Holodeck A Holographic Environment Simulator , or holodeck as it is most commonly refered to , was a form of holotechnology designed and used by the Federation Starfleet which ran holographic program s . They were installed aboard starship s , space station s , and at Starfleet institutions for use in entertainment , training , and investigative purposes . ( ) History . Prior to the late 24th century , Federation starships were not equipped with holodecks . ( ) In 2151 , the Starfleet vessel encountered a vessel belonging to an alien race known as Xyrillian s , who had advanced holographic technology in the form of a holographic chamber , or holo - chamber for short , which was similar to the holodeck technology commonly used by the Federation Starfleet two centuries later . ( ) A holo - chamber was later installed aboard a Klingon battle cruiser after an encounter with a Xyrillian vessel discovered " hitchhiking " behind their ship . ( ) In the 23rd century , the vessel was equipped with holographic technology including holographic communications and combat training simulations . ( ) The recreation room aboard starships employed holographic technology . The had a recreation room located in Area 39 of the ship . ( ) By 2364 , the Federation Starfleet was already installing holodecks aboard their vessels . ( ) During the 2360s and 2370s , a starship could have one or more holodecks depending on the vessel ' s size or purpose . For example , the compact did not have a holodeck while the larger had at least seven . ( ) In 2366 , Data and Deanna Troi brought Lal to the holodeck in order to choose an appearance . ( ) The had at least two holodecks . The holodecks of the were the only places other than sickbay where The Doctor was able to exist ( prior to obtaining his mobile emitter ) after his program was modified by the crew so he wasn ' t so tightly tied into the sickbay ' s systems . ( ) B ' Elanna Torres used the " Voyager " s holodeck for a holographic orbital skydiving session . ( ) Purpose . The most obvious function of a holodeck is to provide entertainment and diversion for a starship ' s crew , as they typically spent months or years on missions . ( ; ) A holodeck can be used to create training simulations and exercise environments not otherwise available or safe , including starship battle simulations , physical and combat simulations , and the Bridge Officer ' s Test . ( ; ) The holodeck ( or holographic research lab ) can be used as a laboratory to aid in analysis , such as recreating the scene of a crime or accident to aid in forensic investigations . ( ; ) They can be used to visualize a 3D scene from alternate data sources for analysis ( ; ) or used as a brainstorming tool . ( ) The holodeck could also be used to test a person ' s beliefs or motives by creating a program to trick them into revealing their actions . ( ) Design . A typical holodeck consisted of a room equipped with a hologrid containing omnidirectional holographic diode s , enabling holographic projections and hologram s . Elements of transporter technology and replicator s were used to create holodeck matter by the manipulation of photon s contained within force field s to give objects the illusion of substance as well as actual matter . This matter could exist outside of the holodeck for brief periods of time ( such as snow ) before they would lose cohesion and revert back to energy without the support of the hologrid . ( ) Holodecks were powered by holodeck reactor s . ( ) Holodecks had database s to store programs , holograms and holographic template s . ( ) A holobuffer stored complex holograms when inactive . ( ) Due to the ability to store highly complex energy patterns , it was possible in some cases to store a person ' s physical parameters from his or her transporter pattern in the holodeck database . This could , in turn , be available for use in creation of holograms . ( ) While viewing programs , a user could delete holocharacters using character deletion algorithm s . ( ) Holodecks had general systems and modes of operation that were used in holographic programs . They employed spatial orientation system s to simulate parts of a holocharacter , such as left - or right - handedness . ( ) Holodecks could also have a program element called a perceptual filter to hide anachronisms to the program ' s time period , such as uniforms and communicators , in order to prevent them from raising the character ' s ire and curiosity . ( ) Among the viewing modes on a holodeck was objective mode , in which the user didn ' t interact with the characters , and subjective mode , in which the viewer could interact with the characters as well as alter his or her surroundings . ( ) Holodecks could be equipped to change gravity in three dimensions . ( ) The holodeck could be controlled from an exterior control panel , the interior arch control or through bridge control relay s in some designs . This arch could be summoned at any time to change the parameters of a running holoprogram . Matter and energy were interchangeable as such objects created on the holodeck could be either matter or energy . ( ; ; ) Holodecks included components such as bi - converter interface s . ( ) When a user experienced a holographic environment , the holodeck walls could generate holographic images that appeared to extend for an unlimited distance , seemingly much larger than its own dimensions . The walls could be revealed if someone