On November 5th, 2018 Voyager 2 has finally exited the heliosphere of our solar system. This makes it the second ever man-made craft to achieve this.
The first one was the Voyager 1, which makes perfect sense. Coming in second is no small feat. The big difference between Voyager 1 and 2 is the fact that the plasma sensors still work on the Voyager 2 which allows scientists to see the space between the stars like never before.
When the Voyager was launched, NASA had no idea how big the bubble of plasma surrounding the sun is. They also did not expect the craft to last long enough to even get there.
As for the Voyager 2, its purpose was to measure the speed, density and other properties of the solar winds. What happened on November 5th was something the scientists did not expect. The researchers saw drastic drops in the speed of the solar winds while picking up more cosmic rays which originated from another part of the galaxy. This led scientists to believe that the spacecraft did leave the sun’s plasma bubble.
Interestingly, the measurements picked up by Voyager 1 and Voyager 2 are entirely different. This is probably due to the fact that the crafts exited the heliosphere in different locations. The sun was also in another part of its 12-year cycle at the time Voyager 1 breached the bubble.
Currently, both spacecrafts are healthy considering they left earth in 1977. It is unclear for how long the crafts can function in the freezing temperatures. Voyager 2 is displaying a temperature of around 3.6 Celsius. This is very close to a temperature that may freeze its hydrazine fuel so some instrument may need to be turned off.
The scientists are now hoping to see out this mission until 2027, which is when both crafts turn 50.