The Voyager program is an American scientific program that launched two unmanned space missions, the probes Voyager 1 and Voyager 2. These were launched in 1977 to take advantage of a favorable alignment of the planets during the late 1970s. Although they were designated officially to study just the planetary systems of Jupiter and Saturn, the space probes were able to continue their mission into the outer solar system, and they are expected to push through the heliosheath in deep space.
These two space probes were built at the Jet Propulsion Laboratory in Southern California, and they were paid for by the National Aeronautics and Space Administration (NASA), which also paid for their launchings from Cape Canaveral, Florida, their tracking, and everything else concerning the space probes.
As of 2012, Voyager 1 is the farthest manmade object that has ever been sent from the Earth. On 15 June 2012, scientists at NASA reported that Voyager 1 might be very close to entering interstellar space and becoming the first manmade object to leave the Solar System.
Both of these scientific missions into outer space have gathered large amounts of data about the gas giants of the solar system, and their orbiting satellites, about which little had been previously known. In addition, the trajectories of the two spacecraft have been used to place limits on the existence of any hypothetical trans-Neptunian planets.