takes an unexpected action in the program which hits the wall , for example , if a person were to throw a holographic rock at the walls and the program was not able to react to show the rock continuing into the holographic image it created . ( ) Holodecks were equipped with safety protocols to prevent serious injury during their use , though these could be disengaged by the user when required . When protocols were deactivated , holographic obstacles had the same effects on a person as the objects or instances they simulate ; holographic bullets or a steep drop could be fatal in such a scenario . ( ; ; ) How the security protocols were circumvented differed ; in one instance , it required the voice authorization of two senior officer s , ( ) while in others the authorization of the individual such as the ship ' s captain , or the person who started the program was enough . ( ) Safety protocols could also be unintentionally disabled due to software errors or physical damage to the holodeck ' s hardware system . The status of safety protocols could be reviewed by the computer upon the request of an operator . The use of a tricorder within the holodeck could also be done to query the current safety protocol status . Abilities and limitations . By the 2370s , holodeck technology was able to have fine enough control over magnetic containment fields that holographic objects could interact with matter on a biologically small level , for example , in replacing a person ' s organ with a simulated one that mimicked its functionality . ( ) Molecule - sized magnetic bubbles replaced molecules in full resolution holographic objects , which a computer could manipulate individually in three dimensions . However , the complexity of electron shell activity and atom ic motions that determined biochemical activity in living creatures could not be projected holographically . This prevented replicators from duplicating life and resurrecting the dead . The computer used large magnetic bubbles to simulate surfaces and textures rather than creating an object at the molecular level . However , objects created within the holodeck did not exist beyond the holodeck itself , as they only existed as energy . ( ) Since holodeck technology could be used with replicator technology , there were some instances where real objects were replicated within the holodeck and used to interact with the holographic program and / or users ; since these objects were real material composed of matter , they could leave the holodeck fully intact . A holodeck could modify the appearance of persons within it . Holograms could be augmented with force beams to simulate solid , tangible objects or with replicator technology to create actual solid matter such as food stuffs . All food eaten on the holodeck were replications . No other type of simulation could survive outside of the holodeck . A holodeck also had the ability to create holodecks within holodecks , and holodeck programs were able to be saved to a tech cube that could be inserted into an enhancement module to form an optronic data core with information to " last a lifetime . " ( ) The holodeck reactor , which powered the holodeck on 24th cenutry Federation starships like " Voyager " , was incompatible with other ship systems . ( ) Failure of a holodeck ' s matter conversion subsystem could cause the loss of solid objects within the holodeck environment . Materialization error s occurred in the holodecks in 2370 following the ship ' s exposure to plasmonic energy in the atmosphere of the planet Boraal II . ( ) Even though holographically created characters , just like characters in a story book , were never self - aware and never knew that they were not real , there were a few rare instances in which that rule did not hold true . During a " Sherlock Holmes " holodeck simulation in the late 2360s , Geordi La Forge and Doctor Katherine Pulaski argued that playing with Data was impossible and unfair to them as he had memorized all the Sherlock Holmes novels and could easily solve the cases . In order to level the playing field , La Forge requested that the holodeck create an opponent intelligent enough to defeat Data . Even though La Forge meant Holmes , his request had specifically noted Data . As a result , the holodeck created a self - aware holographic character of who was not only fully aware of his own consciousness , but who subsequently argued that he had a right to exist and leave the holodeck to pursue his life as he wished . ( ) Another holographic writer , known as Felix , created the fully self - aware program of Vic Fontaine for the crew of Deep Space 9 , Vic being completely aware of his holographic nature despite being a 1950s lounge singer , often offering the crew personal advice on relationship issues . ( ) Holoprograms . Starships with a holodeck normally had a vast list of holoprogram s in their computer . Several notable programs aboard the included : Notable programs aboard the included : Notable programs aboard the included : Notable programs aboard the ' s recreation room included : Appendices . Background information . The concept of the holodeck originated in , when Gene Roddenberry came up with the idea of a " simulated outdoor recreation area " on the " Enterprise " for the third season of . This idea never came to fruition , probably because of budget constraints . ( " " , p . 