Modern Attitude Control and Co-design for the Biomass Satellite (Earth Explorer Core Mission 7)

The purpose of this paper is to describe the current results and future activities of the European Space Agency (ESA) Robust AOCS technology program in support to the Biomass, Earth Explorer Core Mission 7. Due to the specificity of the chosen Biomass configuration this activity is driven by the expected interaction between the large flexible reflector antenna structure and its attitude control system. Currently ESA has developed a technology program to enable the capabilities of integrating the structural sizing and control system design in order to avoid interactions problems. The objective is the development of an Integrated Modeling, Control and Analysis framework IMCA: it incorporates uncertainty modeling via LFT's, robustness analysis via the Structured Singular Value μ and various robust control synthesis techniques such as H∞ and μ methods. This framework results as natural multivariable extensions of the classical Bode frequency domain techniques. It shall be integrated with a structural design loop into an unified computational framework to exploit control structures interactions in order to increase the spacecraft capabilities, such as better pointing stability, and to improve the overall design when compared to the traditional approach. Following the conclusion of the Phase A, the outcome of two parallel activities will be presented.