Xi: The universe is vast and exploration of it will never end

China on Monday launched the space lab module Mengtian, taking the assembly of the country's space station Tiangong to its final stage.

President Xi Jinping once said that the space station is a key achievement in China's space industry, and space mission is an important part of the dream to make China stronger. Xi has made video calls to Chinese astronauts in orbit three times.

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