The Science of Avatar

¹⁸ DISTURBING THE WORLD

Among Avatar’s many striking images are aerial views of RDA’s great unobtanium mine on Pandora. It looks like a lunar landscape cut out of the green, across which giant machines crawl. The sheer scale of all this is brought home to us in Jake’s first scenes on Pandora, when, fresh off the Valkyrie shuttle from orbit, he is tiny beside dump trucks, their wheels taller than a standing human—but in other shots we see how the trucks themselves are dwarfed beside the tremendous excavators in the pit.

The size of an RDA excavator, a DD40 Heavy Duty Class Wheel Loader, is staggering. You could fit seventeen soccer pitches on its mighty back. At five hundred metres long, it is over a hundred metres longer than the largest ships currently operating on Earth’s oceans (Maersk E-class container vessels). And it’s over three hundred metres high: there are only about fifty taller skyscrapers in the world today. An excavator is a single machine the size of a city block.

There is something awesome in the sight of huge, single-purpose engines like these. As a boy in the 1960s I was struck by the futuristic machines in Gerry Anderson’s Thunderbirds, such as the Crablogger in the episode “Path of Destruction,” which crashes through the jungle pulling out trees with its gigantic claws like a child pulling up blades of grass. Even today I can’t help but be awed when I glimpse the machines that clear-cut the big managed pine forests close to my home in northern England. A “harvester” will fell a tree with its chainsaw, rollers force the tree stem between “delimbing knives” that strip the trunk of its branches, and logs are cut to a specified length. A huge twenty-year-old tree can be processed in minutes. Later a “forwarder” picks up the logs to carry them to great heaps by the roadside for collection. There are humans in the cabs of these machines, but not a lumberjack’s foot touches the ground. It’s not quite the gigantic slash-cutter we see in Avatar, but the principle isn’t far away.

The unobtanium mines on Pandora resemble open-cast mining operations here on Earth—and especially the huge operations now underway around the world to extract oil sands.

Oil sands (also known as tar sands) are a kind of bitumen deposit. Bitumen is a dense and sticky form of petroleum that can collect in layers of sand or clay and water. Such deposits occur around the world, and in fact were exploited in ancient times in the Middle East for the water-proofing of reed boats, and creating Egyptian mummies. The world’s largest deposits are in Canada and Venezuela, each of which is said to have reserves equivalent to the world’s total reserves of crude oil. (Maybe this is why Jake Sully was sent to fight in Venezuela.) The Athabasca Oil Sands, in Alberta, Canada, have been the scene of the commercial extraction of bitumen since 1967. The Athabasca operation employs what are said to be the biggest power shovels and dump trucks in the world. The oil sands themselves are typically in a layer fifty or so metres deep, sitting on top of limestone strata. To mine them you have to clear the land of trees and brush, then remove what the miners call the “overburden,” the topsoil and layers of peat, sand and gravel, and then the extraction is done. This is roughly the technique used in the Pandoran unobtanium mines.

The modern extraction process, which requires huge amounts of energy for steam injection and refining, was until recently considered uneconomical—but that’s changed through a combination of better technology and rising oil prices. Production in Canada has grown to the extent that the country has become the largest contributor of oil and refined products to the United States. Environmental issues are regularly raised. State and national governments apply strict rules; for instance all such projects are required to implement a land reclamation plan. But environmentalists object that oil sands extraction processes generate more greenhouse gases per barrel than the production of conventional oil.

Meanwhile, at the time of writing there are plans to open up a huge iron ore mine in Arctic Canada, far to the north of any operation of a similar scale previously—an opportunity provided, ironically, by the global-warming retreat of the polar ice. Just as on Pandora, there is native fauna to be moved out of the way, including caribou, Arctic foxes and polar bears, and local people to deal with in the Inuit.

I suppose that if the world suffers the ecocide we looked at in Chapter 2 we can expect such operations to proliferate. Nobody would care about the impact on the environment, because there would be no environment to save, any more than on the lifeless moon. Certainly satellite views of the operations in Athabasca and elsewhere are starkly reminiscent of Avatar’s scenes of unobtanium mining on Pandora.

The principal unobtanium mine, humanity’s most distant industrial operation, is known as RDA ESM 01—RDA Extra-Solar Mine 01. Operators in sealed cockpits use chemical charges to break up the overburden, which is then removed with excavators, dozers and dump trucks. The unobtanium ore is removed with excavators and trucks, but a pure enough deposit can spontaneously levitate, requiring specialised belt diggers to feed into covered trucks. Over the thirty years of its expected lifetime the three pits of ESM 01 will eventually merge into a crater four kilometres across. But RDA is already looking at further deposits to develop.

All this is very plausible. Today we’re pretty competent at mining the Earth. And we are already working out how to mine other worlds.

