Contingency Mitigation Aspects for Reflector Based Satellite SAR Systems

Contingency mitigation, especially with respect to potential failures of Transmit-Receive Modules (TRMs) is a critical issue for SAR system concepts based upon planar phased array antenna fed large-deployable reflector (LDR) instruments. One promising approach is defocusing the LDR from the usually employed paraboloid shape. This opens a trade-space which has to be carefully investigated. Based on the current instrument and spacecraft geometry of Tandem-L we here assess the potential of reflector shaping to mitigate potential TRM failures. In particular we discuss the potential for re-optimization of the transmit pattern in such a contingency case. We find that for the defocused reflector, the impact of a potential TRM failure on the transmit pattern can be largely mitigated with acceptable impacts on nominal operations.