Cloaking device

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Not to be confused with Cloak of invisibility.

A Klingon Bird of Prey from Star Trek VI: The Undiscovered Country fires while using a cloaking device

In several science fiction universes, a cloaking device is an advanced stealth system which causes an object, such as a spaceship or individual, to be invisible and extremely difficult to detect with normal sensing instrumentation.

1 Conceptual origins
2 Scientific experimentation
3 Holographic Cloak
- 3.1 Optical camouflage
4 See also
5 References

[edit] Conceptual origins

[edit] Star Trek cloaking device

This article or section may contain original research or unverified claims.
Please improve the article by adding references. See the talk page for details. (October 2007)

In Star Trek, cloaking devices were first introduced and used by the Romulans in the Original Series episode "Balance of Terror", though the device was only referred to as "a practical invisibility screen." The invisibility came as a surprise to the crew of the USS Enterprise, who considered it only a theoretical possibility. In a later episode, "The Enterprise Incident", the Enterprise is sent on a mission to capture one of the devices, and the device is first given its name in that episode. Decades later, the episode "Minefield" of Star Trek: Enterprise contradicted this by revealing that Romulans possessed a form of cloaking technology in the mid-22nd Century, suggesting that what was featured in "Balance of Terror" et al was some sort of improvement, or that, for some reason, Starfleet Intelligence (or perhaps agents in the Temporal Cold War) suppressed knowledge of the cloaking devices encountered a century earlier, after the 4th season opener which ended the temporal cold war thread, all references to cloaking devices were removed by the new show runner, this could taken as part of the restored timeline. Enterprise also encountered several other races with cloaking technology, including briefly obtaining a cloak-capable pod belonging to the Suliban. In addition, the Mirror Universe Enterprise was also fitted with a Suliban cloaking device in the two "In a Mirror, Darkly" episodes. The Suliban cloaking device allowed the Mirror Enterprise NX-01 to fire weapons while cloaked.

The device was next seen in Star Trek III: The Search for Spock being used by Klingons. The original script of Star Trek III featured Romulans as the antagonists, but was rewritten to feature Klingons. Much of the plot relied on the use of a cloaking device, although prior to Star Trek III the Romulans were the only race to have developed cloaking technology. To explain how the Klingons acquired cloaking technology, fans have speculated that as part of an earlier mentioned Romulan-Klingon alliance, the cloaking device was given to the Klingons in return for warp drive. Critics of this theory point out that this requires the Romulans to have fought an interstellar war without faster-than-light drives. The Enterprise episode "Minefield" shows cloak-using Romulans in a system that was far away from Romulan space, which would certainly have required the use of a warp drive. The alliance must have existed, however, as Romulans have been seen using a Klingon ship in the original series. This has led some fans to theorise it was this ship, the D-7, that was traded to the Romulans as opposed to the warp drive.

Cloaking is not perfect. In "Balance of Terror", the Enterprise was still able to detect the Romulan ship on motion sensors, and in the Star Trek: Deep Space Nine episode "The Search" we learn that running at a high warp speed may allow detection. The biggest weakness is that the device has such high power demand, it must be deactivated for a ship to enter combat. Thus, an alert enemy can target it normally when the ship decloaks. Another weakness on older Klingon ships is the need to drop the force field in order to use the cloak as it utililizes the same power systems as the shields. This was shown in the movie Star Trek Generations where the Enterprise was able to cloak the Klingon vessel using an ionic pulse and then target the cloaking ship whose shields had to go down in order for the cloak to engage. A major plot element of Star Trek VI: The Undiscovered Country was the invention of a new type of cloaking device that would allow firing whilst cloaked. However, it was learned that the prototype ship using it could be tracked by plasma (ionized gas) exhaust from the ship while moving at impulse. It is very strange that no such technology was shown to be possessed by the Klingons 70-80 years later.

In the Star Trek: The Next Generation episode "Redemption", the Federation discovers a way to use nets of tachyon beams to set traps for cloaking ships.

In the Star Trek: Voyager episode "Prophecy", Voyager encounters a Kirk-era Klingon vessel wandering the Delta Quadrant. A brief exchange between Janeway and Tuvok indicates that a simple method of detecting cloaked ships of that era is common knowledge in Voyager's time. "As detection methods advance, so too do cloaking devices".

