Group 1 - The Shenzhou 20 astronaut crew has been in orbit for 90 days, with astronauts Chen Dong, Chen Zhongrui, and Wang Jie nearing the midpoint of their mission [1] - Today marks the third anniversary of the launch of the Wentian laboratory module, which Chen Dong witnessed during its launch [3] - The Shenzhou 20 manned spacecraft was successfully launched on April 24, 2025, by the Long March 2F Yao 20 rocket from the Jiuquan Satellite Launch Center [5] Group 2 - The Shenzhou 20 crew entered the "space home" and immediately began their work, focusing on life sciences, microgravity physics, and new space technologies during their 90-day mission [9] - Various tasks such as docking, medical rescue, emergency training, and system pressure drills are being conducted as planned [11] - Routine activities include environmental monitoring, equipment maintenance, inventory management, medical checks, and exercise [13][14] Group 3 - The crew conducted their first spacewalk on May 22, where they installed a space debris protection device and performed inspections [16][18] - This was the first time astronauts exited through the core module's node cabin, and Chen Zhongrui completed his first spacewalk [18] - On June 26, the crew successfully completed their second spacewalk, which lasted approximately 6.5 hours, enhancing the efficiency of future spacewalks by about 40 minutes [20][21] Group 4 - On July 8, the Tianzhou 8 cargo spacecraft separated from the space station, transitioning to independent flight [23] - The crew confirmed the status of the docking passage and watched the launch of the Tianzhou 9 cargo spacecraft, which delivered approximately 6.5 tons of supplies, including scientific experiment materials and space suits [25][27] - The Shenzhou 20 crew's 90-day mission has been fulfilling and exciting, with hopes for successful future work and updates from the "Tiangong" [29]

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].

Core Points - The Shenzhou-20 mission successfully conducted its first extravehicular activity (EVA) with astronauts Chen Dong, Chen Zhongrui, and Wang Jie collaborating closely with ground support [1][11] - This EVA marked the first for astronaut Chen Zhongrui and the fourth for Chen Dong, who became the first astronaut to exit both the weather observation airlock and the node cabin [1][3] Summary by Sections - **EVA Details** - Astronaut Chen Dong opened the node cabin door, allowing light from space to enter [3] - The node cabin's exit is smaller in diameter by 15 centimeters compared to the weather observation airlock, requiring careful maneuvering during the EVA [5] - The astronauts completed approximately 8 hours of extravehicular activities before returning to the node cabin [9] - **Mission Achievements** - The EVA successfully installed a previously transferred space debris protection device and conducted inspections and maintenance of external equipment [7] - This mission validated the assembly construction model where equipment is operated before astronauts exit, providing valuable insights for future large-scale assembly operations [11] - The new space debris protection device enhances the safety and stability of the space station's operations [11]

Core Points - The Shenzhou-20 mission successfully conducted an extravehicular activity (EVA) where astronauts Chen Dong, Chen Zhongrui, and Wang Jie installed a space debris protection device and performed equipment inspections [1][6] - This mission marks the first time astronauts exited through the node cabin instead of the airlock, enhancing operational flexibility and reliability [6][7] - The coupling of astronaut EVA with cargo operations represents a new approach to improve efficiency in space station tasks [8] Group 1 - The Shenzhou-20 crew completed an 8-hour EVA, successfully returning to the Tianhe core module [1][6] - The choice of the node cabin for EVA allows for reduced transfer distances and better performance testing of backup systems [7] - The mission involved extensive preparation and training to address the complexities of working in the smaller space of the node cabin [7][8] Group 2 - The mission aims to ensure the long-term operation of the Chinese space station, which is expected to function for over ten years [8][9] - Astronauts are essential for tasks that require fine motor skills and quick decision-making, which cannot be fully replicated by robotic arms [10] - The collaboration between astronauts and robotic systems is crucial for the maintenance and operation of the space station [10]