During my adolescent years, some of the most fascinating
books I read were what were then referred to as the “Heinlein Juveniles”. These were imaginative “space operas” written
by Robert Heinlein with such a solid underpinning of real science to them that
the young reader would not only get excited about the possibilities of space
exploration, but also pick up some of the fascinating science associated with
space flight. They inspired many of my
generation to dream of adventures in space while contemplating the interesting
science behind it, and also led many of us to pursue careers in science and
engineering.
Nowadays, novels for that age group are known as “Young
Adult” fiction. It has been my hope to
find some modern day novels that might inspire the current generation of youth, then recommend any worthy books to parents
and teachers. Specifically I am looking
for books with a sound scientific basis that will also excite young people
similar to the way the above mentioned Heinlein books did for people of my
generation. Indeed, I have encountered
some really good recent science fiction yarns for young people. James Patterson’s Maximum Ride series comes to mind, as well as Harry Turtledove’s Crosstime Traffic series. Other books of more mass appeal such as the Hunger Games series are really good and
thought provoking science fiction stories, but no books of the grand space
opera variety were evident in my searches.
Enter Homer Hickam’s new young adult novel Crater. Many of you may recognize Homer as the author
of the inspirational autobiographical book The
Rocket Boys. The
Rocket Boys was the basis for a
popular movie in the late 1990s known as October
Sky. In fact, I would recommend both
the book and the movie to readers and movie watchers of all ages. I will never forget the reaction of my mother
to seeing a trailer for October Sky
on TV. That promotional footage showed
boys launching their homemade rockets and also contained a heated argument about
space between the young protagonist and his father. Such scenes were witnessed in real life by my
mother decades before, prompting her to ask me, “Did someone make a movie about
your life?”
But back to Crater. I won’t write enough detail to spoil reading
it for anyone. The story takes place on
the future colonized Moon. Our heroes
are an orphaned teenage boy named Crater Trueblood and Maria, who is the slightly
younger granddaughter of a powerful owner of a helium 3 mine. They undertake a long journey on an important
mission that involves travelling across the inhospitable lunar surface. Crater must avoid enslavement by outcast genetically
modified misfits, while also escaping death at the hands of very malevolent and
grotesque cyborg commandoes who are intent on making sure our young heroes
never reach their destination. I will
only tell you this much more: two of my favorite characters are Gillie who is kind of an intelligent
iPhone made of living organic goo, and Pegasus
– a real live horse who Crater finds in the lunar wastelands. For those who find the latter character as
incredulous as I did at first, Hickam presents Pegasus’ existence in at least a
passably realistic and scientifically plausible way.
I thoroughly enjoyed the book. It contained high adventure peppered with
cool scientific principles, such as: solving the world’s energy problems by
mining the Moon’s massive quantities of helium 3 and shipping it back to Earth
for use in nonpolluting fusion reactors that produce enormous amounts of
electricity from just small amounts of helium 3. There are also spacecraft which follow
“cycler” orbits that minimize the fuel and expense required for deep space
flight. I could list more.
OK now, I get to the uncomfortable part. Though most of the science in the book is
very sound, I found some scientific inaccuracies that prompted me to contact
Homer to see if he would object to my publishing a review that would include their
mention. After reading my short list of
scientific flaws, he graciously informed me that he had no problem with my
covering them. So here goes …
1) On
pages 29-30, the beginnings of Earth rise from the vicinity of the Apennine
Valley is mentioned. As is typical of
locations on the near side of the Moon, the Earth would never rise nor set, but
essentially maintain a relatively fixed position in the sky that would only
vary a little from stationary (this wobbling effect is called lunar libration) because of the
Moon’s elliptical or oval shaped orbit.
The only times the Apollo astronauts saw Earth rise was when they were
in orbit around the moon, since it was their orbital motion that caused the
Moon to rise and set. There is one thin
strip on the Moon where rising and setting of Earth could occur and that is at
the extreme edges of the lunar hemisphere visible from Earth where libration
would occasionally cause the Earth to rise a little above the horizon and then
shortly thereafter set where it rose.
2) On
page 245-246, the heroes travel up to an altitude of 60 miles on a space
elevator extending up from the lunar surface and once that height had been
achieved, they were in a condition of microgravity. The only way microgravity conditions can
exist at that altitude above the lunar surface would be for objects travelling
at the orbital speed for that altitude.
The part of the elevator at 60 miles high would not be travelling at
orbital speed. In fact the weight of
objects in the elevator at that altitude would be (by my calculations) about
93% of what it would be on the lunar surface.
3) The
most viable place for a shuttle to rendezvous with a space elevator is at the
lunar equivalent of geosynchronous orbit (that is, selenosynchronous orbit) and
that is also the place where microgravity conditions exist. Of course, the elevator’s counterweight would
be even farther out. The shuttle craft
(that was to take our heroes to the cycler ship Elon Musk) would not have been docking at 60 miles altitude because
the part of the elevator at that altitude would be far below orbital
speed. Going at the elevator’s low lateral
speed at that altitude, the ship would drop like the proverbial rock. The only way a shuttle could pick people up from
an elevator at that altitude would be for it to do a rocket powered landing on
a platform attached to the elevator, then take off under rocket power.
4) On
page 289, it is stated when Crater extracts water from the lunar soil, “water …
filled the resulting hole. Before the
pool could evaporate, Crater used a hand pump to fill a collapsible container
…”. Liquefied water exposed to high
vacuum evaporates vigorously fast (almost explosively). It would dissipate as fast as it formed. As a teenager I experimentally exposed a cup
of water to vacuum and saw this happen first hand.
I might also add that there are a few references to centrifugal force that should properly be termed
centrifugal effect. This is the apparent pseudo-force that seems
to pull outward on a massive object moving in a circle that is held in its path
by an inward pulling true centripetal force.
Instead of being a true force, centrifugal effect is merely a side
effect of the object trying to travel in a straight line which the centripetal
force does not permit. For instance, if
someone in a circular rotating space station “drops” a ball, it appears to fall to the floor in a
slightly curved path and seems to be
pulled down toward the floor by a force causing the ball to flee in an opposite
direction from the center of the station.
That appearance of being
pulled away from a center is the very source of the term centrifugal, from the Latin words “centrum” for center and “fugit”
meaning “to flee” or “run away from”, as opposed to centripetal with “petal” derived from ”petus” meaning “seeking”;
thus, a centripetal force tries to pull things toward the center of a circle.
However, someone standing outside the space
station (assuming the station has transparent walls) will see that the apparently falling ball is really
traveling in a straight line path that is tangent
to the circular surface of the space station (due to the ball’s inertia because
of Newton’s first law of motion) until the ball hits the floor; whereupon, it
takes on the circular motion of the floor of the space station but appears to be sitting still to someone standing
inside of the rotating space station. The
ball will appear to have weight seemingly because it is being pressed against
the floor by a centrifugal force, but in reality it is just the ball’s inertia trying to move it in a straight line in
a direction that is tangent to the rotating motion of the station. Thus, it is actually being held in place by
the true centripetal force imparted by the structural strength of the space
station’s “floor”. In short, there is no such thing as centrifugal force; instead, what we call centrifugal force is just an observed effect caused by the centripetal force.
I heartily recommend Crater,
regardless of those few objections. Judging from its subtitle, "a helium 3 novel", it appears that Crater may possibly be a first novel in the "helium 3" series of books and thus could offer readers something to anticipate as far as future adventures for Crater and Maria. Regardless, Crater
was a fun tale in which the main characters seemed real enough to care
about with a plot of high interest to keep my attention until the
end. Give it to a young person in your
life who likes a good read.
