In 1977, NASA launched two spacecraft, Voyager 1 and Voyager 2, to explore the outer reaches of our solar system. The two probes belong to the same Voyager program and are identical. These probes carried a wealth of scientific instruments and cameras on board, The best for the technology of the time, and their mission was to study the planets and moons of our solar system, as well as the interstellar space beyond.
The premises of a grand tour
While Voyager 1 was the first to reach interstellar space in 2012, it was Voyager 2 that had the more extensive tour of our solar system. Launched on Aug. 20, 1977aboard a Titan III rocket, Voyager 2 flew by Jupiter in 1979, Saturn in 1981, Uranus in 1986, and Neptune in 1989.
It was the first and only spacecraft to visit Uranus and Neptune, two of the most distant and least explored planets in our solar system. After these very important and historic fly-bys, the probe is currently moving away from the Sun, at a slower speed than its sister Voyager 1.
Research and development at the highest levels
After a very long phase of negotiations, the American Congress granted 360 million dollars for the entire program. An additional $7 million from Congress made it possible, among other things, to develop a reprogrammable computer, which was critical to the success of the mission. the Cores of the probes that provide for such an ambitious journey were three radioisotope thermoelectric generators (RTGs), which converted the heat generated from the decay of radioactive isotopes into electricity. This allows the probe to continue operating even in the extreme cold and darkness of the outer solar system.
A human heart in a mechanic body
The scientific instruments on board Voyager 2 included cameras, spectrometers, magnetometers, and plasma detectors. However, among these jewels of technology, there is a more “human component”. The Voyager Golden Record is a gold-plated recorded disc containing images and sounds from Earth, which the probe, as well as its sister spacecraft, carries with it.
The contents of the recording were selected by a committee chaired by Carl Sagan, the same astronomer who had Voyager 1 take the famous “pale blue dot” photo. Instructions for accessing the recordings and photos are engraved on the disc case, hoping that some intelligent life form anywhere in the universe would find it.
Back to business, it’s SCIENCE time.
One of the most significant discoveries made by Voyager 2 was the existence of active volcanoes on Io, one of the moons of Jupiter, the fourth largest satellite in the solar system and the densest of all. The probe also showed that the rings of Saturn are composed of icy particles, and it discovered several new moons orbiting Uranus and Neptune.
Voyager 2 also provided important insights into the structure and dynamics of the outer planets’ atmospheres. For example, it revealed the presence of a hexagonal–shaped jet stream at Saturn’s north pole.
The farther it is more I want to get there.
As mentioned before Voyager 2 is so far the only thing produced by human being able to study these planets from so close. It took the spacecraft 8 and a half years to reach Uranus, making its closest approach on Jan 24, 1986, at about 81,500 km. The signals from the probe took 3 hours to reach the Earth.
Voyager 2’s observations lasted just six hours when scanning the planet with a far-infrared spectrometer, but in that small amount of time, scientists could learn far more about Uranus than they had learned from more than 200 years of observations from Earth. It showed that Uranus and Neptune have highly tilted magnetic fields, unlike the more aligned fields of the inner planets. After this flying kiss, Voyager 2 continued its journey to its next destination, Neptune.
Last chapter of the main history
Arrived near the planet over ten years after its launch, on Aug. 25, 1989, after a journey of over 5 billion km, observation of the most remote planet in our solar system officially began.
Despite the great distance, the probe successfully explored the Neptunian system, deviating by just 10 km from the expected trajectory and sending many images and data to Earth. Every bit of information was an extraordinary discovery. Voyager 2 made it possible to obtain the first close-up images of Neptune and Triton, highlighting their color and the presence of atmospheric formations and allowing the precise calculation of their mass, average temperature, and rotational speed. Geysers of gaseous nitrogen were unexpectedly found on Triton’s surface.
The first chapter of a new novel
After completing its mission to study the outer planets, Voyager 2 continued to explore the limits of our solar system, The RTG battery will allow it to operate, although in a limited way, until 2025. It is currently in the heliosheath, the outermost layer of the heliosphere, where the solar wind interacts with the interstellar medium. Scientists are still receiving data from Voyager 2, which is helping to improve our understanding of the boundary between our solar system and interstellar space.
The epilogue of the hero
In conclusion, the Voyager program has been one of history’s most successful space exploration programs. Its journey of exploration has expanded our knowledge of the outer solar system and the interstellar medium beyond. Even after more than four decades in space, Voyagers 2 and 1 continue to send back valuable data to help us better understand our place in the universe.