In the Universe there are many phenomena that generate X-rays. However, the Earth atmosphere completely absorbs this radiation from space, and thus systems to detect it have had to be flown above the atmosphere.
Only since the early 1960s it has been possible to identify cosmic X-ray sources, first by using X-ray detectors on-board rockets and, later, satellites.
Early pioneering X-ray investigations utilized very small spacecrafts, such as SAS-1 and SAS-2. Second generation X-ray satellites, like the American HEAO-1 and Einstein, and the European EXOSAT, transmitted the first images of X-ray cosmic sources.
The Italian-Dutch SAX Satellite, successfully launched on April 30 1996, is intended as a bridge between the second generation satellites and the third generation which will be established with NASA's Advanced X-ray Astrophysics Facility (AXAF) and ESA's X-ray Multi Mirror (XMM) satellites.
It is the first X-ray mission (and, of the coming near-future satellites, the only one) that has the capability of observing sources over more than three decades of energy - from 0.1 to 300 keV - with a relatively large area, a good energy resolution, associated with imaging capabilities (resolution of about 1') in the range of 0.1 - 10 keV.
Project Organization
Program Participants
Scientific Goals
Scientific Program
Satellite Description (with an exploded view of the SAX subsystems)
The X-ray Measuring Instruments
The Satellite Subsystems
Operational Features
Launch Description
Major System Data
Bibliography