Planetary probe is first to pass beyond heliosphere
When Caltech’s Ed Stone watched the launches of Voyager 1 and Voyager 2 from Cape Canaveral in 1977, he had only a glimmer of hope that either probe would survive to reach interstellar space. “The space age was only 20 years old,” says the missions’ principal investigator. “We had no idea how long spacecraft could last.”
Thirty-six years later, Stone announced that Voyager 1 had become the first human-made object to pass beyond the heliosphere, the giant invisible bubble inflated by subatomic particles from the sun, and enter the space between the stars (SN Online: 9/12/13). Based on measurements from the probe’s instruments, Voyager made its exit in August 2012.