Many have wondered why the Federation did not begin using cloaking devices after Kirk captured one. The reason is that Gene Roddenberry depicted a Starfleet that morally rejected such a "sneaky" technology despite the obvious strategic advantage being ceded to the Romulans. An in-universe explanation is that the Federation signed a peace agreement in 2311, the Treaty of Algeron, in which they promised not to develop cloaking technology ("The Pegasus"). Satisfied that the Federation would not develop threatening technology, the Romulans then turned their attentions inward, and for the most part withdrew from galactic affairs for over fifty years ("The Neutral Zone"). However, the "The Pegasus" did depict a failed covert Federation programme to develop a phased cloaking device.

In Deep Space Nine, the Romulan Empire allowed Starfleet to place a cloaking device on board the USS Defiant. Originally, the Federation was only allowed to use the device in Gamma Quadrant space, in exchange for any Federation intelligence gathered from the Defiant. However, that restriction soon was regularly ignored by Captain Sisko, who used the device to hide from Klingon vessels during the brief breakdown in relations between those two powers. It was also discovered that the Dominion could detect a cloaked ship by scanning the area with an anti-proton beam. It's not clear if the Federation is still prohibited from using cloaking technology, or if the two powers have since signed a new agreement regarding such technology.

Jem'Hadar warriors are born with the ability to "shroud" themselves naturally making them invisible to the naked Human eye and most sensors, though this cannot be achieved if the individual is suffering from Ketracel White withdrawal due to the intense concentration required. This concentration also forces a Jem'Hadar to stop shrouding before performing any action requiring focus, such as attacking. The Tosk, who are possibly related to the Jem'Hadar, possess a similar ability.

In Star Trek Nemesis, the Remans developed a new cloaking device which was impenetrable to Federation scans. This was employed on Shinzon's ship the Scimitar. The Reman cloaking device employed Thaloran radiation as the source of power. The radiation also had the affect of transforming biomatter to stone. Like the Klingon ship in Star Trek VI, the Scimitar had the ability to fire while cloaked, and also demonstrated the ability to raise its shields. This reflects a fundamental change in cloaking technology, as the biggest drawback of no shields has been overcome.

[edit] Star Wars cloaking device

Cloaking devices play a much less significant role in the Star Wars universe. The first Star Wars reference to cloaking devices is heard in The Empire Strikes Back when Captain Needa states that no ship as small as the Millennium Falcon can be equipped with a cloaking device—however, the Expanded Universe has appeared to contradict this in places, mentioning that Emperor Palpatine's shuttle had a cloaking device, as did the personal spaceship of his early apprentice, Darth Maul. Various retcons have been proposed, most notably by Dan Wallace who suggests that this discrepancy could be retconned as Needa referring to power requirements of early hibridium cloaking prototypes, or possibly the power requirements of the old, failing, stygium cloaking devices.^[1]

The Expanded Universe Star Wars books and games have included and elaborated upon cloaking devices, and have presented a solution to the earlier problem as to how big a ship has to be equipped with such a device: the original cloaking devices were small objects created from very rare naturally occurring stygium crystals. However, in later years (such as during the Empire) these crystals seem to have been depleted, with the surviving devices being extremely expensive, only ships as important as Palpatine's shuttle would be equipped with them. By the time of The Empire Strikes Back, the only cloaking devices known to exist (without the aid of stygian crystals) were much larger, and required vast amounts of power, as well as the design being an Imperial military secret. It is one of these far less practical devices that Captain Needa was referring to.

In the Star Wars: Battlefront II game, a Bothan Spy has the ability to activate a cloaking device which also hides the weapon.

The plot of the Rebel Assault II video game concentrates on the danger presented by a type of TIE fighter that can cloak, according to the game the first ship of the size with such a capability. This "TIE Phantom", a modified V-38, was the brainchild of the genius Grand Admiral Martio Batch. The new fighter had undergone some combat experience and entered production before the factory and all existing models were destroyed. The cloaking device of the TIE Phantom seems to be fueled by oridium ore and produces a "cloak field" that renders the fighter effectively invisible to both electronic sensors and human sight. The fighter becomes visible a short time before firing, suggesting the cloak field renders the ship double-blind. As the fighter cloaks or uncloaks, various parts of it fade in and out of view and the ship shimmers a bluish color. The TIE Phantom's cloaking device is considered by some to be more of an active stealth system with electronic systems to break up incoming sensor beams and a refractive surface covering to make it harder to spot visually.

In the PC game TIE Fighter, the Vorksnix Project manages to develop an experimental cloaking device that is small enough to be used on a Corvette. However, it had a significant flaw in that it was very unstable when used in conjunction with a hyperdrive. Attempting to operate both at the same time would cause the ship to explode.