In Avatar’s 2154, human colonies exist on the moon and Mars. And in our time there have been several studies on how you might mine these new worlds.

What is there to mine on the moon? Well (see Chapter 6), there’s water, maybe in trace amounts in the lunar soil, and helium-3, the right isotope of the element for the most effective operation of fusion plants, which is lacking on Earth. But these treasures are thinly scattered—it would be like harvesting dew—and strip-mining on a vast scale would be required. Imagine robot tractors crawling across the lunar surface, scooping up the regolith, processing tonnes of the stuff to sift out the minute fractions of water and helium-3, and perhaps baking the rest to extract oxygen. As for power, the unshielded sunlight is an obvious energy resource; perhaps areas of the wide, flat lunar seas could be melted to form gigantic solar-energy collectors.

The lunar conditions will invalidate much of our terrestrial experience of heavy industry and manufacturing; we will have to rethink everything. Moon dust, shattered by meteorite rain but unweathered, is extraordinarily abrasive, as the Apollo astronauts learned when they tried to make their spacesuit seals for their second or third moonwalks. The vacuum makes most lubricants useless; they would just boil away. And the low gravity causes problems with simple things like fluid flow, because of novel bubble effects in liquids. Lessons we learn on the moon, however, could be transferred to other worlds. It’s strange to think that low-gravity adaptations made to the feed lines on a Samson rotorcraft to enable it to operate on Pandora, for example, might have been learned on the humble moon.

In the Avatar future, in fact, RDA does maintain a lunar helium-3 facility. And the mining operations must have left a mark. Maybe by Jake Sully’s day the face of the moon in the sky, more or less unchanged for billions of years before humans came along, is pocked and scraped by mines, and the dust seas gleam, covered by tremendous solar-panel mirrors.

Meanwhile the best plans we have to get to Mars and back involve industrial processing of Martian resources from the very first landing—in fact, we would need to make a start even before humans get there. According to Robert Zubrin’s “Mars Direct” proposal, Mars would be reached with a wave of spacecraft capable of manufacturing their own return fuel from Mars’ carbon dioxide atmosphere, at a fraction of the cost of hauling that fuel all the way from Earth (the Apollo craft carried their own return fuel to the moon).

The key ingredient to support life, however, is as always water. And there seems to be plenty on Mars. As Percival Lowell suspected there is water-ice on Mars’ surface at the poles, just waiting to be scooped up. At lower latitudes, the spaceprobes have found evidence of water in the past: for example, what appear to be the remnants of gigantic, catastrophic flooding episodes, and perhaps even the tide marks of ancient seas. Where did all the water go? Perhaps it was drawn into aquifers in Mars’ interior by geological processes like the great subduction flows on Earth; Mars, smaller than Earth, cooled more rapidly, making its crust and mantle more able to trap and store water. Thus the first large-scale industrial operations on Mars are likely to be drilling for water—and the technical challenges there are almost as severe as on the moon.

From 2004 to 2007 I worked with a team from the venerable British Interplanetary Society on a design study of a manned base at the Martian north pole. It was a weighty study; project leader Charles Cockell is a professor of astrobiology at the Open University. And in the course of the study we worked on proposals on how you’d drill on Mars, specifically in our case because we wanted to extract an ice core. Just as on Earth, such cores, drilled from ice caps built up by snowfall year on year, contain records of climate variations reaching deep into the past.

Deep drilling, the kind you’d need to go down kilometres to a low-latitude Martian aquifer, is hugely challenging in terms of mass, power and manpower. Rotary drilling as we use on Earth is a tested technique, relatively low power, mechanically simple, and easily fixed in case of failure. But it requires a heavy support infrastructure, and in the dusty, cold, high-friction Martian environment any moving-part system would be vulnerable to many failure modes—lubrication failures, abrasion of bearings, loss of seal integrity.

A deep borehole will always require stabilisation to keep it from collapsing. The way this is done on Earth is to pump in a “working fluid” such as water or mud slurry. Water or mud will not work in Martian conditions; either would freeze immediately. Possibly some low-temperature lubricant oil would be suitable, but it would be very expensive to import such a fluid from Earth: you’re looking at tonnes of material, and if lost such a fluid load could not be replaced. The trick is to use working fluids produced from local materials, and the best bet may be to liquefy Mars’ carbon dioxide atmosphere. Unfortunately, carbon dioxide plus liquid water yields carbonic acid, a weak acid but corrosive; you would have to keep temperatures low enough throughout the borehole that ice chips do not melt, which will affect drilling rates, and to use corrosion-resistant materials.

This brief experience taught me a lot about the challenges of transferring heavy industrial operations to another world. In Pandora’s low gravity and toxic air, every tool, every machine, every material used will have to be redesigned, every technique re-examined.

