The grand and lonely journey
On 5th of September, 1977, NASA launched Voyager 1 space probe. So far it has traveled 125 AU as of August 2013, and it is still traveling at the relative speed against the Sun at 17 km per second, which is the fastest speed of an object made by mankind. The rocket engine that lift Voyager 1 was Titan IIIE. NASA did great missions which took advantage of The Planetary Grand Tour and gravitational slingshot. Using gravity energy during the mission, Voyager 1 and 2 are now into the eternity of interstellar travel of lonely and silent.