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From: chiaraviglio@husc2.UUCP (lucius)
Newsgroups: sci.space
Subject: Re: why Mercury (liquid metal) used for ion rocket?
Message-ID: <1005@husc2.UUCP>
Date: Sun, 2-Nov-86 00:30:02 EST
Article-I.D.: husc2.1005
Posted: Sun Nov  2 00:30:02 1986
Date-Received: Mon, 3-Nov-86 22:42:43 EST
References: <8610310012.AA13920@s1-b.arpa>
Organization: Harvard Univ. Science Ctr., Cambridge, MA
Lines: 15
Summary: Specific impulse depends on molecular weight only in adiabatic expansion-driven propulsion systems.


	My understanding of the way that ion drives work is that they
accelerate the ions out backwards electrostatically, a procedure that is not
temperature-dependant, and thus will lose no more energy in unuseable heat for
large-molecular-weight substances than small-molecular-weight substances.
Therefore, other factors are the considerations in choosing a propellant.

-- 
	-- Lucius Chiaraviglio
	   lucius@tardis.harvard.edu
	   {insert your favorite brave system here}!seismo!tardis!lucius

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