Abstract
The Exoplanet Characterisation Observatory (EChO) is a space mission dedicated to investigate exoplanetary atmospheres by undertaking spectroscopy of transiting planets in a wide spectral region from the visible to the mid-InfraRed (IR). The high sensitivity and the long exposures required by the mission need an extremely stable thermo-mechanical platform. The instrument is passively cooled down to approximately 40 K, together with the telescope assembly, by a V-Groove based design that exploits the L2 orbit favourable thermal conditions. The visible and short-IR wavelength detectors are maintained at the operating temperature of 40 K by a dedicated radiator coupled to the cold space. The mid-IR channels, require a lower operating temperature and are cooled by an active refrigerator: a 28 K Neon Joule-Thomson (JT) cold end, fed by a mechanical compressor. Temperature stability is one of the challenging issues of the whole architecture: periodical perturbations must be controlled before they reach the sensitive units of the instrument. An efficient thermal control system is required: the design is based on a combination of passive and active solutions. In this paper we describe the thermal architecture of the payload with the main cryo-chain stages and their temperature control systems. The requirements that drive the design and the trade-offs needed to enable the EChO exciting science in a technically feasible payload design are discussed. Thermal modelling results and preliminary performance predictions in terms of steady state and transient conditions are also reported. This paper is presented on behalf of the EChO Consortium.
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References
Tinetti, G., et al.: EChO. Exoplanet characterisation observatory. Exp. Astron. 34(2), 311–353 (2012)
EChO Yellow Book, ESA SRE 2013 2 EChO, (2013)
Eccleston, P., et al.: EChO Assessment Study Design Report, ECHO-RP-0001-RAL, Issue 3.0 (2013)
Focardi, M., Farina, M., Pancrazzi, M., Di Giorgio, A. M., Pezzuto, S., Ottensamer, R., Pace, E., Micela, G.: EChO electronics architecture and SW design. Experimental Astronomy EChO Special Issue, submitted (2014)
Planck collaboration: Planck early results. II. The thermal performance of Planck. Astron. Astrophys. 536, A2 (2011)
Shaughnessy, B. M., Eccleston, P.: Thermal Design of the Mid-Infrared Instrument (MIRI) for the James Webb Space Telescope. International Conference on Environmental Systems (ICES) 2008, San Francisco, California, USA, paper 2009-01-2410 (2009)
Morgante, G., Terenzi L.: EChO TMM/GMM Description and Results Technical Note, ECHO-TN-0001-IASFBO, Issue 1.0 (2013)
Morgante, G., et al.: Cryogenic characterization of the Planck sorption cooler system flight model. J. Inst. 4, T12016 (2009)
Acknowledgments
We want to acknowledge here the fundamental contribution of the EChO system team to this work. The Italian participation to the EChO mission was supported by the Italian Space Agency (ASI) in the framework of the ASI-INAF agreement “Missione EChO: assessment phase”, I/022/12/0.
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Morgante, G., Terenzi, L., Eccleston, P. et al. Thermal control system of the Exoplanet Characterisation Observatory Payload: design and predictions. Exp Astron 40, 771–800 (2015). https://doi.org/10.1007/s10686-015-9469-7
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DOI: https://doi.org/10.1007/s10686-015-9469-7