What is Chang'e 4 ? [Explainer]

Chang'e 4 (Chinese: 嫦娥四号; pinyin: Cháng'é sìhào) is a planned Chinese lunar exploration mission, to be launched in December 2018, that will incorporate an orbiter, a robotic lander and rover. Chang'e 4 will be China's second lunar lander and rover. It was built as a backup to Chang'e 3, as Chang'e 2 was to Chang'e 1. Following the successful landing of the Chang'e 3 mission, the configuration of Chang'e 4 will be adjusted to meet new scientific objectives. Like its predecessors, the spacecraft is named after Chang'e, the Chinese Moon goddess. 

Source: Wikipedia