Protection or Prison?

Force fields are a staple of science fiction - sometimes waved away as future technology, sometimes presented with an attempted explanation, but usually large in scale and mounted on spaceships. Here I’m going to take a look at some of the challenges and opportunities presented by their smaller cousins, personal shields, in science and science fiction.

[Note: In several cases the behaviour, nature and consequences of personal shields form the conclusion of stories. As a result it’s not possible to avoid spoilers in the following.]

Science Fiction Staples

Almost since the start of science fiction, writers have recognised that force shields of some unexplained kind are a necessary prerequisite for many kinds of space opera. Human beings are fragile, sensitive to radiation and gas pressure, able to tolerate a narrow range of accelerations or forces, and specific atmospheric compositions. Protecting us from extremes, without lumbering characters with unwieldy space armour, was necessary if fiction was not going to become bogged down in limitations rather than possibilities.

The majority of science fictional personal force fields fit into this category of narrative conveniences, shields which are not explained but instead treated as subject to Clarke’s Third Law: any sufficiently advanced technology is indistinguishable from magic.

An interesting early example where this is recognised, albeit indirectly, can be found in the Foundation saga by Isaac Asimov. The short story The Big and the Little (Astounding, Aug 1944, later incorporated into the novel Foundation, 1951), follows the rise of merchants in the hierarchy of the Federation. Merchant Hober Mallow makes a career of trading amongst the Foundation’s neighbours, and notices a worrying trend: with the retreat of the Galactic Empire, the rim worlds are losing their knowledge of atomic power. To get to the truth, he bribes a power technician on the planet Siwenna with a device that arises from the Foundation’s science, but which is seen as magic by the regressing populations of neighbouring worlds:

“The molecules of air caught in the sudden surge of atomic disruption, tore into glowing, burning ions, and marked out the blinding thin line that struck at Mallow’s heart—and splashed! While Mallow’s look of patience never changed, the atomic forces that tore at him consumed themselves against that fragile, pearly illumination, and crashed back to die in midair.”

This amazing personal shield earns Mallow access to the power plant… but is designed to fail a few days later, so that the technology does not spread further. Such personal shields become emblematic of the Foundation’s growing power as it preserves and develops knowledge lost to others around it. Even the captain of a ship coming from the rump of the surviving empire (in the next story, Dead Hand, in Astounding, April 1945) is astonished:

“An individual force-shield?” Riose glared. “You speak extravagance. What generator could be powerful enough to condense a shield to the size of a single man? By the Great Galaxy, did he carry five thousand myria-tons of atomic power-source about with him on a little wheeled go-cart?”

The details of the technology are never explained, although it is clearly atomic in nature.

Also unexplained, but essential for human survival, is the “null field” widely deployed through John Varley’s Eight Worlds series. In this future, humanity has been driven from Earth and instead occupies a range of artificial environments throughout the Solar System. Several of those, including particularly Venus, are habitable only as a result of the development of personal forcefields.

In the Bowl (short story, Varley, F&SF, Dec 1975), describes a man prospecting for delicate and explosive gemstones on the surface of Venus, under a deep atmosphere that distorts light such that the horizon seems to curve away upwards. From the perspective of a newcomer to the planet, we’re told that:

“The Venusians use null fields for just about everything. Rather than try to cope with a technology that must stand up to the temperature and pressure extremes, they coat everything in a null field and let it go at that.”

….

“It simplified a lot of things. Airlocks, for instance. What we did was to simply walk into the tent. Our suit fields vanished as they were absorbed into the tent field. To leave one need merely walk through the wall again, and the suit would form around you.”

Like many aspects of the genetic engineering, memory/personality recording and blackhole technologies in the Eight Worlds, null fields are never fully explained, but their utility and the need for them are obvious.

Some fictions are more explicit still about the alien quality of such technology. In Isaac Asimov’s Lucky Starr series of juvenile novels (written as by Paul French) the protagonist is gifted a personal shield device by powerful and ancient aliens on Mars, as a signal of his individual qualities and virtue.

