In the mid-1990s, a NASA program was created at JPL called New Millennium which was designed to flight-test new technologies for future space and Earth-observing missions. The first flight project created under New Millennium was Deep Space 1, a spacecraft built to test a dozen new technologies including an ion engine.
Launched October 24, 1998, from Cape Canaveral, Florida, on a Delta II rocket, Deep Space 1 carried out most of its technology testing in the two months immediately after launch. The ion engine was used to add thrust as the spacecraft orbited the Sun. On July 29, 1999, the spacecraft flew by asteroid 9969 Braille. Since its primary mission ended in September 1999, Deep Space 1 went on an extended mission flying by comet Borrelly in September 2001. This successful flyby resulted in the best ever images of a comet's nucleus.
Mass: 486 kilograms (1,071 pounds) total, composed of a 373-kilogram (822-pound) spacecraft plus 31 kilograms (68 pounds) hydrazine fuel for thrusters and 82 kilograms (181 pounds) xenon for ion engine
Advanced technologies: Ion propulsion system, solar concentrator arrays, autonomous navigation, autonomous flight software, beacon monitor, miniature camera/spectrometer, plasma instrument, small deep-space transponder, Ka-band solid-state power amplifier, low-power electronics, multifunctional structure, power actuation and switching module