Voyager 1 was launched on September 5 , 1977 by NASA from Cape Canaveral aboard a Titan IIIE Centaur rocket , shortly after its sister craft , Voyager 2 on August 20 , 1977 . The Voyager 1 probe was launched on September 5 , 1977 , by the National Aeronautics and Space Administration from Space Launch Complex 41 at Cape Canaveral , Florida , aboard a Titan IIIE\/Centaur launch vehicle . Two weeks prior , the twin Voyager 2 probe had been launched on August 20 , 1977 .