The Linear Fallacy

The hazards of prediction are many - particularly, as Yogi Berra observed, about the future. One such hazard is tropes such as monorails that even the full Rasputin treatment won't kill. But another, and my closing theme for this year, is the impulse to project current trends into the future.

When the above image of a midfuture New York City was imagined - presumably in 1899, though possibly 1900


Update ...

Blogger glitched badly and ate most of this post! I'll try to recover it, but it may be gone along with 2010 ....

Update II ...

A (considerably revised) version of the lost post is now up as the first post of 2011.

Transport Nexus III: I Brought My Heart to San Francisco

Truth to be told, in all but the narrowest technical sense (driving the car) she brought me; it was my wife Paula's inspiration and effort that got us here. In any case the move and settling-in process account for the lack of posts here in the last couple of weeks, but now RM is up and running again.

In itself all this has nothing at all to do with space travel, but it does inspire some further thoughts about space stations. Recent discussion threads have included noteworthy heresies on this point.

In the traditional understanding that we all grew up on, an orbital station had two primary functions. One was to serve as a center for orbital operations such as communications, weather observation, and so forth; the other was to serve as a transport nexus, the meeting point between shuttles coming up from the surface and deep space craft arriving from other worlds.

Time and technology spoiled the first of these. All the observation and communications relay functions that Clarke and Heinlein expected space stations to perform are instead done by a host of satellites, and no crews are needed to change burned-out vacuum tubes.

The comment thread heretics challenged the second function as well. For a long time to come, spacecraft (or the modules that make them up) will be built and serviced on the ground, where the industrial infrastructure is. Work on orbit will be limited to final assembly, requiring no large staff of orbital workers. Deep space ships may well arrive and depart from individual parking orbits, with no need and no advantage to matching orbits with a big fixed orbital facility.

Space stations, in short, may have become obsolete before any had been built. The ISS, so far as I can tell, serves exactly none of the traditional functions of a space station. For practical purposes it is not a space station at all but a sort of training ship for future deep space missions.


Being obsolete is, in a surprising number of cases, no bar to success. San Francisco was technologically obsolescent from the very beginning of its history as a major city.

From a pre-industrial perspective it is the logical location for a seaport, a transhipment point between oceangoing ships and craft serving the vast inland waterway formed by San Francisco Bay and its outliers, which in turn provides access to rich agricultural regions: the wine country, Santa Clara (now Silicon) Valley, above all the Central Valley.

The railroad era - already well established by 1849 - changed all that, at any rate in principle. San Francisco, at the end of a rugged peninsula some 60 km long, is not a convenient rail terminus (except from the south). The original transcontinental railroad had its western terminus far inland at Sacramento, accessible to water transport; the line was later extended to Oakland, accessible to seagoing ships. And indeed Oakland eventually did supplant San Francisco as a seaport, though it took more than a hundred years, and the physical transformation of port facilities by the container revolution, to accomplish it.

What Oakland has not yet managed to supplant is Gertrude Stein, whose quip, "there's no there there," is practically her sole claim to fame. (Along with Alice B. Toklas brownies.)

San Francisco did not become a suburb of Oakland because of a combination of local circumstances and sheer inertia. Steamboats long remained more economical for regional transport around the Bay Area, and railroads were expensive to build so far from existing industrial centers. By the time these factors changed, San Francisco was already a major port, and network effects took over. It had infrastructure and port services, and the availability of these more than made up for the potential freight charge differential for east-west rail traffic.

Even when the port finally declined a broader network effect continued. In the current era San Francisco is, functionally, the downtown core of the Bay Area metropolitan region, accounting for about a tenth of the regional population but a much larger proportion of metropolitan services. These services to and beyond the region have only an incidental connection its original function as a seaport.


Unfortunately for space stations, the particular circumstances that allowed San Francisco to grow as a port even in the railroad era do not seem to apply in space. On the other hand, cities have always been defined less by their initial primary functions than by the secondary and tertiary services that they are uniquely suited to provide. If - for whatever reason - there are a large number of people in Earth's orbital space, they will probably aggregate in ways that allow them to have lunch together without having to undertake space missions just to get to a restaurant.

Where people go, cities will probably follow.



The image of San Francisco and environs was taken from the ISS.

The Unspecified Drive

Deep space propulsion is, unsurprisingly, a major concern of this blog. I regularly specify the performance of interplanetary craft fitted with some form of high specific impulse drive. Sometimes I describe it as a nuclear electric or solar electric drive, sometimes simply as electric, often not even that much. Sometimes, especially when discussion takes us to the wide open spaces beyond Jupiter, I allude to fusion.

Since I got myself in a bit of hot water, or some more exotic (and much hotter) coolant, by some snide remarks about fission power plants, a few comments on deep space propulsion are in order.

First of all it is not the main barrier to widespread interplanetary travel. That would be the sheer amount of costly design engineering needed to build a fleet of prototype spacecraft, followed by the cost of getting them all into space.

But once we are up there, how we get around is an important concern. The current limit to human space missions is about six months, beyond which the health consequences of prolonged microgravity become severe. Longer missions require a spin hab, adding cost and complexity. Even with spin habs, radiation and ordinary human factors limit practical mission duration to a couple of years or so.

Within these constraints we could reach Mars with chemfuel (and a spin hab), but the Hohmann round trip to the main asteroid belt is two and a half years, without any stay time at the destination, while to Jupiter and back is five and a half years. This is too long for regular human travel.

So for a human interplanetary presence we need fast orbits. These are above my math pay grade to calculate, but a klugewerks of flat space modeling, sketching orbits, interpolation, and sheer guesswork indicates that reaching Mars in three months or Jupiter in a year calls for a mission delta v in the range of about 30-100 km/s, and therefore some form of high specific impulse drive. Even NERVA style nuclear thermal rockets - the classic Atomic Rockets that gave the website its name - fall short of this requirement.

The time honored high specific impulse drive in science fiction is ion propulsion, used in real life to send the Dawn mission to Ceres and Vesta, but not suited to much larger human-carrying spacecraft. To a great many people, however, 'ion drive' is more or less synonymous with electric drive in general.

The most likely such drive for human missions appears to be some form of plasma jet. Unlike ion drive this is a thermal drive: The plasma has a meaningful temperature - and it is extremely hot. But the thrust chamber is a magnetic field, so it won't melt. Only the gizmos that produce the field are exposed, and they don't get up close and personal with the plasma. They and their supporting struts must have heat shielding, forming a 'lantern' structure.

(The strictly technical term for this drive is electrothermal magneto-plasma propulsion - doesn't that sound exactly like classic Trek technobabble? "I've engaged the electrothermal magneto-plasma thrusters, Keptain - she canna take much more!")

So far plasma drive has gone no further than the laboratory bench, but there don't seem (yet) to be any serious problems in scaling it up to be suitable to large spacecraft. Like many forms of electric drive it has no inherent exhaust velocity and therefore no fixed specific impulse. At least in principle these drives can be configured either to expel a relatively large flow of relatively (very relatively!) cool plasma at lower velocity, or a smaller quantity of hotter plasma at higher velocity.

The effect is very closely analogous to gearing; these drives can be set for a higher acceleration and lower specific impulse or vice versa. VASIMR is supposed to achieve this not only in principle but in engineering practice, permitting clever tweaking of engine settings to get the optimum performance in each phase of flight.

For all of its advantages, electric drive has one essential drawback. It does not produce its own energy, as chemfuels do, or even use a reactor directly to heat the propellant, as nuke thermal does. It must be plugged into an external electric power supply. This is seriously inconvenient, because it takes a lot of electric power, tens to hundreds of megawatts, to drive a big, human carrying ship even at milligee acceleration.

For travel in the inner system I am partial to solar electric power. It hums along quietly with little fuss and practically no moving parts. But the butterfly's wings must be enormous, a hectare for every few megawatts, and extremely light. Even milligee forces may be problematic when the wing structure is that big and that light. And solar electric fades rapidly with distance from the Sun, unsuitable for travel beyond Mars.

