Letter to the Editor

Herschel Space Observatory^*

An ESA facility for far-infrared and submillimetre astronomy

G. L. Pilbratt^1**, J. R. Riedinger^2***, T. Passvogel³, G. Crone³, D. Doyle³, U. Gageur³, A. M. Heras¹, C. Jewell³, L. Metcalfe⁴, S. Ott² and M. Schmidt⁵

¹ ESA Research and Scientific Support Department, ESTEC/SRE-SA, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands e-mail: gpilbratt@rssd.esa.int
² ESA Science Operations Department, ESTEC/SRE-OA, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
³ ESA Scientific Projects Department, ESTEC/SRE-P, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
⁴ ESA Science Operations Department, ESAC/SRE-OA, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain
⁵ ESA Mission Operations Department, ESOC/OPS-OAH, Robert-Bosch-Strasse 5, 64293 Darmstadt, Germany

Received: 9 April 2010
Accepted: 10 May 2010

Abstract

Herschel was launched on 14 May 2009, and is now an operational ESA space observatory offering unprecedented observational capabilities in the far-infrared and submillimetre spectral range 55–671 μm. Herschel carries a 3.5 m diameter passively cooled Cassegrain telescope, which is the largest of its kind and utilises a novel silicon carbide technology. The science payload comprises three instruments: two direct detection cameras/medium resolution spectrometers, PACS and SPIRE, and a very high-resolution heterodyne spectrometer, HIFI, whose focal plane units are housed inside a superfluid helium cryostat. Herschel is an observatory facility operated in partnership among ESA, the instrument consortia, and NASA. The mission lifetime is determined by the cryostat hold time. Nominally approximately 20 000 h will be available for astronomy, 32% is guaranteed time and the remainder is open to the worldwide general astronomical community through a standard competitive proposal procedure.