Image Credit: JPL/NASA


Deep Space 1 was an engineering test flight for a dozen new technologies, including highly-efficient ion engines and autonomous navigation software. Asteroid 9969 Braille was a bonus science target.


DS1's primary mission was a resounding success. All 12 technology tests were successful. The mission is credited with proving the effectiveness of ion engines for long-duration spaceflight and advancing the field of spacecraft navigation.

DS1 contributed to asteroid science by finding intriguing similarities between Braille and Vesta. It also returned valuable science data during its bonus flyby of comet Borrelly during an extended mission.

24 Oct 1998: Launch

Mission Type: Flyby

Launch Vehicle: Delta 7326-9.5 Med-Lite (first use of this model)

Launch Site: Cape Canaveral Air Station, Launch Pad 17-A, United States

NASA Center: Jet Propulsion Laboratory

Spacecraft Mass: 486.32 kg at launch

Spacecraft Instruments:

  1. MICAS miniature integrated camera-spectrometer
  2. PEPE plasma experiment for planetary exploration technology

Spacecraft Dimensions: 2.5 m high, 2.1 m deep, and 1.7 m wide

Spacecraft Power: Solar

Maximum Power: 2500W (2100W used to power ion engine)

Antenna Diameter: 0.274 meters

Maximum Data Rate: 20 kilobits per second
Total Cost: Deep Space 1 has a total mission cost of $152.3 million comprised of $94.8 million for development, $43.5 million for launch, $10.3 million for operations, and $3.7 million for science.


Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, Monographs in Aerospace History No. 24, by Asif A. Siddiqi
NSSDC Master Catalog: Deep Space 1

Deep Space 1 (DS1) 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 were 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 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.

DS1 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. DS1 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 DS1 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-tracker- a single flyby of Borrelly in September 2001. By the end of 1999, the ion engine of DS1 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, DS1 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 DS1 on 18 December 2001, signaling the end to one of the more successful deep space missions in recent history.​

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