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.
Global attractivity in time-delayed predator-prey systems
Abstract For a predator-prey model with time-delay due to gestation, criteria are obtained for persistence and global attractivity. The global attractivity criteria apply only to models with a decreasing prey isocline.