Gary Knell, President and CEO of National Geographic Society, gives opening remarks at an event to celebrate the 40th Anniversary of the launch of the Voyager 1 and 2 missions, Tuesday, September 5, 2017 at National Geographic Society Headquarters in Washington. Voyager 1 was launched September 5, 1977, with a mission to study Jupiter and Saturn, but now the twin Voyager spacecrafts are on a journey into interstellar space to search for the heliopause, a region never reached by any other spacecraft. Photo Credit: (NASA/Aubrey Gemignani)