The Voyager program was a famous American scientific program that employed two robotic probes, Voyager 1 and Voyager 2, to study the outer Solar System. They were launched in 1977 to take advantage of a favorable alignment of Jupiter, Saturn, Uranus, and Neptune, and were exploring the outer boundary of the heliosphere.
Data and photographs collected by the Voyagers' cameras, magnetometers, and other instruments revealed previously unknown details about each of the giant planets and their moons. Although their original mission was to study only the planetary systems of Jupiter and Saturn, Voyager 2 continued on to Uranus and Neptune, and both Voyagers were tasked with exploring interstellar space.
Both craft carry with them a 12-inch golden phonograph record that contains pictures and sounds of Earth along with symbolic directions on the cover for playing the record and data detailing the location of our planet. The record is intended as a combination of a time capsule and an interstellar message to any civilization, alien or far-future human, that may recover either of the Voyagers.
On August 25, 2012, data from Voyager 1 indicated that it had become the first human-made object to enter interstellar space, traveling "further than anyone, or anything, in history" followed by Voyager 2 in 2016 with first direct measurements of the density and temperature of the interstellar plasma. Their mission has been extended three times, and both probes continued to collect and relayed useful scientific data until the contact was finally lost in 2027 (Voyager 1) and 2028 (Voyager 2).
Voyager 1's last photograph called "Pale Blue Dot" ist one of mankinds most important. It is a photograph of planet Earth taken on February 14, 1990 from a record distance at that time of about 6 billion kilometers (3.7 billion miles, 40.5 AU), as part of the Family Portrait series of images of the Solar System. In the photograph, Earth's apparent size is less than a pixel; the planet appears as a tiny dot against the vastness of space, among bands of sunlight scattered by the camera's optics.
Voyager 1, which had completed its primary mission and was leaving the Solar System, was commanded by NASA to turn its camera around and take one last photograph of Earth across a great expanse of space, at the request of astronomer and author Carl Sagan (1934-1996). In his 1994 book "Pale Blue Dot: A Vision of the Human Future in Space" he expresses his thoughts on a deeper meaning of the image:
Consider again that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives.
The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there - on a mote of dust suspended in a sunbeam.
The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that in glory and triumph they could become the momentary masters of a fraction of a dot.
Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner.
How frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light.
Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity - in all this vastness - there is no hint that help will come from elsewhere to save us from ourselves.
The Earth is the only world known, so far, to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment, the Earth is where we make our stand. It has been said that astronomy is a humbling and character-building experience.
There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another and to preserve and cherish the pale blue dot, the only home we've ever known.
Carl Sagan, Pale Blue Dot: A Vision of the Human Future in Space, 1997 reprint, pp. xv-xvi
Voyager 1 and 2 are not heading towards any particular star. In about 40,000 years, Voyager 1 will pass within 1.6 light-years of the star Gliese 445 traveling at a speed of 17 km/s, swing by it, and it will continue to orbit around the center of our Milky Way galaxy.
Voyager 2 is traveling at a speed of 15.4 km/s and if undisturbed for 296,000 years, it should pass by the star Sirius at a distance of 4.3 light-years.
History of the Future
"V'Ger must evolve. Its knowledge has reached the limits of this universe and it must evolve. What it requires of its god, doctor, is the answer to its question, "Is there nothing more"?"
Commander Spock in: Star Trek: The Motion Picture
After NASA engineers have seen the movie "Star Trek: The Motion Picture", they were frightened to death and refused to build any further Voyager probes that nothing similar like in the film could ever happen.
There is also the opinion that at least the two golden phonograph records should be collected again that aliens do not laugh at the fashion accidents and the ridiculous picture and sound quality from the 1970s (you never get a second chance to make a first impression).
And the director of the Lunar Base Museum Sarl Cagan urgently needs them for an exhibition. :-)