And on Pandora the intense magnetic fields around unobtanium deposits are a novel significant problem for industry. Machines and tools can’t contain any ferromagnetic elements such as iron, cobalt or nickel because they would become so strongly magnetised their moving parts would seize up. Even some non-ferromagnetic elements like manganese become magnetic when combined with other elements, which limits the use of steel alloys and other materials. There are compounds that will work, such as tungsten carbide, but these are exotic and expensive. In addition, whenever you move a conducting material in a magnetic field electrical currents are induced. These can heat the material, interfere with circuitry, and interact with the global magnetic field to produce a resistance to motion. A miner swinging a pick would feel like he was underwater, and the faster he moved the hotter the pick would get—not that a human miner would be allowed anywhere near an unobtanium lode.

Still, by the time RDA reaches Pandora it will be able to build on decades of experience of mastering hostile environments in the solar system. And everything we learned on Earth, since the days thousands of years ago when we were chipping flint nodules out of chalk beds, will have been rethought.

¹⁹ COPIES, CELLS AND COMPUTERS

In the movie Avatar we only glimpse Earth, but we see a lot more of the human colony on Pandora, the “Resources Development Administration Extra-Solar Colony,” more popularly known as Hell’s Gate.

And here we get to see some of the technological advances achieved by mid-twenty-second century Earth.

One challenge of the operations we see on Pandora is the sheer mass of the machinery required, such as the mining gear, the military hardware, the fixed structures at Hell’s Gate and elsewhere. Interstellar flight is always likely to be expensive, and the more mass you have to haul out, the more expensive it gets.

Given this, it would make sense to manufacture as much of your equipment as you could on Pandora using in situ resources. To get things up and running quickly you might bring out smart but lightweight components such as electronics from Earth, while manufacturing dumb but heavy components on Pandora.

And the way RDA achieves the latter is by using a much-advanced version of a novel manufacturing technique called stereolithography, or “3D printing.”

This is a kind of photocopying of solid objects, in which computer-controlled machines build up a component by spraying on layer by layer. Typically, systems working today have used plastics, but there have been experiments using metals and ceramics. Advantages of the technique are its ability to construct more complicated and intricate shapes than any other primary manufacturing technology, and its flexibility—one system can turn out any component you like, whereas otherwise you’d have to bring along specialised plant for each type.

Today, commercial systems are used to manufacture items like jewellery, but they are also being trialled on a larger scale, for example in projects where buildings are constructed layer by layer by robots pouring fast-setting concrete. There are also home-workshop experiments you can download, such as the “Reprap” project, the Replicating Rapid-prototyper, devised by Adrian Bowyer of the Buckinghamshire Chilterns University College in England. As you can imagine, there are fascinating intellectual property rights issues to be resolved around this technology.

Even on Earth, if we could manufacture a lot of what we need at home we might cut transport costs significantly. And stereolithography certainly cuts the cost of transport to Alpha Centauri, where the RDA manufactures its own ground vehicles, mine equipment, weapons, building elements, even clothing. As we’ll see, however, the use of this technology imposes some constraints on the kinds of machinery that can be used on Pandora.

Remarkably, experiments at the Massachusetts Institute of Technology have tried using the 3D-printing technique to make artificial human bones. In the course of Avatar we get a look at a number of other medical advances.

Former Marine Jake Sully is stranded in a wheelchair, the result of a traumatic injury he suffered on active service. He’s aware that a “spinal” can be fixed, but only at a price beyond the means of his veteran’s benefit. In the context of the movie, Jake’s paralysis serves a key narrative function. Like his eco-devastated Earth it provides another extreme starting point for his personal story; it makes Jake vulnerable to manipulation by Quaritch—and it amplifies the joy he feels, and we share, when he first drives his avatar body, and is able simply to run again.

But it is good to know that in the real world some steps are being taken towards alleviating this terrible condition.

A “spinal” is a spinal cord injury. The spinal cord is a long, thin bundle of nervous tissue that extends from the brain. The cord is contained for protection in the bony vertebral column. Together, cord and brain make up the central nervous system. The cord’s main function is to transmit neural signals between the brain and the rest of the body: “motor information,” data about the body’s movements, travels down the cord from brain to body, and “sensory information,” data recorded by the senses, travels back up the cord from body to brain. The cord also has some independent functions; it serves as a centre for coordinating various reflexes.

It’s estimated that in the United States, for example, there are some forty cases of spinal cord injury per million people per year. The spinal cord can be damaged by trauma, as in Jake’s war injury, or through a tumour, or through a developmental disorder like spina bifida, or a neurodegenerative disease. The vertebral bones or the discs between the vertebrae can shatter and puncture the cord itself. In the more severe cases, such as Jake’s, a patient can suffer a significant loss of motor and sensory functions to major areas of the body, all the way to full body paralysis (quadriplegia) below the site of the injury. In addition a patient can suffer bowel and bladder malfunctions, a loss of sexual function, spasticity and neuropathic pain, and in the longer term muscle atrophy and bone degeneration.

