Unlike its older twin, Voyager 2 still has a working instrument that NASA says "will provide first-of-its-kind observations of the nature of this gateway into interstellar space". Voyager 1 had already prepped us for this.
Voyager 2's plasma science experiment provided the first direct look at what happens to the solar wind as the spacecraft enters interstellar space. "We're in a different place - one is in the northern hemisphere and the other is in the southern hemisphere - and it's a different time in the solar cycle".
Each probe contains a golden record embedded with snapshots of Earth's sounds, images and messages in the hope that another civilization may someday chance upon it and learn about human civilization. The gold-plated copper disk bears sounds, images and spoken greetings in multiple languages to depict Earth's diversity of life and culture, meant to communicate with potential extraterrestrial beings who may encounter them. The space agency said the change hinted at the possibility of nearing interstellar space, something it has now confirmed a little over a month later.
The two spacecraft were created to last five years and study Jupiter and Saturn.
The Voyager missions have been an astonishing success for NASA.
Launched from Cape Canaveral, Florida, on August 20, 1977, the dairy cow-size Voyager 2 began its odyssey with a grand tour of the outer solar system, making vital discoveries at Jupiter and Saturn and returning some of the best views yet of Uranus and Neptune. On that day, instruments aboard the spacecraft detected an increase in the strength of magnetic fields from the interstellar region, and the number of galactic cosmic rays, which originate from far beyond the solar system, jumped. This is the border that NASA believes both Voyager 1 and Voyager 2 have sailed past. That is a zone between 0.16 and 1.6 light-years away from the sun.
What now? It's estimated it will take about 30,000 years for Voyager 2 to leave the solar system by flying beyond the Oort Cloud, a ring of icy objects that is believed to encircle the sun, way beyond the furthest planets. It is possible that in coming years, as the sun reaches the peak of its roughly 11-year activity cycle, its outbursts could push the heliopause farther out again, perhaps even beyond Voyager 2. One astronomical unit (or AU) is the average distance from the sun to Earth.
The solar system and beyond. "Outside the bubble, most of the material comes from other stars that exploded 5, 10, 15 million years ago".
"Both spacecrafts are very healthy if you consider them senior citizens", Voyager project manager Suzanne Dodd said.
But until then, long may the explorations continue.
Now travelling more than 56,327 kilometres an hour in the direction of the constellation Ophiuchus, Voyager 1 is the fastest human-made object in space.
"The Voyager spacecraft are now ahead of that wave in the clear air of interstellar space".