Don Gurnett, University of Iowa, Iowa City, Iowa

Topic: "After 36 Years Voyager 1 Reaches Interstellar Space"  (Video)

Abstract: Thirty-six years after launch, in one of the greatest space achievements of all time, the NASA Voyager 1 spacecraft reached the heliopause, which is the boundary between the hot ionized gaseous envelope of the Sun and the relatively cool interstellar plasma. In this talk Professor Gurnett will discuss his role in the Voyager mission, which consisted of two spacecraft, Voyagers 1 and 2, launched in 1977 on the “Grand Tour” of the outer planets Jupiter, Saturn, Uranus and Neptune. After completing the Grand Tour in 1989 and on escape trajectories outward from the Sun, the name of the mission was change to the “Voyager Interstellar Mission” with the objective of reaching the heliopause and penetrating into the interstellar medium. In April 2013, the Iowa instrument on Voyager 1 made the critical observations showing that the spacecraft had reached the interstellar plasma at a distance of more than three times as far as Pluto. Having crossed the heliopause, it is now possible for the first time to measure the magnetic fields in interstellar space and undisturbed cosmic ray intensities incident on the solar system.