The Star Wars universe's cloaking devices were a major element of The Thrawn trilogy: it was explained that cloaking devices in the Star Wars galaxy are limited by fundamental laws of physics (in order to observe, one must be observable as well) and were never put into widespread use because of this limitation. The cloaking device renders a ship effectively "double-blind"; a ship using a cloaking device can sense nothing about its surroundings. Although a cloaked ship could fire while cloaked, it would be firing blindly and the probability of hitting its target would be minimal to the point of impracticality, even with the addition of a fire control predictor computer to the system. Worse, basic navigation was impossible, and a cloaked ship might end up fatally ramming an enemy ship or a friendly ship. Communication with a cloaked ship is also impossible.

Despite the Empire's attempt to produce and use a cloakable fighter, cloaking devices were never widespread in the Star Wars universe. Using the insane Dark Jedi Master Joruus C'baoth, Imperial Grand Admiral Thrawn successfully implemented a plan whereby C'baoth would use the Force to communicate with the firing crews on cloaked Dreadnaughts, allowing him to A) fool the New Republic into thinking he had developed or obtained a weapon that could fire through planetary shields, which he had not, and B) in the ingenious conquest of the planet Ukio with its defenses intact. Ukio was an important foodstuff-producing plant vital to Thrawn's plans to rapidly expand his forces with clones, and when his fleet advanced Ukio activated their planetary shields, rendering them impervious to orbital bombardment. However, Thrawn had already positioned cloaked Dreadnaughts beneath the planetary shield, and using C'baoth's communication with the cloaked ships, he executed an incredibly well timed maneuver: his Star Destroyers would fire at ground targets that were directly underneath the cloaked Dreadnaughts; the Star Destroyer fire would be deflected by the shield, but C'baoth would order the cloaked ships to fire a split second later: to the observers on the ground, it appeared that the Star Destroyers were firing through the planetary shield, and Thrawn fooled them into thinking this was some sort of new superweapon which they had no defense against. The government of Ukio then contacted Thrawn and surrendered, with their planetary defenses fully intact for Thrawn to take control of. However, the ruse was eventually revealed, and with the death of C'baoth, cloaking devices were again rendered impractical for widespread deployment.

Grand Admiral Thrawn also devised a use in which a cloaking device was used to conceal several squadrons of TIE fighters and mole miners inside a freighter's cargo bay, which was then piloted into a heavily-used shipyard (Sluis Van). The freighter's cargo was cloaked instead of static damped, to reduce suspicion as to the surprise in the cargo bay. The freighter was scuttled explosively, and the fighters released in a surge to the complete surprise of the yard's defenders. This was timed to coincide with an attack by several Star Destroyers.

Thrawn also developed one additional tactic involving the use of cloaking devices—as a siege weapon. This tactic was only used once, involving, as it did, an enormous amount of resources, but it was highly successful. Essentially, Thrawn attacked the then-New Republic controlled Couruscant with a full fleet. As the battle progressed to the point that Thrawn wished, Thrawn's flagship Chimaera (as well as other Star Destroyers present at the battle) began to launch 22 cloaked asteroids, knowing, and intending, that the energy of the launches would be detectable by surface-based sensors. However, the asteroids were launched cloaked, and to further the confusion of the defenders, the tractor beam emitters had shunts attached to them, allowing them to draw power—and thus be detectable on the sensor boards—without them actually doing anything. So, when the New Republic military detected a grand total of 287 tractor launches from Chimaera and other Star Destroyers present, they were faced with the possibility of having to find up to that number of cloaked asteroids, in unstable orbits around Coruscant, that would eventually crash down on the planet. As a 40-meter asteroid would do an incredible amount of damage on a planet with Coruscant's population density, they were unable to lower the planetary shields. Besides requiring massive amounts of energy, this also prevented any ships from landing, shutting the planet off from food supplies and other important imports.

In the Dark Nest trilogy showed that the Chiss, a species that Thrawn belonged to, utilized a Star Destroyer design that featured a working cloaking device.

In the two Knights of the Old Republic games, the player and his/her character can wear a personal Cloaking Device, called a Stealth Field Generator. The player can wear it to sneak behind enemies but will be revealed once they attack or if they go too close to enemies. Sith Assassins from Star Wars: Knights of the Old Republic II The Sith Lords also use Stealth Field Generator devices to attack enemies, but their only difference from the player is, their weapons can attack while the generator is active and only switched off once the assassin is injured. In Knights of the Old Republic II, G0-T0's Yacht also poses a clocking device to protect it from republic and other ships due to its pirating of trading ships entering the Nar-Shadda system, the Jedi Exile deactivated this from four controls inside the yacht and as soon as they escape the ship, it is almost instantly destroyed.

