Galactic X-ray observations from the scientific satellites Copernicus and Ariel V.

This thesis describes the pre-flight preparation and analysis of results from two scientific satellites engaged in the study of cosmic X-ray Astronomy. The places occupied by Ariel V and Copernicus in current X-ray Astronomy are reviewed and areas of current interest are noted. Supernovae and their remnants as x-ray sources are reviewed and the ability of x-ray measurements to probe the energetics of such systems is discussed. The Copernicus satellite provides a stabilised platform from which high resolution soft x-ray sources can be studied. The study of two strong soft supernova remnants are described in detail. Puppis A, providing the greatest surface brightness at 1 KeV, was mapped in two dimensions with the grazing incidence telescopes aboard Copernicus. The map, with the highest resolution to date, indicates the existence of a bright extended source with unresolved softer components. The data is consistent with a thermal source resulting from the interaction of a shock wave with a massive interstellar cloud. The Vela X observations indicate excess 0.5 - 1.5 KeV emission near, but not coincident with, the pulsar. The pulsar contribution must be less than previously reported. An unexpected 2.5 - 7.5 KeV flux was recorded from Vela X and this can be explained by an extended non-thermal region. The Ariel V Observing Programme is discussed and the Leicester Sky Survey Experiment is described in detail. Finally, Ariel V data was used to follow up the Copernicus observations of Vela X and show that the region contains several variable sources and yet still allows the extended harder x-ray source suggested.