## 4 Conclusions  
This paper investigates the collision safety of LEO megaconstellations under the current space debris environment. A collision evolution calculation method for large-scale space debris and large-scale satellites is proposed. By filtering and partitioning data, the computing efficiency is improved while satisfying high accuracy. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Collision Target Type** & **Space Debris \(D\) Number** & **Space Debris \(c\)** \\ \hline Starlink satellites and intact objects & 624 & 17 \\ Starlink satellites and space debris \(D\) & 65 & 132 \\ Starlink satellites and space debris \(c\) & 64 & 132 \\ Whole objects and whole objects & 1643 & 385 \\ Intact objects and space debris \(D\) & 466 & 74 \\ Intact objects and space debris \(c\) & 465 & 74 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Amount of space debris produced by different collision types. Figure 17: The amount of space debris generated by different collision types. The lower orbital altitude of the Starlink constellation improves the safety of the constellation and the stability of the space environment, but the collision risk faced by the constellation is still high. A satellite needs to have good orbital maneuverability and collision warning capabilities. The risk of a second collision in a constellation increases exponentially. This study has proposed a calculation method for the collision safety assessment parameters of an LEO megaconstellation. The short-term collision probability and long-term average collision probability of the constellation are used to evaluate the safety of the constellation to improve the reliability and effectiveness of the constellation safety assessment. Through a simulation of the Starlink Phase I constellation, the results show that after the deployment of the Starlink constellation, the probability of a short-term collision in the constellation shell increases by 30-40%, the probability of at least one collision in the constellation lifetime is 70.2%, and the probability of a secondary collision increases by 25.3% after a collision. These models not only offer insights into orbital safety but also present valuable references and practical applications. The innovative findings of this study introduce novel methodologies and concepts to effectively mitigate the risks associated with constellation collisions. The main topics for possible future improvements are as follows. Space debris has become a growing problem in the space sector, and the deployment of large constellations consisting of hundreds or thousands of satellites is an environmental concern. The occurrence of a collision causes more serious consequences. The method for how to avoid the collision of constellation satellites and improve the safety of constellation in-orbit operation should be further investigated. Building upon existing research, there is a need to refine perturbation and collision models while considering the distribution and evolution of fragments post-collision. This involves integrating evaluation models and exploring objective, simple, easily verifiable, and replicable methods to assess the LEO spatial environment. Furthermore, expanding the scope of research to encompass other constellations under construction or already operational is essential, including the consideration of various collision scenarios such as satellite-to-satellite collisions and collisions involving space devices. This expanded approach will facilitate a more comprehensive evaluation of collision risks across different scenarios. Conceptualization, M.H. and C.Y. ; methodology, C.Y. ; simulation, C.Y. and W.X. ; writing--original draft preparation, C.Y. and Y.R. ; writing--review and editing, Y.R. ; visualization, Y.R. ; supervision, M.H. All authors have read and agreed to the published version of the manuscript. This research received no external funding. The data are available from the corresponding author on reasonable request. Data access is restricted to research and educational applications.