After 47 years and 15 billion miles, the Plasma Science Experiment aboard NASA’s Voyager 2 spacecraft has been turned off. NASA’s twin Voyager spacecraft were originally designed for a four-year ...

Although mostly empty, it contains thin gas, dust and cosmic rays. This area starts where a star’s influence—such as the Sun’s solar wind—ends at the heliopause. Having crossed this boundary in August ...

Voyager 1 entered interstellar space first. It crossed the heliopause, the boundary between the heliosphere and interstellar space, in August 2012. Voyager 2 followed suit in November 2018.