To continue reading up to 10 premium articles, you must register , or sign up and take advantage of this exclusive offer: SpaceX said Monday it plans to fly two private citizens on a mission around the moon by late 2018 as part of a lunar journey that would last about a week and travel deeper into space than any human has ventured before. SpaceX founder Elon Musk would not name the two individuals, who he said approached the company and would pay for the flight.