From: "Geoffrey A. Landis" <geoffrey.landis@lerc.nasa.gov>
Newsgroups: sci.space.tech
Subject: Re: Books on terraforming?
Date: 30 Sep 1996 16:11:49 GMT

In article <52if0m$8ps@ringer.cs.utsa.edu> Paul Rivera,
privera@ringer.cs.utsa.edu writes:
>	Does anyone know of any books on terraforming?

Seems this question comes up every month or so.  I ought to post this to
my web page so that people know:

The best reference book on terraforming is Martyn Fogg's book
_Terraforming_

A review that I posted last year follows.

Review:
     
     Terraforming: Engineering Planetary Environments, by Martyn J. Fogg,
SAE Press 1995.  ISBN 1-56091-609-5, $39.00 hardcover
     Review by Geoffrey A. Landis
     
     Terraforming is the concept ofaltering the environment of a
planetary surface to make it suitable for (terrestrial) life.  The
scientific literature about terraforming tends to be sparse, not to
mention scattered over a number of journals and books.
     This book, by British planetologist Martyn Fogg, is an exhaustive
book-length review of the scientific literature on terraforming, written
at a level that's accessible to the casual (but scientifically-literate)
reader.  His references are quite thorough, and he is quite meticulous to
credit the originator of each idea he mentions, so if you need more, you
know where to go to look it up.
     It's published, oddly enough, by the Society of Automotive
Engineers.  Why the SAE?  In explanation, Martyn says, SAE considers
themselves to be first and foremost an engineering organization, and
terraforming--planetary engineering-- is engineering on the largest scale.
     Martyn Fogg is a regular writer of "science fact" articles for
Analog, and the book reads quite smoothly.  He starts with a review of
the development of terraforming in science fiction, particularly
crediting Olaf Stapleton with the first lengthy description of
terraforming (Venus, in Last and First Men, 1930), Jack Williamson with
coining the term in 1942 ("Collision Orbit", in Astounding Science
Fiction), and crediting Heinlein with the first use of terraforming as
the background for an entire book, complete with a quantitative
discussion of the energy required, in Farmer in the Sky (1950).  Note
that these beat by over a decade the first scientific discussions of
terraforming, Sagan's proposal to terraform Venus in 1961, and the
proposals to terraform Mars by Burns and Harwit, and (independently)
Sagan, in 1973,
     From here, he starts out with a review of how the ecology on a
planet works, paying particular attention to how carbon, nitrogen,
oxygen, phosphorus, and energy cycle through the system; emphasizing that
we are the beneficiaries of a huge "gratis" energy flow provided by the
sun and by the Earth's tectonic activity, that keeps the environmental
cycles working and acts as an invisible "subsidy" to the human occupation
of the Earth.
     His next chapter discusses environmental modifications of the Earth,
both incidental, and deliberate (i.e., solar shields to counter
greenhouse warming.)
     Finally, 200 pages into the book, he discusses terraforming other
planets.  He starts with Mars, discussing the early (1973) models of Mars
that suggested that, since Mars was once apparently warmer and wetter
than it is now, a small "push" in the right direction might "snap" Mars
into an alternative, warmer equilibrium due to a runaway greenhouse
effect.
     To his credit, after a long discussion of the possibility of
"gentle" terraforming of Mars, he then discusses the very likely case
that Mars is not in a such metastable state, and discusses "hard"
terraforming, with a wide analysis of techniques such as nuclear mining,
cometary impact, importing volatiles from icy moons, and enhancing solar
radiation.  He closes with an example terraforming scenario using all the
tools available.  Of particular interest is his analysis of time scales. 
His terraforming example requires roughly 200 years to reach the stage
where simple anaerobic microorganisms and algae can survive, and as much
as seven thousand years to completely terraform to a human-breathable
atmosphere.  A long term project indeed!
     In the following chapter he discusses the much more difficult
problem of terraforming Venus.  His discussion of Venus gives an
excellent historical background.  When Sagan first proposed terraforming
Venus by "seeding" algae into the clouds in 1961, Venus was though to be
much more Earthlike than it is now known to be.  We now know that the
temperature of Venus is significantly hotter, the atmospheric pressure
tremendously higher, and the chemical environment a lot harsher, than was
thought in the pre-Pioneer days.  Venus has just too damn much
atmosphere.  He also points out that, even if it were possible to
engineer organisms to sequester the carbon dioxide from the Venus
atmosphere, the process would take between eleven thousand and 1.1
million years, depending on how optimistic one is about how efficient
photosynthesis could be made to become.  Nevertheless, many science
