Subject: Review: "Moonfall", Jack McDevitt

From: "Rob Slade, doting grandpa of Ryan and Trevor" <[email-masked]>
Date: 25 Jun 1999 23:47:54 -0400

"Moonfall", Jack McDevitt
	Review Copyright 1999 Robert M. Slade

Watch out!  It's a comet, come to wipe out ... no, not the earth.  Just
the moon.  Then bits of the *moon* wipe out the earth.

Wonderfully sympathetic characters.  Interesting twist on an old premise.
A bit *too* much tension: by the time the hero survives the cataclysm you
begin to wonder why half the book is left, and by the end you are almost
willing for everyone to die, just so long as the darn thing finishes!
Along the way a few too many of the plot twists are telegraphed well in
advance: not a lot come as any surprise when they do show up.

An awful lot of people from NASA and other space institutions get thanked.
In many areas careful research is evident.  A number of astronomical,
astrophysical, and cosmological facts are presented correctly.  Readers of
the RISKS-FORUM Digest would be quite happy with the fact that it is small
errors, in combination, that create the biggest problems.  However, when
the plot action starts happening, all the careful research goes out the
window.

A major factor in the plot are a number of "single stage to orbit"
spaceplanes.  The space station seems to have an inexhaustible supply of
fuel for them.  However, the idea behind an SSTO is that while it uses a
huge amount of fuel to get up, it needs almost nothing coming down.  There
just wouldn't be any reason to have that much fuel on hand.

Now, despite what "BattleStar Galactica," "Starship Troopers," and other
quality training materials may show you, fireballs do not billow, nor do
clouds roll, in the vacuum of space.  Absent the fairly minor curvatures
imposed by gravity, and the effect of the odd collision, everything in
space moves in pretty straight lines, including light, hot gases, and
rocks of whatever size.  Shockwave "fronts" do not exist in space.
Dodging debris would be a zero sum game, since unless every piece had the
same velocity, in which case matching speed once would take care of
everything, decreasing your delta-V with respect to one chunk would tend
to increase it with respect to something else.

Also, having achieved the relative safety of earth orbit in concert with
some of the bits that were going your way would give scant relief: shortly
you would round the earth and start heading into a bunch of stuff going
the other direction.  Orbital dynamics is not a real strong point in this
book.  The biggest error, though, is granted to the biggest piece of rock.
POSsible IMpactor number 38, dubbed Possum in the book, makes two very
exciting passes on an elliptic orbit around the earth.  The first one is
definitely east to west, while orbit two is west to east ...

%A   Jack McDevitt
%C   10 East 53rd Street, New York, NY  10022-5299
%D   1998
%G   0-06-105112-8
%I   HarperCollins/Basic Books
%O   U$6.50/C$8.50 fax: 212-207-7433 fax: 212-207-7222
%P   544 p.
%T   "Moonfall"

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