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Another way to pose the problem is, what
would a viable, economic space program look like at the end of
the 21st century?
The British have acquired a taste for the
recent style of space opera - note Ian M. Banks' series, Ken
Macleod, Colin Greenland's Take Back Plenty,
Peter Hamilton's popular mega-scale space operas, and more
recently Alastair Reynolds and Charles Stross - all working with
futures fragrant of gargantuan techno-sizzle. Interestingly,
all these authors and futures are somewhat vaguely socialist.
In this they contrast with the sober, often nostalgic near-future
looks at the spaced program by Stephen Baxter, notably Titan.
A greatly expanded economy will surely
be necessary to afford the vast space resources beloved of epic
drama. Real-world moderate, welfare-state socialism, as seen
in Europe, can afford no grand space operas. Europe has no manned
space program at all. The investment for economic benefit is
too steep - hundreds of billions just to set up a single solar
power satellite in near-Earth orbit, for example. The second
such satellite would cost far less, of course, since the infrastructure
would be done - but that first step is a killer.
Unless one envisions a society with limitless
wealth (say, by matter duplication using the transporter, that
Star Trek staple), there will always be limits. And the sad lesson
of most advanced societies is that they get fat and lazy. Both
anarchist and libertarian societies may avoid this, because they
aren't top-down socialist. But nobody knows that, because they
haven't been tried.
In these operatic futures the classic criticism
of left-socialist economics has gone unanswered: that markets
provide far greater information flow than do top-down, directed
economic systems. Through prices, each stage from raw materials
to finished product has an added cost attached, as an increased
price to the next step. This moves economic information through
great distances and over time, which feeds back to the earlier
stages, all working toward higher efficiency. Classical socialism
ends up starved for feedback. Committees or commissars are not
enough to replace the ever-running detail of prices.
Politics does not offer simple maps, but
one should distinguish between the Banks/Reynolds/Stross pole
and the Macleod pole. The BRS pole seems Libertarian/anarchist,
and by Libertarianism I mean anarchism with a police force and
a respect for contract law. Macleod is the closest thing to a
true classical socialist, as in The Stone Canal.
But even Macleod is all over the board. Though socialism was
his earliest fancy, he experiments with multiple social structures.
In later works he espouses variants of libertarianism and anarchism,
and even occasional capitalism.
The BRS pole is very muscular, quite capable
of militarism and imperialism when necessary (consider Banks's
Use of Weapons). Socialism isn't just cradle-to-grave
security here. Contracts count for a lot (Reynolds' Revelation
Space), and mild anarchism is often the preferred social
structure of the major protagonists. In Charles Stross's Singularity
Sky the aliens are capitalists who value everything
in trade in terms of its information content, a breath of hip
economics.
The whiff of welfare socialism in these
novels contrasts with the bright, energetic atmosphere. This
calls into question whether advanced socialist societies could
plausibly support grandiose space-operatic futures.
In some ways, popular socialist thinking
parallels Creationism. Unable to imagine how order and increasing
complexity can arise from unseen competitive mechanisms, socialists
fall into the belief that advanced societies must come from top-down
direction - often, in practice, from a sole master thinker, the
Chairman-for-life so common in totalitarian states. In politics,
everybody is entitled to their own opinion. But everybody is
not entitled to their own facts - especially not in economics.
In SF, economic dodges began well before
Star Trek's moneyless economy. Idealists have
always hated mere money. It seems so, well, crass. Still,
with no medium of exchange, there is no way to allocate scarce
resources, so inevitably politics and brute force dictate outcomes.
Typically in such regimes, one can still
amass wealth, just by owning things. To avoid state controls
and taxes, barter returns - presto, we're back in the Middle
Ages.
Money isn't the object of people's lives,
it's just how we keep score. Money measures economic matters.
Without it, we can't see what works and what doesn't.
Few in SF ever go beyond this simple truth.
Certainly Trek seems oblivious to it.
Granted, there are still too many future
societies where one doesn't even get to see how the plumbing
works, let alone the economy. However odd the future will be,
it surely won't be a repeat; economics evolves. The leftish space
operas of recent years have plenty of quantum computers and big,
Doc Smith-style planet-smashing weaponry, but the hard bits of
real economics they swerve around. Maybe because they haven't
any real answers, or aren't interested. Opera isn't realism.