For the asteroid belt and Jupiter the practical alternative is nuclear electric drive, which was the cause of my original grump. All vivid if misleading imagery of clanking steam engines aside, nuclear power plants are heavy, filled with complex plumbing that must operate for months under fiercely hostile conditions, and produce two or three times their useful output in waste heat, which must be got rid of through large radiators with their own demanding plumbing.

That eerie green glow is produced by the disintegration of money.

There is an upside to all this downside: Ships with nuclear or solar electric drive have plenty of juice at the main switchboard, making these drives, especially nuke electric, well suited to laser stars. All you need is the laser installation; the power supply is already provided, and you can zap away as long as you want to hold down the trigger.

But the general messy inconvenience of carrying around a naval-equivalent fission power reactor accounts for much of the appeal of fusion. In principle, and popular imagination, fusion is an ideal power source for a plasma drive, because the fusion plasma and the thrust plasma can be one and the same. VASIMR in fact is a byproduct of fusion research; in a conceptual sense it is a derated fusion drive.

Fusion in practice could turn out to be another matter. What else is new? The easiest fusion reactions to sustain (and we can't yet fully sustain any of them) release most of their energy as neutrons, useless for propulsion, but - irony alert - suitable for heating a steam boiler.

On the other hand, fusion propulsion is in some respects simpler than fusion power for earthly energy needs. It does not need to be an economical means of producing electric power. In fact to serve as a drive it need not produce any electric power at all, though any fusion drive would likely produce some 'bleed' power.

There are alternatives to fusion, all about as speculative as fusion itself. Orion is arguably the least speculative of the bunch, though the organ music and black cape factor has pretty much overshadowed the actual technical challenges of building a spacecraft that must nuke itself thousands of times, at close range, in the course of normal operation. (Those have to be some badass shock absorbers!)

But on the whole the specific technical details of a high specific impulse drive matter surprisingly little. What matters is how heavy the thing is, relative to the thrust power it puts out. The benchmark here is is a specific power output of roughly 1 kW/kg, or a megawatt per ton, for the full drive installation including thrusters, power supply, and waste heat radiators. (For a complete drive bus add propellant tankage and keel structure; mate it all to a payload to get a ship.)

Example: Suppose a 100 MW, 100 ton VASIMR style drive engine. With exhaust velocity tuned to 75 km/s, specific impulse near 7500 seconds, propellant mass flow is 36 grams/second, producing about 2.7 kN of thrust, enough to push a 500 ton ship at just over a half a milligee, gradually increasing as propellant is burned off. If half the departure mass is propellant (250 tons, plus 100 tons for the drive, leaving 150 tons for tankage, structures, and payload), mission delta v is just over 50 km/s. Full power burn duration is about 80 days. This broadly corresponds to the requirement for a fast, three month orbit to Mars.

Tune the same drive to an exhaust velocity of 150 km/s, specific impulse near 15,000 seconds. Propellant mass flow falls to about 9 grams/second, producing 1.3 kN of thrust, pushing the ship at a quarter of a milligee. With the same mass proportions our ship has a mission delta v of just over 100 km/s and full power burn duration of 11 months, approximating a one year trip to Jupiter.

Improving on this performance will not be easy. To reduce travel time on semi-brachistochrone orbits with prolonged burns you must reach a higher peak speed in less time, and must therefore increase both thrust and specific impulse. In the flat space approximation, drive power increases as the inverse cube of travel time - that is, you need eight times the drive power output to cut travel time in half.

The good news, such as it is, is that this also works the other way. An early generation drive with a more modest 250 W/kg power output can still take a relatively fast orbit to Mars. But you pretty much need fusion drive, or an equivalent array of oscillating hands, to reach Jupiter in a few months, or for practical travel to the outer planets.

Still, the Solar System as far as Jupiter should be a decent sized playground for a while.



The image comes from a NASA publication on VASIMR.

Accelerando

Comments on our last exciting episode discussed, among many other thread drifts, the concept of an Accelerando, a speeding up of technological progress that is presumed, in many circles, to culminate in the Singularity. (See the comment thread, starting around #180.)


I will argue - and I've made this argument before - that the real Accelerando happened roughly a hundred years ago, say in the period from about 1880 to 1930.

The Industrial Revolution began a hundred years earlier, but most people in 1880, even in industrialized countries, still lived essentially postmedieval lives. (Cribbing from my own comment follows:) Railroads and steamships had transformed long distance travel, but on a day to day basis people walked, or if they were quite well off they used horses. They lived by the sun; the only artificial lighting was candles or oil lamps, the same as for centuries. A few large cities had gaslight; reputedly it made Paris the City of Lights.

By 1930, millions of people were living essentially modern lives. They drove cars to homes with electric lighting, talked on the phone, streamed entertainment content on the radio or played recorded media on the phonograph. To a person from the pre-industrial world a hand-crank telephone and an iPhone are equally magical; to a person from 1930 the iPhone is an nifty piece of 'midfuture' technology, not remotely magical. (Gee whiz, Tom, a wireless telephone with moving pictures! And it all fits in your pocket!)

Militarily a good part of the Accelerando played out in the course of World War I; people went in with cavalry and came out with tanks and aircraft. Commenter Tony handily expanded on this theme:

Murray and Millette made this point in their operational history of WWII, A War to be Won. They pointed out that a lieutenant in 1914 had little in common with the colonel that he himself had become by 1918. Yet that same colonel would have easily recognized the overall form, if not the detail, of war in the 1990s.

How do you measure an Accelerando? One handy benchmark is human travel speed. Here the Accelerando actually began a bit before the Industrial Revolution. Stagecoaches could maintain a steady speed of about 15-20 km/h by combining advanced carriage design with the infrastructure innovation of fresh horses for each stage. Ordinary travellers could thus maintain human running speed for hours.

The first steam locomotive ran in 1804. General purpose steam railroading began in 1825-30, and a locomotive appropriately called The Rocket reached 47 km/h in 1829. Rail speed data in the 19th century is amazingly sparse, but I would guess that locomotives exceeded 100 km/h by midcentury. The next doubling was reached in 1906 by a (steam!) racing car. The next doubling after that, to 400 km/h, was achieved in 1923 by an airplane.

Mach 1 was reached in 1947, and then of course things got wild. Yuri Gagarin reached orbital speed, a shade under 8 km/s, in 1961, an accelerando of 25x in 14 years, with another bump up to lunar insertion speed of 11 km/s in 1968.

Things have settled back a shade since then. Most of the 500+ human space travellers have piddled along at orbital speed, while since the retirement of Concorde the civil standard for long distance travel is high subsonic.

In this particular case the period 1880-1930 actually falls between stools - steam railroading was already pretty well developed by 1880, while aviation in 1930 was just starting to combine low drag airframes with high power engines.

Other technologies would give different results. Some, like computers, are still in the rapid transition phase of railroads around 1840 and airplanes around 1950. The overall Accelerando of the Industrial Revolution is a sort of weighted average of many individual and interrelated tech revolutions. And sometimes an older, mature-seeming tech gets a new power jolt, as has happened with railroad speed since the Japanese bullet trains of the 1960s.


Science fiction is the literary child of the Accelerando, and emerged as a distinct genre of Romance in just about the period 1880-1930. Jules Verne published From the Earth to the Moon in 1865; Hugo Gernsbach launched Amazing Stories in 1926.

In 1800 no one speculated about the world of 1900, because no one imagined it would be all that different from the world they already knew. And in 2000 there was only limited speculation about the world of 2100. Indeed the future has gone somewhat out of style, replaced in part by the enchantment of retro-futures.

The future has lost its magic not so much (if at all) because our technical progress has reached a 'decelerando,' but because we have learned to take technical progress for granted. It is a lot harder to get a Gee Whiz! reaction these days, a sort of psychological decelerando. As I've suggested in the last couple of posts, the challenge of interplanetary travel is not how to do it but why to spend the money.

(As a far more modest example of psychological discounting, where in this holiday retail season are the iPad rivals? Did Apple blow everyone else's tablet devices back to the drawing board, or has everyone else decided that tablets are a niche market they'll leave as an Apple playground? I haven't a clue.)

This is where I am supposed to wrap my arguments neatly in a bow, but I am not sure what the summation should be. So instead I will toss the question out for comments.



