Flat retroreflective arrays and foils for satellite laser ranging

Retroreflective structures play an important role in laser-based space applications, serving as navigation aids for spacecraft docking and enabling precise orbit determination through satellite laser ranging. These structures must deliver a high return signal over long distances while being durable, and capable of operating in the challenging conditions of space for extended periods. Flat retroreflective structures such as retroreflective foils would be beneficial to ensure a seamless integration with various satellites, particularly CubeSats. This study analyzes the far-field diffraction patterns of various commercially available retroreflective foils, which are crucial for calculating the optical cross-section. While the retroreflected signal from these foils is notably weaker than that of conventional corner-cube retroreflectors of equivalent area, it remains several orders of magnitude stronger than that of a diffusely reflecting surface. Beyond conventional retroreflective foils, which rely on arrays of microprisms, we explore the potential of flat retroreflective structures based on metasurfaces. These nanostructures offer intriguing possibilities, such as wavelength-dependent retroreflection, and may be engineered for compatibility with space environment. In the future, such advanced designs could enable innovative applications like satellite identification or attitude determination. Moreover, we theoretically analyze how the changing attitude of the satellite affects the return signal of potentially coherently retroreflecting arrays. • High diffraction angle due to small sub-apertures. • Experiments show that this angle is enlarged in practice due to non-idealities. • Thus, the required retroreflecting area is increased significantly for SLR. • A manufacturing tolerance of ∼ 90 nm is required for a coherently reflecting array • A coherently reflecting array has to be fine pointed due to beam steering effects.