[amsat-bb] Re: I: ionic propulsion motor

[Greg D.]

Ah, perfect.  This is what I was looking for, thanks.  I was puzzled by the 
electron gun, and the other complexities.  Now it makes more sense.  But, 
one question...  By the animation, it looks like the grill switches back and 
forth between positive and negative charge.  So, the engine operates in a 
pulse mode?  And, I guess the magnets have a beam-forming role?  (ok, so 
that's two questions...)

Greg  KO6TH


----Original Message Follows----
From: "jmfranke" <jmfranke@cox.net>
To: Félim Doyle M3HIM <Felim.M3HIM@ntlworld.com>,"Greg D." 
<ko6th_greg@hotmail.com>,<amsat-bb@amsat.org>
Subject: Re: [amsat-bb] Re: I: ionic propulsion motor
Date: Sun, 3 Sep 2006 10:58:25 -0400

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
>
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