Cross-Scale Light Absorption Properties of Surface Bionic Microstructures for Spacecraft Stealth

To address the problem that the black coating for spacecraft optical stealth easily falls off, this study constructs a light-absorbing spacecraft surface based on a micro/nanostructure through imitating a natural light-trapping structure. In this paper, we first analyze the optical properties of a basic stealth structure with the finite difference time domain (FDTD) method and establish a mapping relationship between the light absorption rate of the basic stealth structure and its multiscale factors. Then, imitating the microstructural characteristics of the blackened parts of butterfly wings, we design a multilayered and multiscale complex stealth structure to achieve the optical stealth characteristics of low reflection and high absorption of sunlight on the surface of the spacecraft. Simulation analysis shows that the bionic microstructure can be used to change the optical properties of the metal surface to a certain wavelength band; the complex stealth structure designed based on the butterfly wing can absorb 80.18% of visible light and reduce the overall brightness of the high-orbiting spacecraft by four orders of magnitude.