It took 35 years but Voyager 1 is about to cross the boundary from our solar system into interstellar space.
New data revealed today in the journal Science suggest that the craft is now more than 11 billion miles from the sun.
The big moment is still in the offing -- there have been previous false reports -- but this time scientists believe that it is only a matter of time before the spacecraft leaves the region around our sun known as the heliosphere and enters interstellar space. Three papers described the elevated presence of charged particles from outside the heliosphere as well as the absence of any charged particles from inside the heliosphere.
It's unclear how much farther the probe still needs to travel before it departs into interstellar space, with estimates ranging from months to years. It has a long trek to go given that the heliosphere is believed to be at least 8 billion miles beyond our solar system, according to NASA.
Its companion craft, known as Voyager 2, is believed to still be inside the heliosphere, about 9 billion miles from the sun. Like Voyager 1, it also lifted off in 1977, one year after Apple introduced its first computer, the Apple I. Voyager 1, which was built to remain operational for only five years, is expected to lose power on its instrumentation by the year 2020 and will get shut down by 2025.
Last summer, scientists pored over data which seemed to suggest that Voyager 1 had broken free of the Sun's magnetic field.