Group 1 - The 55th Paris Air Show opened on June 16, showcasing China's aerospace technology capabilities, including the debut of the Long March 6A and Long March 12 rocket models [1][3] - China Aerospace Science and Technology Corporation displayed various rocket models, including Long March 2D, Long March 3B, Long March 6A, Long March 8, and Long March 12, along with the Dongfanghong 3E all-electric small communication satellite [1] - The exhibition included multimedia presentations on sounding rockets, communication satellites, remote sensing satellites, and China's advancements in Beidou navigation, manned spaceflight, lunar exploration, deep space exploration, and international cooperation [1] Group 2 - The Long March 6A is a new generation of non-toxic, pollution-free rocket designed to meet the diverse and dense launch demands of future satellites, while the Long March 12 is a new medium-sized liquid rocket that enhances capabilities for sun-synchronous orbit and low Earth orbit constellation networking [3] - The Long March 12 rocket features a simple and reliable single-core series configuration, improving the payload capacity and large fairing envelope, contributing to the high-quality development of China's space transportation system [3] Group 3 - China Great Wall Industry Corporation, authorized by the government, focuses on commercial launches, satellite system delivery, and space technology cooperation, aiming to promote the globalization of China's commercial aerospace products [5] - Since the 1990s, the Great Wall Company has completed 101 commercial launches, delivering 74 international commercial satellites and 261 domestic commercial satellites, along with providing 52 rideshare launch services [5] - As China's aerospace products gain competitiveness, the Great Wall Company serves as an international platform, integrating various resources to offer more competitive and advanced products and services to the global market [5]

Core Viewpoint - The article discusses the function and evolution of the "排焰口" (exhaust ports) on rockets, highlighting their importance in the separation process of multi-stage rockets and the advancements in rocket technology over time [1][3][4]. Group 1: Function of Exhaust Ports - The primary function of the exhaust ports is to release high-temperature and high-pressure gases generated during the ignition of rocket engines during stage separation [1][3]. - Exhaust ports are designed to manage the gas flow and prevent damage to the lower stage of the rocket during the separation process [3]. Group 2: Evolution of Design - Historically, the design of exhaust ports has evolved, initially using rod structures to allow smooth gas discharge, as seen in earlier models like the Long March 2 and Long March 3 series [3]. - With advancements in rocket technology, newer designs have shifted towards smaller or even absent exhaust ports, as demonstrated by the Long March 2F, which adopted a grid hole design, and the Long March 5, 7, and 8, which utilize cold separation methods [3].