Core Viewpoint - The article highlights the increasing concern over space debris, which poses significant risks to spacecraft and astronauts, as evidenced by the recent incident involving the Shenzhou 20 mission being delayed due to suspected collision with space debris [1] Group 1: Space Debris Overview - Space debris, also known as "space junk," includes various objects in Earth's orbit that are no longer operational, ranging from defunct satellites to tiny fragments [1] - As of 2024, there are over 1 million pieces of debris larger than 1 centimeter in space, primarily resulting from satellite disintegration and rocket collisions [1] - A notable incident in 2009 involved a collision between Iridium 33 and the defunct Cosmos 2251 satellite, generating thousands of trackable debris pieces [1] Group 2: Risks and Challenges - Small debris poses a significant challenge due to its high velocity and potential to cause severe damage to spacecraft, particularly affecting heat shield integrity during re-entry [2] - There are approximately 36,000 pieces of debris larger than 10 centimeters in near-Earth orbit, and collisions are not rare occurrences [2] Group 3: Regulatory and Mitigation Efforts - There is currently a lack of international legal frameworks for space debris management, although various countries, including China, are working to establish guidelines [2] - The United Nations has set forth guidelines to mitigate space debris, including a recommendation that space objects should not remain in orbit for more than 25 years [2] - China has implemented regulations for small satellites, mandating that those operating above 2,000 kilometers should actively move to a "graveyard" orbit [2] Group 4: Technological Solutions - Multiple countries are exploring cost-effective and efficient methods for debris removal, such as using nets to capture debris and incinerate it in the atmosphere [3] - China's space agencies have recognized the threat of space debris and have taken preventive measures, including the installation of debris protection devices during the Shenzhou 20 mission [3]