Current treatments amount to administering anti-inflammatory agents or cold saline immediately after the injury. These wouldn’t help Jake walk again. It seems that at present, despite the dreadful outcome of a spinal cord injury, there is comparatively little research being done into new treatments, because of the small (in percentage terms) number of sufferers.

But there are some promising developments. Treatment involving neuronal protection, and even the regeneration of damaged neurons, are being investigated to treat conditions like Alzheimer’s Disease and Parkinson’s Disease, conditions of the central nervous system which have some similarities to spinal cord injuries.

Stem cell treatment seems the most promising approach to neurological regeneration, and attracts a lot of publicity. Stem cells are found in most multicellular organisms. They can renew themselves through cell division, but can also differentiate into a range of specialised cell types. They can be found in embryos, where they go on to produce all the specific tissues the embryo requires. There are also adult stem cells which can act as a repair mechanism for the body, replenishing damaged specialised cells.

In their application in medicine, stem cells are introduced into injured tissues. The cells come from the patient’s own body, so there is no risk of rejection. With proper management the stem cells can be trained to differentiate into the kind of cells needed to repair the damage. The first successful stem cell treatment was as far back as 1968, a bone marrow transplant. It is hoped that stem cell treatments will one day transform medicine by treating conditions ranging from cancer to cardiac failure.

For “spinals” like Jake’s these treatments are in their infancy. It has proved difficult to persuade stem cells to differentiate into spinal motor neuron cells, the type of cell that transmits messages from the brain to the spinal cord. But some success was reported in this in 2005 by researchers at the University of Wisconsin-Madison. And in 2010 the first spinal-injury patient was treated with human-embryonic stem cells.

Another bit of evidence we see of advanced biomedical knowledge in Avatar’s twenty-second century is the creation of the avatars themselves, derived from “human DNA mixed with DNA from the natives”—the Na’vi. This is a topic we will return to in Chapter 31, but for now we can note that this is a remarkable achievement of genetic engineering.

Here at the beginning of the twenty-first century, genetics is another area of rapid advance and great promise for medicine. A gene is a unit of inherited material encoded by strands of the double-helix molecule DNA (that’s how it works in creatures from Earth, at least). The idea of gene therapy in medicine is to insert genes into an individual’s cells to treat conditions such as hereditary diseases, where harmful mutant versions of a gene can be replaced with functional ones. The idea was raised in the 1970s, and the first attempts focused on diseases caused by single-gene defects, such as cystic fibrosis. The first successful treatment in the U.S. took place in 1990, when a four-year-old girl was treated for a genetic defect that left her with an immune system deficiency. In a trial in London in 2007 a patient was treated for an inherited eye disease, and in 2009 researchers in America gave enhanced colour vision to a squirrel monkey, in experiments hopefully leading to a cure for colour blindness.

An interesting review in the April 2010 issue of the journal Nature summed up the decade since the first full decoding of the human genome, all one hundred thousand genes, the “blueprint of life.” Progress in using genetic data in medicine has actually been slower than expected, because of the complex genetics behind many diseases, apparently exaggerated claims after a few early successes in the 1990s—and the death of a patient in 1999, after a severe reaction to attempts to give him repaired genes. At the time of writing, no patients have actually been cured of common genetic diseases by gene therapy.

And then there are ethical and other doubts about the technique, as with so many other areas of modern medicine. For instance, babies can be “screened” in the womb for genetic conditions, possibly treated, or, perhaps, aborted if the parents choose. Many people will have doubts about where to draw the line in terms of such choices. Then there is the question of inheritance. There are two basic types of gene therapy. You can insert the therapeutic genes into the somatic cells of the patient—that is, the non-reproductive cells of the body. In this case any effects will be restricted to the patient only, and not passed on to any offspring. Or you can insert genes into germ cells—that is, reproductive cells, sperm or eggs. These changes would be heritable and can be passed on to future generations. These techniques are so controversial that in many countries, including the UK, tampering with the human germ line is a specific criminal offence.

One very unpleasant offshoot of gene therapy research could be “smart” biological weapons. You could target a specific group or individual with a particular DNA pattern, and trigger a natural or engineered disease. It must be hoped that this doesn’t occur to any SecOps think tanks on Pandora—but it is a possibility, since we know from the creation of the avatars that humans have to some extent mastered Na’vi genetics as well as their own.

The medical treatments discussed here are more or less at the experimental stage today. Perhaps the successful ones will be routinely available by the mid-twenty-second century. But it seems likely they will be costly. Aside from the evident cost of fixing Jake’s spinal injury, we see scientist Max Patel wearing glasses! If you can build an avatar, you’d think you could fix short-sightedness—but, obviously, only at the right price.

