Safari: Instrument design of the far-infrared imaging spectrometer for spica

W. Jellema*, C. Pastor, D. Naylor, B. Jackson, B. Sibthorpe, P. Roelfsema

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

8 Citations (Scopus)
129 Downloads (Pure)


The next great leap forward in space-based far-infrared astronomy will be made by the Japanese-led SPICA mission, which is anticipated to be launched late 2020's as the next large astrophysics mission of JAXA, in partnership with ESA and with key European contributions. Filling in the gap between JWST and ALMA, the SPICA mission will study the evolution of galaxies, stars and planetary systems. SPICA will utilize a deeply cooled 3m-class telescope, provided by European industry, to realize zodiacal background limited performance, high spatial resolution and large collecting area. Making full advantage of the deeply cooled telescope (<6K), the SAFARI instrument on SPICA is a highly sensitive wide-field imaging photometer and spectrometer operating in the 34-210 μm wavelength range. Utilizing Nyquist-sampled focal-plane arrays of very sensitive Transition Edge Sensors (TES), SAFARI will offer a photometric imaging (R ≈ 2), and a low (R = 100) and medium resolution (R = 2000 at 100 μm) imaging spectroscopy mode in three photometric bands within a 2'x2' instantaneous FoV by means of a cryogenic Mach-Zehnder Fourier Transform Spectrometer. In this paper we will provide an overview of the SAFARI instrument design and system architecture. We will describe the reference design of the SAFARI focal- plane unit, the implementation of the various optical instrument functions designed around the central large-stroke FTS system, the photometric band definition and out-of-band filtering by quasioptical elements, the control of straylight, diffraction and thermal emission in the long-wavelength limit, and how we interface to the large-format FPA arrays at one end and the SPICA telescope assembly at the other end. We will briefly discuss the key performance drivers with special emphasis on the optical techniques adopted to overcome issues related to very low background operation of SAFARI. A summary and discussion of the expected instrument performance and an overview of the astronomical capabilities finally conclude the paper.

Original languageEnglish
Title of host publicationInternational Conference on Space Optics, ICSO 2014
EditorsZoran Sodnik, Bruno Cugny, Nikos Karafolas
Number of pages9
ISBN (Electronic)9781510616158
Publication statusPublished - 14-Nov-2017
EventInternational Conference on Space Optics, ICSO 2014 - La Caleta, Tenerife, Canary Islands, Spain
Duration: 7-Oct-201410-Oct-2014

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceInternational Conference on Space Optics, ICSO 2014
CityLa Caleta, Tenerife, Canary Islands


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