In the courtyard of China Academy of Launch Vehicle Technology, there is an inconspicuous three storey building, with tall trees standing upright in front of the door and red bricks and white walls set off against each other. This small building, known as the "test flight building", looks very old compared with the rows of tall buildings built later, but it occupies a pivotal position in the minds of the older generation of "Rocket Academy people". To the south of the small building, there used to be an airplane runway. For a period of time, Factory 211, located here, focused on aircraft maintenance, and the small building was mainly used for command and observation during aircraft test flight. This is also the origin of the name "test flight building". In the 1950s, Factory 211 was put under the jurisdiction of the First Branch of the Fifth Research Institute of the Ministry of National Defense (the predecessor of the Rocket Technology Research Institute) and served as the final assembly factory for missile trial production. The "test flight building" thus completed the mission transformation from aircraft maintenance to missile development. At that time, the factory environment was very difficult and scientific research equipment was extremely scarce. However, the staff always firmly believed that they should develop domestic missiles as soon as possible. More and more young talents gather here from all directions of the motherland, and on a piece of white paper, they depict the grand prospect of developing the missile industry. Lu Shoumao is the former technician of the Fourth Room of the Overall Design Department. Recalling the past, he remembered clearly: "There were several people crowded around a table, and the legs of the table were uneven, so we had to put a brick under it. Once, we spread the drawing on the table to see, because there were many people, we suddenly pushed the table over. Looking down, it turned out that the legs of the table fell off the brick." Compared with the hard working environment, the task is a serious challenge. In the "test flight building", scientific researchers are stepping up their translation and learning of technical materials and drawings, racing against time every day. Chen Qiqi, the director of the Beijing Institute of Intensity Environment of the former research institute, recalled: "After getting the missile drawings, the first thing is to paint - first cover the drawing paper on the original drawing, use a pen dipped in ink to paint a little, then paint the full set of original drawings, print them, and hand them over to the factory for production. In order to catch up with the schedule, more than 10 mapping teams worked overtime every day and worked hard for more than a month to complete the task." Missile manufacturing is completely different from aircraft maintenance. Aircraft maintenance depends on riveting, while missile manufacturing mainly relies on welding. Most production processes need to be learned from scratch. The factory has sent some employees abroad to study welding technology. They cherish the rare opportunity. In order to practice their welding skills, some masters tied sandbags on their arms. In the process of missile development, many teachers simply live in the factory with quilts in their arms, "rolling around" day and night. Forging needs to import some large-scale equipment, and it will take 3 years to arrive. Workers can't wait to rely on it. They use a 12 pound sledgehammer to manually correct, and just "knock" out qualified products. They had only one belief in their hearts: "No matter how difficult it is, we should build a Chinese 'morale bomb'." The east wind rises in the sky. On November 5, 1960, China successfully launched the first missile - Dongfeng I, and China's missile industry achieved a breakthrough from scratch. The success of imitation is just the beginning. If you want to develop independently, the road ahead will be more difficult and challenging. The majority of scientific researchers fully tap the potential of the Dongfeng 1 missile and carry out independent research and development work in a "small step and fast walk" way. When Dongfeng II was developed, it was catching up with the "three-year difficult period".