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Proceedings Paper

Far-infrared space interferometer study IRASSI: motivation, principle design, and technical aspects
Author(s): Hendrik Linz; Luisa Buinhas; Roger Förstner; Matthias Lezius; Divya Bhatia; Simon Batz-dorfer; Katja Beha; Ulf Bestmann; Bernd Eissfeller; Meltem Eren Copur; Eloi Ferrer; Kathrin Frankl; Oliver Krause; Yongjin Moon; Mathias Philips-Blum; Silvia Scheithauer; Meiko Steen
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Paper Abstract

The far-infrared (FIR) regime is one of the few wavelength ranges where no astronomical data with sub-arcsecond spatial resolution exist yet. Also medium-term satellite projects like SPICA, Millimetron or OST will not resolve this malady. For many research areas, however, information at high spatial and spectral resolution in the FIR, taken from atomic fine-structure lines, from highly excited CO and especially from water lines would open the door for transformative science. These demands call for interferometric concepts. We present here first results of our feasibility study IRASSI (Infrared Astronomy Satellite Swarm Interferometry) for an FIR space interferometer. Extending on the principal concept of the previous study ESPRIT, it features heterodyne interferometry within a swarm of 5 satellite elements. The satellites can drift in and out within a range of several hundred meters, thereby achieving spatial resolutions of <0.1 arcsec over the whole wavelength range of 1–6 THz. Precise knowledge on the baselines will be ensured by metrology employing laser frequency combs, for which first ground-based tests have been designed by members of our study team. In this contribution, we first give a motivation how the science requirements translated into operational and design parameters for IRASSI. Our consortium has put much emphasis on the navigational aspects of such a free-flying swarm of satellites operating in relatively close vicinity. We hence present work on the formation geometry, the relative dynamics of the swarm, and aspects of our investigation towards attitude estimation. Furthermore, we discuss issues regarding the real-time capability of the autonomous relative positioning system, which is an important aspect for IRASSI where, due to the large raw data rates expected, the interferometric correlation has to be done onboard, quasi in real-time. We also address questions regarding the spacecraft architecture and how a first thermomechanical model is used to study the effect of thermal perturbations on the spacecraft. This will have implications for the necessary internal calibration of the local tie between the laser metrology and the phase centres of the science signals.

Paper Details

Date Published: 6 July 2018
PDF: 18 pages
Proc. SPIE 10698, Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave, 1069852 (6 July 2018); doi: 10.1117/12.2313801
Show Author Affiliations
Hendrik Linz, Max-Planck-Institut für Astronomie (Germany)
Luisa Buinhas, Univ. der Bundeswehr München (Germany)
Roger Förstner, Univ. der Bundeswehr München (Germany)
Matthias Lezius, Menlo Systems GmbH (Germany)
Divya Bhatia, Technische Univ. Braunschweig (Germany)
Simon Batz-dorfer, Technische Univ. Braunschweig (Germany)
Katja Beha, Menlo Systems GmbH (Germany)
Ulf Bestmann, Technische Univ. Braunschweig (Germany)
Bernd Eissfeller, Univ. der Bundeswehr München (Germany)
Meltem Eren Copur, Univ. der Bundeswehr München (Germany)
Eloi Ferrer, Univ. der Bundeswehr München (Germany)
Kathrin Frankl, Univ. der Bundeswehr München (Germany)
Oliver Krause, Max-Planck-Institut für Astronomie (Germany)
Yongjin Moon, Univ. der Bundeswehr München (Germany)
Mathias Philips-Blum, Univ. der Bundeswehr München (Germany)
Silvia Scheithauer, Max-Planck-Institut für Astronomie (Germany)
Meiko Steen, Technische Univ. Braunschweig (Germany)

Published in SPIE Proceedings Vol. 10698:
Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave
Makenzie Lystrup; Howard A. MacEwen; Giovanni G. Fazio; Natalie Batalha; Nicholas Siegler; Edward C. Tong, Editor(s)

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