关键词: 月球重力场, 卫星跟踪卫星, 激光干涉星间测距系统, 非保守力补偿系统, GRAIL

Abstract: The lunar satellite gravity exploration is the international development trend and focus of deep space exploration in the 21st century. The precision measurement of lunar gravitational field is an important part of international lunar exploration mission, which determines the optimum design of lunar probe orbit and the suitable selection of ideal landing point from manned spacecraft in the lunar surface. Firstly, the future twin-satellite program for the Gravity Recovery and Interior Laboratory (GRAIL) lunar gravitational field exploration is introduced including general overview, pivotal payloads, and scientific objectives and research investigations. Secondly, the executive suggestions are expatiated including the feasible demonstration of lunar satellite tracking modes, the optimal selection of key payloads from lunar satellite, the optimized design of lunar satellite orbital parameters, and the previous implementation of simulative research. (1) Because the measurement accuracy of the medium-long-wavelength lunar gravitational field is high based on the Satellite-to-Satellite High-Low/Low-Low Tracking associated with the Doppler and Very Long Baseline Interferometry mode (SST-HL/LL-Doppler-VLBI), the technical requirement is low, the lunar gravitational field can be quickly, low-costly and high-efficiently determined, the successful experiences of integrated system from the dedicated Earth’s gravity satellite－the Gravity Recovery and Climate Experiment (GRACE) are used for reference, the requirement to orbital accuracy is low, and the farside signals of lunar gravitational field can be obtained effectively, it is optimal to use the SST-HL/LL-Doppler-VLBI mode in the future first lunar satellite gravitational exploration mission in China. (2) The high-accuracy key payloads including the interferometric laser ranging system, compensated system of nonconservative force from lunar gravity satellite and Earth’s Doppler-VLBI system should be developed in advance. (3) The optimal design of orbital altitude (50~100 km) and intersatellite range (100±50 km) for lunar gravity satellite is an important guarantee on the successful execution of future lunar satellite gravity exploration mission in China. (4) The emulational technique should be used in the whole processes of development and operation from lunar gravity satellite including scheme demonstration, system design, parts development, production test, practical application and malfunction analysis. This study has not only the important reference value to the successful execution of future lunar satellite gravity exploration in China, but also the comprehensive guiding significance to the development direction of international future planetary gravity exploration in the solar system.

Key words: Lunar Gravitational field, Satellite-to-satellite tracking mode, Interferometric laser intersatellite ranGing system, Compensated system of nonconservative force, GRAIL