The arcjet and the ion drive are different.
The arcjet uses an electric arc to heat a gas/fluid/solid. The expanding gas/plasma then works like a conventional rocket motor. One of the valuable attributes is that the gas/fluid/solid need not be combustible, hence it is safer than a conventional rocket. Also, higher temperatures can be achieved, and hence larger expansion ratios can be obtained. The arcjet is normally easier to regulate than conventional chemical rockets.
The ion engine uses electrostatic force to drive or push against ions. The thrust is derived from the electrostatic force acting against a heavy ion. For a given accelerating voltage, thrust is proportional to the atomic mass of the propellant. There is also an accompanying electron gun that adds a small thrust, but is primarily added to neutralize the emitted ion cloud so the ions are not attracted back to the spacecraft which, without the counter current electron gun, would be developing a negative charge.
Hope this helps,
John WA4WDL
----- Original Message ----- From: "Félim Doyle M3HIM" Felim.M3HIM@ntlworld.com To: "Greg D." ko6th_greg@hotmail.com; amsat-bb@amsat.org Sent: Sunday, September 03, 2006 6:14 AM Subject: [amsat-bb] Re: I: ionic propulsion motor
Greg,
By 'ion motor' I take it you are referring to the Ammonia powered arcjet. I did not realise that the two were synonymous. The following items would indeed suggest that they are similar if not the same concept.
http://www.esa.int/SPECIALS/SMART-1/SEMLB6XO4HD_0.html http://www.daviddarling.info/encyclopedia/A/arcjet.html
Historically, I have had a much different idea of ion drive which did not involve ejecting gas at high speed. If anyone has the time, I would appreciate being enlightened.
73 de
Félim M3HIM IO91ot Aylesbury, Buckinghamshire, UK ----- Original Message ----- From: "Greg D." ko6th_greg@hotmail.com To: amsat-bb@amsat.org Sent: Saturday, September 02, 2006 8:28 PM Subject: [amsat-bb] Re: I: ionic propulsion motor
How does this compare to the ion motor we had on AO-40? Also, is there an English translation anywhere? I get the general idea looking at the pictures, but the details escape me.
Thanks,
Greg KO6TH
----Original Message Follows---- From: "Francesco Grappi" f.grappi@tin.it To: amsat-bb@amsat.org Subject: [amsat-bb] I: ionic propulsion motor Date: Sat, 2 Sep 2006 10:47:14 +0200
HI Luc,
Very interesting animation and explanation ... Thank you 73" Francesco IW4DVZ
-----Messaggio originale----- Da: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org]Per
conto
di Luc Leblanc VE2DWE Inviato: sabato 2 settembre 2006 9.27 A: AMSAT-BB@amsat.org Oggetto: [amsat-bb] ionic propulsion motor
HI
Here is a link explaining the ionic motor propulsion system with a nice animation (in French) the SMART-1 first lunar European space probe will crash on the moon on
September
3 at 0541 UTC.
Could be usable for our HEO fleet? It seems pretty simple at the first
look.
http://www.radio-canada.ca/nouvelles/AFPanimation/SmartFR3008/
"-" The medium is the message...The content is the audience...;)
Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb