From: dietz@cs.rochester.edu (Paul Dietz)
Newsgroups: sci.space,talk.politics.space
Subject: Re: Justification for the Space Program
Date: 7 Jan 93 20:51:56 GMT
Distribution: usa, world
Organization: University of Rochester

In article <jfelder-070193115431@latvia.lerc.nasa.gov> jfelder@lerc.nasa.gov (James L. Felder) writes:

>O.K., I just started following this group today, and already I see one of
>my favorite topics up for vorciferous debate, so I'll just wade in here.  I
...
>Premise 1.  We live on a finite planet with finite resources.
>
>Premise 2.  Our technological society is highly dependent on resources that
>are being used up faster than they can be replaced.
>
>Premise 3.  Economists seem to insist that we must continue to grow to
>increase our standard of living, and the public and politicians seemed to
>have bought into this premise.  For proof one only has to look at the last
>election to see cries that we are "loosing the American Dream" because we
>are not better off than our parents held up as worthy compaign issues.  The
>strong implication is that an ever increasing, I would hazard
>materialistic, standard of living is something we must all strive for.
>
>Premise 4.  We will not stumble across some unlimited sources of energy
>(fusion) or materials (say a way to mine the earths core) here on earth.
>
>Conclusions.  Energy and materials will become increasingly hard to obtain,
>and that eventually the net energy and material production will decline
>below what is required to maintain some existing standard of living.Unless
>we find a way to circumvent the limited resources of our planet, we as a
>technologically advanced society will cease to exist.  People will continue
>to exist, but society will not be as we know it.  I do not know the time
>frame, nor care to hazard a guess, but the end seems to me to be
>unavoidable.  



There are a number of problems with this argument...

  "We live on a planet with finite resources"

Finite does not mean limited.  First, the amount present may be so
large as to be effectively unlimited.  Fertile nuclear materials
(U-238 and Th-232) fall into this class.  Second, aside from
nuclear uses, elements are not consumed in use, they merely become
less concentrated.  The free energy required to extract materials
goes as the log of the dilution (higher in practice, but practice
changes).

  "Resources are being used up faster than they are being replaced"

That a resource is limited and not renewable matters only if its
is very hard to replace with some substitute.  Fossil fuels are
an example -- there is no reason why we should not be able
to survive indefinitely without them, if some other source of
energy is available.

  [paraphrased] "Growth is necessary to avoid social calamity"

Then we are in big trouble, since growth in resource use cannot
continue forever.  For example, if energy use grows 1%/year,
then in 10,000 years we are consuming the entire power output
of the observable universe.

In the short term, however, there is no reason why resource use
on earth cannot be increased.  There is no reason why we could
not supply several times the current population with several times
the current US per capita energy consumption indefinitely.

   "No inexhaustible energy source on earth"

At least two are already in the engineering stages (solar and fission
breeder).

"Too Expensive!" you may say.  Well, now, yes, but manufacturing
productivity increases about 3%/year.  It gets cheaper to make things.
Moreover, if we had to make a lot of solar collectors or nuclear
reactors, economies of scale would drive costs down still further.
And it's a lot easier to start down a learning curve when you can
build smallish things on the ground rather than enormous things in space.
Realize that the current world output of PV modules would take
more than a century to make enough to cover one 10 GW powersat.
Space colonization schemes are implicitly assuming big productivity
increases.

   "If we don't go now, resources will be too expensive"

This "window of opportunity" argument falls apart under close
examination.  Resource prices have typically fallen over time, even as
richer deposits have been exhausted.  Moreover, a space program uses
relatively little in the way of natural resources.  What it does use a
lot of is labor, talent and knowledge.

Look at the price of a shuttle orbiter.  It costs more than its own
weight in gold.  The cost of the elements and energy that do go into
its manufacture is a piddling small fraction of its total cost.  The
same is true of an airliner.  The raw aluminum in a 747, for example,
would cost perhaps a quarter of a million dollars.

Increased raw material prices would only make a space program *more*
feasible, by increasing the potential profit.

	Paul F. Dietz
	dietz@cs.rochester.edu
Newsgroups: sci.space