The image of a North American train c. 1900 comes from a public library site in Kansas.

Searching For McGuffinite

Humans will reach the planets in this century; at least there is a rather good chance that we will, without ever needing to be explicit about Step Two. The inherent coolness of space travel, along with national vanity and parochial economic interests, has turned out to be sufficient for half a century. There is no inherent reason why this should not remain the case into or through the midfuture, as our steadily growing capabilities carry us outward.

What this highly plausible space future does not have room for, however, is most of our favorite space tropes. Last post I made a comparison of space to Antarctica. The popular literature of polar exploration is tiny, and most of what there is deals with the early days. (Amundsen and Shackleton are the two names I remember off of hand.) Real space travel may turn out very similar. People will work very hard and spend a great deal of money to see to it that dramatic adventures do not happen in space.

Nor does the human scale of the thing lend itself to space opera. In the early interplanetary era - and, in all likelihood, for a long time after - there may be hundreds of people in space, but probably not thousands and certainly not millions. There will be a space economy, but no economy in space: the ships will be transports, not liners, and certainly not tramp freighters. (Sob!)

For story purposes this is not what we want. We want a lot of people in space. We want the outposts to grow into bases, then towns, then cities, and of course we mostly want them to end up fighting space battles with each other. For this we need a justification.

At least in 'Murrican science fiction, the profit motive is enshrined as probably necessary and certainly sufficient reason to go into space on whatever scale is desired. This attitude is not just confined to the libertarian-minded; Evil Megacorps in Space are a variation on the same theme. (I am not sure how it is elsewhere. Clarke's space midfuture, at least in his earlier stories, seemed not unlike the 'realistic' vision I portrayed above.)

The most popular profit motive has been mining. This is only natural. Mining fits the broad Western trope, and it does take people to the most Godforsaken places.

You have to make a few friendly assumptions to get space mining for terrestrial use to pan out (so to speak). But the subtler problem is then what? Suppose we learned that the rings of Saturn are full of McGuffinite. There is not going to be a rush of would-be Belters heading out to be Ringers instead.

Instead there will be some very big consortium formed, or a handful of them, probably with more than cozy relationships with existing national or para-national space agencies. A very focused program will develop the technology to do one thing: Go to the rings of Saturn, extract McGuffinite, and bring the stuff back to Earth. This effort will not go anywhere or do anything else. (With a limited but potentially important exception I'll get to below.) It will involve the necessary minimum number of humans in space, especially Saturn space; from every operational perspective the optimum is zero.

And once in place, beyond Earth orbit the mining operation may scarcely interact with other space activity. Mining transports headed for the Rings do not stop off at Mars or Titan. The experience of developing countries is that resource extraction infrastructure is not very helpful. The rail line runs from a seaport to the mine, and even the seaport is chosen for access to the mine, not its potential as a general trade entrepot.

Resource extraction is an economic monoculture, and like other monocultures it does not support a rich ecosystem.

The most popular political McGuffinite, a great power arms race, has a rather similar problem. As earlier discussions here have shown, great power warfare scenarios offer little role for space cruisers in whatever form. Only for laser stars that may well be robotic, and kinetic killer buses that will certainly be.

A somewhat different matter is resource extraction in space for use in space, such as the popular lunar shipbuilding industry. This is not McGuffinite, because it is not a reason to go into space. It is something you do only when you are already in space, and in a big way.

And of course there are other complications. Building spacecraft requires an enormous industrial base, and every pipe wrench has to come up from Earth unless you set up a pipe wrench factory or at least a fab. The lower energy cost of orbit lift from the Moon can evaporate quickly when you consider all the front end and operating costs.

It will be a long time before we have production industries in space.

An exception could be propellant, because space travel uses so much of it, and it is fairly simple stuff. Once we are regularly going somewhere with accessible volatiles, there will be consideration of obtaining propellant from them. This is not as simple as it is often made to sound. For example, all the ice on Mars is no use to deep space craft unless you lift it to Mars orbit, a major spacelift operation even if you can do it with a one stage vehicle. And there is no space infrastructure on Mars but what we take there.

I would say that the early interplanetary era ends on the day that a ship makes a routine burn in Earth orbital space using propellant that did not come from Earth.

Propellant production differs from McGuffinite mining in one crucial respect: It is inherently tied to the rest of the space infrastructure. And space travel is no longer entirely geocentric; for the first time, some of what happens in space stays in space.

Still a long ways from the Solar Confederation versus the Planetary Union, but everything has to start somewhere.

If I were working out a future history with a serious illusion of plausibility, I would stay away from McGuffinite. It is an ancient, overused crutch, and not a convincing one. Given worlds enough and time (and both are available), exports to Earth may well arise, as consequences rather than cause of space exploration. These may be - almost certainly will be - entirely unexpected and counterintuitive.

To quote myself, from last year's 'A Solar System For This Century':

Someone will find out that burgundy grapes grown in a Martian greenhouse have a distinct flavor. Pretty soon they are shipping back little airline size bottles that sell for $500, with just enough for a toast, and 'robustly Martian' ends up being used to describe burgundies from lands where Charles the Bold once ruled.

Unlike McGuffinite, Martian burgundy doesn't have to be globally profitable - paying back the cost of going to Mars in the first place, or even the cost of the transport system. It only needs to be locally and marginally profitable ('marginal' in the formal economic sense, not precarious). Those little bottles only need to pay for themselves, their contents, and the extra propellant to get them to Earth. Ivan Q(ing) Taxpayer already paid for the transport ships, though you'd never know it from the collected works of the wine industry council.

Multiply such serendipities and, gradually, the human space ecosystem grows more complex. Oenologists now have a place on Mars, bringing a body of specialized knowledge and also an outlook on life and civilization.

This sort of thing takes time, probably lots of it, because it cannot be planned, it can only evolve. It may not happen. Indeed it probably will not happen, even in a future of interplanetary travel, because space travel is inherently so difficult.

But it is the one most likely path to get you from Earth to space opera.



The imagined image of Cassini, as so often, comes from Atomic Rockets.

First Stage

We can already do, and have done, a great deal in space. We have scouted all the major planets, landed on the Moon, Venus, Mars, and Titan, and dropped among the clouds of Jupiter. We have passed through the heliopause into interstellar space.

The International Space Station has shown that crews can live and work aboard a spacecraft for years, with no emergency requiring evacuation to Earth or urgent support from Earth.

This is the primary requirement for human interplanetary travel. At a fundamental level, add a drive bus and you are good to go. Nor is any really major handwave needed for a solar or nuclear electric drive capable of reaching Mars in 2-4 months. (If Mars leaves you cold, adjust for the destination of your choice. It will probably be colder.)

All you need to wave is a check for $200 billion or so, to pay for developing your vehicle and mission from conceptual design to flight testing and human spaceflight certification.

Do not expect to get there for much less than that. The Airbus A-380 and Boeing 787 Dreamliner - commercial products of private industry, working in a mature kindred technology - each cost some $15 billion to develop. Such projects simply require an enormous amount of costly engineering work and one-off fabrication.

SpaceX and Scaled Composites do not prove otherwise. They prove only that the ecosystem has a place for small, agile skunkworks that can underpay top talent to work on exciting projects. Even technologies like 3-D printing won't really change the equation, because initial space costs are mainly engineering costs, and engineering at the cutting edge remains a craft trade.

But for a trillion US dollars or equivalent, give or take, you could probably build yourself a decent start on the classical rocketpunk midfuture: a second generation station with spin hab; outposts on Luna and Mars with ships to serve them; a human mission to Jupiter; altogether up to a few hundred people living in space. Call it the Clarke-Kubrick vision, though it could equally well be called the Ley-Bonestall vision.

The specifics are all freely subject to change. Commenters have challenged such rocketpunk-era verities as an orbital station as transfer point, and of course there are debates about where we should actually go and in what sequence. But this infrastructure, or something comparable, is the trillion dollar admission ticket to everything else.

A trillion dollars is a lot of money. More precisely it is a staggering, awesome, incomprehensible amount of money. It might end up being more than we are willing to spend on space travel in this or any century. But it is not impossible money. It is comparable to NASA's cumulative budget from its beginning to the present day, and about twice the cost of another public transportation system of similar age, the Interstate Highway System.

