Deep Space 1
Deep Space 1
Nation: U.S. (73)
Objective(s): asteroid flyby
Spacecraft: DS 1
Spacecraft Mass: 489 kg
Mission Design and Management: NASA JPL
Launch Vehicle: Delta 7326-9.5 (no. D261)
Launch Date and Time: 24 October 1998 / 12:08:00 UT
Launch Site: ESMC / launch complex 17A
1) MICAS miniature integrated camera-spectrometer
2) PEPE plasma experiment for planetary exploration technology
Results: Deep Space 1 (DS 1) was designed to test innovative technologies appropriate for future deep space and interplanetary missions. It was the first in a new series of technology demonstration missions under NASA's New Millennium program. The spacecraft's main goals are to test such technologies as ion propulsion, autonomous optical navigation, a solar power concentration array, a miniature camera, and an imaging spectrometer during a flyby of the asteroid 1992 KD (renamed 9969 Braille).
A month after launch, on 24 November 1998, controllers fired the Deep Space 1's ion propulsion system (fueled by xenon gas) while the spacecraft was 4.8 million kilometers from Earth. The engine ran continuously for 14 days and demonstrated a specific impulse of 3,100 seconds, as much as ten times higher than possible with conventional chemical propellants.
DS 1 passed by the near-Earth asteroid 9669 Braille at 04:46 UT on 29 July 1999 at a range of only 26 kilometers at a speed of 15.5 kilometers per second. It was the closest asteroid flyby at the time. Photographs taken and other data collected during the encounter were transmitted back to Earth in the following few days. DS 1 found Braille to be 2.2 kilometers at its longest and 1 kilometer at its shortest.
Once the very successful primary mission was over on 18 September 1999, NASA formulated an extended mission. Originally, the plan had been to make DS 1 fly by the dormant Comet Wilson-Harrington in January 2001 and the Comet Borrelly in September 2001, but the spacecraft's star tracker failed on 11 November 1999.
Mission planners revised the manifest to include a flyby that would not require a star-trackerýa single flyby of Borrelly in September 2001. By the end of 1999, the ion engine of DS 1 had expended 22 kilograms of xenon to impart a total delta V of 1,300 meters per second. On its way to Borrelly, it set the record for the longest operating time for a propulsion system in space.
By 17 August 2000, the engine had been operating for 162 days as part of an eight-month run. On 22 September 2001, DS 1 flew past the coma of Comet Borrelly at 16.5 kilometers per second to obtain pictures and infrared spectra of the nucleus.
NASA terminated contact with DS 1 on 18 December 2001, signaling the end to one of the more successful deep space missions in recent history.
Editor's Note: This mission profile was originally published in Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, by Asif A. Siddiqi, NASA Monographs in Aerospace History No. 24.