Scientists were able to use data from an instrument on Voyager 2 called the Plasma Science Experiment to detect a sharp drop in the speed of solar particles around the spacecraft on November 5, meaning that it had left the heliosphere and entered an area with no solar wind flow.
Based on readings from its onboard instruments, the mission's scientists have determined that Voyager 2 has left the solar system's heliosphere, a protective bubble of particles and magnetic fields created by the sun.
Both Voyager crafts, then, aren't expected to leave the solar system anytime soon.
NASA says it will take about 300 years for the Voyager 2 to reach the Oort Cloud and as much as 30,000 years to fly beyond it. The entire region of the sun's bubble of influence in the galaxy is known as the heliosphere, whereas the region Voyager 2 has just traversed is called the heliosheath, which lies between the termination shock and the heliopause.
It explored the Jupiter, its magnetosphere, and moons in greater detail than had the Pioneer spacecraft that preceded it. Voyager 2 also used Jupiter as a springboard to Saturn, using the gravity-assist technique.
The instrument will be able to take unprecedented observations in this part of interstellar space and send them back to mission scientists.
Voyager 2 now is slightly more than 11 billion miles (18 billion kilometers) from Earth. Non-essential instruments and systems such as the cameras aboard the twin spacecraft have been turned off to preserve power.
Of course, that's a rather long time - particularly when one considers that the Voyager probes are already massive overachievers when it comes to longevity.
Voyager 2 is very cold - about 3.6 degrees Kelvin and close to the freezing point of hydrogen - causing concerns about the probe's thruster.
Dodd said it's possible for each spacecraft to continue operating for up to 10 more years. The space agency hopes it will be able to collect data from the spacecraft until at least 2025. "There are hard decisions ahead, but those will be made with getting the most science value back". "If we get out to 2027, that will be a 50-year mission".
Voyager 2 launched in 1977, 16 days before Voyager 1, and both have traveled well beyond their original destinations.
"The mission is uncovering new mysteries", Opher said.
Remote-control programming allowed the spacecraft to keep flying well beyond their intended targets and explore more of the "final frontier".
As one of our most-distant emissaries, Voyager 2 carries a Golden Record, a gold-plated phonograph record containing images and sounds of life and culture on Earth. "This is what we've all been waiting for".