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Path: utzoo!linus!decvax!tektronix!uw-beaver!ssc-vax!eder
From: eder@ssc-vax.UUCP (Dani Eder)
Newsgroups: net.space
Subject: Re: space elevators
Message-ID: <577@ssc-vax.UUCP>
Date: Wed, 26-Oct-83 13:58:39 EDT
Article-I.D.: ssc-vax.577
Posted: Wed Oct 26 13:58:39 1983
Date-Received: Thu, 27-Oct-83 22:21:34 EDT
References: <12817@sri-arpa.UUCP>
Organization: Boeing Aerospace, Seattle
Lines: 10


                                         25 October 1983

     A correction to the comment on rocket efficiencies.  While it is true that the fact that most of the lift-off weight of current rockets not being payload introduces an inefficiency, current rocket engines are quite efficient at converting chemical energy into thrust. Typical figures are 75% for engines at sea 
level to 97% in vacuum, the difference due to back pressure from the atmosphere
at the engine nozzle exit.

                                                       Dani Eder
                                                       Boeing Aerospace