[edit] Stargate cloaking device

In the TV series Stargate SG-1, Goa'uld Tel'tak cargo ships have an imperfect cloaking device which makes them invisible but still allows for detection; this has been modified (to the surprise of SG-1 and the dismay of the Tok'ra) by the System Lord Apophis to cloak entire Ha'tak motherships. Anubis, a partially Ascended goa'uld (and therefore in possession of some of the knowledge of the race that built the Stargates, the Ancients, who also Ascended), regularly used Al'kesh (mid-range bombers) that were capable of cloaking. (It was unclear whether all Al'kesh ships in all the goa'uld fleets could cloak, or just those used by Anubis and Apophis after his takeover of Sokar's fleet; since those are the only Al'kesh ever seen to cloak, however, the latter possibility seems more likely.)

In "The Shroud", when Daniel Jackson has become an Ori Prior, he upgrades The Odyssey with a cloaking device, powered by a ZPM.

There are also cloaking devices that cloak individual persons, such as the one that Nirrti uses. These cloaks can be counteracted by a Transphase Eradication Rod. The Sodan use a personal transphase cloak (similar in technology to Merlin's hidden display) and which has also been acquired by for use by SG teams as depicted in "Uninvited".

The Puddle Jumpers in Stargate Atlantis have cloaking devices that make them completely undetectable to all known sensors as well as the naked eye. These devices can also be interfaced with Ancient shield technology, such as that of Atlantis, allowing them to cloak the shielded object. However, the shield and cloak cannot operate at the same time, making the object vulnerable to attack.

[edit] Other references

In the Family Guy episode, Stuck Together, Torn Apart, Joe explains that the police surveillance van is fitted with a cloaking device that disguises the vehicle as "two homeless people fighting over a wedge of cheese".

In the Xbox 360 video game Mass Effect, the SSV Normandy is equipped with a stealth system that relies more on the masking of thermal emissions rather than optical invisibility. In the game, ship sensors detect emissions such as heat and radiation from other ships' engines. The Normandy's stealth system shunts these emissions into sections of the ship's hull, where the energy is stored and kept from leaking out. As a result, the ship becomes completely invisible to passive sensors (visual detection is still possible, but unlikely against the darkness of space). The Normandy can only maintain "stealth mode" for a few hours before having to vent the energy into space and thus reveal its position, otherwise the contained energy will boil the inside of the ship.

The title character of the Predator films uses an imperfect cloaking device; although the Predator is virtually invisible while stationary, movement causes a characteristic "shimmer" effect, and it's wrist blades extend inside the field. Unlike the other mentioned types of cloaking field, the device equipped to the Predator Suit allows for continuous cloaking, even during hand-to-hand combat. Contact with water, even as shallow as a puddle, causes the device to temporarily short-circuit, rendering the Predator visible.

In the 1996 Doctor Who television movie based upon the long-running British series, Doctor Who, the Doctor's TARDIS was said to possess a "cloaking device" that got stuck, leaving it in the form of a British police box. This was a continuity break with the series (which always used the term "chameleon circuit"), possibly due to the film being partly produced by American broadcaster FOX, and/or desire for a more commonplace phrase. In the 2005 episode "Boom Town", Rose calls the mechanism a cloaking device, and the Doctor corrects her.

"Boom Town" also contains the first mention of the perception filter. A perception filter is a field generated by a TARDIS that convinces people to ignore it, which in the case of the Doctor's TARDIS makes the normally anachronistic police box seem perfectly ordinary wherever it lands, no matter how out of place it may be. In "Boom Town," the TARDIS also imparts a perception filter to a stone slab near a fountain in Cardiff, which Torchwood Three has attached to an elevator, as seen and first named in the Doctor Who spin-off Torchwood. In "The Sound of Drums" it is suggested that the field extends to objects associated with the TARDIS, such as the keys used to open it. Perception filters can also be added to other objects, such as the fob watches used by the Doctor and the Master. The field does not work if the object it surrounds draws too much attention to itself, or if someone is specifically searching for the object in question.

