The SAS-3 X-ray observatory.
Abstract
The experiment section of the Small Astronomy Satellite-3 (SAS-3) launched in May 1975 is an X-ray observatory intended to determine the location of bright X-ray sources to an accuracy of 15 arc-seconds; to study a selected set of sources over a wide energy range, from 0.1 to 55 keV, while performing very specific measurements of the spectra and time variability of known X-ray sources; and to monitor the sky continuously for X-ray novae, flares, and unexpected phenomena. The improvements in SAS-3 spacecraft include a clock accurate to 1 part in 10 billion, rotatable solar panels, a programmable data format, and improved nutation damper, a delayed command system, improved magnetic trim and azimuth control systems. These improvements enable SAS-3 to perform three-axis stabilized observations of any point on the celestial sphere at any time of the year. The description of the experiment section and the SAS-3 operation is followed by a synopsis of scientific results obtained from the observations of X-ray sources, such as Vela X-1 (supposed to be an accreting neutron star), a transient source of hard X-ray (less than 36 min in duration) detected by SAS-3, the Crab Nebula pulsar, the Perseus cluster of galaxies, and the Vela supernova remnant.
- Publication:
-
Johns Hopkins APL Technical Digest
- Pub Date:
- December 1975
- Bibcode:
- 1975JHATD..14...14M
- Keywords:
-
- Digital Command Systems;
- Sas-3;
- Satellite Attitude Control;
- Spaceborne Astronomy;
- X Ray Astronomy;
- Crab Nebula;
- Galactic Clusters;
- Novae;
- Nutation Dampers;
- Satellite Design;
- Supernova Remnants;
- X Ray Sources;
- Astronomy