Asimov was certainly aware of the problems with personal shields given our current technology, and his characters voice them:

“You feel nothing. Yet what appears to you as smoke is a barrier which is resistant to short-wave radiation and impassable to material objects of larger than molecular size.”
“You mean it is a personal force-shield?”
“That is a crude description, yes.”

David said, “Great Galaxy, it’s impossible! It has been definitely proven that no force-field small enough to protect a man from radiation and from material inertia can be generated by any machine capable of being carried by a man.”

“And so it is to any science of which your fellows are capable of evolving.” (David Starr, Space Ranger, ch 11).

The gift of this mask-shield saved the life of David (a.k.a. Lucky) Starr several times in the first novel, and again in the second. However, Asimov quietly retired the personal shield early in the series - presumably finding that an unharmable protagonist presented a challenge to maintaining reader tension.

By contrast, the device in Poul Anderson’s novel Shield is the result of co-creation between ancient Martians and the human crew who have spent five years living and working with them, reaching a synthesis of the sciences beyond previous discoveries of either race. Unfortunately, on returning to Earth with the only copy of the device, Pete Koskinen discovers that vested interests will do anything to stop him from using the personal shield or letting it fall into other hands.

Anderson spends an early chapter describing the operation of his shield, as Koskinen discusses it with an engineer, Vivienne Cordeiro:

“A two-way potential barrier, I suppose, analogous to a mountain range between the user and the rest of the world. But I’ve determined myself, today, that it builds from zero to maximum within the space of a few centimeters. Nothing gets through that hasn’t the needful energy, sort of like the escape velocity needed to get off a planet. So a bullet which hits the screen can’t get through, and falls to the ground. But what happens to the kinetic energy?”

“The field absorbs it.” he said, “and stores it in the power pack from which the field is generated in the first place.”

This cylindrical and adjustable field allows light to penetrate, so the user can see out, and - unusually practically for these things - also comes equipped with an air-cycling device so the user doesn’t suffocate. However it has many of the flaws of other such devices, including susceptibility to the passage of heat or laser weapons, immobility, and the need for an occupant to stock up on food and water inside the field lest they be starved out. More importantly it has the potential to destabilise the somewhat despotic post-nuclear-war world order, in which America has declared the world its Protectorate and acts ruthlessly to quash any hint of dissent in the name of preventing another conflagration.

While the above cases make some attempt to explain the alien origins of shields (if not always their function), in many others, such as in the Borg of the Star Trek universe or Star Wars’ battle droids, personal force-shields are simply shown as unexplainable but undeniable alien realities.

Sword and Spaceship

An interesting subset of personal shields in science fiction share a common trait: their ability to stop penetration correlates directly to the velocity of a projectile. As a result supersonic penetrators such as bullets, or even in some cases weaponised light, are effectively stopped, while slower moving objects can be passed through the field with little or no impediment.

An early advocate of such technologies was E E ‘Doc’ Smith in his Lensman series. While much of the fighting in this series was on a mental and intellectual plane, a memorable bunch of support characters are the Valerian Marines: robust, six-foot men of Dutch descent boasting muscles developed by their upbringing on a heavy-gravity planet. These mercenaries famously wield heavy battle axes, designed to bypass personal shields which scale in resistance with the cube of the velocity of a weapon rather than its mass or momentum. Near the opening of Galactic Patrol (novel, 1950; combining short stories, 1937), Smith describes a battle in which "Explosive and solid bullets detonated against and ricocheted from that highly efficient armour, the beams of DeLameter hand-projectors splashed in torrents of man-made lightning off its protective fields of force." By contrast "the minions of the Law had one remaining weapon, carried expressly for this eventuality. The space-axe - a combination and sublimation of battle-axe, mace, bludgeon, and lumberman's picaroon, a massively needle-pointed implement of potentialities limited only by the physical strength and bodily agility of its wielder." Against this, any force field ultimately proves ineffectual.

