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>From OTA@S1-A Thu Oct 29 03:55:23 1981

SPACE Digest                                      Volume 2 : Issue 21

Today's Topics:
		      Re: IC's and the space program
			 Re: SPACE Digest V2 #20
				ERRATA   
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Date: 28 Oct 1981 11:13:56-EST
From: cjh at CCA-UNIX (Chip Hitchcock)
To: space at mit-mc
Subject: Re: IC's and the space program

   Certainly there was a greater need for miniaturization in our
space program, since there was less time and money available to
develop the grossly powerful boosters the Russians were using
(it's something of a truism that in the "space race" the Russians
went for brute power while we went for compactness). Consider
that the first Russian satellite weighed something over 100 pounds
while the first American satellites were in the 5-10 pound class
but certainly did more than 5-10% as much work.

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Date: 28 Oct 1981 1205-PST
From: Terry C. Savage <TCS at USC-ECL>
Subject: Re: SPACE Digest V2 #20
To: Space-Enthusiasts at MIT-MC
cc: TCS at USC-ECL
In-Reply-To: Your message of 28-Oct-81 0402-PST

VLSI TECHNOLOGY HAS BEEN ENCOURAGED IN A GENERAL WAY BY THE SPACE PROGRAM,
BUT THE LINKAGE IS NOT REALLY DIRECT. THE MAIN MOTIVATION FOR THE
IMPROVEMENT IN SEMICONDUCTOR TECHNOLOGY HAS BEEN FOR EARTH BASED
COMMERCIAL APPLICATIONS, SUCH AS LARGE, FAST COMPUTERS. SEMICONDUCTOR
PROCESSING IS VERY CAPITAL INTENSIVE, AND THE SMALL VOLUME ENTAILED IN
MOST SPACE APPLICATIONS IS INSUFFICIENT TO JUSTIFY THE CAPITAL EXPENSE.
THE CURRENT PUSH FOR EXPANDING SEMICONDUCTOR CAPABILITIES COMES PRIMARILY
FROM THE MILITARY'S VHSIC PROGRAM, WHICH WILL HAVE SPACE APPLICATIONS BUT
IS NOT DRIVEN BY SPACE.

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Date: 28 Oct 1981 2221-PST
From: Ted Anderson <OTA at S1-A>
Subject: ERRATA   
To:   space at MIT-MC  

I was called to my attention (by only one person) that my figures for dropping
rocks on the earth were in error.  In particular they were high by a factor of
4.18 (the number of joules in a calorie).  I forgot that a tonne of HE is
a billion calories not a billion Joules.

The calculation is straight forward:
The potential well of the earth is about 11 km/s.  Thus the kinetic energy is
.5*11000^2 Joules/Kg = 6e7; a tonne is 1000 kg so we have, 6e10 J/Tonne;
now divide by 4e9 J/Tonne for HE and we get: 15 Tonnes of energy per tonne
of mass.

Sorry to foul it up in the first place.

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End of SPACE Digest
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