An energy shield is a form of technology commonly found in
science fiction, but also in development for real-life space travel [ [http://space.newscientist.com/article.ns?id=dn11623&feedId=online-news_rss20 'Deflector' shields could protect future astronauts - space - 18 April 2007 - New Scientist Space] ] .
A number of efforts to design defensive energy fields are occurring in real life, most notably the efforts to design a
deflector shieldto protect spacecraft that leave the natural defense of the earth's magnetic field. These would generally involve creating a cloud of charged plasma around the ship, which would stop highly charged particles, from the sun or distant supernova, from reaching the ship.
Additionally, deflector shield like effects have been reported by plastics manufacturing companies. These involve incredibly high voltages developing across plastic sheets moving in an arc across an array of guide rollers. The humidity at certain times of the day would reach a certain point, creating ideal conditions for the effect to occur. The air under the arc of rapidly moving plastic is said to become nearly solid, stopping attempts to walk through or even extend ones arm into the region. It was a nuisance and was solved by properly grounding the rollers and walkway.
Typically, energy shields (often referred to as simply "shields") are some form of force field designed to protect against weapons by deflecting or absorbing their impact. The field is projected along the surface of, or into the space around, a starship, space station, planet, moon, or building. Some are small enough for a person to wear in combat, such as in the "Dune", "
Stargate" or "Halo" universe. They are often depicted as translucent or invisible film-like surfaces that glow when impacted.
The concept goes back at least as far as the 1920s, in the works of E.E. 'Doc' Smith and others; and
William Hope Hodgson's " The Night Land" (1912) has the Last Redoubt, in which the remnants of humanity shelter, protected by something very like one. Although fictional, deflector shields have some resemblance to real devices such as magnetic fieldgenerators or plasma windows.
The phrase "Shields Up!" which saw widespread use in
Star Trek, probably had its origin in classical warfare, when infantrywould raise their shields to defend against incoming arrows or other projectiles. The order would be given when it was time for the soldier to raise his shield from the carry position. The intuitive connotation of raising or lowering one's guard (as in boxing) is no doubt responsible for the ubiquity of the expression in science fiction.
The abilities and exact functionality of energy shields vary; in some works (such as in the
Star Trekuniverse), energy shields can stop both energy beams (e.g. phasers) and physical projectiles, both natural and artificial; in others, such as the Star Warsuniverse, there are multiple types of deflector shields—so-called ray shieldswhich are designed to stop energy beams (such as laserand blaster weapons), and particle shieldswhich are designed to stop kinetic projectiles, missiles, bombs, etc.
Energy shields usually work by absorbing or dissipating the energy of the incoming attack; prolonged exposure to such attacks weakens the shield and eventually results in the shield's collapse, making the ship's hull (or building's walls, or planet's surface) vulnerable to attack. Larger energy shield systems, or those powered by bigger energy sources, can absorb/dissipate more damage before failing -- so that larger
starships, for example, can mount much stronger shields than a small, single-person starfighter, much in the way that a sea-going battleshiphas much thicker armor than a tiny patrol boat. However, in some universes, shields are completely invulnerable to all technology of the time, yet can only be operated for a limited period of time, or at a great expense of energy. This is often used in games to give the player temporary invulnerability, such as the Iron Curtain used by the Soviet Union in , along with many online games.
In some science fiction works, a shield does not deflect attacks but rather absorbs them, dissipating the energy of the attack. These shields are most commonly called "screens", "defensive shielding", or even more common, simply "shields."
Personal shield generators, while providing great protection from conventional weaponry, often prove vulnerable to slow moving projectiles as in the spear thrown by
Rogue Trooperin 2000 AD or the knife thrown by Colonel Jack O'Neill to penetrate Goa'uldshields in the Stargateuniverse, the rationale being that a personal shield must allow relatively slow-moving air to pass through it to allow the wearer to breathe. However, in Stargate Atlantis, McKay uses a personal shield they discovered that allowed air to pass through but didn't allow him to eat or drink.
The personal shield used by
John Crichtonin Farscapeis only activated by pulse weapon fire, and automatically shuts down after a certain period of time to conserve energy. The shield is designed to protect against pulse fire, but will even allow its user to stand in molten lava and remain unharmed, though the user must continually shoot themselves with a pulse weapon to prevent the shield from deactivating. This deactivation leaves the wearer vulnerable to attacks that use other energy like the kinetic energy of a rock.
Dune universethe use of Holtzman effectpersonal shield generators is risky, for hits by laser weapons ( lasguns) can trigger a large atomic explosion.
Energy shields in Star Trek
Star Trekwere used for defense from environmental hazards, and defense against weapons. A Constitution class starship's shields could take up to 90 photon torpedoes at once. ().