In the anime series Ghost in the Shell: Stand Alone Complex (continuing in its second season under the name 2nd GIG), Section 9 employs "optical camouflage" suits which allow the wearer to render himself completely invisible. The older models did not hide shadows or body heat, but as Solid State Society suggests, later models were designed that cloaked even these methods of detection. Often characters using this optical camouflage will disengage it after using it for a short period of time, but they have been known to use it while firing and attacking. Presumably the camouflage eats away at a power source, so it's best used for short time sets. Sometimes the suits can be seen slightly, and other times not at all; in episode 21 "Eraser", there is a scene where the Major can plainly see two enemies using optical camouflage, but it is unclear whether Section 9 simply has the best quality optical camouflage or not. In the series, the camouflage seems to become disrupted when it comes into contact with water, while in the original movie it does not, although as the movie is set after the series, this could be due to technological advances.

The Deathscythe Hell from the 1995 anime Mobile Suit Gundam Wing employs an active camouflage system that makes it invisible to visual and sensor detection.

In the 2002–2003 anime series Gundam Seed and its 2004–2005 sequel Gundam Seed Destiny, some mobile suits and space warships are cloaked using the synthetic prism-like particle known as Mirage Colloid.

In the Metal Gear series, portable cloaking technology is a reality. Within this series, the "stealth camouflage", as it is referred to, comes in the form of a small device about the size of a bulky CD player and in the MGS remake at the end, Otacons type resembles a bulky scientific calculator. When activated, the user becomes mostly invisible, save for a slight "ripple-effect" when in motion. The device is also featured anachronistically in Metal Gear Solid 3, where the game is set in the 1960's. The device does have a drawback; it is depicted to consume stamina so great that the wearer needs to replenish his/her stamina every now and then, whereas its modern counterparts do not feature such limitations. Players can acquire this camouflage for themselves as a reward for accomplishing special task(s) prior to completion of the game. (ex. collecting all of a certain item, remaining undetected for the entirety of the game, or performance on special sections of the game.)

In the RTS game Total Annihilation (TA) a small number of units have the ability to cloak, becoming invisible. The starting unit of both ARM and CORE, the Commander unit, has the ability to cloak. Other units which can cloak include the ARM 'Shooter' sniper Kbot and the ARM 'Infiltrator' and CORE 'Parasite' spy Kbots. The ARM 'Podger' and CORE 'Spoiler' vehicles can lay land mines which are automatically cloaked (although this feature can be deactivated to save energy if necessary). Both sides can build cloakable Fusion power plants. Cloaked units in TA will uncloak if they fire a weapon, use their nanolathe or if an enemy unit approaches within a specific radius, they will also uncloak if the player runs low on/out of energy. Also, although invisible, they are still detectable by radar. All cloaking devices (with the obvious exceptions of both mines and reactors) consume exponentially larger amounts of energy while moving, and fail completely upon the activation of a weapon or tool. With the exception of the Commanders, all other units with cloaking ability come with Total Annihilation: The Core Contingency expansion pack. Also present in TA are related concepts such as radar invisibility and radar and sonar jamming.

In the RTS game Homeworld, one can build cloak generators to hide a fleet, and playing as the Kushan gives you access to the cloaked fighter. However, the technologies are far down the tech tree, and cloaked ships can easily be detected by proximity sensors or sensor arrays. Furthermore, the cloaked fighter has weak attack power, long construction time, and must decloak when attacking. In the sequel, Homeworld 2, both races are able to build the cloak subsystem which performs a similar function to cloak generators.

