>>3091 The NASA Solar Technology Application Readiness (NSTAR) program provided a single string, primary IPS to the Deep Space 1 spacecraft. The 30-cm ion thruster operates over a 0.5 kW to 2.3 kW input power range providing thrust from 19 mN to 92 mN. The specific impulse ranges from 1900 s at 0.5 kW to 3100 s at 2.3 kW. The flight thruster and PPU design requirements were derived with the aid of about 50 development tests and a series of wear-tests at NASA GRC and JPL of 2000 hours, 1000 hours, and 8193 hours using engineering model thrusters. The flight-set masses for the thruster, PPU, and DCIU were 8.2 kg, 14.77 kg, and 2.51 kg, respectively. About 1.7 kg mass was added to the PPU top plate to satisfy the DS1 micrometeoroid requirements. The power cable between the thruster and PPU was comprised of two segments which were connected at a field junction. The thruster cable mass was 0.95 kg, and the PPU cable mass was 0.77 kg. The xenon storage and feed system dry mass was about 20.5 kg. A total of 82 kg of xenon was loaded for the flight. Thrusters and PPUs were manufactured for NASA GRC by Hughes, and the DCIU was built by Spectrum Astro, Inc. The feed system development was a collaborative effort between JPL and Moog, Inc.
The DS1 spacecraft was launched on October 24, 1998. In-space testing and the IPS technology demonstrations were completed within the next three months. By April 27, 1999, the primary thrusting of the NSTAR engine system, required to encounter the asteroid Braille, was completed. The thrusting time at the end of April was 1764 hours. Thruster input power levels were varied from 0.48 kW to 1.94 kW. On July 26, 1999 DS1 obtained spectrometer data and images of Braille fifteen minutes after the flyby.
The DS1 mission was extended to continue a thrusting profile until the encounter with the comet Borrelly in September 2001. By October 30, 2000 the ion engine had accumulated 6630 hours of thrusting. The NSTAR ion engine has already demonstrated a propellant throughput in excess of 30 kg. For comparison purposes, a SERT II ion engine expended about 9 kg of mercury. Propellant throughput is an approximate signature of total impulse capability. After the encounter with comet Borrelly, the ion engine will have operated for more than 10,000 hours.
The preceding was an excerpt from:
Sovey, J. S., Rawlin, V. K., and Patterson, M. J.: "Ion Propulsion Development Projects in U. S.: Space Electric Rocket Test 1 to Deep Space 1." Journal of Propulsion and Power, Vol. 17, No. 3, May-June 2001, pp. 517-526.
