U.S. to establish Space Force by 2020: Pence

U.S. Defense Secretary James Mattis (2nd L) greets U.S. Vice President Mike Pence at the Pentagon, Virginia, the United States on Aug. 9, 2018. U.S. Vice President Mike Pence said Thursday that the United States plans to establish a Space Force by 2020, an idea floated by President Donald Trump and questioned by many top officers at the Pentagon. (Xinhua/Ting Shen)