Published online by Cambridge University Press: 25 April 2016
A broad-band (2-190 keV) Australian X-ray satellite could provide a spectral sensitivity substantially better than HEAO-1 or any presently approved spacecraft. It would be virtually unique by providing simultaneously data over a wide energy range with high sensitivity and energy resolution in the little measured region above 30 keV. These measurements are vital to our understanding of such diverse topics as the cyclotron line production mechanism in binary sources, the structure of the magnetosphere of neutron stars, the origin of the diffuse cosmic X-ray background and the nature of the giant power sources in active galaxies and stellar black holes. Details of the proposed spacecraft and scientific objectives are given.