Charles L Harness established a similar form of shielding in his 1953 novel The Paradox Men (a.k.a. Flight into Yesterday). In his future American Imperium, a third of the population is enslaved. The Society of Thieves steals from the rich, Robin-Hood-like, and uses the funds to emancipate the poor. The individual Thieves have personal force fields which snap on when they are at risk - whether or not they are aware of it. The authorities have no idea how, and, as we’re told:

“The few Thieves we’ve taken alive don’t know either. Under Shey’s persuasion they indicated that it was a velocity-response field based electrically on their individual encephalographic patterns, and was maintained by their cerebral waves. What it really does is spread the bullet impact over a wide area. It converts the momentum of the bullet into the identical momentum of a pillow.” (chapter 2)

The origin of these fields are never explained any further, and may originate from the mind of a god-like advanced human afflicted with amnesia who is caught up in this milieu. Their primary role in the narrative is to motivate the return of this society to the use of swords, and to rituals such as personal duelling. Despite their sharp edges, swords move too slowly to activate any significant resistance. However Thieves are also vulnerable to energy beams and to explosive impacts powerful enough to lead to internal injury despite the efforts of the shields.

A slightly later proponent of velocity-limited fields was Frank Herbert. The great houses of his galaxy spanning empire in Dune (novel, 1965, and sequels) are equipped with large shields designed to protect infrastructure and ships, and also with personal shields. These permit the passage of particles below a threshold velocity (usually 6-10 cm/s), in order to permit the exchange of atmosphere and allow the user to breathe. A young Paul Atriedes explains the effect during a self-defence lesson early in the book:

"What a dolt my father sends me for weaponry," Paul intoned. "This doltish Gurney Halleck has forgotten the first lesson for a fighting man armed and shielded." Paul snapped the force button at his waist, felt the crinkled-skin tingling of the defensive at his forehead and down his back, heard external sounds take on characteristic shield-filtered flatness. "In shield fighting, one moves fast on defence, slow on attack." Paul said. "Attack has the sole purpose of tricking the opponent into a misstep, setting him up for the attack sinister. The shield turns the fast blow, admits the slow kindjal!" Paul snapped up the rapier, feinted fast and whipped it back for a slow thrust timed to enter a shield's mindless defences.

The in-universe explanation invokes the same “Holtzman” fields used to nullify gravity and permit faster than light travel in Dune. The result is that projectile and directed energy weapons are replaced in Dune with melée weapons and martial arts which focus on the very slow and controlled use of handheld daggers.

These examples are all firmly seated in the long history of space opera, which can be traced back to swashbuckling stories of adventure here on Earth. In each case, part of the goal of the writer was to return some aspects of science fiction from long-distance, mechanised weaponry to more classical adventure stories and personal battles between characters.

Perilous Prisons.

A personal shield has clear advantages for its users in terms of personal protection and environment stability. However a number of authors have speculated about the possible drawbacks of shield technology. 

An amusing parable of this kind is Early Model by Robert Scheckley (short story, Galaxy, August 1956; adapted for radio as part of anthology series X-Minus-One). In the story, a human explorer, Bentley, attempts to make first contact with a new species on the planet Tels IV. As part of an essential equipment set so bulky he can barely walk, he has been equipped with a billion dollar’s worth of brand new prototype shield device. Not only is he strapped into it without instructions on removing it (deliberately, to ensure a complete and reliable test), but it decides for itself when to come on… as for example when he is offered a symbolic ritual spear as part of a welcome ceremony.

“When a Protec force field goes on, it appears as an opaque black sphere, some ten feet in diameter. If it is struck, it repels with a force equal to the impact. White lines appear in the sphere's surface, swirl, coalesce, vanish. And as the sphere spins, it screams in a thin, high-pitched wail.

All in all, it was a sight hardly calculated to win the confidence of a primitive and superstitious people.” 

It also chooses to protect him against a puppy, and even from more passive threats:

“He fell asleep again and immediately began to dream that he was locked in a prison of bright red sponge rubber. He could push the walls out and out and out, but they never yielded, and at last he would have to let go and be gently shoved back to the center of the prison. Over and over, this happened, until suddenly he felt his back wrenched and awoke within the Protec's lightless field.