Another technological advance obvious in Hell’s Gate is computer technology.

Consider the Hell’s Gate Ops Centre control room. (Avatar’s creative team visited such locations as a real-world oil rig, the gigantic Noble Clyde Boudreaux in the Gulf of Mexico, to use as a model for interiors like this.) We see large-scale wraparound screens that respond to the touch and movement of the operator. In another instance, in the avatar lab, Max Patel swipes one tablet-like screen over another, taking an image to carry away with him to show Grace Augustine, as easily as he might pull a piece of paper from a pin-board. Three-dimensional displays are the norm, and there is an emphasis on graphic and tactile interactions, in an environment saturated with computing. These scenes recall recent experiments in “ubiquitous computing,” in which computers become embedded in the surroundings. Nokia’s Ubice is one prototype. In Microsoft’s Lightspace system, surfaces in a lecture room become screens for displaying documents and images; like Max you can pick up a virtual item from one display and move it to another.

The Ops Centre also features a holotable, with a continuously updated summary of conditions across RDA’s operations on Pandora. This is a very impressive, fully searchable holographic display, which Jake is able to reach into, tracing for Quaritch the internal structure of Hometree with his hands. Holography, the science of 3-D projection, is quite an old technology. The principles on which it is based were first set out in 1947 by the British physicist Dennis Gabor, who got a Nobel Prize for his trouble. Information about the amplitude and phase of light waves—that is, how intense they are and how they relate to each other—are stored as patterns of interference. Computer programs “ray-trace” back from these interference patterns to recreate the light rays that gave rise to those patterns, and so give the illusion that the object that emitted or reflected the light in the first place is present. Indeed, that “object” might only ever have existed in the electronic imagination of a computer.

Human-machine interaction (HMI) is the academic study of the interaction between people and computers. It is the intersection of a number of fields, from ergonomics and human factors to computer design. It arose partly because of bad examples of human-machine interfaces leading to calamity—for instance, it is thought that the Three Mile Island nuclear accident was partly due to operators struggling with a poor and confusing interface. HMI practitioners develop theories of interaction, come up with design methodologies and processes, and invent new kinds of interfaces and interaction techniques. A long-term goal is to minimise the barriers between a human’s cognitive model of what she wants to accomplish and the machine’s understanding of the task.

This makes sense in terms of what we see of the computer interfaces in Avatar, which seem a logical development from modern technology, our tablets and smart phones, with their applications which respond to touch, and can sense physical movements such as tipping and shaking thanks to internal accelerometers and GPS positional awareness. All of this builds an illusion that the computer applications are part of our physical world.

But if the human interfaces look familiar, current trends would suggest that we ought to anticipate huge advances in computer power by 2154.

“Moore’s law” is an empirical observation that thanks to technological advances and commercial pressure the speed of computer systems (as well as other parameters such as memory storage and relative cheapness) is growing exponentially. This was first described by Intel co-founder Gordon E. Moore, who in 1965 noted that the number of components in integrated circuits had doubled every year since the invention of such circuits in 1958. The doubling is cumulative, like compound interest, so in ten years the increase (two multiplied by itself ten times) would be over a thousandfold.

Similar studies based on other ways to calculate computing power give different values for the doubling time, but all of the same order of magnitude. Futurologist Ray Kurzweil has claimed the law has been working since the mechanical calculating machines of the early twentieth century. And it’s still working today, nearly half a century after Moore’s original paper. As of November 2010, according to the “TOP500” list that keeps a rank of such things, the most powerful non-distributed computer system in the world, a Chinese supercomputer called the Tianhe-1A (“the Milky Way”) was capable of around twenty-five hundred trillion elemental mathematical calculations per second (2.5 petaflops, in the jargon). The TOP500 list, maintained since 1993, confirms a version of Moore’s Law based on the big machines’ processing speeds, with a doubling time of fourteen months.

But Moore’s Law makes even mighty machines look dumb very quickly. With a fourteen-month doubling the Law should ensure that a laptop, presumably available for the same kind of comparative price as today, will pass the power of that big Chinese machine in a mere fifteen years. I won’t depress you here by telling you when the supercomputers, or indeed your phone, will become more powerful than your brain. We’ll consider that stuff in Chapter 32; it would certainly help with the tricky business of linking Jake to his avatar to have the whole process buffered by computers much more powerful than either brain.

Moore’s Law must have a limit beyond which it breaks down; in the end it will come up against fundamental physical limits. But by Avatar’s mid-twenty-second century the world will surely be utterly saturated by extremely advanced computer technology. Just as today it’s in your TV and car and phone, by then we must anticipate that it will be everywhere, in your clothes, your home, in every gadget you use—even in the very fabric of your body, which might swarm with tiny smart medical-repair nano-robots.

