Sky & Telescope - June 2022 - 57

BOOK REVIEW by Peter Tyson
Pie in the Sky
ASTEROIDS: How Love, Fear, And Greed Will Determine Our Future In Space
Martin Elvis
Yale University Press, 2021
295 pages, ISBN 978-0-300-23192-2
US$30, hardcover
" UNTIL RECENTLY, 'space' and 'greed'
didn't often turn up in the same sentence, "
writes Martin Elvis, an astrophysicist
at the Center for Astrophysics,
Harvard & Smithsonian, in Asteroids.
" Space is too noble an enterprise to connect
with filthy lucre. " That's changing,
and fast, Elvis says in this provocative
look at the future of asteroid mining
and other space industries. In recent
years, myriad start-ups have arisen that
aim to make a profit beyond Earth.
That's a good thing, Elvis argues.
With market forces in play, space
technologies will improve, and costs to
go into orbit and beyond should come
down significantly. This will reap benefits
in all three areas Elvis focuses on
in this book: love, fear, and greed - his
shorthand for science, planet protection,
and commercialism.
Love. Asteroids can teach us about
the origins of our solar system and even
of life itself. Could they have brought
the water that life as we know it
requires? Ceres, the dwarf planet, might
be 30% water by mass. If none of that
water was lost to space during a collision
with our world, Elvis notes, only
about five Ceres-like bodies crashing
into us would have filled our oceans.
These small, rocky bodies might also
have introduced the organic molecules
our organisms need. The Murchison
meteorite, which fell in Australia in
1969, is so rich in organics that a newly
cut slice of it smells like asphalt or tar,
Elvis says. Did the organics in such bodies
season the " stone soup " within early
oceans that enabled life to develop?
Astrobiologists Christopher Chyba and
Carl Sagan suggested this idea in a 1992
Nature paper and, Elvis says, " it's still
looking like a good bet. "
Fear. Most astronomers agree it's
only a matter of time before a rock akin
in size to the one that wiped out the
non-avian dinosaurs 66 million years
ago threatens Earth. Will we be ready?
So far, we've located about 90% of the
biggest near-Earth objects,
but finding the final 10%
won't be easy, Elvis says.
They could be lurking
behind the Sun, in orbits
that only slowly bring them
toward our planet. If we do
detect a monster in time,
we might be able to change
its orbit - and have it miss
us - using one of four
methods under consideration,
what Elvis calls hammers,
nukes, tractors, and billiards.
Greed. Commercial space pursuits
could help us on both the love and fear
fronts, Elvis asserts. He delves deepest
into asteroid mining. The resources are
staggering: The iron content alone of
the main-belt asteroids exceeds iron
reserves down here by more than 10
million times. Their water is equally
valuable. To lift a 1-kg liter of water
from Earth's surface into low orbit costs
about $20,000, he says. Depending
on how much H2O is needed in space,
getting it from asteroids could prove far
more economical. A chief use would be
for rocket fuel; another is life support
( " something astronauts are quite keen
on, " Elvis notes wryly).
In 2013, Elvis estimated the number
of precious-metal, ore-bearing asteroids
we know of at 10. Within a decade, he
says, that number could reach a couple
thousand. Each one of them could be
worth $1 billion or more.
Whether anyone can actually make
a profit off such activities remains
unknown. But one thing's certain, Elvis
says: Once a single profitable asteroidmining
venture succeeds, it will trigger
an " asteroid rush, " with all the legal
and other complexities that entails.
Other commercial enterprises in
space are progressing faster. Megaconstellation-building
and
space tourism are well
under way, and for-profit
space labs are in the offing.
One company hopes to use
microgravity to 3D-print
living human organs to ease
transplant needs. Others
might create a special type
of glass in orbit that Elvis
says could be 100 times
better for optical fibers now
used for high-data-rate
internet connections across oceans.
Elvis does pause to consider the
ethical implications of space industry.
A future base on the Moon's nearside
might be so brightly lit that we could
see it from Earth. " Is that inspiring? "
Elvis asks. " Or is it sacrilege? " He wonders
whether we should set aside certain
exceptional locales, such as Mars's
Valles Marineris, as wilderness areas.
No one could possibly think of all
the ramifications of mining the asteroids
and other profit-making space
pursuits ahead of time, but Elvis makes
a valiant effort in this book. His humor
and insights, together with the fascinating
facts he constantly marshals, make
the many as-yet unanswerable questions
he leaves the reader with go down easy.
¢ PETER TYSON owns an asteroid. Well,
a piece of a meteorite, anyway - from
the Campo del Cielo iron bolide that fell
in Argentina about 4,500 years ago.
sk yand tele scope .o r g * JUNE 2022 57
http://www.skyandtelescope.com
Sky & Telescope - June 2022

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