The ESA Sentinel-4 Mission is part of the European Commission Copernicus Programme for monitoring the Earth. It is going to provide free data on trace gas concentrations and aerosols in the atmosphere to support real time operational services of air-quality for Europe. The Sentinel-4/UVN Instrument will be placed in a geo-stationary orbit on board of the Meteosat Third Generation Sounder (MTG-S) satellite.

We develop and build the core main optics of the Sentinel-4/Ultra-violet/Visible/Near- Infrared (UVN) instrument, which comprises a telescope, a UV-VIS spectrometer and a NIR spectrometer.

The very demanding performance requirements led to an instrument design, which sets the demands on manufacturing and alignment quality to a new level. To achieve the optical quality, the lens mounting was optimized to utilize
technologies, which provides an undistorted, highly centered and stable lens position capable for extended bake-outs to reduce potential contaminations in the UV wavelength range. Furthermore, a completely new gluing and clamping technology has been established and the centering was optimized almost to the peak of precision.

Our colleague Dr. Simon Chelkowski presented the various challenging technical solutions, which have successfully been achieved within the Project, in the frame of the International Conference on Space Optics (ICSO 2020). The Event took place virtually from March 30 to April 2, 2021. His presentation and paper on "Sentinel-4/UVN Combined Optical Assemblies" gave insides on the topics passive athermalization as well as lens gluing, centering and clamping.

Pictures © Florian Brill on behalf of Jena-Optronik GmbH.

The contract was carried out under a programme of and funded by the European Space Agency.
The views expressed herein can in no way be taken to reflect the official opinion of the European Space Agency.