In the RTS game StarCraft, the Terrans possess cloaking devices, which allow Wraiths to turn invisible, as well as Personal Cloaking for Ghosts. The Dark Templar also learned how to bend light to make themselves virtually invisible. The Protoss Arbiter has the ability to automatically cloak all nearby friendly units, excluding the Arbiter itself and any other Arbiters. The Protoss Observer remains perpetually cloaked, but has no attack. Incidentally, the Terran devices use Energy (both devices instantly draw 25 Energy units when activated, and then consume 1 Energy unit per second until deactivated) to stay active (and the Ghost uses the same Energy pool for cloaking and the Lockdown ability), while Protoss cloaking abilities are "always on" and do not consume Energy. The Zerg do not have cloaking technology, but most Zerg land units can "burrow" to hide from enemies; like cloaked units, burrowed units are invisible to most units, but unlike cloaked units, they are also immobile and cannot attack (except the Brood War expansion Lurker unit, which attack only while burrowed). In Starcraft cloaked units may attack without becoming uncloaked, but certain buildings and units with the Detector attribute can reveal their positions, allowing enemy units to target them. These include the Terran Science Vessel, Terran Missile Turret, Zerg Overlord, Zerg Spore Colony, Protoss Observer, and Protoss Photon Cannon. In addition, Terran Vulture Spider Mines (which themselves remain burrowed and invisible except to Detector units - at least until triggered), while not able to directly reveal cloaked units, can themselves be triggered by (and attack) cloaked non-hover ground units. The Terran ComSat Station add-on to their Command Center building, while lacking the detector attribute for it's own sight radius, can use a Scanner Sweep to temporarily reveal any cloaked (or burrowed, or otherwise hidden) units in a target area anywhere on the map. Certain effects, such as Irradiate or Ensnare, that are accompanied by visual effects, have the side-effect of making affected units visible, to all players, even while cloaked (but not while burrowed). Attacking while cloaked will reveal the presence of a unit to the enemy (and to astute human players, the location of the unit, since muzzle flashes and in-flight projectiles of cloaked units are still visible), most likely prompting the use of one of the above counter-measures (detector unit, scanner sweep, area-effect ability) to reveal the cloaked unit. Cloaked or burrowed ground units (including Spider Mines), detected or not, will prevent buildings from being constructed, and airborne Terran buildings (or Infested Command Centers) from landing, on top of them - the positions they occupy will be shaded red (marked as non-buildable) in the building placement template. Cloaked and burrowed units, even when not detected, are not invincible, and can still be harmed by spider mines (if applicable to the unit type in question), area-effect attacks (i.e. psionic storms and nukes) or units with splash-damage weapons (like Reavers or siege-mode Siege Tanks) attacking nearby targets.

In the computer and video game Deus Ex, one of the types of augmentation canister the player finds allows them to choose between either cloaking, or radar transparency, making them invisible to either humans and animals, or robots and cameras, respectively. These augmentations cannot be used for very long because of their extremely high power requirements, especially if used in conjunction with other augmentations.

Almost all larger fleet craft (battleships) have the ability to cloak themselves in the video game series Colony Wars. In this mode they are invisible, cannot attack, and cannot be attacked.

Cloaking devices are one of the items used in Super Smash Bros. Melee. Any character who uses it remains vulnerable to enemies' attacks but their damage percentage does not increase. The item’s trophy states the game of origin to be “Top Secret” but appears to be an allusion the Nintendo 64 game Perfect Dark.

The Command & Conquer series of RTS games by Westwood Studios has multiple instances of cloaking. In the original Command & Conquer game, Nod had the capability to build stealth tanks armed with missiles, the tanks were completely invisible but uncloaked if they came to close to an enemy unit or fired their weapons. In Red Alert: Counterstrike, a tank that fires missiles can cloak, but uncloaks if it gets too close to an enemy. In Command & Conquer: Red Alert 2, Albert Einstein creates a "mirage tank" which can changes its outward appearance to look like vegetation. In Command & Conquer: Tiberian Sun, the Brotherhood of Nod can create Stealth Tanks, which are invisible except to special sensors until it uncloaks to fire missiles. Also the Brotherhood has the ability to create large "Stealth Generators" that can cloak entire bases, making the area of a base seem like empty ground. Similar technologies are employed by Nod in Command & Conquer 3: Tiberium Wars, with the stealth tank being almost identical as in Tiberian Sun. The stealth generator has been replaced with the Disruption Tower, which while it creates a large cloaking field, is not cloaked itself, and so is vulnerable to attack (similar to the arbiter in StarCraft.) Nod also have new cloakable units, such as the vertigo bomber, and the tiberium harvester. The avatar mech is also capable of cloaking, by ripping the cloaking device from a stealth tank. this destroys the stealth tank in the process.

In Douglas Adams' Life, the Universe and Everything, the third novel in the Hitchhiker's Guide to the Galaxy series, Slartibartfast's ship, the Bistromath, utilizes a Somebody Else's Problem field. The SEP field relies on the mind's propensity to ignore anything which is it not expecting to see or cannot explain. This technology was developed because "the technology required to actually make something invisible is so complex that most of the time it's simpler to take the thing away and hide it." The technology is much simpler than a cloaking device because it relies on human nature, and in addition can be run for centuries on a single 9V battery. The main disadvantage to the SEP field is that the cloaked object needs to be unexpected, thus the Bistromath is designed to look like an Italian bistro.

