Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site ssc-vax.UUCP
Path: utzoo!linus!decvax!ittvax!dcdwest!sdcsvax!sdcrdcf!hplabs!tektronix!uw-beaver!ssc-vax!eder
From: eder@ssc-vax.UUCP
Newsgroups: net.space
Subject: Re: Trivia Question (diamond rockets)
Message-ID: <149@ssc-vax.UUCP>
Date: Thu, 17-May-84 08:43:24 EDT
Article-I.D.: ssc-vax.149
Posted: Thu May 17 08:43:24 1984
Date-Received: Tue, 22-May-84 01:05:14 EDT
References: <576@sri-arpa.UUCP>
Organization: Boeing Aerospace, Seattle
Lines: 16

17 May 1984

     Many solid rocket nozzles are made of a carbon-carbon composite, for
example the Star-48 motor used on PAM-D's and the SRM-1 motor used on the
IUS.  These are made by forming a graphite-epoxy structure, then heating
it until the epoxy chars, leaving carbon fibers reinforced by carbon
particles.
     The composition of this nozzle is nearly 100% carbon, which is the
same as diamond.  The nozzles are used because they are strong for their
weight at the extremely high temperatures they operate at.
     The nozzle throats (the narrowest part) DO erode during the motor
operation, but it is hard to find anything that won't do that at
those temperatures (6100 F for a Star-48).

Dani Eder / Boeing Aerospace / ssc-vax!eder / (206)773-0570