The NASA Solar Technology Application Readiness (NSTAR) is a type of spacecraft ion thruster called electrostatic ion thruster. It is a highly efficient low-thrust spacecraft propulsion running on electrical power generated by solar arrays. It uses high-voltage electrodes (including two fine grids) to accelerate ions with electrostatic forces.
Development and performance
The purpose of NSTAR program was to develop a xenon-fueled ion propulsion system for deep space missions. The NSTAR electrostatic ion thruster was developed at NASA's Glenn Research Center and manufactured by Hughes, and Spectrum Astro, Inc. in the early 1990s. The feed system development was a collaborative effort between JPL and Moog Inc.
The ions are accelerated through two fine grids with roughly a 1300 V difference between them for 2.3 kW operation, with a thrust of 20-92 mN, a specific impulse of 19000-30500 N·s/kg (1950-3100 s) and a total impulse capability of 2.65 x10 Ns on DS1.
In 1996, the prototype engine endured 8000 hours of continuous operation in a vacuum chamber that simulates conditions of outer space. The results of the prototyping were used to define the design of flight hardware that was built for Deep Space 1 probe. One of the challenges was developing a compact and light weight power processing unit that converts power from the solar arrays into the voltages needed by the engine.
Performance
The engine achieves a specific impulse of up to three thousand seconds. This is an order of magnitude higher than traditional space propulsion methods, resulting in a mass savings of approximately half. Although the engine produces just 92 millinewtons (0.331 ounce-force) thrust at maximum power (2,100W on DS1 mission), the craft achieved high speed because ion engines thrust continuously for long periods of time. "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."
Applications
Deep Space
The NSTAR ion thruster was first used on the Deep Space 1 (DS1) spacecraft, launched on 24 October 1998. The Deep Space mission carried out a flyby of asteroid 9969 Braille and Comet Borrelly. Deep Space 1 had 178 pounds (81 kilograms) of xenon propellant, with a total impulse capability of 2.65 x10 Ns and was capable of increasing the speed of DS1 by 7900 miles per hour (12,700 kilometers per hour, 3.58 km/s) over the course of the mission. It used 2.3 kW of electrical power and was the primary propulsion for the probe.
Dawn
The second interplanetary mission using NSTAR engine was the Dawn spacecraft, launched in 2007 with three redundant units with a 30 cm diameter each. Dawn is the first NASA exploratory mission to use ion propulsion to enter and leave more than one orbit. Dawn carried 425 kg (937 lb) of on-board xenon propellant, and was able to perform a velocity change of 25,700 mph (11.49 km/s) over the mission.
Proposed uses
As of 2009 NASA engineers state that NSTAR engines, in the 5-kilowatt and 0.04 pound-thrust range, are candidates for propelling spacecraft to Europa, Pluto, and other small bodies in deep space.
See also
- Electrically powered spacecraft propulsion
- NEXT (ion thruster) – Space propulsion system, a gridded electrostatic ion thruster
- Advanced Electric Propulsion System – Spacecraft propulsion system by NASA. 50kW Hall-effect thrusters, now for Lunar Gateway
References
- ^ "NASA Solar Electric Propulsion Technology Application Readiness (NSTAR)". NASA's Glenn Research Center. April 21, 2009. Archived from the original on January 11, 2003. Retrieved 2015-03-18.
- 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.
- ^ "Innovative Engines - The NSTAR Program". NASA Glenn Research Center. Archived from the original on 2004-12-08. Retrieved 2015-03-18. Has diagram, and photo that shows exit grid.
- ^ "NSTAR". Encyclopedia Astronautica. Archived from the original on 2014-02-09. Retrieved 2015-03-18.
- ^ In-flight performance of the NSTAR ion propulsion system on the Deep Space One mission. Aerospace Conference Proceedings. IEEExplore. 2000. doi:10.1109/AERO.2000.878373.
- ^ Bond, T.; Benson, G.; Cardwell, G.; Hamley, J. (1999-04-06). NSTAR Ion Engine Power Processor Unit Performance: Ground Test and Flight Experience. Aerospace Power Systems Conference. SAE International. doi:10.4271/1999-01-1384.
- Rayman, M.D.; Chadbourne, P.A.; Culwell, J.S.; Williams, S.N. (1999). "Mission design for deep space 1: A low-thrust technology validation mission" (PDF). Acta Astronautica. 45 (4–9). Elsevier: 381–388. Bibcode:1999AcAau..45..381R. doi:10.1016/s0094-5765(99)00157-5. Archived from the original (PDF) on 2015-05-09.
- "Contributions to Deep Space 1". NASA. Archived from the original on 2023-04-10.
- Dawn - Key spacecraft characteristics. 2014.
- NSTAR Ion Engine Xenon Feed System: Introduction to System Design and Development Archived 2016-03-04 at the Wayback Machine. Edward D.Bushway (PDF)
- Rayman, Marc; Fraschetti, Thomas; Raymond, Carol; Russell, Christopher (April 5, 2006). "Dawn: A mission in development for exploration of main belt asteroids Vesta and Ceres" (PDF). Acta Astronautica. 58 (11): 605–616. Bibcode:2006AcAau..58..605R. doi:10.1016/j.actaastro.2006.01.014. Retrieved April 14, 2011.
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