Xref: utzoo sci.space.shuttle:3909 sci.space:14981
Newsgroups: sci.space.shuttle,sci.space
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Space Shuttle SRB exhaust gas makeup.
Message-ID: <1989Oct25.022019.14407@utzoo.uucp>
Organization: U of Toronto Zoology
References: <1989Oct24.222743.23580@agate.berkeley.edu>
Date: Wed, 25 Oct 89 02:20:19 GMT

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.)
-- 
A bit of tolerance is worth a  |     Henry Spencer at U of Toronto Zoology
megabyte of flaming.           | uunet!attcan!utzoo!henry henry@zoo.toronto.edu