Tim Furniss/LONDON
A Boeing Delta II booster launched NASA's $152 million Deep Space 1 (DS1) technology demonstrator spacecraft from Pad 17 at Cape Canaveral, Florida, on 24 October. The DS1 is flying the first NASA New Millennium "faster, better, cheaper" technology development and demonstration mission.
The Spectrum Astro-built DS1 uses a high efficiency, low-thrust xenon ion propulsion system built by Hughes Electron Dynamics. The ion engine will propel the DS1, with the aid of an "artificial intelligence" guidance and navigation system, towards a 15km/s, 10km-distant, flyby of asteroid 1992 KD in July 1999. The craft may later rendezvous with comets Wilson Harrington and Borrelly in January and September 2001, respectively.
An ion engine is 10 times more efficient than a heavier chemical propulsion system. Consuming less propellant - in the case of the DS1, 180kg of xenon - and operating for a much longer period at very low thrust, it can increase the velocity of a spacecraft on a long interplanetary journey as effectively as can a quick one-off firing of a chemical engine. The propellant weight saving can be translated to more payload.
The second Deep Space mission technology demonstrator will fly as part of the Mars Polar Lander mission, to be launched in January next year. Two 100mm-long, 4kg DS2 microprobes will be deployed from the Lander before its own entry into the Martian atmosphere and will plunge into the surface at a velocity of about 200m/s to return subsurface data to the the orbiting Mars Global Surveyor.
The DS3 will be a three-satellite optical interferometer astrophysics demonstration mission and will be followed by a DS4 earth observation technology mission to demonstrate an advanced miniaturised land imager.
Source: Flight International
