The Deep Space 1 extended mission: Challenges in preparing for an encounter with comet Borrelly

Following the successful conclusion of its 11-month primary mission in September 1999, Deep Space 1 embarked on an ambitious extended mission. The spacecraft is using its ion propulsion system to help deliver it to an encounter with comet 19P/Borrelly in September 2001. Along the way, the very small operations team has faced numerous challenges with an aging and debilitated spacecraft that was not designed for a comet encounter. The progress in reaching comet Borrelly is described as are the plans for attempting to return science data from this high-risk conclusion to the extended mission.