This time he had real difficulty finding the controls. He hunted desperately by feel until the bad air made him gasp in panic. He located the controls at last under his chin, released the field, and began to search groggily for the source of the new attack. He found it. A twig had fallen from the thatch roof and had tried to land on him. The Protec, of course, had not allowed it.”

Unlike many of the other shields here, Scheckley’s does not allow the passage of air - so when the aliens become determined to destroy him, its constant activation becomes problematic. He risks being suffocated and starved, and completely unable to retreat to his own vessel. Unsurprisingly, the aliens become convinced that he has a devil on his back.

A similar problem - the inability to shed a shield that has become a prison, arose elsewhere. While most science fictional television series where personal shields appear do not attempt to explain them, the television series Stargate Atlantis (2004-2009) spent an early episode exploring the consequences of one such device. This series involves humans exploring the technology of a lost city of the Ancients, while isolated from home by distance and energy limitations. In order to use the technology, a specific genetic marker is required, and - after receiving a treatment to implant the marker - Doctor Rodney McKay decides to test his by activating a personal invulnerability device (episode “Hide and Seek”, 2004). The result is a skin-tight field that allows the passage of air, but stops everything else - whether matter or energy. It also dissipates impacts, with some form of inertial dampener.

Initial tests include firing a weapon at McKay and throwing him off a balcony, to the delight of all. However when a mealtime arrives, McKay is unable either to deactivate the shield or to consume food or drink. Instead, solid and liquid just bounces off the impenetrable layer. It becomes apparent that the device’s controls are purely mental, and its field is being maintained by McKay’s deeply embedded fear of violent death (which, given his career and posting, is perhaps reasonable). However, the scientist is at risk of death from dehydration and starvation before he is tricked into overriding his own subconscious fears. Unfortunately, the shield’s internal energy supply is rapidly depleted by a series of dangerous encounters, in which McKay is exposed to risks that might not have been taken if the shield did not exist.

Subsequent episodes include the discovery of a second shield, and its use by an unscrupulous trickster to pose as a defending hero. When this shield is also depleted, the man is left vulnerable and unprepared for attack.

The shields here promote overconfidence, and emphasise the degree to which misuse of such a shield could place the user in more danger than its absence. This is also emphasised in a short story which pokes affectionate fun at some of the tropes of twentieth century science fiction. Great Lost Discoveries II - Invulnerability (Fredric Brown, 1961; the other two in the series are Invisibility and Immortality) suggests that an invulnerability-granting force field was discovered by a naval officer, Lieutenant Paul Hickendorf in 1952. Being en-route to the first hydrogen bomb test on a Pacific atoll at the time, he decides to hide out on the island to prove its efficacy against heat and radiation. The field works flawlessly - but he is thrown off Earth above escape velocity, and rapidly exhausts the air carried inside the field before eventually falling into the Sun.

Psychological Shields

If force shields have physical flaws, then have they also got psychological ones?

No Shield from the Dead is a short story by Gordon R Dickson, that first appeared in Worlds of IF, January 1953. The protagonist, government Comptroller Terri Mac is decoyed to a party which he soon realises is populated by actors. Bemused he loses no time in bragging about his invulnerability to his remaining host after the actors are dismissed and he finds himself trapped:

“Why? You senile old fool, don’t you know that I’m shielded. Don’t you know that all government officials from the fifth class up wear complete personal shields that are not only crack-proof but contain all the necessary elements to support life independently within the shild for more than twenty hours? Don’t you know that I’ll be missed in two hours at the most and tracked down in less than sixty minutes more? Are you crazy?”

In fact the old man’s intention is not to physically attack Mac. Instead, his goal is to introduce a two hour gap in the man’s surveillance record. In this overly officious world, that would not only prevent him from rising further through the hierarchy, but also lead to interrogation, bringing to light certain sins of the past. Despite Terri Mac’s impenetrable shield, he remains vulnerable to the actions and decisions of others - and to his own decisions. Ultimately, backed into a corner, he is unable to resist a psychological breakdown that his shield does nothing to prevent.

