Title
Design and first light of the Sentinel-5 UV1 spectrometer optics
Author
Jansen, R.
Day, J.P.R.
Vink, H.J.P.
de Vreugd, J.
van Beekum, E.R.J.
van der Laan, L.W.
van 't Hof, A.C.A.
Gielesen, W.L.M.
Koehler, J.
Contributor
Neeck, S.P. (editor)
Martimort, P. (editor)
Kimura, T. (editor)
Publication year
2019
Abstract
Sentinel-5 is an Earth atmospheric monitoring mission developed within the Copernicus program. The mission objective is to monitor the composition of the Earth's atmosphere on a daily basis. TNO is developing the UV1 spectrometer subsystem as well as the two telescope subsystems. In this paper, the design of the UV1 spectrometer is described and its major design and verification challenges are discussed. The UV1 optical design is based on a classical Offner-type spectrometer which has been adapted to employ freeform optics and an aspheric off-axis grating. It generates a magnification of 0.4. A structural, monolithic housing has been designed that is optimized for stability, accessibility and integration of optical components. To realize a thermo-mechanically stable construction, both housing and mirror bodies are built from aluminum. Four out of five mirrors have a dedicated black coating for absorbing out-of-band light. For further stray light suppression, a graded short-pass filter is employed on the last optical element just in front of the detector. Performance verification of a standalone spectrometer without telescope, entrance slit, limiting aperture stop and flight detector is a major challenge. For this verification TNO developed dedicated ground support equipment that will be used under both ambient and vacuum conditions; a dedicated optical stimulus that mimics the illumination from the telescope in terms of pointing and NA, a Slit Assembly that mimics the homogenizer entrance slit and a Test Detector to determine the image plane and to measure the optical performance with high accuracy. At the time of writing this article, the first (proto-flight) model has been aligned and performance verification is about to start.
Subject
High Tech Systems & Materials
Industrial Innovation
Aspheric grating
Copernicus
Free-form optics
Imaging spectrometer
MetOp-SG
Sentinel 5
UV1
To reference this document use:
http://resolver.tudelft.nl/uuid:1368019b-17b6-4cef-ac1a-c4108fea94b0
DOI
https://doi.org/10.1117/12.2532400
TNO identifier
871937
Publisher
SPIE
ISBN
9781510630055
ISSN
0277-786X
Source
Proceedings Sensors, Systems, and Next-Generation Satellites XXIII, 9-12 September 2019, Strasbourg, France
Article number
111510Q
Document type
conference paper