Energy shields in "Halo"
In the video games "" , "
Halo 2" and " Halo 3", rechargeable energy shields are worn by Elites, placed as stationary defenses, and equipped by the Human Spartan-IIs as a core component of their MJOLNIR powered armor. While not "deflector" shields in the most literal sense (all but the stationary shields absorb energy, much like a Langston Field) Shields in the game are temporarily disabled after absorbing a set amount of energy; however, after a short time, the shield recharges as power is dumped into the shield mechanism from the armor's built-in reactor. "Jackal" enemies have what resemble riot shields based on similar technology, deployed from a buckler-type device worn on the forearm, while the Elites originally had a shield similar to a Jackal's arm shield in the E3 preview for Halo: Combat Evolved. In Halo 3 the bubble shield is introduced, it resembles a giant bubble that will block any projectiles shot or plasma fired at it. Although it deflects projectiles anybody can simply walk through it; just like a bubble.
Energy shields in Stargate
Shields are seen many times throughout the
Stargateuniverse, the most powerful usually being Ancient, Ori and Asgard shields. They are used on all capital ships from all races such as the Goa'uld Ha'takand Human Prometheus and Daedalus class ships. However they all require massive amounts of power with ancient shields requiring zero point modules to power them. The Goa'uld system lords carry personal shields that can resist the energy of a staff weapon blast or machine-gun fire from an SGC standard issue P90 with ease. However, Goa'uld personal shields allow the user to breathe and interact with objects outside the shield, and the field is designed to allow slow-moving objects to penetrate it. This can make the user vulnerable to thrown knives, spears, arrows and other slow-moving projectile weapons to an extent. Ancient shields are even worse: although they provide complete protection from everything, they only let air through, resulting in the user dying of starvation or thirst if they don't know how to deactivate the shield (at least this shield requires the Ancient gene to activate).
Defense screens in Farscape
Peacekeeper defense screens consist of two overlapping energy fields which can protect the ship from kinetic and energy based attacks and can even resist the effects of extreme gravitational forces. Single energy fields suffer from numerous imperfections, with some gaps being large enough for shuttles or fighters to pass through, but with two energy fields operating simultaneously the majority of these imperfections are resolved, and the ship can be protected completely.
When not used properly the defense screen installed on Moya had some unusual side-effects. During a confrontation with a
Halosianship, an energy beam was fired at Moya while the defence screen was charged to 62 percent. For unclear reasons this caused the crew to switch bodies, and they required the Halosian ship to fire upon them two more times to restore them to normal.
Protoss Plasma Shields
In StarCraft, the Protoss employ a shielding technology which works by employing Khaydarin crystals to amplify the user's natural psionic power in order to generate an energy field which can resist hits to a certain extent. The shield automatically recharge while the user is not under fire, presumably because the shield is psionic in nature and the user obviously can't concentrate on the shield while fighting; though this does not explain the presence of a shield on structures or entirely robotic units.
In game, the shield does not experience damage reduction against certain weapons unlike regular armor (meaning the shield always take 100% damage minus shield level). Additionally, the target cannot be injured until it's shield is completely depleted at which point it starts taking damage normally. This is probably a game balance issue as Protoss units cannot be repaired by any means, unlike the other two races (Zerg can regenerate and Terrans can repair mechanical units with SCV units, as well as deploy Medics in the expansion pack). To counter this, shields can be recharged nearly instantaneously with a specialised structure, although the one-time charge is very limited (hardly enough for a Carrier).
Energy shields in the "Earth 2150" trilogy
Several years before the first game, the Lunar Corporation discovered ruins of an alien base on the Moon. Within the base's tunnel systems, they found several technological artifacts, such as an
anti-gravitypropulsion system, a shield and and orbital bombardment system what would later become known as Project Sunlight. The only thing known about this shield is that it's magnetic in nature. The reverse-engineered version was deployed on all vehicles as a form of protection against solar radiation. Later, engineers found that it can be used to counter all forms of energy-based weaponry. After some initial difficulties (Earth's own magnetic field and atmosphere interfered), it was deployed as standard-issue equipment on all LC hovercraft. However, it had a weakness: although energy weapons were rendered totally ineffective by this new defensive system, it was totally useless against normal kinetic and explosive weaponry. Worse yet, both opposing sides have managed to steal and copy the shield, resulting in much weaker, but just as effective replicas.
In game, the shield is depicted as a bubble-shaped white-blue net briefly appearing around the shielded unit or structure whenever it was hit by an energy-based weapon (ED laser and ion, UCS plasma, or LC Electro and Sonic cannons). Although the unit takes no damage from the hit, it damages the shield greatly: a determined opponent can take out a fully charged shield in seconds, especially since it regenerates very, "very" slowly and that it is completely helpless against non-energy weapons such as rockets. Additionally, the LC version can take twice as much beating as the others, somewhat making up for their comparatively weak energy weapons. It was probably put in as a counter to the game's most powerful weapons (not counting WMDs).
* [http://news.bbc.co.uk/2/hi/science/nature/6567709.stm Space shield to block radiation] BBC news
* [http://www.orion-nasa.us/20-apr-2007-ras.html Scientists to Construct Experimental Magnetic Deflector Shield for Spacecraft.]
* [http://memory-alpha.org/en/wiki/Shields The Star Trek Wiki] Information For Star Trek Shields
Force field (science fiction)
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