Welcome to the history books, Voyager 2. NASA launched the spacecraft in 1977 and, all those decades later, it finally entered the space between the stars. He joins Voyager 1, which entered interstellar space in 2012.
NASA announced on Monday that Voyager 2 has left the heliosphere, an area the agency describes as "a vast bubble around the sun and planets dominated by solar material and magnetic fields."
Data shows the probe crossed on November 5 and is now 11 billion kilometers (18 billion kilometers) from Earth.
Voyager 2 carries an instrument called Plasma Science Experiment (PLS), which detects the properties of the solar wind. NASA noted that PLS saw a serious decline in solar wind particle velocity on November 5. After that, it did not capture any solar windflow, indicating the probe entering the interstellar space.
"Our studies start in the sun and extend to everything the solar wind does," says Nicola Fox, director of NASA's Heliophysics Division. "Getting Voyagers to send information about the limit of the Sun's influence gives us an unprecedented glimpse of truly unexplored territory."
Voyager 2 was launched a few weeks before Voyager 1, and both survived long for their original five-year missions to study Jupiter and Saturn. NASA scientists are now excited to learn what the probes can teach us about the realm beyond the heliosphere boundary.
In addition to passing the interstellar landmark, Voyager 2 is also NASA's longest mission. The space agency hopes to be able to collect data from the spacecraft by at least 2025.