Test evolution: RADARSAT-1 to RADARSAT-2
Test methodology for large spacecraft like RADARSAT-1 and RADARSAT-2 has been modified over the last decade resulting in changes to test environments. These changes in the required test environment have necessitated improvements in the test configuration modelling, instrumentation, and data acquisition systems. This paper will identify the significant changes and how the RADARSAT-2 assembly integration and test program has implemented these improvements.
RADARSAT-2 space segment design and its enhanced capabilities with respect to RADARSAT-1
RADARSAT-2, designed to be operational for 7 years, will provide continuity for the RADARSAT program. The RADARSAT-2 satellite design includes significant enhancements over its predecessors. The satellite features advanced radar imaging capabilities and will provide image data of the earth in a variety of spatial resolutions, polarizations, and incidence angles. This paper is intended to provide a top-level overview of the RADARSAT-2 space segment designed by MacDonald, Dettwiler and Associates Ltd. (MDA) in response to the requirements specified by the Canadian Space Agency (CSA). It provides the overview of each component of the space segment, such as the synthetic aperture radar (SAR) payload, the spacecraft bus, the extendible support structure (ESS), and the launch vehicle (LV). It also describes the major activities during spacecraft assembly, integration and testing (AI&T). The enhanced capabilities of RADARSAT-2 in comparison with those of RADARSAT-1 are highlighted throughout this paper.
The role of dissolved oxygen in supercritical water in the oxidation of ferritic–martensitic steel
Abstract To assess the role of dissolved oxygen in supercritical water on the growth processes of oxide scales, a marker experiment of ferritic–martensitic steel was performed by exposing to supercritical water (H 2 16 O) containing marked 18 O 2 at 600 °C under 25 MPa. The oxide scale was analysed by using Secondary Ion Mass Spectrometry (SIMS). The oxygen isotope profile shows that dissolved oxygen and supercritical water react with metals simultaneously. Dissolved oxygen changes the oxidation/reduction potential of supercritical water leading to an increase in the oxidation rate. The oxidation rate increases with increase in dissolved oxygen content in supercritical water. The mechanism of the effect of dissolved oxygen on oxidation is discussed.