I am very doubtful that the private sector can or will take us into deep space on its own. But the largest corporations have revenue and market capitalizations of a few hundred billion dollars, so - given persuasive enough reason to believe that it would be profitable - it is not utterly out of bounds to imagine a global commercial consortium raising a trillion dollars.


The time scale of space is really, in large part, the money scale of space. If space spending in the later 20th century had remained at Apollo levels we might well have had the Clarke-Kubrick vision on schedule in 2001. At the levels of space spending and resulting space progress that we have seen over the last 35 years it is about in line with what we might expect for 2101.

It could as easily be 2071, or 2171. (Or never.) Given a sufficient (hand)wave of great power muscle flexing it might be 2031. But I will use 2101 as my conservatively optimistic benchmark. This presumes that we continue going into space in the same rather muddled, low-keyed, but persisting way we have since those heady early years.

So. At the start of the 22nd century, or broadly comparable date of your choice, we have regular interplanetary travel, but still very little of it, and what there is is very expensive.

Production jetliners, as I've often mentioned, cost about $1 million per ton at the factory ramp. But commercial jets can be sold for that price because Boeing and Airbus expect to build several hundred of them, spreading out the development cost and permitting semi-mass production efficiencies.

The first generation of interplanetary ships will be handbuilt prototypes. The second generation will still be largely handbuilt, though modular construction will begin to allow limited production runs of standard hab pods and the like. So a ship capable of carrying 10-20 people on an interplanetary mission, with departure mass of 1000 tons, dry mass 500 tons, gross payload 200 tons, might cost $5 billion assembled on orbit and ready for loading.

Adjust ticket prices accordingly. Suppose that your ship can make 10 round trips to Mars in a design service life of 25 years, so charge each round trip $500 million up front. Add another $500 million for 500 tons of propellant lifted from Earth - don't expect launch cost under $1 million/ton at the modest traffic volume of the early interplanetary era. And don't expect to get it from anywhere else, not at this stage.

So (simplistically!) $1 billion for our ship to make one round trip to Mars. It carries 20 people in transport configuration, so that will be $50 million, please. For a first class ticket $100 million - not for the caviar and steaks but the chef and stewards.

I confess a personal weakness for Pullman class interplanetary travel. The Realistic [TM] space travel alternative of doing basic preventive maintenance on microgravity toilets for 200 million miles would get old even faster.

But a note of practical caution to my libertarian minded readers. A world with so much loose money sloshing around the economic elite that it can send a Pullman car full of billionaires to Mars every two years is also a world with thousands of Paris Hiltons. Never mind poverty and social injustice. At some point sheer annoyance will bring out the guillotines.

Ahem, back to the point.

What happens after the early interplanetary era, in the second century or two of space travel, is much more conjectural, even by the necessarily naive standards of this essay.

Personally I think that by far the most likely human space future, through the 22nd century and well beyond - in short, through the midfuture - is far more like Antarctica than Heinlein: a chain of scientific and technological outposts, gradually extending outward.

Space is remote, costly to reach, difficult to live and work in, implacably indifferent to human life, and filled with things that fascinate us.

It is probably not filled with McGuffinite.

The human Solar System may well belong to artists, not writers. A deep space effort like this provides all of the lovely images - dawn on Mars, gliding through the rings of Saturn, everything Chesley Bonestall imagined and more - but not many plot lines, and certainly not the favorites among this bloodthirsty audience.

Which might be a feature, not a bug: a Solar System touched more by our aspirations than our failings.



That is probably not what you want, but I will save other possibilities for another post.


The image of an ESA concept for Mars exploration comes from a Romanian space website.

Home Away From Home

The comment thread on my previous post about space patrols raised the issue of base stations for more prolonged missions, extending to years.

This has application far beyond military or quasi-military patrols. In fact it is fairly fundamental to any extensive, long term human presence in deep space. Whether or not we put permanent bases on the surface of Mars, Europa, or wherever, we will surely place permanent or semi-permanent stations in orbit around them. Particularly because the stations can be built in Earth space, where the industry is (at least initially), and flown out to where they will serve.

Hab structures intended for prolonged habitation should be fairly large, if only because if you are going to live for years in a can it should be at least be a roomy one. And they must be thoroughly shielded against radiation, much more than ships that you only spend a few months aboard every few years.


So let us play with some numbers. Make our spin hab a drum, 200 meters in diameter and 100 meters thick. Volume is thus about 3.14 million cubic meters. The ISS has about 1200 m3 of pressurized volume and a mass of some 300 tons, for an average density near 0.25, but the mass includes exterior structures such as keel and wings. Let average interior density be about 0.16, for a mass of 500,000 tons.

If we allow 100 cubic meters per person the onboard population (whether 'crew' or simply residents, or a mix) can be up to 30,000 people. This is about twice the density of a middle class American urban apartment complex. Given that much of the usable volume must be working areas, public spaces, and so forth, the actual crew or population might be more on the order of 10,000 people, equivalent to a decent sized small town or a fairly large university or military base. Thus the hab has 10 times the volume of an aircraft carrier and twice as many people.

Spin the hab at 3 rpm and you get almost exactly 1 g at the rim.

By my standard rule of thumb the cost of this hab is on order of $500 billion. That is a steep price tag, but on the other hand it is only five times the cost of the ISS, and you need very few of these unless you are engaged in outright colonization.

Now, shielding. The standard for indefinite habitation is about 5 tons per square meter of cross section. (Earth's atmosphere provides about 10 tons/m2.) Portions of the hab where people do not spend much time, and exterior to where they do spend time, can be counted toward the shielding allowance. So let us say that the outer 10 meters of the interior (about 35 percent of the volume) are used for storage, equipment rooms, and the like. This provides about 2 tons per square meter of shielding, 40 percent of the requirement.

The remaining 3 tons per square meter of exterior shielding must cover about 125,000 square meters of surface, so shielding mass is about 375,000 tons, adding 75 percent to the mass of the hab, now 875,000 tons. This shielding need not be 'armor.' As I recall, water provides pretty good shielding against GCRs, your biggest radiation problem, and water is so useful that having 375,000 tons of it on hand in a reservoir will never be amiss.

Moreover, to move the hab you can vent off the water (or pump it out) and not need to lug the mass, assuming you can replace it wherever you are going. The deep interior of the hab, more than 25 meters from the surface (about 28 percent of the volume) is still shielded by the rest of the hab structure, so the hab can carry a reduced population during the transfer.

You are still moving a half million ton payload, so don't expect to rush it unless you have a really badass drive bus handy. Habs being repositioned across the Solar System probably travel on Hohmann orbits, and have drive accelerations of a few dozen microgees, good for about 1 km/s per month of steady acceleration.


For a smaller hab structure, scale down the linear dimensions by half, to 100 meters diameter and 50 meters thick. Structural mass, volume, and capacity are all reduced by a factor of 8, to 400,000 cubic meters, 60,000 tons, and a crew / resident population of about 1500-4000. Our 'mini' hab is now broadly comparable in volume, mass, and crew to an aircraft carrier.

Surface area is only reduced, however, by a factor of four, to about 30,000 square meters. Moreover, the smaller hab provides less interior self-shielding. If we keep the same proportions our internal reserved zone is just 5 meters deep and provides only 20 percent of the needed protection, not 40 percent.

We now need about 120,000 tons of shielding - twice the unshielded mass of the hab. If we move the hab fully shielded our payload mass is 180,000 tons. Remove the shielding and payload mass is just 60,000 tons, but no part of the smaller interior is fully self-shielded, so any crew on board during a 'light' transfer must be relieved every few months. On the bright side, if you have a 100 gigawatt drive bus floating around, or about $100 billion to buy one, you can take a fast orbit and get there in a few months.


The image shows a drum-hab station ship with a spin hab of the full sized type described above, 200 meters in diameter by 100 meters thick, fitted with a heaviest class drive bus for transfer. I am delicately ignoring details of the connection between the spin drum and the hub structures.

