First Comet Encounter

Dr. James L. Green, Director of Planetary Science at NASA, speaks during a symposium commemorating a quarter-century of comet discoveries, Friday, Sept. 10, 2010, in the Knight studio at the Newseum in Washington. The International Sun-Earth Explorer-3 (ISEE-3) spacecraft flew past the comet Giacobini-Zinner on Sept. 11, 1985 which established a foundation of discoveries that continue today. Photo Credit: (NASA/Paul E. Alers)