Technical characteristics of the relay communication satellite “Queqiao” for Chang’e-4 lunar farside exploration mission

Abstract

Chang’e-4 (CE-4) is a mission that probes land softly on the farside of the Moon to peform scientific exploration for the first time in the world. The relay communication for the lander and the rover on the lunar farside to maintain contact with the Earth stations during their landing and surface operation is a key problem to be resolved. As an important part of Chinese Chang’e-4 farside exploration mission, Queqiao relay communication satellite provides relay communication support for the lander and the rover on the lunar farside. Different from other spacecraft for lunar mission, a Halo orbit around the Earth-Moon liberation point 2 is used first in the world to provide a continuous communications links to the lander and the rover on the farside of the Moon. A series of technical challenges have to be faced. Based on the analysis to the mission characteristics and mission requirements, the technical difficulties are identified and solutions for these problems are given, including selection and design of mission orbit, the relay communication system design trade-off, onboard instruments’ adaptibility to the very low on-orbit temperature environments, etc. The system design overview and flight profile of the Queqiao are given in this paper. Technical characteristics and technical innovation of the Queqiao satellite are summarized. The future technical development prospect or lunar relay communication missions is also given in this paper.