The shuttles approximate the NASA Shuttle, as a visual size reference. The deep space ships docking up to it are large fast transports, 300 meters long, ten times heavier than the patrol ship discussed last post. The station ship itself is about 675 meters long by 450 meters across the outrigger docking bays.

In my image the station ship is no aesthetic triumph. Allowing for my limitations as an graphic artist (compare to commenter Elukka, from the last comment thread), the transport class ships don't look too bad, but the station ship merely looks tubby instead of grand. Some modest architectural improvements might yield a more impressive appearance with little change in overall configuration.

Of course the interior will matter immeasurably more to the people on board. Mostly, presumably, it will resemble the interior of a very large oceangoing ship, corridors and compartments, probably including some fairly imposing public spaces, comparable to the grand saloon of a 20th century ocean liner or even larger. It can be as elegant or as sterile as you like (or both, depending on deck and sector). The third popular choice, rundown industrial gothic, is constrained by how far you can go in that direction before the algae dies or the air starts leaking out.

So find yourself a cubby and make yourself at home. You might be here for quite a while.

Space Patrols

We now return you to your regularly scheduled blog.

The discussion thread about 'temperate and indecisive conflicts' veered, among other things, into a discussion of patrol missions in space. [Oops, wrong thread - the discussion arose on the 'Industrial Scale of Space' thread.] My first reaction was that (so long as you aren't dealing with an interstellar setting) there is no place in space for wartime patrol missions. But the matter might be more complicated, and for story purposes probably should be.

According to The Free Dictionary, patrol is The act of moving about an area especially by an authorized and trained person or group, for purposes of observation, inspection, or security. This fits my own sense of the word, and is in fact a bit broader, 'security' including SSBN patrols, which are not observing or inspecting anything, just waiting for a launch order if it comes.

In a reductionist way you could say that all military spacecraft are on patrol, since they are all on orbit, and if they are orbiting a planet they have a very regular 'patrol area.' But this is not what most of us have in mind. We picture a patrol making a sweep through an area, looking for anything unusual, ready to engage any enemy they encounter, or report it and shadow it if they cannot engage it.

Back in the rocketpunk era it was plausible that, say, Earth might send a patrol past Ceres to see if the Martians had established a secret base there. But (alas!) telescopes 'patrolling' from Earth orbit can easily observe the large scale logistics traffic involved in establishing a base; watch it depart Mars and track it to Ceres. If you want a closer look you can send a robotic spy probe. If you engage in 'reconnaissance in force' by attacking Ceres, that is a task force, not a patrol.

In an all out interplanetary war there may be plenty of uncertainty on both sides, but very little of it can be resolved by sending out patrols.


But of course all-out war is not the context in which the Space Patrol became familiar. I associate it with Heinlein's Patrol; apparently the 1950s TV series had an independent origin (unlike Tom Corbett, who was Heinlein's unacknowledged literary child).

The rocketpunk-era Patrol, which in turn gave us Starfleet, was placed in the distinctly midcentury future setting of a Federation. This is as zeerust as monorails. But plausible patrolling is not confined to Federation settings. It can justified in practically any situation but all out war.

Orbital patrol in Earth orbital space will surely be the first space patrol, and could be imagined in this century. It might initially be a general emergency response force, because travel times in Earth orbital space are short enough for classical rescue missions. On the interplanetary scale, with travel times of weeks or more likely months, rescue is rarely possible. But eventually power players will want some kind of police presence or flag showing in deep space.

As so often in these discussions, I picture a complex and ambiguous environment in which policing, diplomacy, and sometimes low level conflict blur together. To take again our Earth-Mars-Ceres example, there are kinds of reconnaissance that cannot be carried out by robots (short of high level AIs). If Ceres closes its airlocks to liberty parties from a visiting Earth patrol ship, that conveys some important intelligence information.


The ships that perform these missions will be fairly large (and expensive). They must carry a hab pod providing prolonged life support for a significant crew: at least a commander and staff, SWAT team of espatiers, and some support for both.

Let us say a crew of 25 - which is cutting the human presence very fine. Now we can venture a mass estimate. Allow 100 tons for the hab compartment plus 25 tons for crew and stores plus 75 tons other payload, for a total payload of 200 tons. Let the drive bus be 200 tons for the drive, including radiators, and 100 tons for tankage, keel, and sundry equipment.

Our patrol ship with a crew of 25 thus has a dry mass of 475 tons, mass fully equipped 500 tons, plus 500 tons propellant for a full load departure mass of 1000 tons. Cost by my usual rule of thumb is equivalent to $500 million, perhaps $1 billion after milspecking, expensive compared to military planes, cheaper than major naval combatants.

This is no small ship. If the propellant is liquid hydrogen the tanks have a volume of about 7000 cubic meters, equivalent to a 7000 ton submarine. The payload section is about two thirds the mass of the ISS and of roughly comparable size, though the hab is probably spun giving the prolonged missions.

Armament is necessarily modest. The 75 tons of additional payload allowance probably must include a ferry craft for the espatiers and an escort gunship or two, plus their service pod, leaving perhaps 15-20 tons each for kinetics and a laser installation. The laser might be good for 20 megawatts beam power, with plug power from the 200 megawatt drive engine.

This ship is no laser star, but the laser is respectable. Assuming a modest 5 meter main mirror and a near IR wavelength of 1000 nanometers, at a range of 1000 km it can burn through Super Nano Carbon Stuff at rather more than 1 centimeter of per second. Its armament is also rather 'balanced.' My model shows that this laser can just defeat a wave of about 1000 target seekers, each with a mass of 20 kg, closing at 10 km/s - thus a total mass of 20 tons, comparable to its kinetics payload allowance.

Deploying troops, or personnel in general, is impressively expensive: About three fourths of the payload and cost of a billion dollar ship goes to support and equip a crew of 25, with perhaps a dozen espatiers. For comparison the USS Makin Island (LHD-8) displaces 41,000 tons full load, carries a crew of 1200 plus 1700 Marines, and costs about $1.8. So by my model it costs about as much to deploy one espatier as 80 marines.

And this ship is about the minimum patrol package, so standing interplanetary patrol is a costly and somewhat granular business, something not everyone can afford.

Discuss.



Apparently this cover is from the current reissue of Heinlein's Space Cadet.

Rix Pix 2010: Cold Bath

For the most part I keep this blog free of my politics, except as my broad political philosophy shapes my opinion on the topics discussed here - which is quite a bit.

But I have made a long term tradition of putting out my US election forecasts and commentary, originally as an email. Now that I have a blog I hijack it. The nearly half of you who come from elsewhere can skip this without perceptible loss; in fact so can my fellow 'Murricans. But I actually invite you to stick around; some global perspective would be interesting in comments.


I am a yellow dog Democrat, and we're gonna take a shellackin' tomorrow night.

This is the least of surprises. The country has a nasty economic hangover, and who is the electorate going to take it out on but the party in power? (I could say a word or two about the Bundesbank, for whom every year is 1924, but they aren't on the US ballot.) I think the argument that Obama's policies helped keep us from going over a cliff is valid, but it is not a vote getter.

House of Representatives - net Dem loss 56 seats, GOP takeover

House Democrats will bear the brunt of it. My call is thoroughly middle of the road, and leaves the next House with 235 Republicans and 200 Democrats, an 18 point GOP margin. Some of those Republicans are convincing evidence of interstellar travel, but they will be shuffled off to the remoter reaches of C-Span and YouTube, and the GOP House will focus on keeping the legislative branch tied up in knots, which is both easy and effective for them.


Senate - net Dem loss 6 seats, Dems retain majority

Senate Democrats will also take a drubbing, but will probably keep the majority, not that narrow Senate majorities are good for a whole lot, especially when the other party has the House.

Sorry, Harry Reid. He may be remembered as a very effective Majority Leader, but Nevada is a stranded space colony, and the colonists will send the Imperial governor out the airlock. I won't be so sorry about Feingold; a bit self righteous and a bit of a showhorse were a bit too much.


President Obama

He is not on the ballot, but will take a media beating in the short run. This is irrelevant to his political fate. Barring the unforeseen, meaning mainly a crisis abroad, that will depend on what happens to the US economy over the next two years. Adam Smith's animal spirits did not come across for him and the Dems this year, but I would not bet against them two years from now.

