Pulsed laser irradiation technology, which utilizes the momentum coupling effect to apply a recoil impulse by generating plasma plumes on the debris surface to decelerate and deorbit it, has become an important means of space debris removal. However, most research focuses on idealized geometric models, ignoring the fact that debris usually has irregular shapes. The surface curvature of the debris is a critical parameter affecting the efficiency of momentum transfer, and a comprehensive understanding of these parameter effects is crucial for designing effective laser removal strategies. Therefore, this study systematically investigates the influence of surface curvature on the velocity increment of irregular space debris, providing a theoretical reference for the design and parameter optimization of active debris removal systems.

In order to simulate the geometric characteristics of irregular debris, two representative models were established: the ellipsoid model and the parabolic cylinder model. These two models achieved the continuous variation in curvature, thereby simulating a series of different shapes. Numerical simulations based on the impulse coupling theory were conducted. The debris material was set to aluminum alloy, with a laser energy density of 58 kJ/m² and an impulse coupling coefficient of 1.13 × 10⁻⁴ N·s·J⁻¹. The core of the analysis was to evaluate the velocity increment as a function of three variables: surface curvature, laser incident angle, and the debris size (i.e., the disk radius of the ellipsoid model and the square side length of the parabolic cylinder model). The total impulse was calculated by the surface integral of the impulse generated over infinitesimal elements, considering the non-irradiated "shadow" areas on the curved surface.

Firstly, under varying laser incident angles (using debris with both an initial disk radius and a square half-side length of 5 cm as examples), the velocity increments for both models decreased monotonically with increasing curvature due to the deviation of local surface normals. This decreasing trend was particularly drastic at high incident angles (e.g., 90°) (Fig.5). The velocity increment of the ellipsoid model eventually converged to 0.024～0.029 m/s. Conversely, the parabolic cylinder model exhibited a critical curvature of 12 m⁻¹, beyond which the velocity increment stabilized at 0.063 m/s and became independent of the incident angle. Secondly, at a fixed incident angle of 45°, larger debris demonstrated higher sensitivity to curvature changes, characterized by a faster decline and a lower steady value in velocity increment (Fig.6). For instance, as the ellipsoid radius increased from 1 cm to 5 cm, the stable velocity increment dropped from 0.083 m/s to 0.026 m/s, primarily driven by the "area-to-mass ratio" effect. Finally, in the parabolic cylinder model, as the square half-side length of the debris increased from 1 cm to 5 cm, the critical curvature required to reach a dynamic impulse balance dropped sharply from 59.212 m⁻¹ to 12.000 m⁻¹, with the corresponding stable velocity increment decreasing from 0.145 m/s to 0.063 m/s (Fig.7). In summary, the simulation results revealed a complex nonlinear relationship among surface curvature, incident angle, debris size, and velocity increment. The following conclusions are drawn: (a) Surface curvature generally has an adverse effect on momentum transfer efficiency, and this effect is most obvious at high incident angles; (b) Larger debris is more sensitive to curvature, characterized by a faster decline in velocity increment and a lower steady value; (c) There exists a critical curvature for the parabolic cylinder model, at which point the velocity increment is independent of the incident angle.

The coupling effects of surface curvature, laser incident angle, and debris size on the velocity increment generated by pulsedlaser irradiation are systematically elucidated.The above findings provide a necessary theoretical reference for the design of laser removal strategies for irregular space debris. The next step should be to establish a general database model of pulsed laser irradiation on debris with different geometric shapes, providing technical guidance for accurately estimating the laser parameters required to remove debris of different shapes.