Technology developments and status of hyperspectral instruments at the European Space Agency

Abstract

ESA actively participates in the development of numerous hyperspectral instruments. The degree of innovation, compactness, or overall technical performance constitute the starting constraint for each prospective instrument. With the launch of the CHRIS instrument in 2001, ESA contributed to the demonstration and evaluation of new hyperspectral technologies. The objective was to achieve a better understanding of Earth’s spectral reflectance. As of today, a strong heritage for spaceborne hyperspectral instruments exists in Europe and more challenging instrument capabilities can be addressed. Hence, a study for a hyperspectral imaging mission in the context of the Copernicus Space Component Expansion programme has been initiated and targets the realization of an instrument covering the VNIR (visible and near-infrared) and SWIR (short-wave infrared) spectral range. The main goal of this mission is to deliver new services for food security, sustainable agriculture and raw materials detection. In another endeavor, ESA’s 8th Earth Explorer mission, the focus lies on the study of vegetation fluorescence and photosynthetic activity. A hyperspectral imager has effectively been built as an elegant breadboard and is planned to be ready for launch in 2022. Other hyperspectral instruments following the route towards compactness and lower cost have been also supported by ESA in recent years. For instance, HyperScout, a hyperspectral instrument, has been launched in February 2018. CHIMA, a Compact Hyperspectral Instrument for monitoring the atmosphere was tested on breadboard level. ELOIS is a higher-performing hyperspectral instrument for land application, for which the development of the Engineering Model has been completed. And CSIMBA is another compact hyperspectral instrument for land applications, of which flight units are currently being manufactured. Evolving technologies, such as complex blazed grating structures, hyperspectral image sensors and free-form optics manufacturing and metrology, enable the achievement of a better instrument performance and hence expand the scope of its use. This communication provides an overview of existing and planned hyperspectral instruments in which ESA participates. Different instrument characteristics and design concepts are described and categorized in view of the targeted applications. The current status of key instrument technology is elucidated and discussed in the perspective of future applications.