On September 5, 1977 NASA launched Voyager 1, a 722-kilogram (1,590 lb) space probe to study the outer Solar System. As part of the Voyager program, the spacecraft is on an extended mission to locate and study the regions and boundaries of the outer heliosphere, and finally to begin exploring the interstellar medium. Its primary mission ended on November 20, 1980, after encounters with the Jovian system in 1979 and the Saturnian system in 1980. It was the first probe to provide detailed images of the two planets and their moons.
"On September 12, 2013, NASA announced that Voyager 1 had crossed the heliopause and entered interstellar space on August 25, 2012, making it the first manmade object to do so. As of 2013, the probe was moving with a relative velocity to the Sun of about 17 km/s (38,000 mph; 61,000 km/h). The probe is expected to continue its mission until 2025 when it will be no longer supplied with power from its generators" (Wikipedia article on Voyager 1, accessed 09-16-2013).