Editing Deep Space 1 (section)

===NSTAR ion engine===
{{main article|NASA Solar Technology Application Readiness}}

Although [[ion engine]]s had been developed at NASA since the late 1950s, with the exception of the [[SERT-1|SERT]] missions in the 1960s, the technology had not been demonstrated in flight on United States spacecraft, though hundreds of [[Hall-effect thruster|Hall-effect engines]] had been used on Soviet and Russian spacecraft.  This lack of a performance history in space meant that despite the potential savings in propellant mass, the technology was considered too experimental to be used for high-cost missions. Furthermore, unforeseen side effects of ion propulsion might in some way interfere with typical scientific experiments, such as fields and particle measurements.  Therefore, it was a primary mission of the ''Deep Space 1'' demonstration to show long-duration use of an ion thruster on a scientific mission.<ref name="MD">{{cite journal |url=http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/19098/1/98-0310.pdf |title=Mision Design for Deep Space 1: A Low-thrust Technology Validation Mission |journal=Acta Astronautica |first1=Marc D. |last1=Rayman |first2=Pamela A. |last2=Chadbourne |first3=Jeffery S. |last3=Culwell |first4=Steven N. |last4=Williams |volume=45 |issue=4–9 |pages=381–388 |date=August–November 1999 |doi=10.1016/S0094-5765(99)00157-5 |bibcode=1999AcAau..45..381R |url-status=dead |archive-url=https://web.archive.org/web/20150509172350/http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/19098/1/98-0310.pdf |archive-date=9 May 2015}}</ref>

The [[NASA Solar Technology Application Readiness]] (NSTAR) [[electrostatic ion thruster]], developed at NASA Glenn, achieves a [[specific impulse]] of 1000–3000 seconds. This is an order of magnitude higher than traditional space propulsion methods, resulting in a mass savings of approximately half. This leads to much cheaper launch vehicles. Although the engine produces just {{convert|92|mN|lk=on}} thrust at maximal power (2,100 W on DS1), the craft achieved high speeds because ion engines thrust continuously for long periods.<ref name="MD"/>

The next spacecraft to use NSTAR engines was ''[[Dawn (spacecraft)|Dawn]]'', with three redundant units.<ref>{{cite web |url=http://dawn.jpl.nasa.gov/mission/spacecraft.asp |title=Dawn: Spacecraft |publisher=NASA/Jet Propulsion Laboratory |access-date=20 November 2016}}</ref>

{{Multiple image |align=center |direction=horizontal |total_width=600
 |image1=Ion Engine Being Installed in High Vacuum Tank - GPN-2000-000597.jpg |caption1=Technicians installing ion engine #1 in the High Vacuum Tank in the Electric Propulsion Research Building, 1959
 |image2=Deep Space 1 spacecraft.jpg |caption2=The fully assembled {{nowrap|''Deep Space 1''}}
 |image3=Deep Space 1 lifted.jpg |caption3=''Deep Space 1'' experimental solar-powered [[Ion thruster|ion propulsion engine]]
}}