Euclid's filter Wheel Render

Instrumentation R&D

Filter Wheel Assembly


Filter Wheel Assembly

The Euclid Satellite will be equipped with a 1.2 m diameter Silicon Carbide (SIC) mirror telescope made by Airbus Defense and Space feeding 2 instruments, VIS and NISP, built by the Euclid Consortium. These instruments are a high quality panoramic visible imager (VIS), a near infrared 3-filter photometer (NISP-P) and a slitless spectrograph (NISP-S).

The filter wheel assembly (FWA) is a critical element of the Euclid’s Near-Infrared Spectrometer and Photometer (NISP). It has been designed, built, assembled and verified by the IFAE and the IEEC-ICE-CSIC.

The IFAE is responsible for the design and manufacturing of the NISP Filter Wheel Assembly (NISP-FWA), a device that allows the NISP instrument to select the optical filter used for the images it takes.

Euclid's filter Wheel Render
Euclid's filter Wheel Render

During the first half of 2018 IFAE built and fully qualified the Engineering Qualifying Model (EQM). This model contained a real fully coated filter and served to completely validate the design of the FWA both in the terms of structural and alignment performance and the validation of the simulations and the optical performance of the filers. The group had to fully commission the Ground Segment Equipment, including an x-y metrology table with the confocal sensor to allow the precise non-contact metrology of the FWA, the interferometer to measure the Wave Front Errors of the filters and the Autocollimator to precisely measure the tip-tilt angle of the filter with respect to the NISP reference surface. All these measurements have been done at operational conditions with the FWA inside the cryostat.

FWA Barcelona Team
Euclid's FWA Barcelona Team Credit: IFAE/ICE

After the successful qualification of the EQM model, IFAE built and tested (with the same procedures as for the EQM) the Flight Model (FM) that was successfully delivered to the Laboratoire d’Astrophysique de Marseille (LAM), where it was integrated in the NISP-FM.

Euclid's filter Wheel Render Assembly
Near-Infrared Spectrometer and Photometer (NISP) installed in the Pay Load Module of Euclid's Flight Model Credit: ESA / Airbus

The Near-Infrared Spectrometer and Photometer (NISP) wasn installed in the Pay Load Module of Euclid’s Flight Model in september 2020.