Staff members of Institute of Optics and Electronics of the Chinese Academy of Sciences discuss the plan of testing the topographical camera installed on the lander of the Chang'e-4 probe in Chengdu, southwest China's Sichuan Province, Jan. 17, 2019. The topographical camera installed on the lander of the Chang'e-4 probe is responsible for both taking colorful high-resolution images on the lunar surface and monitoring the lunar rover Yutu-2. China's Chang'e-4 lunar probe, comprising a lander and a rover, landed on the far side of the moon on Jan. 3, 2019. (Xinhua/Liu Kun)