## 1 Introduction  
Recent years have witnessed mankind accelerating into a new era of lunar exploration and development [1], and there will be more and more cislunar activities [2, 3]. In the future, the number of unmanned lunar probes and manned lunar spacecraft will increase and take more and more \"one small step for individuals and one giant step for humankind\" [4, 5, 6]. Cislunar space is a natural extension of the near-Earth orbit space. In a broad sense, it is a region dominated by the gravitational force of the Earth and the Moon, including near-Earth space, lunar gravitational space, and Earth-Moon transfer space; in a narrow sense, it refers to the Earth-Moon transfer space and lunar gravitational space outside the geosynchronous belt [7; 8; 9; 10]. As the first stop towards deep space, the cislunar space contains various kinds of materials, energy, environments, locations, and other scarce strategic resources [11], which renders it as a strategic space for human survival and development and the main destination and outpost of space mission activities in the future, including deep space confrontation, in-orbit service and maintenance, deep space science and applications, and support for manned exploration far beyond near-Earth orbit [12; 13]. It is foreseeable that space activities of all countries will further focus on the cislunar space. After the announcement of the New Space Exploration Program in the early 21 st century [14], in the future, NASA is planning to launch a nuclear-powered lunar rover to collect more samples from the moon and send them back to Earth by astronauts [15; 16]. On 28 June 2022, the United States launched a new generation of the lunar probe \"Capstone\", the first successful one launched in nearly a decade [17]. As the forerunner of the Artemis Project, this microwave oven-sized probe is advertised as \"the world's first lunar navigation satellite\", marking the substantial deployment phase of the U.S. version of GPS on the Moon [18]. Recently, China announced that its manned lunar exploration project has been launched, which plans to achieve the first landing of Chinese people on the moon before 2030. Futhermore, China will promote the fourth phase of the lunar exploration project [19; 20; 21]: around 2024, the Magpie Bridge-II Relay and CE-6 probe will be launched, to achieve the lunar back sampling return; around 2026 and 2028, CE-7 and CE-8 will be launched, to achieve the lunar south pole resource exploration and constitute the international lunar research station. Meanwhile, China is also demonstrating the construction of a constellation of lunar communication and navigation system--the Magpie Bridge remote integrated constellation system [22], which will be divided into three phases: pilot phase, basic phase, and expansion phase. The pilot phase will be completed before 2030 to support the fourth phase of the lunar exploration project and international lunar research stations; the basic phase will be accomplished before 2040 to realize regional navigation, service manned lunar exploration, international lunar exploration, etc., which can provide relay communication, navigation, and key information support for future lunar surface operations and more complex lunar exploration tasks [23]. On 27 December 2022, Korea's first lunar orbiter, Moonwatch, successfully entered its scheduled orbit around the Moon, and will further help Project Artemis [24]. In early 2023, the Indian Space Organization announced that India's third lunar exploration mission will be launched late this year [25]. The Indian Moonship III lander has successively passed electromagnetic compatibility and critical vibration environment tests and will undertake the relay communication mission and cooperate with the Moonship II propulsion module, thus jointly supporting India's next lunar exploration mission (the lunar rover will work on the lunar surface for about half a month).