404 ) The idea was later used in the episode , which was basically the first appearance of the holodeck , then called a " recreation room " . It never came to existence in live - action production until the pilot of . Its inclusion in that series was originally proposed by Robert Justman , who initially thought of and suggested it as a place where crew members could be " psychically connected " with their homeworld . ( " " issue 115 , p . 71 ) In early episodes of TNG , the series ' production staff had an unwritten rule that the floors in a holodeck simulation shouldn ' t go below the floor level of the holodeck ' s door . This made sense , as burrowing down to the deck below would probably be inadvisable on a starship . Subsequent story requirements and set designs eventually influenced producers to alter their " rule , " deciding that at least one holodeck was a multi - story chamber . ( text commentary , DVD ) The appearance of the holodeck on TNG was affected by having limited finances . Production Designer Herman Zimmerman commented , " " We were in a budget constraint that made us do a set that is a wireframe look . " " Zimmerman and other members of the design team that worked on TNG had a long - standing interest in demonstrating the machinery of the holodeck from inside the room , though this was not made possible until the advent of the Cardassian holosuite in . ( " " ) Despite the fact that the " Galaxy " - class starship was meant to have numerous holodecks , a single set represented these environments on TNG . This was one of the last sets to be built for the show and was also used to represent the " Galaxy " - class cargo bay s , shuttlebay s and gymnasium . ( " " 3rd ed . , p . 10 ) The holodeck arch was a prop that was originally made for TNG : . Although some holodeck programs incorporated the arch to make the task of finding the way out easier , the arch originated as a way to let outsiders know when it was safe or appropriate to enter . ( text commentary , DVD ) The same arch set piece was featured in both TNG and the film . ( " Cinefex " , No . 61 , p . 69 ) For its first appearance on in , the exterior of the holodeck was the same set piece as had previously been seen on TNG , right down to the octagonal door frame , although all had been repainted to match the color scheme for the new " Voyager " corridors . It did not receive a square door arch and updated door panels until its second appearance . There are many discrepancies between episodes pertaining to the abilities and limits of holodeck technology . For example , in , the young Wesley Crusher remains wet with holodeck water , after exiting into a corridor . In , a piece of paper given to Data by James Moriarty is able to be carried outside of the holodeck and into a hall , but upon Moriarty ' s return in , a book thrown outside of the holodeck instantly disappears . Also , in , Cyrus Redblock and Felix Leech disappear slowly after a few moments outside of the holodeck , although a lipstick smudge from a holographic character stays with Picard all the way onto the bridge . Although these inconsistencies can be partially explained by the difference in the types of objects leaving the holodeck , it still leaves quite a few questions about what exactly constitutes the differences . The holodeck can use a degree of replication to make realistic objects for the holodeck occupant to use , so there is a possibility of the computer replicating a real piece of paper with the picture on , as it would be a relatively simple pattern . Some may argue that another discrepancy is the need for holodeck users to change into the appropriate costumes before entering and leaving the holodeck , since the holodeck has the ability to change the appearance of its users ( established in ) . But this may just be an issue of taste , on the user ' s possible preference of replicated clothes versus holographic clothes . Another theory is that the settings of the Holodeck can be altered to not only make weapons be lethal as seen in " " where Picard kills the Borg in a ballroom suite with a machine gun but also to make what events transpired inside it real life like the aforementioned lipstick smudge on Picard Actor Robert O ' Reilly once remarked that , when he appeared as Scarface in , he " really didn ' t understand the Holodeck . " ( ) Ultimately , it is evident to longtime views of the " Star Trek " franchise that the Holodeck is a storytelling device , like many other aspects of the shows , and only behaves consistently within narrative bounds . From the , " Star Trek " writer - producer Ronald D . Moore argued that in a free society of responsible citizens , there should be little or no limit on what an adult can do in a holodeck . Even if others might find certain activities objectionable , what one does in one ' s private space is no one ' s business ; certainly not the government ' s . Of the argument that certain activities should be prohibited on the grounds that they might be harmful or addictive to a holodeck participant , Moore suggested that in a free society , a responsible adult must be permitted to judge risks to his or her own well - being , and to act accordingly . Moore conceded that there might well be circumstances in which someone might object to being replicated on a holodeck , but notes that it would be extremely difficult to define legally what constituted and what was abusive . ( Moore emphasized that he referred to holodeck usage by adults , not by children . ) " "