Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!decwrl!jumbo!stolfi
From: stolfi@jumbo.dec.com (Jorge Stolfi)
Newsgroups: sci.space
Subject: Re: Solid State Fusion for Launchers
Summary: Cheap energy from fusion may delay space colonization.
Message-ID: <13667@jumbo.dec.com>
Date: 3 Apr 89 12:10:33 GMT
References: <1989Apr2.133451.27254@cs.rochester.edu>
Reply-To: stolfi@src.dec.com (Jorge Stolfi)
Followup-To: sci.space
Organization: DEC Systems Research Center, Palo Alto
Lines: 48


Most postings to this newsgroup seem to assume that the discovery of
cold fusion is a great boon to the exploration and colonization of
space.  This does not seems obvious to me.  From what I have read
so far, cold fusion may help space exploration only a litle,
and hamper space colonization quite a lot.

Let's assume that cold fusion will indeed turn out to be a source of
cheap energy, and not a mere laboratory curiosity.  Still, it seems a
safe bet that it will take at least 5 to 10 years for cold fusion power
sources to become sufficiently efficient, practical, and reliabe to be
used in space.  Even then, there is no indication that cold fusion will
be of any use as a first-stage propulsion system.  At this point, the
only use for cold fusion in space that seems plausible enough is as a
source of electricity, which could perhaps be used by relatively
low-thrust ion motors.  Note that energy is only a small fraction of
the cost of a launch, so cheap energy on the ground will not make space
launches much cheaper.   

On the other hand, cheap energy on the Earth means there won't be any
need for solar power satellites (SPS).  Now, SPSes are the only
large-scale space operation that is not obviously an economical
nonsense.  Without SPSes, space colonies would lose their main raison
d'etre; and without space colonies, there is hardly any reason to
consider lunar and asteroid mining.  (By the way, cheaper energy would
make possible to exploit many low-grade ore bodies that now are
uneconomial, so mining the asteroids for the Earth market would make
even less sense that it does now.) 

To summarize, I bet that in the foreseeable future cold fusion may turn
out to be of some use *in* space, but it will not make going *to* space
any easier.  In fact, if it is successful, it will make the
colonization of space a lot harder to sell.  

                Jorge Stolfi @ DEC Systems Research Center
                stolfi@src.dec.com, ...!decwrl!stolfi
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    ``My dear listeners,'' he went on, ``if we are to believe certain
    narrow-minded people --- and what else can we call them? --- humanity
    is confined within a circle of Popilius from which there is no escape,
    condemned to vegetate in this globe, never able to venture into
    interplanetary space! That is not so! We are going to the moon, we
    shall go to the planets, we shall travel to the stars just as today
    we go from Liverpool to New York, easily, rapidly, surely, and the
    oceans of space will be crosed like the seas of the moon!''
        --Verne, _From the Earth to the Moon_ (1865)       
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