PROCEEDINGS ARTICLE | September 29, 2017
Proc. SPIE. 10423, Sensors, Systems, and Next-Generation Satellites XXI
KEYWORDS: Reflection, Imaging systems, Spectroscopy, Luminescence, Fluorescence spectroscopy, Clouds, Vegetation, Spectral resolution, Lawrencium, Absorption
The FLuorescence Imaging Spectrometer (FLORIS) is the payload of the FLuorescence Explorer Mission (FLEX) of the
European Space Agency. The mission objective is to perform quantitative measurements of the solar induced vegetation
fluorescence to monitor photosynthetic activity. FLORIS works in a push-broom configuration and it is designed to
acquire data in the 500–780 nm spectral range, with a sampling of 0.1 nm in the oxygen bands (759–769 nm and 686-
697 nm) and 0.5–2.0 nm in the red edge, chlorophyll absorption and Photochemical Reflectance Index bands. FLEX will
fly in formation with Sentinel-3 to benefit of the measurements made by the Sentinel-3 instruments OLCI and SLSTR,
particularly for cloud screening, proper characterization of the atmospheric state and determination of the surface
temperature. The instrument concept is based on a common telescope and two modified Offner spectrometers with
reflective concave gratings both for the High Resolution (HR) and Low Resolution (LR) spectrometers. In the frame of
the instrument pre-development Leonardo Company (I) has built and tested an elegant breadboard of the instrument
consisting of the telescope and the HR spectrometer. The development of the LR spectrometer is in charge of OHB
System AG (D) and is currently in the manufacturing phase. The main objectives of the activity are: anticipate the
development of the instrument and provide early risk retirement of critical components, evaluate the system
performances such as imaging quality parameters, straylight, ghost, polarization sensitivity and environmental
influences, verify the adequacy of critical tests such as spectral characterization and straylight, define and optimize
instrument alignment procedures. Following a brief overview of the FLEX mission, the paper will cover the design and
the development of the optics breadboard with emphasis on the results obtained during the tests and the lessons learned
for the flight unit.