For much of the movie’s running time, however, humans are occupied with another sort of intelligence—the Na’vi’s—and on waging war against it.

²⁰ APOCALYPSE SOON

War-making features heavily in Avatar, both on Pandora and on Earth. Quaritch and Jake as serving soldiers saw action in theatres such as Nigeria and Venezuela. This is all too plausible. In Chapter 2 we saw that war doesn’t seem likely to vanish from our world any time soon, thanks to pressures from resource depletion and climate change.

And, in Avatar’s future, we have proudly exported war-making to the stars.

RDA needed weaponry on Pandora long before their dispute with the Na’vi started. As Quaritch warned his newbies, the animal life on the moon, from charging hammerheads to pack-hunting viperwolves to plunging mountain banshees, is ferocious enough. But the focus of the movie is the battle with the Na’vi.

The military strategy RDA and SecOps play out on Pandora has some parallels to the recent conflicts in the Gulf and the occupation of Iraq. These contemporary parallels are deliberate on the part of the movie-makers, as signalled for example by Max Patel’s use of the resonant phrase “shock and awe” to describe the assault on Hometree. We see a mixture of the constant threat of aggressive force with efforts to win over the “hearts and minds” of the local people using the avatars.

And, just as in Iraq, privately employed soldiers, like Miles Quaritch of SecOps, a military contractor working under RDA, are a significant part of the Pandoran landscape.

Today, private soldiering is an industry worth globally a hundred billion dollars. Don’t call them “mercenaries,” however. Nowadays they are known by terms like “private military contractors” (PMCs). Many of them are ex-regular service, like Quaritch; indeed the recruiting pool was boosted by the discharging of military personnel in the 1990s following the end of the Cold War.

Around two dozen PMC firms currently supply services to the Pentagon. They are employed to provide supplementary services to regular forces in theatres of operation around the world. In Afghanistan they have been used as guards to the Afghan president. In many parts of the world they are used to support peacekeeping operations in the absence of regular western troops, or to provide training for local forces.

PMCs are also used by private corporations and international and non-governmental organisations. For instance the Irish company Integrated Risk Management Services provides security protection for Shell Oil operations in Bolivia. Thus the use of SecOps by RDA in Avatar to secure mining operations on Pandora is quite realistic.

There are issues around the use of PMCs, including the fact that under some regulatory systems the soldiers could be considered “unlawful combatants,” without the right to prisoner-of-war status, if they use offensive force in a war zone. The position of the Geneva Convention on this seems unclear to me, if only because in 1977 a revising protocol was not ratified by the United States. Still, an officer going rogue like Miles Quaritch—and indeed the PMC firm which tries to mount a coup against the U.S. government in the seventh season of the TV show 24—are surely, hopefully, never going to be typical.

If the use of PMCs to guard the RDA mining operation on Pandora is realistic, the military technology we see deployed there is thoroughly realistic too.

The scenes of war fighting in Avatar, especially the assault on Hometree and the cataclysmic final battle over the Tree of Souls, are memorable and disturbing. And the depiction of the use of flying vehicles is visually very striking.

Quaritch’s warriors ride into action in a variety of specialised aircraft. The craft shown are all capable of VTOL flight (vertical take-off and landing, including the ability to hover). VTOL would work better in Pandora’s lower gravity and thick air than on Earth, in fact. And the use of VTOL was a realistic choice by the designers in tactical terms; VTOL craft would be highly useful for operations in an environment of dense jungle without landing strips.

Some of the aircraft are “rotorcraft,” analogous to modern helicopters, though using ducted fans rather than conventional rotors. The rotorcraft have two contra-rotating rotors in each rotor pod. This stops the craft as a whole spinning in response to a rotor’s turning; single-rotor craft need tail rotors to keep them stable. Meanwhile the Valkyrie space shuttle hovers by swivelling its turbo engines, rather like a Harrier “jumpjet.”

The use of rotorcraft in warfare has developed since the Second World War. Helicopters were used in that war for some medical evacuations, but it was the Korean War that saw their application on a major scale. The rough terrain in Korea made ground evacuations difficult, and the use of helicopters like the Sikorsky H-19, together with mobile army surgical hospitals—the “M.A.S.H.” made famous in the TV show—dramatically reduced fatal casualties on the battlefield. Later, in Vietnam, craft like the AH-1 Cobra attack helicopter, the UH-1 “Huey,” made possible a new kind of warfare in which troops became a kind of “aerial cavalry,” no longer tied to a fixed position but able to be deployed rapidly across the country. The Hueys became an icon of that war, and were involved in fire support for ground troops and were used in aerial rocket artillery battalions.

