Editing Ion thruster (section)

==== International Space Station ====
{{as of|2011|March}}, a future launch of an Ad Astra VF-200 {{nowrap|200 kW}} [[VASIMR]] electromagnetic thruster was under consideration for testing on the [[International Space Station]] (ISS).<ref name="aaESummary20100124">{{cite web|url=http://www.adastrarocket.com/EXECUTIVE%20SUMMARY240110.pdf|title=Executive summary|date=January 24, 2010|publisher=Ad Astra Rocket Company|access-date=2010-02-27|url-status=dead|archive-url=https://web.archive.org/web/20100331171616/http://www.adastrarocket.com/EXECUTIVE%20SUMMARY240110.pdf|archive-date=March 31, 2010}}</ref><ref name="dn20080807">{{cite web |url=http://dsc.discovery.com/news/2008/08/07/plasma-rocket.html|title=Plasma Rocket May Be Tested at Space Station|date=7 August 2008|first=Irene|last=Klotz|publisher=Discovery News|access-date=2010-02-27}}</ref> However, in 2015, NASA ended plans for flying the VF-200 to the ISS. A NASA spokesperson stated that the ISS "was not an ideal demonstration platform for the desired performance level of the engines". Ad Astra stated that tests of a VASIMR thruster on the ISS would remain an option after a future in-space demonstration.<ref name="VASiMRscrapped">Irene Klotz (17 March 2015). [http://sen.com/blogs/irene-klotz/nasa-nixes-ad-astra-rocket-test-on-the-space-station NASA nixes Ad Astra rocket test on the space station] ''SEN News.''</ref>

The VF-200 would have been a flight version of the [[VX-200]].<ref name="Yahoo News">{{cite web|url=https://news.yahoo.com/nasa-test-vf-200-vasimr-plasma-rocket-iss-20110310-155100-110.html|title=NASA to Test VF-200 VASIMR Plasma Rocket at the ISS|date=March 10, 2011|first=Mark|last=Whittington|publisher=Yahoo|access-date=2012-01-27}}</ref><ref name="Yahoo">{{cite news |url=http://www.dailytech.com/Commercially+Developed+Plasma+Engine+Soon+To+Be+Tested+In+Space/article12612.htm|title=Commercially Developed Plasma Engine Soon to be Tested in Space|date=August 11, 2008 |first=Jason|last=Mick|publisher=DailyTech|access-date=2010-02-27|archive-url=https://web.archive.org/web/20150222124839/http://www.dailytech.com/Commercially+Developed+Plasma+Engine+Soon+To+Be+Tested+In+Space/article12612.htm|archive-date=February 22, 2015|url-status=dead}}</ref> Since the available power from the ISS is less than 200&nbsp;kW, the ISS VASIMR would have included a trickle-charged battery system allowing for 15 minutes pulses of thrust. The ISS orbits at a relatively [[low Earth orbit|low altitude]] and experiences fairly high levels of [[atmospheric drag]], requiring [[orbital station-keeping|periodic altitude boosts]] – a high-efficiency engine (high specific impulse) for station-keeping would be valuable; theoretically VASIMR reboosting could cut fuel cost from the current US$210 million annually to one-twentieth.<ref name="aaESummary20100124"/> VASIMR could in theory use as little as 300&nbsp;kg of argon gas for ISS station-keeping instead of 7500&nbsp;kg of chemical fuel – the high exhaust velocity (high [[specific impulse]]) would achieve the same acceleration with a smaller amount of propellant, compared to chemical propulsion with its lower exhaust velocity needing more fuel.<ref name="newscientist.com">{{cite web|last=Shiga|first=David|url=https://www.newscientist.com/article/dn17918-rocket-company-tests-worlds-most-powerful-ion-engine/|title=Rocket company tests world's most powerful ion engine|publisher=New Scientist|date=2009-10-05|access-date=2019-11-16}}</ref> [[Hydrogen]] is generated by the ISS as a by-product and is vented into space.

NASA previously worked on a 50&nbsp;kW Hall-effect thruster for the ISS, but work was stopped in 2005.<ref name="newscientist.com"/>