Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ukma!husc6!bunny!hhd0
From: hhd0@GTE.COM (Horace Dediu)
Newsgroups: sci.space.shuttle
Subject: Re: Atlantis is home!
Summary: 2 booms
Message-ID: <6949@bunny.GTE.COM>
Date: 18 May 89 14:32:43 GMT
References: <272@skipper.dfrf.nasa.gov> <9090001@hp-lsd.HP.COM> <4453@ttidca.TTI.COM>
Organization: GTE Laboratories, Inc., Waltham, MA
Lines: 45

In article <4453@ttidca.TTI.COM>, hollombe@ttidca.TTI.COM (The Polymath) writes:
> In article <9090001@hp-lsd.HP.COM> paulc@hp-lsd.HP.COM (Paul Carroll) writes:
> 
> }By the way, can anyone inform me as to why there are 2 sonic
> }booms, and not just one, from the shuttle?  ...
> 
> One from the Shuttle, one from the chase plane.
> 

No.
The booms come from two different shock waves generated by the shuttle.  At
supersonic speeds the shuttle looks like:

			.                        .
                       .                        .
  		      .  <- shock wave 1       . <- shock wave 2
		     .	(in 3-space, these    .
		    .	 are cones)	      --.
		   .			     /  |
		  .			    /   |
		 .			   /    |
	        .  _______________________/-----|__
               . /   USA                 :      /  |
	      /--                               ---| 
	     <                                  \__|
              -------------------------------------
	       .			  .
		.			   .
		 .  			    .
		  .  			     .
		   . 			      .
		    . 		  yay!	       .
		     .		 o		.
		      .		-|-		 .
		       .BOOM	/ \		  .BOOM
_____________________________________________________ (observer) on ground
(Not to scale).  There are many shock waves, but these are the biggest.  The
nose, and the bumps in the fuselage at the back which cover the engines
cause the two shock waves.

-- 
Horace Dediu                                                  GTE Laboratories
(671) 466-4111                                                40 Sylvan Road
UUCP:  ...!harvard!bunny!hhd0                                 Waltham, MA 02254
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