应对空间碎片，有啥招？（知与不知？）

Core Viewpoint - The article discusses the successful completion of the Shenzhou 20 astronaut team's second spacewalk, focusing on the installation of space debris protection devices and the increasing importance of addressing space debris issues in human space activities [2][3]. Group 1: Space Debris Overview - Space debris refers to all non-functional artificial objects in orbit, including defunct satellites and rocket remnants, with over 44,000 large debris pieces tracked as of 2024, and an estimated 1 million pieces larger than 1 cm posing potential threats to spacecraft [2][3]. - The rapid increase in space debris since the launch of the first artificial satellite in 1957 highlights the need for enhanced protective measures for spacecraft [2]. Group 2: Active Collision Avoidance - Spacecraft typically employ active avoidance strategies for debris larger than 10 cm, relying on a three-step process: monitoring systems to track debris, predictive systems to assess collision risks, and propulsion systems to execute trajectory adjustments [3]. - The effectiveness of these maneuvers requires precise calculations to minimize fuel consumption while maximizing safety, demanding high performance from both ground control and the spacecraft [3]. Group 3: Passive Protection Measures - Passive protection involves installing space debris protection devices, which consist of multi-layer composite structures designed to absorb impact energy, with varying thickness and structure based on the threat level [4]. - The Chinese space station has undergone multiple installations of these protective devices, enhancing the safety of critical components and systems [5]. Group 4: Emergency Response and Repair - In the event of a collision, the space station is equipped with monitoring and emergency response systems to quickly locate and address damage, allowing astronauts to perform repairs under ground guidance [5]. - The design of the flexible solar wings on the Chinese space station accounts for potential impacts from small debris, ensuring continued functionality even if individual components are damaged [5]. Group 5: Active Debris Removal Technologies - The industry is moving towards a comprehensive approach to space debris management, integrating avoidance, protection, and active removal technologies [6]. - Various countries are developing methods for actively removing space debris, such as net capture systems, laser ablation, and robotic arms for debris retrieval [6]. - Global cooperation is essential in addressing the space debris issue, with China actively participating in international efforts to monitor and share information regarding space debris [6].