Deep Space 1

NASA launched the Deep Space 1 spacecraft in October 1998 as part of its New Millennium Program. The primary goal of the mission was to test new, high-risk technologies rather than conduct pure scientific observation. It successfully completed its primary mission in 1999 before embarking on an extended mission.

Deep Space 1 was the first spacecraft to successfully use an ion propulsion system as its primary means of thrust. The system, known as NSTAR, ionized xenon gas and accelerated it using an electrical field to create a highly efficient, low-thrust drive. This technology proved so successful that it paved the way for later missions like the Dawn spacecraft.

During its extended mission, Deep Space 1 successfully flew by the asteroid 9969 Braille in 1999. In 2001, it conducted a highly successful close flyby of Comet 19P/Borrelly. The spacecraft returned incredibly detailed images of the comet's nucleus, which were considered some of the best ever taken at the time.

No, Deep Space 1 did not investigate Comet Hale-Bopp, which had its closest approach to the Sun in 1997 before the spacecraft launched. The mission's primary celestial targets were the asteroid 9969 Braille and Comet 19P/Borrelly. The spacecraft did use its autonomous navigation system to track Mars and various other targets to prove its pointing capabilities.