Abstract

In 2019, three Canadian satellites, developed by the Canadian Space Agency, were successfully launched into orbit. Using the example of Radarsat Constellation Mission (RCM) satellite, we will present the benefits of a seamless collaboration of simulation & test for complex space systems. How does the FE model of a RCM spacecraft represent reality? One way to find out is to perform modal testing and to compare, or correlate the Test and Simulation Results. This is particularly important in the space industry, as launch loads are derived from validated models of the launch vehicles and the spacecraft. A poor model means uncertain loads which increases program risk. This paper presents how modal simulation is used to prepare the test. Indeed, how can we apply simulation for more productive and realistic testing? Before the RCM modal test is performed, requirements must be defined, as sensors such that the required modes can be clearly identified. How many sensors & exciters are required, where are they located and in which directions do they point? Also, in order to visualize test mode shapes, the test engineers requires a wireframe mesh that connects the sensor and exciter nodes. Finally, test article configuration and boundary conditions have to be investigated. During the modal test campaign, simulation and test results did not correlate properly. Based on quantitative and qualitative tools (MAC, MODMAC and Orthogonality), test and simulation FRFs and mode shapes have been compared. Once correlation establishes the differences between both representations, the FE model has to be updated to more accurately represent reality. Based on an optimizer, which can handle large amounts of variables (physical and material properties); the finite element model has been updated. It was complicated by the test boundary conditions in which the spacecraft was bolted to a concrete floor. This paper presents attempts to account for the flexibility of the interface plate and for the effect of the floor and of the underlying soil in the updating process. This paper unpacks all the challenge of the modal simulation-test interaction. In addition, it presents a fully integrated workflow to reduce iteration-engineering loops, improve simulation-test interaction recently developed to simulate space system. Multi-discipline analyses have been performed on the updated FE model to validate the design against specific loading conditions (acoustic, vibro-acoustic, dynamics?).