On September 29th, China successfully launched the experimental satellites 01 and 02 using the Long March 2D carrier rocket from the Xichang Satellite Launch Center. This launch is the 100th launch of the Long March 2D carrier rocket, marking it as the second type of single type carrier rocket in China to exceed 100 rounds. What are the developments and innovations of the Long March 2D carrier rocket? The reporter interviewed the research participants. The Long March 2D carrier rocket, developed by the Eighth Academy of China Aerospace Science and Technology Corporation, is a liquid second stage carrier rocket at room temperature. Since its maiden flight in 1992, it has become the main model for launching in low Earth orbit and sun synchronous orbit in China through continuous development and innovation. Through iteration and integration of existing advantageous technologies, the Long March 2D carrier rocket continues to develop in innovation. According to Fan Chongsheng from the Eighth Academy of China Aerospace Science and Technology Corporation, in recent years, the team has developed a shielding structure and system with interference suppression function to meet the technical requirements of eliminating interference in the same frequency band for multi model parallel testing. This can effectively isolate external interference in the same frequency and other electromagnetic interferences, creating conditions for multi model rocket parallel testing and improving the stability of wireless signal transmission. In addition, the new automated three-axis intelligent turntable is responsible for automatic horizontal adjustment of the inertial group, one key leveling of the work plane, remote control and other functions, which can meet the needs of intelligent testing. Fan Chongsheng stated that rocket testing has become more efficient, convenient, and accurate, improving the quality of comprehensive testing. The efficiency of integrated testing for the entire rocket has increased by more than 30%. It can make the satellite sit more stably in the satellite assembly technology plant, where the satellite is smoothly parked on the upper side of a cone, which is the support cabin connecting the bottom of the satellite and the rocket body. With the increasing payload of satellites, the "weight reduction" of various parts of rockets has become the first problem to be solved. To this end, the 149 factory of the institute has developed a composite material support cabin, which reduces the weight of the product by 20% compared to similar metal material support cabins. Although composite materials have the characteristics of high structural strength and light weight, the surface accuracy and roughness of the product are also within the scope we need to consider. ”Zhang Yanda from the Eighth Academy of China Aerospace Science and Technology Corporation said that making the main "passenger" satellite of the rocket sit more stably is an important indicator in product development. To this end, the technical research team identified the pressure transmission path in complex areas of the product through the analysis and simulation of the curing behavior of composite materials. They conducted preparation experiments on multiple batches and small samples, optimized and adjusted the pressure fixture structure and curing process parameters, effectively balancing the weight and performance of the supporting cabin products, and improved the adaptability of the carrier rocket to the payload, allowing each satellite to have its own "space". Establish a series of product spectra to compare the size of the satellite fairing at the top of each Long March 2D carrier rocket. Lei Xiangheng from the Eighth Academy of China Aerospace Science and Technology Corporation introduced that as the first protection during the takeoff process of a carrier rocket, the "height" and "weight" of the satellite fairing are determined by the size envelope of the launched payload. In order to provide more choices for rocket payloads, we have gradually formed a development concept of series products, improved the product spectrum of satellite fairing, and gradually expanded from diameters of 2.9 meters and 3.35 meters to 3.8 meters and 4 meters, with materials divided into metal and composite materials. ”Lei Xiangheng said. Lei Xiangheng stated that through continuous system research and product development, and the use of integrated molding technology, the co curing molding of the satellite fairing sandwich structure has been achieved, with a production efficiency increase of over 20%, ensuring the product's temperature resistance and wave permeability. (New Society)