The statement didn’t specify what it meant by “space altitude,” but company officials have previously said they were using the altitude of 50 miles, or approximately 80 kilometers, used by NASA and the U.S. Air Force for awarding astronaut wings. “For Virgin Galactic, the major milestone that we perceive is the altitude at which NASA and Air Force folks get their astronaut wings, which is 50 miles,” George Whitesides, chief executive of Virgin Galactic, said last month. “For us and our customers, I think we’ll be focused on 50 miles, at least at the start.” That is below the 100-kilometer...