Voyagers 1 and 2 were launched in 1977 to take advantage of a favourable alignment of Jupiter, Saturn, Uranus and Neptune, and are now exploring interstellar space.
Voyager 1 and 2 have explored all the giant planets of our outer solar system, Jupiter, Saturn, Uranus and Neptune; 48 of their moons; and the unique system of rings and magnetic fields those planets possess. By the anniversary Voyager 1 will have traveled more than 12 billion miles and Voyager 2 more than 10 billion, with both nuclear-powered spacecraft continuing to send back data.
They have been breaking records for almost two decades, the first on Feb 17, 1998, when Voyager 1 passed NASA’s Pioneer 10 probe to become the farthest man-made object. According to NASA, the Voyagers are the first to pass through the heliosheath, which is thought to exist somewhere from eight to 14 billion miles from the Sun. Voyager 1 entered interstellar space on Aug 25, 2012, a first for a spacecraft, and Voyager 2 is en route to do so too.
The Voyagers have enough electrical power and thruster fuel to operate at least until 2020, according to NASA. Eventually, they will pass other stars. In about 40,000 years, Voyager 1 will drift within 1.6 light-years (9.3 trillion miles) of AC+79 3888, a star in the constellation of Camelopardalis, which is heading toward the constellation Ophiuchus.
While the Voyager 2 was launched on Aug 20, 1977, Voyager 1 was launched Sep 5, 1977. Both spacecrafts are equipped with spectrometers, radiometers and cameras, and carry 30cm gold plated copper records featuring sounds and images of Earth.