In the Nintendo game Metroid Prime, a select group of Space Pirates had access to cloaking technology; these are Shadow Pirates. The cloaking technology used up most of the user's energy, which forces them to rely solely on melee weapons in battle. Also because of a design flaw, the cloaking devices gave off high heat ratings, making it possible for players to track down a Shadow Pirate with the Thermal Visor. A few other enemies in the Metroid Prime series featured a cloaking-like device, but could only be seen though different methods.

In Marvel Comics' X-Men series, the superhero group's jet the Blackbird possesses a cloaking device that makes it invisible to both radar and the naked eye. In the 2000 film adaptation, the group's jet is only capable of blocking radar devices.

In the James Bond film Die Another Day, Bond's Aston Martin Vanquish is equipped with a form of Active Camouflage, which worked by having embedded cameras capture the view from one side of the car and then somehow projecting that same view onto the other side.

In the animated television series Exosquad, cloaking devices based on dark matter from the planet Chaos were a rare technology that only the Pirate Clans possessed.

In Master of Orion, a space based strategy game, there were also cloaking devices. In the sequel to that game, Master of Orion II, there were three distinct types of cloaks. The weakest, the "stealth field", merely made ships impossible to detect when not engaged in battle. The "cloaking device" had the benefits of the stealth shield as well as making it harder for weapons to target an equipped ship. The strongest cloak is the "phase cloak" which had all the benefits of the cloaking device but could also for a limited time period put the ship in a phase in which it is completely invisible but unable to attack.

In the British sci-fi comedy show Red Dwarf episode "Backwards", Starbug 2, upon landing in backwards London, engaged a cloaking device to hide it from the locals.

In the Jean-Claude Van Damme movie Street Fighter, Col. William Guile's stealth boat used a form of adaptive camouflage, similar to a cloaking device, that was susceptible to detection by motion, and by being able to see the wake of the boat

In the Wing Commander games, notably Wing Commander II, experimental Kilrathi fighters are equipped with cloaking devices. In rare occasions, cloaking torpedoes were used against friendly capital ships. Since the cloaking device was experimental and not yet perfected, the experimental ships and torpedoes would occasionally "flicker", allowing a quick player to briefly target them and fire. Luckily for the player, due to the high power consumption of the cloaking device, there wasn't much energy available for defensive shielding.

In the Halo series, an alien confederation of several races known as the Covenant have developed a type of active camouflage that allows several of their species to become semi-invisible in ground combat. In Multiplayer mode, an active camouflage item is available to the player and can be set as standard for certain matches.

In the Xbox videogame Brute Force, Hawk, one of the four playable characters, is able to use a cloaking device to hide from enemies. She is also equipped with a melee weapon known as a "Powerblade", which she can use to eliminate enemies after getting close to them, usually using the aforementioned cloaking device. Hawk can attack while cloaked, but this depletes the device's battery rapidly, and she usually must uncloak before attacking. Hawk can also move very fast, but has low hit points, and relies on the support of the other characters in heavy combat situations.

In the PC & 3DO game Star Control II, the Ilwrath Avenger has a cloaking device usable in combat situation which renders the ship black as space, thus making it harder to be targeted and disabling homing capabilities of missiles or the Arilou or Earthling homing lasers. The cloak is not perfect, because the ship is still on the other side of the screen and also the ship can obscure stars in the background, hinting its position. The Avenger, while cloaked, will attempt to ambush ships then use its hellfire cannon to turn it to cinders after achieving a very close range with the target vessel. There was also a rumor of a "Cloaking Device" artifact usable by the Flagship on a Star Control discussion board. Someone even posted a fake screenshot with its whereabouts. The rumor was eventually dismissed, however, the primary developers of the game, Fred Ford and Paul Reiche III revealed their plans to include such a Cloaking Device when Star Control II was still in development. The idea got scrapped because of the lack of time to implement it.

In the first of the Black Library books based on the Horus Heresy, Horus Rising, cloaking devices are used by the defenders of a world known as Sixty Three Nineteen. These "Invisibles" use cloaking devices that bend light around themselves to render themselves invisible although when they move a shimmering effect is created.

In the PC game Crysis, some characters are equipped with a "Nanosuit" which features a cloaking device.

In The Orange Box by Valve Software, the Spy in Team Fortress 2 has a cloaking device in his inventory.

[edit] Scientific experimentation

An operational, non-fictional cloaking device might be an extension of the basic technologies used by stealth aircraft, such as radar-absorbing dark paint, optical camouflage, cooling the outer surface to minimize electromagnetic emissions (usually infrared), or other techniques to minimize other EM emissions, and to minimize particle emissions from the object. The use of certain devices to jam and confuse remote sensing devices would greatly aid in this process, but are more properly referred to as "active camouflage." Alternatively, metamaterials provide the theoretical possibility of making electromagnetic radiation appear to pass freely through the 'cloaked' object.

