As system performance continues to improve at higher resolutions, it becomes increasingly important to establish standards for imaging degradation caused by optical windows. In this study, random surface shapes were simulated on large area optical windows with peak-to-valley (P-v) values of 0.25, 0.5, and 1.0 λ. Modulation Transfer Function (MTF) values were derived for 1,000 cases per P-v value using Monte-Carlo simulations. The specifications achieved a surface accuracy of 0.5 λ and a parallelism of 0.01 mm. MTF measurements showed that the system MTF was 13.5% prior to the installation of the optical window, and 13.1% after installation. This indicates a degradation rate of approximately 3%.

The use of reflective optical systems is essential to acquiring high-resolution image quality in aerospace applications that observe distant objects. The geometric shapes of large-aperture reflective optical systems can be deformed depending on various operating and space environments, which deformation consequently affects optical performance. In this study, we predict the image quality of a reflective aerospace optical system according to various environmental changes. In particular, the shape deformation due to vibration and heat generated from the launch vehicle was mainly observed, and the effect on gravity was also considered. The variations of image quality, such as Modulation Transfer Function (MTF) and wave-front error (WFE), were also observed by importing the deformed shapes into the optical simulation tool. This study is intended to provide approaches to reduce the cost and lead time to develop aerospace optical systems.

The utilization of aerospace technology is growing to meet various requirements of climate change sensing, communications, and the military. Large aperture and precise reflective optical systems such as mirrors are needed to acquire high-quality data, and the requirements of lightness, low cost, and low deformation should also be met to operate in the space environment. In this review, we highlight the recent progress of reflective optical systems for aerospace applications. In particular, optical systems for artificial satellites and homing optics are mainly introduced, and optical and mechanical simulations are discussed according to operating environments. We also discuss various reflective optic designs, materials, and operating principles for aerospace applications, such as a homing head and optical payload. We hope that this review provides approaches for developing surveillance systems, exploring space, and addressing the climate crisis.