectral observation data. This pushed the development of hyperspectral instrument technologies, also towards the miniaturization of instrument elements, taking advantage of electronics, new detector developments, material processes, hyperspectral filters, optical free-form design manufacturing and verification, on-board calibration techniques, on-board data processing and machine learning for image resolution enhancement. In parallel, the advent of smaller-size instruments, with lower development and operation costs is desirable to feed new data usage ideas and markets. ESA actively participates in the development of hyperspectral instruments, each to satisfy specific performance needs. Its participation spans from the shaping of a vision for an instrument, to the initiation of projects and missions, through the support of development activities, on to the instrument launch and subsequent tasks. The first hyperspectral instrument launched by ESA in 2001 was CHRIS, whose purpose was to improve knowledge on spectral reflectance from the Earth. Since then, the understanding of hyperspectral data and its significance has strongly risen and a sound heritage on hyperspectral instruments and applications exists by now. As for recent developments, a hyperspectral imaging mission study in the context of the Copernicus Expansion has been initiated and targets the realization of an instrument for routine observations in the visible-to-shortwave infrared range. In particular, it addresses the management of natural resources and enhances services for food security, sustainable agriculture and raw materials. The degree of innovation, compactness, overall technical challenge and user needs can constitute the starting constraint for each development objective. The evolving technologies enable compactness and a better instrument performance to expand the scope of its use. In order to give a comprehensible overview of the current hyperspectral imagers and technologies, opportunities and challenges, this communication sheds light on different instrument characteristics and design concepts in a categorized view and provides the current status of key technologies.