MULTIPAYLOAD MODELING FOR THE UPPER-ATMOSPHERE RESEARCH SATELLITE

A multipayload spacecraft modeling approach that combines constituent subassemblies (plant and controllers) into a combined system (model sy nthesis) is presented. This technique was used to model the Upper Atmo sphere Research Satellite. The simulation was developed to determine t he amount of controls-structure interaction, and the satellite flight results verified simulation predictions during payload tracking and sc an modes and solar-array sun-tracking modes, The simulation was develo ped using the Dynamics Analysis Design System program, The program was modified to include a multirate sampling capability, a robust analog delay element, a stepper-motor kinematic driver, and a modified flexib le body formulation. The simulation includes the structural models of the satellite components, the dominant flexible modes, the vehicle att itude control system and orbit adjust capability, and all instrument e levation and azimuth control systems. The model includes the flexible modes below 16 Hz and the instrument control systems. This study prese nted simulation results using the synthesized modeling approach and th e in-flight data to validate the approach