The SAX mission

Abstract

SAX (X-Ray Astronomy Satellite) is a programme jointly developed by the Italian Space Agency (A.S.I.) and the Netherland Agency for Aerospace Programmes (NIVR) devoted to systematic, integrated and comprehensive studies of galactic and extragalactic sources in the energy band 0.1 – 200 KeV. Scientific objectives are: • -|Imaging (with moderate angular resolution of 1 arcmin) and broad band spectroscopy over the energy range from 0.1 to 10 KeV. • -|Spectral measurements, spectroscopy and timing on sources from 3 to 200 KeV. • -|All sky monitoring (2–30 KeV) for the investigation of long time variability and localisation and study of transients. The payload complement includes: a low energy (0.1 – 10 KeV) concentrator/spectrometer (LECS), a medium energy (1–10 KeV) concentrator/spectrometer (MECS) consisting of three units, a high pressure gas scintillation proportional counter (3–120 KeV) (HPGSPC) and a phoswich detector system (15–200 KeV) (PDS), all of which have narrow fields of view and have the optical axis coaligned to the same pointing direction. Two wide field cameras (2–30 KeV), field of view 20°×20° (WFC) which point in diametrically opposed directions perpendicular to the narrow field instrument axis, complete the payload. The SAX mission is, for the Payload and Science, under the responsability of a Consortium of Italian Institutes with the partecipation of the Space Research Institute of Utrecht/SRON-Holland and the Space Science Department of the European Space Agency (E.S.A.). The spacecraft has a total mass of 1200 Kg, is three axis stabilised and it will be placed into a circular orbit at 600 Km with an inclination of two degrees, by an Atlas G-Centaur. SAX, to be launched at the end of 1993, will have a minimum mission life time of two years, extendable up to four years.