Though New Wave SF had a leftist tinge,
it had no real political/economic agenda. The common association
of hard SF with libertarian ideas, on the other hand, may have
sprung from a root world view. Science values the primacy of
the individual mind, which can do an experiment (thought experiments,
as with Einstein, or real ones) to check any prevailing theory.
This heroic model lies deep in Western
culture. Individual truth and a respect for facts is the fulcrum
of libertarian theory. Of course, anarchist societies (not socialist),
as in Ursula LeGuin's The Dispossessed, can
depict the struggle of the lone physicist against the collective,
received wisdom. But The
Dispossessed's logic is not about economics
- it is a deeply felt story about a single man's sacrifice and
discovery. The social satires of Pohl and Kornbluth have more
bite, and probably more useful truth for today. The Space
Merchants by its title foretells much we may learn from.
I speak first of economics because it is
something of a science, with its own Nobel Prize, and it influences
the science of space - real space, not the SF operas - quite
crucially. In the end, the accountants want to know who is going
to pay for all this, and why.
What possible economic motive could a space-faring
society have?
Mining the Sky
Motives answer needs.
Within a century we are going to start
running out of two essentials: metals and energy. Within about
50 years most of our oil reserves will be gone--farewell, SUVs!
The Middle East will cease to be a crucial tinderbox, simply
because countries there will be poor and doomed. Most policy
makers know this but seldom speak of it in public--half a century
is unimaginably long for a politician.
I will deal with the vast problems of energy
supply in my next column. Less well recognized is that many metal
ore deposits in the crust of the earth will be mined out within
a century. Of course, substitute materials can be and have been
found. But some are crucial and to substitute something else
changes the world for the worse.
My favorite example of this is oysters.
In Dickens novels you can read of poor people forced to eat oysters,
then a cheap, easily found, but somewhat lower class food, while
the rich ate beef Wellington. Now we gobble down McDonald's burgers
and oysters are a fancy appetizer. Sure, we're well fed - but
I prefer oysters, which as a boy I ate for breakfast in my fisherman
family, little appreciating my luxury.
Technology can help us greatly in the uplifting
of humanity--the great task confronting us. A century ago, aluminum
was a rare metal more costly than silver; now we toss it away
in soft drink cans - then recycle it. But inevitably the poor
nations' growing demand will overburden our demand on the Earth's
crust and we will surely run short of the simplest metals, even
iron.
As it turns out, both metals and energy
are available in space in quantities that we will desperately
need.
We also need a clean environment. Mining
for metals comes second to fossil fuel extraction in its environmental
polluting impact. Coal slag is the #1 water pollutant in the
U.S., with runoff from iron mines the second.
Detailed analysis shows that metals brought
from the asteroids will be competitive with dwindling Earthly
supplies. Better, by refining them in space, we prevent pollution,
particularly of another scarce resource - water.
There is money to be made in that sky.
An ordinary metal-rich asteroid a kilometer in diameter has high-quality
nickel, cobalt, platinum and iron. The platinum-group metals
alone would be worth $150 billion on Earth at present prices.
Separating out these metals takes simple chemistry done every
day in Earthly refineries, using carbon and oxygen compounds
for the processing steps. Such an asteroid has plenty carbon
and oxygen, so the refining could be done while we slowly tug
it toward a very high Earth orbit--a task taking decades.
Steam Rockets
Crucial in all this is the shipping cost,
so attention focuses on how to move big masses through the deep
sky.
Certainly not with chemical rockets, which
have nearly outlived their role in deep space.
Liquid hydrogen and oxygen meet in the
reaction chambers of our big rockets, expelling steam at about
4.1 km/sec speeds. That is the best chemical rockets can do,
yet to get to low Earth orbit demands a velocity change of about
9 km/sec - over twice what the best rockets can provide without
paying the price of hauling lots of added fuel to high altitude,
before burning it. This means a 100-ton launch vehicle will deliver
only about 8 tons to orbit - the rest goes to fuel and superstructure.
Moving around the inner solar system, which
takes a total velocity change of 20 or 30 km/sec, is thus a very
big deal. Current systems can throw only a few percent of their
total mass from ground to Mars, for example. Big velocity changes
("delta-V" in NASAspeak) of large masses lies far beyond
any chemical method. To get from Earth to the biggest asteroid,
Ceres, takes a delta-V of 18.6 km/sec, which means the payload
would comprise only halfof one percent of the vehicle mass.
