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From: gwh@typhoon.Berkeley.EDU (George William Herbert)
Newsgroups: sci.space.shuttle,sci.space
Subject: Re: Space Shuttle SRB exhaust gas makeup.
Summary: I should know better by now...
Message-ID: <1989Oct26.025442.17842@agate.berkeley.edu>
Date: 26 Oct 89 02:54:42 GMT
Sender: usenet@agate.berkeley.edu (USENET Administrator;;;;ZU44)
Reply-To: gwh@typhoon.Berkeley.EDU (George William Herbert)
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In article <1989Oct25.022019.14407@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes:
>In article <1989Oct24.222743.23580@agate.berkeley.edu> gwh@typhoon.Berkeley.EDU (George William Herbert) writes:
>>	A _dash_ of aluminum???  The majority of the thrust is achived
>>by the aluminum component of the fuel !
>>	The actual materials are Ammonium Perchorate, Aluminum powder, PVC
>>binder and extra bits to stabilize.  It's about 99% those three.
>
>If we're being picky, the numbers (according to NASA) are 69.83% ammonium
>perchlorate, 16% aluminum, 12% rubber (it's not PVC, it's a polybutadiene
>acrylic acid acrylonitrile polymer), 2% curing agent, and more or less
>0.17% iron oxide catalyst.
>
>And don't sneer at the idea of doing without the aluminum, because the
>rubber is also a fuel; similar combinations without aluminum have almost
>as high a specific impulse.  (For that matter, ammonium perchlorate by
>itself is apparently non-trivial as a monopropellant, although it's not
>used that way because its physical properties aren't right.)

	Okay, Henry, you got me :)
I had a tech paper from some time back that had PVC listed as the propellant,
but i checked again and Heny appears to be right.  Maybe it got changed sometime.

	As for the 'no aluminum' bit, it really was described as making
most of the difference.  There's a whole lot more energy in Al than rubber...

	
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George William Herbert  UCB Naval Architecture Dpt. (my god, even on schedule!)
maniac@garnet.berkeley.edu  gwh@ocf.berkeley.edu
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