Modeling and Analysis of the New FAST Feed Cabin Configuration under Different Illumination Modes postprint

Abstract: A new feed cabin configuration for the Five-hundred-meter Aperture Spherical radio Telescope (FAST) is proposed to extend the observation zenith angle from 40° to at least 50°. This research involves theoretical modeling, mechanical analysis, and numerical simulations to evaluate the configuration’s performance under both backward illumination (BI) and non-backward illumination (NBI) modes. The results indicate that the new feed cabin configuration meets key requirements such as cable force distribution, low condition number, and high firstorder natural frequency. Additionally, accuracy analysis confirms that the system maintains high accuracy under structural deformations caused by stress. Comparison analysis shows that BI mode generally exhibits superior performance compared to NBI mode, but both modes meet relevant constraints within 50° zenith angle, which is expected to provide greater flexibility for observations. This research lays the important foundation for the new feed cabin’s practical application and offers valuable insights for the FAST’s future upgrade.