Newsgroups: sci.space.shuttle
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Blowing Up the Shuttle
Message-ID: <1990Apr13.041751.26146@utzoo.uucp>
Organization: U of Toronto Zoology
References: <9689@ingr.com>
Date: Fri, 13 Apr 90 04:17:51 GMT

In article <9689@ingr.com> whitehrc@ingr.com (Robert C. Whitehead) writes:
>I hope everyone remembers the basis for the argument about
>the Shuttle generating a 1.2 megaton blast if it were
>range-saftied on the pad.
> ...
>	5% STRUCTURAL DAMAGE AREA (aka 50% casualty area,
>	meaning that 50% of the people in this area die)
>	Defined as area of 1.2 psi overpressure
> ...
>Range Saftey declared on the pad; SRB and ET RS devices are triggered
> ...
>5% STRUCTURAL DAMAGE AREA (aka 50% casualty area,
>meaning that 50% of the people in this area die) = 7,341' radius

Unfortunately, this *still* doesn't add up to 1.2MT.  A quick spin of
the old Nuclear Bomb Effects Computer (revised edition, 1964) (an AEC
"publication" -- a circular slide rule -- based on data from The Effects
of Nuclear Weapons) shows a yield just under 10 *kilo*tons to produce
1.2psi overpressure at 7341ft.  This assumes a ground burst, the yield
for optimum burst height is even smaller.  (By comparison, the 1.2psi
overpressure radius for a 1.2MT ground burst is *seven miles*.)  That's
a fairly good case; evidently an exploding rocket doesn't behave quite
the same way as a nuclear bomb, because the yields for your higher-
overpressure radii are even smaller, mostly down in the 2-3kT range.

Could someone using an N.B.E.C. have read the distance scale, which is
in miles, as thousands of feet instead?  It's interesting that your
radius is 7 thousand feet and the 1.2MT radius is 7 miles.

And where did you get the idea that 50% of people die at 1.2psi??
T.E.o.N.W. estimates 50% fatalities at about *fifty* psi and negligible 
fatalities below about 35, although some injury to lungs is possible
at 7psi or so in worst-case conditions.

>According to my sources, this compares favorably to the blast
>caused by 1 megaton of TNT.

Can you identify your sources?  They seem to disagree drastically with
the numbers from the US government's bomb-effects experts.
-- 
With features like this,      |     Henry Spencer at U of Toronto Zoology
who needs bugs?               | uunet!attcan!utzoo!henry henry@zoo.toronto.edu