Using chemical rockets to carry people
or cargo anywhere in deep space was like the Europeans discovering
and exploring North America using birch bark canoes--theoretically
possible, but after all, the Indians did not try it in reverse,
for good reason.
For thirty years NASA ignored the technology
that can answer these challenges. In the late 1960s both the
US and the USSR developed and ran nuclear rockets for hundreds
of hours. These achieved double the exhaust velocity of the best
chemical rockets, in the 9 km/sec range. These rockets pump ultra-cold
liquid hydrogen past an array of ceramic plates, all glowing
hot from the decay of radioactive fuel embedded within. The plume
does not carry significant radioactivity.
Those early programs were shut down by
nuclear-limiting treaties, appropriate for the Cold War but now
out of date. We will need that technology to venture further
into space. NASA has gingerly begun building more of the nuclear-electrical
generators they ran many missions with, including the Voyagers
(still running after over a quarter of a century, and twice as
far away as is Pluto) and the Viking landers on Mars. These are
simple devices powered by the decay of two pounds of plutonium
dioxide, yielding 250 Watts of heat. Indeed, simply heating spacecraft
in the chill of space is the everyday use for small radioactive
pellets, which were embedded into every spacecraft headed outward
from Earth orbit.
Even this tentative step back to the past
seems to acutely embarrass NASA. They elaborately describe how
safe the technologies are, because we live in a Chicken Little
age, spooked by tiny risks.
Far bigger accidents have already happened.
Four large nuclear reactors have fallen from orbit, none has
caused any distribution of radioactive debris. In fact, a Soviet
reactor plunged into the Canadian woods and emitted so little
radioactivity we could never find it. Embedded in tough ceramic
nuggets, the plutonium cannot be powdered and inhaled. 
Beyond this return to our past capabilities,
NASA is considering building a nuclear-driven ion rocket. This
will yield exhaust velocities (jetting pure hydrogen) of 250
km/s - a great improvement. But the total thrust of these is
small, suitable only for long missions and light payloads.
Using hydrogen as fuel maximizes exhaust
velocity (for a given temperature, lighter molecules move faster).
And we can get hydrogen from water, wherever it can be found.
We've discovered from our Mars orbiters that Mars has plenty
of ice within meters of the surface. Comets, the Jovian ice moons
- all are potential refueling stations.
But holding hydrogen at liquid temperatures
demands heavy technology and careful handling. Water is easier
to pump, but provides only a third the exhaust velocity. Many
believe that ease of handling will drive our expansion into space
to use water, not more exotic fuels.
Living Off the Land
What could our space program be like right
now, if we hadn't shut down the nuclear program? The road not
taken could already have led us to the planets.
The key to the solar system may well be
nuclear rockets - nukes to friend and foe alike. The
very idea of them had of course suffered decades of oblivion,
from the early 1970s until the early days of the 21st Century.
Uranium and plutonium carry over ten thousand times as much energy
per gram than do chemical rockets, such as liquid hydrogen burning
liquid oxygen.
So in the end, advanced rockets may well
be steam rockets, all the way from the launch pad to Pluto. Chemical
boosters can get a nuke rocket into orbit, where it turns on.
Whether with liquid hydrogen married to liquid oxygen, or with
water passing by slabs of hot plutonium, they all flash into
plumes of steam.
Real space commerce demands high energy
efficiency. Realization of this returned to NASA in 2002, with
the hesitant first steps of its nuclear Project Prometheus (bureaucracy
loves resplendent names).
The first rush of heavy Mars exploration
will probably prove the essential principle: refuel at the destination.
Live off the land. Don't haul reaction mass with you. Nuclear
rockets are far easier to refuel because they need only water
- easy to pump, and easy to find, if you pick the right destination.
Nearly all the inner solar system is dry as a bone, or drier.
If ordinary sidewalk concrete were on the moon, it would be mined
for its water, because everything around it would be far drier.
