Constellation design for the successive monitoring of a lunar landing process

Abstract

Addressing the lunar remote sensing constellation's tracking observation of the surface lander, this paper proposed a constellation orbit design and mission planning method. In order to ensure that each satellite attains the longest imaging window over the target, all of the satellites will pass approximately vertically above the lander's trajectory. The irregular lander trajectory is fitted to a straight line using least squares. Based on the spatio-temporal relationship between the target and satellite, several specific observation orbit points are determined, and the orbit is solved according to the Lambert equation. However, a single satellite usually cannot track the lander all the way. This paper then configures the remaining satellites based on the zenith-pass principle, and furthermore, calculates the imaging window and imaging attitude for each satellite. Ultimately, at the same satellite orbital altitude, the constellation can achieve full-travel tracking of the lander's trajectory with a minimum number of satellites.