How do fresh graduates enter the space system unit? Ask the master to point out the maze.

Every year, aerospace-related units such as Aerospace Science and Technology Corporation, Aerospace Science and Industry Corporation, and subordinate units of the General Armament Department (the Jiuquan Satellite Center you mentioned belongs to the army) will recruit new graduates. I don't know which school you study in. Generally, these institutions will hold job fairs in Tsinghua, Beihang University, Harbin Institute of Technology, Northwest Institute of Technology and other institutions. You can also pay attention to recruitment websites such as Zhilian and ChinaHR, and they will post recruitment notices. Just submit your resume. These companies are not mysterious, just like other companies. As long as you are good enough, you can work in these companies.

As for skills, it depends on what kind of work you want to do. If you are an engineer, I think you just need to keep a down-to-earth research spirit and excellent technical skills. Systems engineering theory and engineering control theory are also needed, because aerospace engineering is a huge and complex project.