In Avatar’s design, Cameron wanted the warcraft to be visually striking, but also to reflect real-world technology. As a result many of the craft have analogues in the inventory of U.S. fighting forces today. The Samson is a general-purpose utility aircraft comparable in size and function to the modern UH-60 Blackhawk, which is used for general air support functions such as medical evacuation, transport, command and control, and support for special operations. The Scorpion gunship, heavily armed, is comparable to modern attack helicopters like the AH-64 Apache, used for precision strikes and armed reconnaissance missions—Apaches are seeing a good deal of action in the Libyan conflict at the time of writing. The Dragon gunship is a heavily armed transport, combat and command and control aircraft which is a hybrid of several current types of craft. It is a transport like the C-130 Hercules, but with its heavy armament it is perhaps most similar to the AC-130 Spectre airborne gunship, a variant of the Hercules developed as a weapons platform for ground attack during the Vietnam War.

The Valkyrie space shuttle is pressed into service as a bomber during the Tree of Souls attack. In combat the Valkyrie serves a role like the Boeing C-17 Globemaster III, a large military transport in operation since the 1990s for the USAF and other air forces. The C-17’s purpose is the airlifting of troops and cargo to operating bases; it combines a very heavy lift capacity with an ability to land on short airfields.

Other weaponry in use on Pandora is also thoroughly recognisable from modern parallels. You could surely fire a modern gun in Pandora’s moist, toxic air, as long as its moving parts weren’t corroded or jammed—as indeed you could fire a gun in space. A bullet carries its own oxidising agent in the explosive of the sealed cartridge, so guns aren’t dependent on the oxygen content of the air, if any. As for corrosion, armies have been dealing with the problems caused by warm, soggy environments like Pandora’s for a century or more, through the use of proper lubricants and frequent cleaning. But on Pandora you would always have to watch out for the jamming of components by the intense magnetic fields.

For the assault on the Tree of Souls the engineers put together pallets of mine explosives, to be dropped out the back of the Valkyrie shuttles. It is pilot Trudy Chacon who describes these improvised weapons as “daisycutters.” This is a Vietnam-era nickname for the BLU-82 weapon system, a fifteen-thousand-pound conventional bomb to be dropped from an aircraft like a C-130. It was one of the largest conventional weapons ever used, and was retired in 2008 to be replaced by the even more powerful GBU-43/B MOAB—Massive Ordnance Air Blast. The daisycutter’s original purpose was to flatten an area of Vietnam forest into a helicopter landing zone. Later, in Afghanistan, it was used as an anti-personnel weapon and for intimidation purposes; it has a very large lethal radius, a hundred metres or more, as well as creating an explosion that’s visible and audible over very long distances.

By its charter, RDA is not allowed to deploy any weapons of mass destruction on Pandora, or indeed to use excessive military force. We see ethical dilemmas on these lines played out in the course of the movie, as Jake, Grace and others oppose Quaritch and Selfridge. But fine ethical distinctions might not have been clear to the Na’vi on the receiving end of the RDA’s improvised daisycutter. Still, an organisation with space travel capabilities could easily do a lot more damage if it tried; a small asteroid prodded towards an impact on the Tree of Souls would unleash energies equivalent to a nuclear weapon.

You might ask if the makers of Avatar have been conservative in their depiction of war-making, with vehicles and weapons with such close parallels to modern gear. The assault on Pandora is some hundred and forty years into the future. A hundred and forty years ago, it was the era of the Civil War in the U.S. and the Franco-Prussian War in Europe; war fighting tactics and technologies have evolved hugely since then. In 2154, would armed forces still be using craft and weapons so similar to those in use now?

Well, specific military technology designs can endure a long time if they work well enough (as indeed they can in the civilian world). The Hercules, or variants of it, has been flying for over fifty years already, and the B-52 bomber, first flown in 1952, has a projected out-of-service date of 2050, by which time it will be a century old! And in Avatar the Samson, for example, is a century-old design.

Then there’s the challenge of the environment. The aircraft shown in the film were primarily designed to operate in Earth’s atmosphere, and have now been adapted for Pandora, with its toxic gases and volcanic products in the air (see Chapter 17), and powerful magnetic fields. You would need to retune turbine and rotor systems, remodel intake ducts, recalculate fuel mixes, harden systems against electromagnetic fields. To face the challenge of such a difficult environment you would want to be able to rely on a robust, proven, veteran workhorse. The Samson is just such a workhorse, tested over decades in a variety of environments on Earth, from the Antarctic to the Honduras—including operations where hardening against electromagnetic fields was necessary, which is why on Pandora it responds relatively well over a “fluxcon,” an area of strong magnetic flux.