I know the economic conventional wisdom is that a sluggish economy will persist for years, but the ECW usually just mirrors the recent past. In some alternate world we will turn away from consumption and austerity will become a way of life. This is the same alternate world where 9/11 made Americans serious and thoughful about foreign policy.

In the real world we are 'Murricans. We like to buy stuff. We have had to put it off because some of us lost jobs and more found out their homes weren't piggy banks after all (or found they were broken ones). We will start buying stuff again. So the economy will probably pick up enough for Obama to claim credit in 2012, whether he deserves it or not. In the meanwhile he will discover the world, because that is what presidents do when they can't get anything through Congress.


California

The Golden State is apparently on a different planet in this election from the rest of the US, and politically a much more habitable one. This in spite of the fact that the Great Recession hit harder here than in most places, and a dozen lost colonies' worth of abandoned housing developments.

Perhaps that is because the face of the GOP in California is Arnold Schwarzeneggar, who as it turned out was not only no Terminator, but also no Ronald Reagan. As it looks now, Barbara Boxer will be re-elected Senator, but at least to me the big story will be the second coming of Jerry Brown, who I voted for in the 1970s and have already voted for again.

And on the footnotes of politics front I will go out on a bud, as it were, and venture that Proposition 19 will pass, making personal possession of marijuana legal under state law.



The image of the Acropolis comes from a collection of travel photos.

The Industrial Scale of Space

How many people does it take to build a spaceship? The actual fabrication process might be entirely automated, but how large must a community or society be to have the productive muscle, and range of specialized skills, needed to build and operate spacecraft?

This question lurks behind the last couple of discussion threads, and many earlier ones. It is implicated in a number of classic SF tropes. How long can a crew keep their ship going before they need repairs that only a cageworks can perform? Are outpost colonies condemned to slide to pre-industrial conditions? (Or extinction, if they cannot survive without industrial technology.) Can more robust colonies maintain space fleets?

Note that industrial scale is quite different from techlevel, which is more or less whether a society knows how to build and maintain spaceships at all, and what kinds. A familiar example of industrial scale is automobiles. With a good machine shop you could build a car entirely from scratch, fabricating all the parts, but the cost in labor and shop time would be many times the cost of a production car.

A nod to Henry Ford, and once again to Adam Smith, who lived so early in the dawn of the Industrial Revolution that he only mentions the steam engine in a footnote, but who hit on the importance of the division of labor.


So, how many people does it take to build a spaceship? Certainly no more than three billion, the world population at the time of Apollo. And I would say no less than about 100 million, because France had to partner up in the ESA in order to get in the game. Even the grotesque exception that proves the rule, North Korea, has a population of 25 million.

I grant that national space programs are political entities, and an imperfect metric of industrial capacity - which is in any case part of an interdependent world economy, not neatly partitioned by borders. But it is the metric we have, and the ability to build space boosters corresponds roughly to the ability to build large commercial airframes, also confined to a few big economies.

Only a very large economy, a large industrial infrastructure, can support the web of factories and skunkworks, launch and tracking sites, academic institutes and training facilities, with their hundreds of specialized skills, that go into present day space operations.

This blog generally presumes, for the sake of discussion, that in the Plausible Midfuture the cost of space travel will be very much lower than it is today. This is further presumed to be not because spacecraft become cheaper, but because they become more productive. Today, $100 million buys you a booster good for one trip to orbit, carrying a few tons. In the PM it might buy a shuttle capable of hundreds of orbital missions, or a deep space ship making biennial Earth-Mars trips for decades.

The ships may still cost just as much, and building and operating them may likewise require an equally large industrial base. Note that the industrial base means much more than just the shipbuilding industry as such - it means the tools that build the tools that build the tools. There may be a time when spacecraft fabrication, as such, has largely moved into space, but still relies on Earth's vast and mature industry for its own most sophisticated components.

But could future techs drastically reduce the needed industrial scale, to the point where smaller communities - in the extreme case, individual households - could maintain themselves in space?

I am going to sidestep all pseudo-technical discussion of nanotech, 3-D printing, and all of that. Basically we are talking about replicators, where 'replicator' is really just techjargon for a compact super machine shop that can fabricate any desired item, including a copy of itself. Presumably all routine processes can be automated, so that the only human labor is setting up the job (the industrial equivalent of 'rules of engagement' decisions).

I can't think of any reason in principle why a midfuture tech couldn't build that capability on a pretty small scale, whether it fits in a backpack or a Winnebago.

It will not abolish costs, because its existence creates an opportunity cost: It can only make one thing at a time, so you have to choose. And for a portable home replicator to make a duplicate of itself may take quite a long time. My computer has far more speed and power than a 1960s mainframe, but it chugs away for hours on one 3-D render.

And replicators will not abolish economies of scale. Take making cars. The core replicator element might be able to make anything that will fit in its fab chamber - today a car, tomorrow a CAT scan machine. But if you dedicate it to making cars you can set up the shop floor to bring steel in one door and roll cars out the other. You can hire people who know about cars to do the detailed job specifications, so the AIs won't have to waste time on handholding.

Taken one at a time these advantages are incremental, but add them all up across supply chains and industries and they become overwhelming. Organized industries will continue to have an essential advantage over do-it-yourself, an advantage that will drive trade and economic life in general. This does not mean that people cannot live 'off the grid,' but doing so will take more work to maintain any given standard of living.


Now, to add one more chainsaw to juggle, the ability of communities to live independently in space is a matter of techlevel. A space population cannot sustain itself if the cost of keeping one person alive in space is more than one person-year of labor output. (A population can be sustained by Earth, of course, as the ISS is sustained now.)

In fact, for an economically independent society the cost of sustaining one person must be a good deal less than one person-year of output, because a society must support many people - most obviously children - who are not productive in any immediate economic sense.

Today it costs several hundred million a year to keep one person in space, on order of 10,000 person years of output. This cost can surely be reduced dramatically, let us say to 100 (current) person-years of output. Productivity has increased roughly tenfold in the 200 years of the Industrial Revolution; if it continues at the same pace, independently space-living populations become just barely viable in the 25th century, with most adults working to keep the hab going.

This still does not mean that your libertarian commune of 100 households can head off for the stars. There remains that little matter, or all too big a matter, of the industrial scale of space. If the industrial scale of technology - the advantages of scale - remain high, while all-round techlevel increases, it might take a mega-hab cluster of 100 million people to provide the range of skills and internal efficiencies needed to sustain itself in space.

To get small, economically independent and self-sustaining groups living in space you need both an increase in overall techlevel and a similarly dramatic reduction in the industrial scale required to support space operations.


For those of you who want one, which is a lot of you, here are a few escape hatches:

Most obvious and shameless, rich people, whose income is a lot more than average per capita productivity. But unless they are also making their money in space, this is merely a case of Earth subsidizing people in space, not an economically independent space population.

Another escape hatch, invoked in comment threads, is to make do with less. Science as a practice and profession is an outgrowth of Western monasticism. (Take that, mystical Eastern monks!) And there is a distinct ascetic streak in the space movement. Among the stars we can live at one with Nature, drawing on the essentials of energy and matter, unencumbered by smooth talkin' lawyers and fancy talkin' wimmin, or pretty talkin' gents as the case may be.

In practice, what doing with less - living closer to the productivity threshold - means is that people spend much of their time cleaning balky toilets, or fixing plumbing for more exotic but equally noisome fluids. That is what 'keeping spacecraft going' will be largely about, with the occasional call for a replacement part, whether you order it from stock or fab it onboard.

Faking it. Some people may seem to live independently on a small scale without really doing so, or only within narrow limits. Take one of my favorite tropes, the Serenity style space freighter. It is plausible to me that such a ship could keep going for quite a long time, perhaps many years, on just fuel and the most basic supplies. That is what it was designed to do.

Note that a ship like this probably cost more from the builder than a core zone ship that is designed for pull & replace servicing between runs. And eventually it will need to go into a cageworks for replacement or scrapping. But in the meanwhile it goes and goes.