[edit] Philadelphia Experiment

Main article: Philadelphia Experiment

The Philadelphia Experiment was a secret experiment conducted by the U.S. Navy at the Philadelphia Naval Yards at Philadelphia, Pennsylvania, on or before October 28, 1943, which went horribly awry. The experiment was allegedly to cast a veil of radar and possibly optical invisibility or transparency around a ship. Though most mainstream experts argue the incident is an urban legend, a number of people argue that the Philadelphia Experiment could be genuine. Whether true or not, the Philadelphia Experiment has had a major ripple effect on conspiracy theory, and elements of the Philadelphia Experiment feature in many other conspiracy tales and provided the basis for various movies and miniseries.

[edit] Metamaterial research

Optical metamaterials have featured in several recent proposals for invisibility schemes. "Metamaterials" refers to materials that owe their refractive properties to the way they are structured, rather than the substances that compose them. (Opals are a well known example of a naturally occurring metamaterial.) It has been demonstrated that such materials can take on optical properties unattainable by natural substances. Most famously, a negative refractive index is possible.

On February 14, 2005, Andrea Alů and Nader Engheta at the University of Pennsylvania announced in a research paper that plasmons could be used to cancel out visible light or radiation coming from an object. This 'plasmonic cover' would work by suppressing light scattering by resonating with illuminated light, which could render objects "nearly invisible to an observer." The plasmonic screen would have to be tuned to the object being hidden, and would only suppress a specific wavelength: An object made invisible in red light would still be visible in multiwavelength daylight.

A concept for a cloaking device was put forward by two mathematicians in one of the UKs Royal Society journals [1]. Shortly afterwards, blueprints for building a cloaking device were put forward in the journal Science by researchers in the US and UK [2]. However, "Scientists not involved in the work said the plans appear feasible but that they would require more-advanced substances than currently exist" [3].

While no one has yet been able to make a cloaking device for light, in October 2006, a US-British team of scientists created a metamaterial which made an object invisible to microwave radiation [4]. Since light is just another form of electromagnetic radiation, this is the first step to a cloaking device for light, though more advanced nano-engineering techniques will be needed due to visible light's short wavelengths.

On April 2, 2007, 2 Purdue University engineers announced a theoretical design for an optical cloaking device based on the 2006 British concept. The design deploys an array of tiny needles projecting from a central spoke that would render an object within the cloak invisible in a wavelength of 632.8 nanometers. [5]

[edit] Duke University experiments

On October 19th, 2006 the AP reported that a team of British and American scientists had demonstrated a prototype metamaterial based device that rendered a copper cylinder invisible to microwaves. In the prototype, microwaves passing through the cloaked object were significantly dimmed but the researchers believe this behavior can be improved. [6]. Engineers David Schurig and David Smith of Duke University successfully, although not completely, hid or "cloaked" the central copper ring by surrounding it with concentric rings of metamaterial standing one centimetre tall and spanning 12 centimeters. The rings were sandwiched between two plates so that microwaves could only travel through the cloak in the plane of the rings, as described in the paper published online October 19, 2006 by Science.

[edit] Active camouflage

Main article: Active camouflage

Active camouflage (or adaptive camouflage) is a group of camouflage technologies which would allow an object (usually military in nature) to blend into its surroundings by use of panels or coatings capable of changing color or luminosity. Active camouflage can be seen as having the potential to become the perfection of the art of camouflaging things from visual detection.

[edit] Holographic Cloak

Holographic imaging could technically be used to generate a cloak by projecting the image behind the obect being cloaked.

Some disadvantages are:^{[citation needed]}

The release of heat emissions.
The object being cloaked might not be invisible to sensoring equipment.
Holographic technology is not yet commercially practical, which means it would cost a lot to develop and maintain.
The power requirements for this kind of technology are not yet verified.

[edit] Optical camouflage

Optical camouflage is a kind of active camouflage in which one wears a fabric which has an image of the scene directly behind the wearer projected onto it, so that the wearer appears invisible. The concept exists for now only in theory and in proof-of-concept prototypes, although many experts consider it technically feasible. It is an example of active camouflage (or adaptive camouflage). Recently it has been reported that the British Army has tested an invisible tank.[7]