Conceived after the Mariner missions, the Voyager mission was officially approved in 1972, and the two probes, Voyager 1 and Voyager 2, were launched in 1977. Originally conceived to survey the gas giants of Jupiter, Saturn, Uranus, and Neptune, the two probes have since reached their intended missions and far surpassed them. The first target planet, Jupiter, was reached by Voyager 1 in 1979; Neptune was surveyed by Voyager 2 10 years later in 1989. One reason that allowed the pair of probes to travel so quickly was a rare planetary alignment that offered gravity assists, cutting down the mission time by more than 20 years. Since then, both probes have traveled far past our planetary system, and in 2012, Voyager 1 officially entered interstellar space.
As part of their mission, the two probes provided a wealth of information from the farther planets, especially regarding Jupiter and Saturn. What were previously thought to be uninteresting planets surprised scientists; it was found that one of Jupiter’s moons, Io, exhibited more than 10 times the amount of volcanic activity of Earth. Another moon, Europa, was hypothesized to contain a liquid ocean beneath its icy surface. Saturn’s rings, originally thought to be uniform, consisted of icy rocks of different shapes and sizes.
As Voyager 2 continued its flyby of Uranus and Neptune, it unveiled these previously mysterious planets. Meanwhile, Voyager 1 headed toward the edge of the solar system, heading into interstellar space, shortly joined by its twin. Interstellar space begins at the heliopause, where the solar wind and interstellar wind meet. The imaging systems of both probes were turned off in 1990 to prioritize battery life and memory usage.
The Voyager probes have now traveled for nearly 40 years; yet, it would take an estimated 85,000 more years for the probes to reach the nearest star system to our solar system, if they were heading in that direction. Despite being the farthest traveled manmade object, it is still barely a stone throw away in the cosmic sense. While some people may find this fact defeating, it also truly encapsulates how small we are and the presence that we hold in the universe around us. As Carl Sagan says, “Every one of us is, in the cosmic perspective, precious. If a human disagrees with you, let him live. In a hundred billion galaxies, you will not find another.” While the Voyager mission has told us new things about what lies beyond our planet, perhaps it can allow us to appreciate what we have here even more.
- Alex Du