Extend this concept a bit and you have a whole outer-fringe ecosystem that was costly to build in the first place, and would be costly to fully overhaul and restore to factory standard, but is relatively cheap to operate, and can be operated safely for decades or even generations before its service life is finally at the limit.

So this ecosystem, once built, can go for a long time as if it were independent of outside support - and can come, culturally, to take independence for granted. Though the bill will eventually come due.

The practical effect is much like Ken Burnside's 3-Gen rule, but the basis is entirely different. The 3-Gen rule argues that 'normal' human societies lack the social discipline to maintain something as complex as a hab. In my case the hab is not expected to replace or renew itself, only go a long time before either one is needed.


And there you have it. If you want small, independent, more or less self sustaining space habs in the midfuture, I have no Space Patrol, and no reason to send it to stop you if I did. Just be aware of the techlevel you are implying, 4-5 orders of magnitude improvement over what we have achieved in 50 years of space travel.

Space is hard. Even with enormous progress in both our overall capabilities and our specific space techniques it will still be hard.



This image of the ISS from Astronomy Picture of the Day deserved a reprise.

Barbarians in SPAAACE !!! - Part II

Barbarians you want, barbarians you get. My last post left itself open to a threadjacking, and the commenters were quick to oblige. Barbarian hordes 1, temperate and indecisive, 0.

First of all, what do we mean by 'barbarians?' There turns out to be more than one definition. In comments on the last post I used it in a quasi-technical sense to mean nomadic or semi-nomadic peoples who lived on the fringes of the agrarian age world, and periodically invaded and laid it waste, or so the 'civilized' survivors claimed. But there turn out to be two other relevant definitions, at least.

A second meaning is gross violators of civilized norms, a sense of the word in which the last century produced more and worse barbarians than any before it. This is relevant to conflict because it gave us World War II, enough said.

In the beginning the word means simply people who did not speak Greek, and applied equally to Egyptians and Thracians. The late Romans applied it to all those people who made border security difficult and finally impossible, and whom the Romans viewed, well, barbarians.

In the popular culture this image comes right down, via Gibbon, to Conan the Barbarian. Because from Tacitus on, the 'barbarians' were seen not just as savages but also at times Noble Savages, free of the constraints and artifices of urban civilization. This third meaning - essentially 'barbarian' as a trope - is the one that concerns Romance, so that is the one I will concentrate on here.

This is why I set aside 'barbarian' in the sense of civilization gone bad. No matter now much a rogue state traps itself out like a heavy metal band, if you are filing weekly reports of how many people you massacred, you are not a 'barbarian' in the sense that Conan is.

(Having said that, I admit a Hollywood tendency to conflate 'barbarian' and 'totalitarian' elements that would hardly go together in real life - think of the original Klingons on Trek TOS.)

I will say a bit more, though, about the sense of 'barbarians' as warlike nomadic peoples, by quoting another eminent 18th century Briton, Adam Smith:

A nation of hunters can never be formidable to the civilized nations in their neighbourhood. A nation of shepherds may. Nothing can be more contemptible than an Indian war in North America. Nothing, on the contrary, can be more dreadful than Tartar invasion has frequently been in Asia.

From my 'Murrican perspective the likes of Andrew Jackson, not to mention George C. Custer, could have a word or two about this, but on the grand strategic level Smith is right. By sometime around 1700 the First Nations lost any prospect of stopping the European incursion. There just weren't enough of them. Even if they had learned to be shepherds, or cowhands, gunpowder had closed that window of opportunity. Compare to the fact that the Norse - Vikings, no less, the scourge of Europe for 300 years - found the local Skraelings more than they wanted to deal with.

In any case, nomadic peoples got into the history books as 'barbarians' because their ordinary way of life made most of the adult male population warriors. There's no obvious futuristic counterpart. People who have spaceships have a huge advantage over people who don't, but the advantage is in mobility, not fighting as such (other than the ability to throw kinetics).

This does offer a tempting analogy to the Vikings, and the rather similar Homeric sea rovers who helped finish off Mycenaean Greece. Seamanship provides no inherent advantage in a fight on land, though a ship's crew is already a cohesive unit, a big advantage over hastily assembled militia. But the raiders' advantage in actual fighting came more from practice than from their previous way of life.


Hastening a bit through Step Two, here is a scenario, as hackneyed as it deserves to be. The Empire is collapsing. This is actually one of the easier pieces of space opera to justify - just combine post-Apollo funk with the real estate bubble, and scale up. It would be the least of surprises if a period of spectacular space expansion were followed by retrenchment, and when Earth sneezes the outposts get pneumonia.

A 'pre-collapse' could be developing in the Back of Beyond even as the Empire is still growing. As in a classic bubble, sound enterprises - colonies, mines, whatever - give way to bubblicious ones, local shortages and crises develop, and law and order can begin to fray. This can go on for a long time before anyone on Earth really grasps the implications. (When they do grasp the implications is when collapse goes into high gear.)

A scavenger subculture plausibly develops, starting with surplus equipment sold for scrap prices and moving on to equipment that has been abandoned outright.

Scavenging permits some classic mining tropes that otherwise are hard to justify. The problem with mother lodes and claim jumping in space has always been that if you can reach one mother lode in the vastness of space you can probably reach many others. But there are only so many abandoned space stations to go around.

The next step, for some scavengers, will be not waiting for abandonment. If a struggling colony cannot defend its orbital station it is yours to salvage.

Really this is just Mad Max with spaceships instead of bikes, and the reason it works is that it doesn't really need to work - the scavenger subculture does not need to be a sustainable way of life. It is, after all, part of a collapse process. The Homeric sackers of cities ran out of cities to sack, except in Egypt where they ran into Rameses III. The scavengers will, in time, run out of stuff to scavenge.

In the meanwhile some of them might learn to do more with less, learning to maintain a high techlevel with a much smaller population base - replicators, nanotech, whatever - while others evolve from scavengers (and sometimes raiders) to traders. So the scavenger subculture has its positive side as well, and best of all it gives you three classic SF tropes for the price of one.

Are the scavengers 'barbarians?' Obviously not in the narrow historical sense of being Eurasian steppe nomads, but their way of life implies a sort of nomadism while it lasts. Some may well qualify as 'barbarians' in the moral sense, the worst of them robbing struggling habs and colonies of their means of survival.

And even the best of them might be 'barbarians' in their disconnection from large formal institutions. Their progenitors worked on contract for large firms or other institutions; later they are working just to keep going, sometimes trading, sometimes raiding, mostly scrounging and patching.

For practical purposes they will pretty much do.

There are variations on this theme. As commenters have suggested, parts of a space economy could slide into decline and collapse while the rest of it thrives - rustbelt worlds of declining industries. And we see in the present day world that world trade interests find it cheaper to pay off the occasional Somali businessman than to pay for a massive naval mobilization to suppress piracy.

Like the Wild West, or the great age of Caribbean piracy, or the terrible and grand 12th century BC that Homer sang, the era of scavengers will not last long, not in historical terms (though it might persist for decades). But it will cast a long shadow as a formative experience of the new, rising worlds.

Sort of hard to resist, isn't it? These tropes do exist for a reason ...




This pop-culture barbarian image graces the Interstellar Empire page header at Atomic Rockets, which I have not linked to enough lately.

Temperate and Indecisive Contests

Edward Gibbon contributed much to science fiction; without him there could be no fall of the Galactic Empire. In chapter XXXVIII of The Decline and Fall, summing up his theme, he speculates on a historical what-if that has never been followed up on in SF, so far as I know, and probably won't be: What if there were another wave of barbarian invasions?

Post-apocalyptic fiction has plenty of goth/biker barbarians (and post-Gibbon history has shown that 'civilized' people can be plenty barbaric), but old style barbarian conquest of civilized lands has been relegated to the sword & sorcery shelves.

Gibbon agrees that barbarian conquest has had its day, and gives several reasons. The first and most basic is the Russians, who by Gibbon's time had pretty much solved the problem of the Eurasian steppe nomads at the source: The plough, the loom, and the forge are introduced on the banks of the Volga, the Oby, and the Lena; and the fiercest of the Tartar hordes have been taught to tremble and obey.

