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Proceedings Paper • Open Access

A very wide band telescope for Planck using optical and radio frequency techniques
Author(s): Guy Fargant; Denis Dubruel; Myriam Cornut; Jean-Bernard Riti; Thomas Passvogel; Peter de Maagt; Michel Anderegg; Jan Tauber

Paper Abstract

Planck associated to FIRST is one of the ESA scientific missions belonging to the Horizon 2000 programme. It will be launched by an Ariane 5 in 2007. Planck aims at obtaining very accurate images of the Cosmic Microwave Background fluctuations, thanks to a spaceborne telescope featuring a wide wavelength range and an excellent control of straylight and thermal variations.

The telescope is based on an off-axis gregorian design consisting of two concave ellipsoidal mirrors with a 1.5-meter pupil, derived from radio frequency antenna, but with a very wide spectral domain which ranges from far infrared (350 μm) up to millimetric wavelengths (10 mm). Its field of view is large (10 degrees) owing to a high number of detectors in the focal plane. The short wavelength detectors (bolometers operating at 0.1 K) are located at the centre of the focal plane unit while the long wavelength ones (based on HEMT amplifier technology operating at 20 K) are located at the periphery.

The Planck telescope operates at a temperature below 60 K. This level is achieved in a passive way, i.e. using a cryogenic radiator. Furthermore, this radiator must accommodate a set of coolers dedicated to the focal plane unit, cooling one of the experiments down to 0.1 K.

The Planck mission leads to very stringent requirements (straylight, thermal stability) that can only be achieved by designing the spacecraft at system level, combining optical, radio frequency and thermal techniques in order to achieve the required performance.

Paper Details

Date Published: 21 November 2017
PDF: 12 pages
Proc. SPIE 10569, International Conference on Space Optics — ICSO 2000, 105692I (21 November 2017); doi: 10.1117/12.2307864
Show Author Affiliations
Guy Fargant, Alcatel Alenia Space (France)
Denis Dubruel, Alcatel Alenia Space (France)
Myriam Cornut, Alcatel Alenia Space (France)
Jean-Bernard Riti, Alcatel Alenia Space (France)
Thomas Passvogel, ESA-ESTEC (Netherlands)
Peter de Maagt, ESA-ESTEC (Netherlands)
Michel Anderegg, ESA-ESTEC (Netherlands)
Jan Tauber, ESA-ESTEC (Netherlands)

Published in SPIE Proceedings Vol. 10569:
International Conference on Space Optics — ICSO 2000
Georges Otrio, Editor(s)

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