And recall that all the aircraft we see onscreen, save for their more complex components like missile tracking and guidance electronics, have had to be manufactured in the stereolithography plants on Pandora. It has been necessary to choose designs, however elderly, that did not need the most modern exotic materials technology, such as (in 2154) exotic ceramics and nanomaterials, beyond the reach of the matter printers. Again, the Samson is one such veteran design. A lack of ground support on Pandora for more advanced systems is another factor.

But this is an instance where we also have to allow for some creative licence. Avatar is about a clash of cultures, the heavy-handed technological human civilisation versus the graceful Na’vi, living lightly in their world. The heavier the human tech, and the grungier it looks, the more striking that contrast is going to be, in every shot when we see the two sides in opposition. And the echoes of Vietnam are deliberate, including references to Apocalypse Now (1979), with its famous scenes of helicopter gunships flapping over the jungle.

The depiction of much of the military hardware in the movie, and the way it is used, is thus thoroughly realistic, at least in terms of today’s technology. One item you won’t see walking around modern battlefields, however, is an AMP suit.

Standing four metres tall on two legs and with its two grasping hands, the Mk-6 Amplified Mobility Platform has a sealed cabin within which its operator (wearer?) rides. The suit’s motions are slaved to the operator’s through servo armatures moved by the operator’s arms, as we see when Quaritch “boxes” inside a suit, with the machine’s huge arms aping the colonel’s jabs. Foot-pedals actuate the legs. The suits come heavily armoured, with weapons ranging from automatic cannon to an ugly-looking slasher knife. The suits have a good deal of built-in smartness, such as an autonomous ability to keep their balance, and even a “walk-back” facility if the operator is disabled. But the amplification of strength and range of motion between the operator’s movements and the suit’s response takes a lot of training to master.

The AMP suit is an outcome of modern-day experiments in developing powered “exoskeletons” for military purposes. An exoskeleton would be like a wearable robot, a mobile machine like a suit of armour with limb movement at least partially supported by the power supply. The aims would be to provide greater strength and speed, as well as armour protection and sensory enhancements, with none of the loss of the fine control the wearer would have over her own body movements. Other applications, perhaps of partial exoskeletons rather than complete ones, might include prosthetics and medical care—an aid to nurses in lifting heavy patients delicately, for example.

The first experimental exoskeleton was co-developed by General Electric and the U.S. military in the 1960s. This programme was said to have been inspired by the powered armour featured in the 1959 Robert Heinlein science-fiction novel Starship Troopers, a classic case of the interaction of science fiction and science. Later fictional examples include Marvel’s Iron Man, and of course the “power loader” machines of James Cameron’s own Aliens (1986).

That first GE suit was too heavy, its motions too violent and uncontrolled. A light and capacious power unit has always been a nagging design issue. But developments continue on various fronts. Lockheed Martin’s appropriately named HULC (Human Universal Load Carrier) is a pair of battery-powered hydraulic legs that reinforce a soldier’s limbs, and give her the ability to carry heavy weights at around fifteen kilometres per hour. Exoskeletons are also being studied as part of the U.S. military’s “Future Force Warrior” advanced technology demonstration project—a lightweight, wearable infantry combat system designed to address the needs of the “Army After Next” in the future. There’s even a civilian-grade exoskeleton, the HAL-5 (Hybrid Assisted Limb), a full-body machine made by the company Cyberdyne; this is already on sale in Japan, and is in use as a support by elderly and infirm people.

You might alternatively regard the AMP suit not as an exoskeleton but rather as an example of a “mecha,” a name given to ambulatory manned fighting robots in some genre fiction. The distinction between mecha and exoskeletons is vague, but roughly speaking a mecha is piloted, while an exoskeleton is worn. The tripodal fighting machines of H. G. Wells’ War of the Worlds are early examples of mecha, as are the “Walkers” of the Star Wars films. Unlike exoskeletons, little military investment seems to have been made in mecha—but a subsidiary of John Deere did produce an experimental six-legged walking harvester! I’ve yet to spot any of those in my local forests.

In the Avatar timeline AMP suits were derived from earlier exoskeleton designs deployed in various war theatres on Earth, and developed for off-world use on the moon and Mars. The suits are formidable weapons in the right circumstances, as we see in the movie during the climactic fight at the remote link shack, when Quaritch in his suit is able to defeat a thanator—and then is able to use his suit’s precision of movement to reach inside the shack to interfere with the equipment there. The suit’s bipedal locomotion could be useful in situations such as Pandora’s dense forests, where the mobility of wheeled vehicles would be impaired. But an AMP suit would always be vulnerable to simple trip-wires, and bolas: thrown weighted ropes, like the one the Na’vi warriors use to bring down Jake. The mighty Star Wars Walkers were similarly vulnerable to bolas.

The ability to wage war on the planet of another star is a quite remarkable accomplishment by those interstellar master traders RDA. But ultimately it is not just the Na’vi RDA finds itself fighting, but Pandora itself: a living world.