Asteroids, as preserved remnants of the solar system’s primordial material, retain original compositional information from the solar nebula. They offer essential insights into solar system formation and evolution processes, validate asteroid origin and collision theories, and advance studies on extraterrestrial resource utilization. Additionally, the observation and monitoring of near-Earth asteroids are crucial for protecting Earth’s cosmic environment, establishing them as a key focus in contemporary planetary science research. The asteroid light curve, which documents the temporal variation of solar radiation reflected from an asteroid’s surface, constitutes a fundamental dataset for determining basic physical properties such as geometric shape and rotational state. Currently, predominant asteroid light curve simulation methods employ simplified scattering models, primarily Lambert and Lommel?Seeliger, which disregard multiple-scattering effects and thus inadequately represent the physical reality of light interactions on rough asteroid surfaces. Consequently, systematic deviations emerge when simulating light curves under conditions of significant surface roughness and multiple scattering. This underscores the necessity for more physically accurate scattering models to achieve precise and reliable asteroid light curve simulations.

This study investigates the implementation of the Oren?Nayar scattering model, which accounts for multiple-scattering effects, within deep-space asteroid exploration using a self-developed digital simulation system for asteroid light curves. The system utilizes the target asteroid’s ephemerides and three-dimensional shape model as input parameters, along with additional simulation parameters including rotational state, orbital elements, and camera specifications. The system calculates the relative spatial geometry and attitude of the Sun?asteroid?observer configuration at designated observational epochs. The asteroid’s surface scattering characteristics are simulated using the Oren?Nayar scattering model under these conditions to generate photometric observation images. Standard corrections, including background subtraction, dark current removal, and flat-field correction, are applied to the generated images. Otsu’s maximum between-class variance method is then employed to isolate the asteroid from the stellar background. The photometric intensity of the target asteroid is extracted from the corrected images to derive the corresponding light curve, enabling refined light curve simulations under multiple-scattering conditions.

Asteroid Bennu is selected as the target body, with ten approach-phase observation periods from the OSIRIS-REx mission chosen as target observation intervals. Photometric observation images of Bennu captured by the PolyCam camera aboard OSIRIS-REx serve as the reference dataset, while a 0.8 m-resolution shape model of Bennu is utilized as the reference shape model (Table 1, Table 2, Fig. 3, and Fig. 4). Experimental validation confirms the viability and reliability of the fine light curve simulation technique based on the proposed digital simulation system (Figs. 5?7). The simulated light curves produced under this method show relative root-mean-square errors below 0.5% compared to measured light curves. Additionally, simulated light curves are generated using the Lcgenerator module of the DAMIT software under identical observation periods and conditions as a control group. Results demonstrate that the digital simulation system achieves substantially improved accuracy compared to DAMIT simulations (Table 4 and Fig. 8), further validating the robustness and precision of the proposed method.

This study presents an innovative asteroid imaging simulation and light curve modeling technique incorporating the Oren?Nayar scattering model, which accounts for multiple-scattering effects, enabling refined asteroid light curve simulations. The developed methodology supports observation strategy formulation across various mission scenarios. In planetary defense source-selection tasks, the technique simulates photometric reflection behavior of near-Earth asteroids with diverse geometric shapes, rotational states, and surface physical properties, providing a physical foundation for evaluating potentially hazardous targets. For joint ground?space monitoring missions, the method, combined with orbital dynamics models, enables simulation and prediction of asteroid brightness variations at specific phase angles, facilitating efficient monitoring strategy design. The proposed digital simulation framework advances precise asteroid physical parameter inversion, enhancing the retrieval of surface and structural properties from observed light curves. The technique demonstrates significant potential for enhancement, including extension to non-convex asteroid surface scattering simulation and incorporation of detailed surface texture descriptors for fine-scale heterogeneity representation. These developments will provide enhanced technical support for future scientific research and deep space exploration missions.