WASHINGTON — A mysterious Russian military satellite parked itself between two Intelsat satellites in geosynchronous orbit for five months this year, alarming company executives and leading to classified meetings among U.S. government officials. The Russian satellite, alternatively known as Luch or Olymp, launched in September 2014 and seven months later moved to a position directly between the Intelsat 7 and Intelsat 901 satellites, which are located within half a degree of one another 36,000 kilometers above the equator. At times, the Russian satellite maneuvered to about 10 kilometers of the Intelsat space vehicles, sources said, a distance so close that...