The first artificial object to reach interstellar space was the NASA Voyager 1 probe. Voyager 1 was confirmed to have entered interstellar space back in September 2013, 36 years after the launch. NASA's Voyager 2 spacecraft was launched in 1977 and is approximately 11 billion miles from the ground at the moment.
Voyager 2 has traveled in the extreme layer of the heliosphere, which is a massive bubble around the sun and planets. Scientists are waiting for Voyager 2 to reach the outer limit of the heliosphere called the heliopause. When it exists the heliosphere, it becomes the second artificial object to do it.
Researchers at NASA say that since the end of August, the Cosmic Ray Subsystem mounted on Voyager 2 measured a 5% increase in cosmic beam velocity striking spacecraft compared to early August. As some of the cosmic beams are blocked by the heliosphere, an increased impact on spacecraft signals that it is close to going out into the heliosphere. When Voyager 1
Researchers note that Voyager 2 is located in another place in Heliosheath, the outer region of the heliosphere, than Voyager 1 was in and out. Timeline may look different to Voyager 2. Another interesting science chat forum that monitors Voyager 2 spacecraft is that the six-year gap between Voyager 1 and Voyager 2 reaches the Heliopause is important.
The team notes that the heliopause moves inward and outward during the sun's 11-year activity cycle. Scientists expect to learn a lot when Voyager 2 reaches the heliopause, but spacecraft is not there yet.