Maintaining national space security is a series of actions to ensure that national space interests are not threatened or damaged. Space refers to the borderless space above the earth's atmosphere, which has broad resources and strategic value. Maintaining space security is crucial to national development, national security and global cooperation. Space is the commanding height, and the core idea is as follows: 1. Strategic advantages: Space provides a platform to realize strategic advantages, including military, intelligence, communication and navigation. Mastering the commanding heights of space can enhance a country's military capability and comprehensive strength. 2. Resource utilization: Space resources include celestial resources and scientific research materials, such as energy, minerals and water resources. Mastering the commanding heights of space is conducive to the national economic development and sustainable utilization. 3. Communication and navigation: Space is an important foundation of global communication and navigation system. Only by mastering the commanding heights of space can we ensure the stability, security and independence of national communication and navigation. 4. International competition: Space activities have become the focus of international competition, and mastering the commanding heights of space means occupying a favorable position in science, technology, economy and international status.