A final example of a personal shield, and one which emphasises the threat of overconfidence can be found in Kristine Kathryn Rusch’s The Room of Lost Souls (Asimov’s, 2008, a sequel to 2005’s Diving Into the Wreck). In this story, a wreck-diver - a person who makes a living salvaging objects or discovering information from long-abandoned space ships - is forced to revisit her past. As a child she had emerged from a room on an ancient space station into which hundreds of others had vanished over the course of centuries, including her own mother. Now she is hired to go back into the room in the hope of finding one of those lost. Her clients - her own father and the child of one of the room’s other victims - claim this is possible due to a personal shield they provide:

“How it works is simple: It acts like a space suit—creating a bubble around the user that contains both environment and gravity and anything else the user might need. It has the same flaws a space suit has as well: It allows a person to enter an environment but not interact with it—or at least, not interact in important ways.

But the shield is different from a space suit as well. From the first discovery of the Room, humans have tried to enter wearing spacesuits, and that has not worked. So Riya Trekov’s device negates something—or protects against something—that a space suit does not. Somehow, that device—that bubble it creates—is the perfect protection against the Room.

At least that is what my father would have me believe.”

However when, doubting her own emotional stability, she hands over the device to a fellow diver for the first attempt, the results are disastrous. In fact, the shield is a box with coloured lights on it, a placebo to conceal the fact that the protagonist is one of the few with a genetic marker which allows her to enter the room safely. In other words, the protection here is psychological rather than physical.

Protection or Prison?

In many ways, personal shields are simply a narrative convenience in science fiction. They mitigate the obvious dangers of travel through the vacuum of space, provide protection against the ray-guns that coevolved alongside them in science fiction, and reduce the requirements for bulky, hard to maintain and harder to move in spacesuits. They may prove not only valuable but vital for settling other worlds - if they can ever be proved viable. However the fictions described here demonstrate that they can be much more than that.

As one of the archetypal technologies of science fiction, they have become emblematic of more advanced cultures and technologies, as in Asimov’s Foundation stories or Star Trek’s Borg Collective. For stories focussing on their creation, even when parodied, as by Fredric Brown - they provide an opportunity to explore creativity and discovery, particularly amongst scientists. 

However in examples ranging from the dawn of science fiction to the current day, personal force shields are also used as a warning against arrogance, and an indication of the limits of technology - in a way that space ship or installation force fields are not. A device optimised against any one threat - such as ballistic weapons or energy guns - or even all of them, almost always has flaws in the form of cutting off light, air-supply or free motion. A subset of stories, including Dune, have gone further and reminded us that sometimes the most advanced technologies can be overcome by the most primitive weapons - swords and spaceships are equally important amongst the nobility of Herbert’s empire.

Force shields - let alone personal defensive shields - lie well beyond our powers to construct. While we can set up electromagnetic fields, given enough power supply, we cannot prevent them interacting (potentially negatively) with anything inside them. Nonmagnetic bullets or concentrated lasers could pass through them effectively unimpeded. Robots can be trained not to pass infrared barrier ‘walls’ but a robot tuned to a different frequency will pass through one with impunity. And any device capable of blocking light-based energy weapons will form an impossible-to-see-out-from black mirror like that encountered by Scheckley’s explorer Bentley. Kinetic energy can be sapped by barriers of air, sound or magnetic pressure, but not with sufficient rapidity to prevent damage to anyone inside them, and not without conservation of momentum transferring much of the damaging force elsewhere - most likely to the occupant. Even the more benign uses proposed for personal force-fields - as programmable clothing, or even as an every-day umbrella (e.g. Delay in Transit, F L Wallace, Galaxy, Sep 1952) - exceed our capacities.

All in all, despite nearly a century in our imagination, personal force shields remain as much a Clarke’s Third Law technology as they ever were. They also remain a warning for those who could become overconfident - a reminder that no protection is perfect while its user remains a fallible human.