Mars is another story. It bears out the
general rule that the lighter elements were blown outward by
the radiation pressure of the early, hot sun, soon after its
birth. This dried the worlds forming nearby, and wettened those
further out - principally the gas giants, whose thick atmospheres
churn with ices and gases. Mars has recently proved to be wet
beneath its ultraviolet-blasted surface. Without much atmosphere,
its crust has been sucked dry by the near-vacuum. Beneath the
crust are thick slabs of ice, and at the poles lie snow and even
glaciers. So explorers there could readily refuel by melting
the buried ice and pumping it into their tanks.
The moons of Jupiter and the other gas
giants are similar gas stations, though they orbit far down into
the gravitational well of those massive worlds, requiring big
delta-V to reach. Pluto, though, is a surprisingly easy mission
destination. Small, deeply cold, with a large ice moon like a
younger twin, it is far away but reachable with a smaller delta-V..
Of course, there are more sophisticated
ways to use water. One could run electricity through it and break
off the oxygen, saving it to breathe, and then chill the hydrogen
into liquid fuel. That would be the most efficient fuel of all
for a nuclear rocket.
But the equipment to keep hydrogen liquefied
is bulky and prone to error - imagine the problems of pumps that
have to operate in deep space at 200 degrees below zero, over
periods of years. An easier method would be to use that hydrogen
to combine with the Martian atmosphere, which is mostly CO2, carbon dioxide.
Together they make oxygen and methane, CH4, both easy to store.
Burn them together in a nozzle gives a fairly high efficiency
chemical rocket. A utility reactor on Mars could provide the
substantial power needed for this.
Still, that would demand an infrastructure
at both ends of the route. Genuine exploration - say, a mission
to explore the deep oceans of Europa, Jupiter's moon - would
need to carry a large nuclear reactor for propulsion and power,
gathering its reaction mass from the icy worlds.
NASA is studying an expedition to Europa
using a nuclear-driven ion rocket, which would carry its own
fuel. It will have to fire steadily for seven years
to get to Europa, land and begin sending out rovers. Testing
the reliability of such a long-lived propulsion scheme demands
decades of work, effectively putting off the mission until the
2020s.
Far better would be a true nuclear fission
rocket throwing hot gas out the back. If it could melt surface
ice on Europa and tank up with water, it could then fly samples
back to us.
The true use of a big nuclear reactor opens
far more ambitious missions. The real job of studying that deep
ocean is boring through the ice layer, which is quite possibly
miles thick, and maybe even hundreds of miles. No conceivable
drill could do it. But simple hot water could, if piped down
and kept running, slowly opening a bore hole. Hot water has been
tried in Antarctica and it works.
To test for life on Europa would demand
that we send a deep-sea style submarine into those dark, chilly
waters. To power it we could play out a thick, tough power cord,
just as do the undersea robot explorers that now nose about in
the hulks of the Titanic and the Bismarck.
Only nuclear can provide such vast powers in space.
Dreadnoughts of Space
This leads to a future using big
nukes. The payload would be a pod sitting atop a big fuel tank,
which in turn would feed into the reactor. Of course, for manned
flights the parts have to line up that way, because the water
in the tank shields the crew from the reactor and from the plasma
plume in the magnetic nozzle. To even see the plume, and diagnose
it, they will need a rearview mirror floating out to the side.
The whole stack will run most of its trajectory in zero gee,
when the rocket is off and the reactor provides onboard power.
A top thick disk would spin to create centrifugal
gravity, so the crew could choose what fractional gee they would
wish to live in. Perhaps forty meters in diameter, looking like
an angel food cake, it would spin lazily around. The outer walls
would be meter-thick and filled with water for radiation shielding.
Nobody could eyeball the outside except through electronic feeds.
Plausible early designs envision a ship
a hundred meters long, riding a blue-white flare that stretches
back ten kilometers before fraying into steamy streamers. Plasma
fumes and blares along the exhaust length, ions and electrons
finding each other at last and reuniting into atoms, spitting
out a harsh glare. This blue pencil points dead astern, so bright
that, leaving Earth orbit, it could be seen from the ground by
naked eye it.
Ordinary fission nuclear power plants are
quite good at generating electrical power but they are starved
for the neutrons that slam into nuclei and break them down. That
is why power reactors are regulated by pulling carbon rods in
and out of the "pile" of fissionable elements - the
carbon can absorb neutrons, cooling the whole ensemble and preventing
overheating.