journalists (e.g., Adrian Berry) have continued to plug the "easy"
terraforming of Venus by "just dropping a handful of algae into the
atmosphere", and Fogg rather thoroughly debunks their optimism. 
Terraforming Venus is hard.  His discussion covers most of the
possibilities for dealing with atmosphere of Venus, ranging from ablating
it away with myriad asteroidal impacts, to freezing it out with solar
shields.
     The penultimate chapter is on fringe concepts and ultimate
possibilities.  He counts terraforming the moon and the larger satellites
of the outer planets under fringe concepts, although in many ways these
would be considerably easier than some of the other things he discusses. 
He then briefly discusses ever further out ideas, including moving
planets, turning Jupiter into a star, and even the possibility of moving
stars.
     OK.  Now to be critical.
     The book is billed as the first textbook on the subject of
terraforming.  I wouldn't call it a textbook; it reviews the subject, but
doesn't attempt to teach the reader the techniques of analysis.  In other
words, having read the book the readers will be familiar with what has
been calculated by others, but will not have the calculational tools to
analyze terraforming calculations themselves.
     In particular, I found the discussion of the greenhouse effect,
critical to an understanding of methods to warm Mars, to be superficial,
barely more thorough than what you might find in the newspaper.  There
was no description of methods used to calculate the amount of greenhouse
warming.  A description of the greenhouse effect ought to include
spectra, show a formula for integrating over the spectrum to compute
total heat balance, and discuss the effect of optical depth.  The book
does not do this, and in fact never even gives a simplified model to
calculate the amount of greenhouse warming.  He does, however, include a
useful empirical equation (unfortunately applicable only to Mars), to
calculate the combined effect of water and CO2 greenhouse effect on
overall surface temperature.
     The book suffers a bit from the fact that the illustrations are a
hodgepodge collection of pictures from various articles, with
nomenclature and units inconsistent from one to another.
     He skims over the discussion of nitrogen.  He claims that an oxygen
atmosphere, even at a few PSI (say, 3 PSI) partial pressure, requires a
nitrogen "buffer" to prevent a fire hazard.  His single reference for
this statement, though, is a rather dubious one.  While he does note that
this is "a disputed figure," after this one note he takes the requirement
for 75% of any atmosphere to be nitrogen as a canonical fact.  This is a
pity, since it allows him to avoid asking the tricky question of how
little atmospheric nitrogen an ecosystem actually requires.  Nitrogen is
a tough problem for Mars, which is nearly absent of N, as far as we can
tell from all the information we have at the present.  Fogg postulates
huge reserves in the form of of nitrate deposits, but I must point out
that there is as yet no real evidence for such deposits, and it is quite
possible that nitrogen on Mars is simply not there.
     He has a chapter on planetary engineering of the Earth, which talks
about reversing greenhouse warming by a sun-shield.  He doesn't note that
reducing sunlight would also reduce photosynthesis, and hence enhance the
greenhouse effect.  (This could, of course, be ameliorated by a dichroic
shield, which selectively passes the wavelengths most useful for
photosynthesis).  I would have liked the flow better if he had put
re-engineering Earth last, with the emphasis that we need to study,
understand, and experiment, and make our mistakes on other planets first
before embarking to mess with the one we live on.  He could have
emphasized how we understand greenhouse effect based on our studies of
Venus; how the "nuclear winter" scenario was proposed based on studies of
the effects of global dust coverage of Mars.
     A small thing that bothered me was that he doesn't very well
distinguish between realistic and far-out ideas.  One of the proposals he
discusses, for example, was to increase the spin of Venus using three
quadrillion objects circulating between Venus and the sun every 2 hours,
each traveling at 10% of the speed of light.  I would personally have put
that into the "fringe concepts" section, myself.  However, that's only a
minor quibble.  Fogg uses the "fringe concepts" pigenhole to discuss the
really far-out concepts.
     Despite my carping on minor details, it's a good book.  At
thirty-nine bucks for a 544 page hardcover, it's a bargain.  I highly
recommend it.
     
     Ordering information:
     Order No. R-153 from SAE Press, 400 Commonwealth Dr., Warrendale PA
15096-0001 U.S.A.; telephone (412) 776-4970.   PA residents 7% sales tax;
Canadian residents 7% GST; overseas shipping $10.


____________________________________________
Geoffrey A. Landis,
Ohio Aerospace Institute at NASA Lewis Research Center
physicist and part-time science fiction writer
http://www.sff.net/people/Geoffrey.Landis