But a bit later in his list Gibbon provides the text of this post. In war, he says, the European forces are exercised by temperate and indecisive contests.

This is of interest to us because, bloodthirsty lot that we are, we want to write about blowing stuff up, especially but by no means limited to spaceships. Temperate! Indecisive! does not sound like the way to sell a war saga. But if the war is intemperate and decisive you won't have much of a saga, because it will end with Chapter Two:

There was a brilliant flash of light.

In fiction this only works once, and probably with real civilizations as well.


The wars of the 18th century were temperate and indecisive, or seemed to be, for fairly basic reasons of technology and economics. Serious warfare, as the 18th century knew it, was expensive stuff: paid regulars and keeping them paid and supplied; artillery; massive fortifications and ships of the line.

And the advantage lay heavily with the defense, tactically and strategically. Enough dirt and stone, or even half a meter of oak, would stop cannon balls. As for the strategic level, experience in the 17th and 18th 16th and 17th century showed what happened to armies that pushed beyond their supply lines: They devastated a province or two, then came down with dysentery and crapped themselves to death.

Thus 18th century war looked at the time like a cohesive system, inherent to an advanced proto industrial society, but this line of Gibbon is usually quoted for its irony value, because along came the French Revolution and Napoleon and all of that.

The modern view through the 20/20 hindsight rangefinder is that the French Revolution raised the stakes of warfare by harnessing the power of national mass mobilization. You could put far more troops in the field than the pre-1789 world had imagined, but only by arousing the mass passions of your population - at which point you were no longer really in control.

But there were a couple of military preconditions to all this. First (or so I gather), the French Revolution showed that a militia rabble could indeed defeat 18th century regulars, if they outnumbered the regulars massively enough and were fired up enough, and second, that with good sergeants you could turn that rabble into a decent army pretty quickly.

I vaguely recall something about an artillery officer from Corsica in this mix, too, and strategic mobility coming back into play, but my ignorance is profound here. Suffice it to say that the 18th century model of temperate and indecisive contests did not hold up.

Now let us imagine midfuture settings. The means of making war in a serious, great-power way are presumably still expensive. The means of simply nuking your enemy back to the stone age are available, and cheaper, but not the means to keep your enemy from nuking you back to the stone age.

Since nuking each other back to the stone age is against the general interest of all parties, could they avoid it by tacitly accepting temperate and indecisive contests, and scaling their objectives to suit?

Doing so by overt treaty, and making war by formalized rules, sounds vaguely tinselly and implausible to us. But the stakes of 18th century war had been implicitly limited by the same Treaty of Westphalia that has given the name 'Westphalian' to the whole concept of a state system and balance of power. Religion, which had made 16th and early 16th 17th century warfare so implacable, was more or less taken off the table as a reason for European states to go to war.

This agreement was possible because bitter experience had taught everyone that neither Protestantism nor Catholicism were going to go away, so there was no point fighting over them.

No such formal agreement might be needed in a future era, only a tacit understanding reinforced by the very powerful motives of elites toward self preservation. The fact that World War II happened does not negate this tendency; in 1939 not only was the atomic bomb still (literally) science fiction, but most of the offensive weapons and tactics of the war were still quasi-experimental and more or less untried. Now elites know what will happen to them, and it tends to concentrate minds.

Some classic SF scenarios lend themselves to temperate and indecisive contests, for example deep space trade wars. Trade warriors may be constrained on the one hand by the risk of burning their profit margin on military spending, and on the other hand by the disadvantages of vaporizing prospective customers.

At the other end of the spectrum, the Starship Troopers logic of racial wars of extermination pretty much points toward, well, wars of extermination. Pick your scenario and take your chances.



The image is a scene from the Battle of Minden, 1759.

Bat Durston and Sherlock Holmes

The mythos of the American West, as regulars here have heard me preach, is a very bad analogy for anything we can plausibly expect to happen in space over the next few centuries. Grubstake miners in the asteroid belt, sodbusters on Mars, and train robbers waiting at the Lagrange Pass for the 4:58 to Titan all differ only slightly in their quotients of probability, and all are very close to zero.

Given worlds enough and time, some civilization may come along that takes Dodge City as its cultural inspiration, but just as in the long gone days of Trek TOS, that is really only good for one episode.

Yet as regulars here also know, I was a fan and advocate of Firefly, which served up Western mythos in straight shots. It even got away with old fashioned Injuns, the Reivers, as incurably savage and implacably hostile as Lakota Sioux in 1950s Westerns. No one was going to smoke a peace pipe with them, and no tears would be shed over wiping out as many of them as possible. One dimensional natives remain alive and well in Hollywood - even, as Avatar showed, when filmed in 3-D.


The tension between Realism [TM] and Romance is is not a problem over on the fantasy shelves. Not many people trouble themselves to explain how dragons might really be possible. Only a few authors have framed fantasy-esque settings within an SF structure, with Anne McCaffrey the most familiar example: Pern is hardly less likely than any other colony planet.

It is not even really a problem in the various retro-future genres that have sprung up - if I want to have a steampunk alt-future city with pneumatic subways, no one is going to point out that electric rail technology made them obsolete by 1888.

It is a problem, potentially, in one other branch of the great super-genre of Romance: mysteries. Mysteries have somewhat the same relationship to horror that SF has to fantasy. In both genres someone generally winds up dead, often in colorfully gruesome ways and with creepy psychosexual overtones. But while horror is unabashed in its supernaturalism and irrationalism, mysteries confront horror with rationalism in the person of the detective.

God, that sounds lit-critty. One swig of meta leads to another ...

In mysteries the confrontation of the rational and the magical is direct, if disguised, and as a result mysteries are a highly stylized form with conventions (in the literary, not fannish sense) that make those of SF look positively lax.

In SF we glide past those tricky questions on orbital trajectory, never having to fire our engines. There may be no stealth in space when it comes to scan technology, but there is plenty of literary stealth. By salting the text with convincing sounding bits and pieces, torch drives and laser apertures, we invite the reader to not notice all the implausibilities of the setting. Move along, move along, nothing to see.

And in space, moving along is wonderfully easy. You don't have to do a thing.



Related post: An Athenian counterpart to Marcus Didius Falco.

The image was snagged from this mystery oriented blog.

Goldilocks Planet

By now you have probably heard media reports of a 'Goldilocks' planet orbiting Gliese 581, the seventh sixth planet found in the retinue of this dim red star.

Mass media hype aside, this discovery is both important and unsurprising. Important because this is the first known planet apart from Earth itself that orbits entirely inside its parent star's habitable zone, and so could potentially harbor life without broiling or freezing it. Unsurprising because nearly 500 extrasolar planets have now been discovered, and sooner or later one was going to turn up in the right orbit.

All we know about Gliese 581g are its orbit, at about 0.15 AU from its parent star, and its approximate mass, about 3-4 times Earth's. We do not even know for sure that it is 'a planet' rather than, say, two planetary-mass bodies orbiting each other. We know nothing about its composition, such as whether there is water vapor in its atmosphere, let alone liquid water on its surface. We know only that liquid water could exist at that distance from the star, unless the planet has an intense greenhouse atmosphere or some other complication.

But let the speculation begin, as naturally it already has. If it is a single body it should be tide-locked to Gliese 581. This used to be a deal breaker, but current thinking is that atmospheric heat transfer is ample to keep the air from freezing out on the nightside.

If the planet has extensive uplands and limited water, the water might (my own speculation) form vast ice sheets on the nightside instead of pooling as oceans. On the other hand, the general feeling seems to be that big planets will have more water, while the heavier gravity should make a rocky surface flatter - how much so is above my pay grade to estimate. But this may well be a waterworld, or even a 'water giant' with a hydrosphere thousands of kilometers deep instead of Earth's thin muddy film of liquid.

As Arthur Clarke said of Jupiter, when it was thought to possibly have a deep hydrosphere, think of the fishing.


I would not rush out to put a colony on Gliese 581g in my setting. It is probably not a world for us. (If any worlds are 'for us' beyond the one we evolved on and any we may one day terraform.) But we are free to imagine a golden-red glint of sun across a very distant sea.


Image source.