The next big revolution in nukes would
then come with the invention of practical thermonuclear fusion
machines.
Fusion slams light nuclei like hydrogen
or helium together, also yielding energy, as in the hydrogen
bomb. Unlike fission, fusion is rich in hot particles but has
trouble making much energy.
Most spaceflight engineers have paid little
attention to fusion, believing - as the skeptics have said for
half a century - that controlled fusion power plants lie twenty
years ahead, and always will. Fusion has to hold hot plasma in
magnetic bottles, because ordinary materials cannot take the
punishment. The most successful bottle is a magnetic donut, most
prominently the Russian-inspired Tokomak.
To make it into a rocket, let the doughnut
collapse. Fusion rockets are the opposite of fusion electric
power planets - they work by letting confinement fail. Ions fly
out. Repeat, by building the doughnut and starting the reaction
again.
The rocket engine core is this come-and-go
doughnut, holding the plasma, then letting it escape down a magnetic
gullet that shapes the plasma into a jet out the back. Rather
than straining to confine the fusing, burning plasma, as our
so-far-unsuccessful power plant designs do, a rocket could just
relax the magnetic bottle.
So these fusion nukes are a wholly different
sort of vehicle. They can promise far higher exhaust velocities
than the fission nukes.
Leaving high Earth orbit, such ships will
not ignite their fusion drives until they are well outside the
Van Allen belts, the magnetic zones where particles are trapped--or
otherwise the spray of plasma would short out innumerable communications
and scientific satellites ringing the Earth. (This actually happened
in 1962, when the USA Project Starfish set off a hydrogen bomb
in the Van Allen belts. People have trouble believing anybody
ever did this, but those were different days, indeed. The ions
and electrons built up charge on our communications satellites,
most of which belonged to the Department of Defense, and electrically
shorted them out. Presto, billions of dollars lost in surveillance
satellites gone dead within the first hour. A colossal embarrassment,
never repeated.)
The Long Prospect
So will we have a space operatic future?
If that means huge spacecraft driven by spectacular engines,
maybe so. Interstellar flight lies beyond the technologically
foreseeable, alas.
But the rest of the space opera agenda
depends on your political prognostications. Will Ian Banks anarchist/socialist
empire arise from remorseless economic forces? Or perhaps Robert
Heinlein's libertarian frontier?
Humanity's current dilemma is exploding
populations amid, and versus, environmental decay and
dwindling resources. Of course we've dodged most of the bullets,
thanks to the engineers and scientists. But we cannot count on
them forever to solve our social problems.
Rick Tumlinson, a leading space advocate,
put it this way:
Ultimately, nearly anything you want to
do in a "sustainable" world will be something someone
else cannot do - and that will mean limits. Limits to when and
where and how you travel, how much you consume, the size of your
home, the foods you eat, the job where you work, even how long
you are allowed to live… Yet Earth's population continues
to grow.
Quite Heinleinesque. Robert Zubrin, an
eloquent exponent of space as the last and greatest frontier,
puts it eloquently:
We see around us now an ever more apparent
loss of vigor of American society: increasing fixity of the power
structure and bureaucratization of all levels of society; impotence
of political institutions to carry off great projects; the cancerous
proliferation of regulations affecting all aspects of public,
private and commercial life; the spread of irrationalism; the
balkanization of popular culture; the loss of willingness by
individuals to take risks, to fend or think for themselves; economic
stagnation and decline; the deceleration of the rate of technological
innovation and a loss of belief in the idea of progress itself.
Everywhere you look, the writing is on the wall.
This is a neat way to summarize the agenda
of an entire culture: the space frontier revolutionaries. They
tend to be Heinleiner-style libertarians. It galls them that
the future of space still lies in government hands.
I've been talking about the nuts and bolts
of moving large masses around the solar system, for exploration
or economics. But the ultimate agenda is one that has lain at
the core of our society for centuries: the promise that expanding
spatial horizons in turn opens those enlightening horizons of
the mind that have made the modern age.
Many concepts will fail, and staying the
course will require leadership.
Consider how John F. Kennedy voiced the
goals of the Apollo program:
We choose to go to the Moon in this decade,
and to do the other things, not because they are easy, but because
they are hard. Because that goal will serve to organize and measure
the best of our energies and skills. |
