DeLorean time machine

A replica of the DeLorean time machine's flux capacitor

The flux capacitor, which consists of a rectangular-shaped compartment with three flashing Geissler-style tubes arranged in a "Y" configuration, is described by Doc as "what makes time travel possible." The device is the core component of the time machine.[3]

As the time machine nears 88 mph, light coming from the flux capacitor begins pulsing more rapidly until it becomes a steady stream. Doc originally conceived the idea for the flux capacitor on November 5, 1955, when he slipped on the edge of his toilet while hanging a clock in his bathroom and hit his head on the sink.[3] A similar, but possibly steam-powered, flux capacitor is also seen in the chimney headlamp of Doc's second time machine, the Time Train, at the end of Back to the Future Part III.[5]

Although the films do not describe exactly how the flux capacitor works, Doc mentions at one point that the stainless steel body of the DeLorean has a direct and influential effect on the "flux dispersal", but he is interrupted before he can finish the explanation.[3] The flux capacitor requires 1.21 gigawatts of electrical power to operate, which is roughly equivalent to the power produced by 15 typical commercial airplane jet engines.

The instruction manual for the AMT/ERTL DeLorean model kit says: "Because the car's stainless steel body improves the flux dispersal generated by the flux capacitor, and this in turn allows the vehicle smooth passage through the space-time continuum."

The time circuits are an integral part of the DeLorean time machine. They were built with an input device and a display. The display was divided into three sections: destination time (shown in red), present time (shown in green), and last time departed (shown in yellow), all annotated with Dymo labels. Each display includes a month, a day, a year, and the hour and minutes in that point in time. The years on the time circuits were limited to four digits and there were no possible negative years that could be reached, i.e. years before 1 A.D. This means the DeLorean could travel to any time from 12:00 am on January 1, A.D. 1 to 11:59 p.m. on December 31, A.D. 9999. It is unknown what would happen if one were to travel to the latter date since, after only one minute, it would be the year A.D. 10000 and the time circuits would no longer be able to show the present time.

The destination time display shows the date that the operator wants the DeLorean to go to (when the operator types in a date using the keypad in the DeLorean, it will be shown in the destination time display), the present time display shows the DeLorean's current location in time, and the last time departed display shows what point in time the DeLorean originally was after making a journey through time. Doc demonstrated its capabilities to Marty after its first test, giving three well-known but erroneous dates as examples: the signing of the Declaration of Independence, July 4, 1776; the birth of Christ, December 25, 0000; and the day that he invented time travel, November 5, 1955.

During the second film, the time circuits began malfunctioning, displaying January 1, 1885 in the destination time display. A bolt of lightning triggered the malfunction to send the DeLorean from 1955 to 1885. Though the vehicle was in mid-air, the spin created by the lightning bolt allowed it to reach 88 mph. Doc was trapped in 1885 and repairs were impossible because the time circuit control microchip, which powered the time circuits, was destroyed by the lightning bolt, and suitable replacement parts would not be invented until at least 1947. Doc placed repair instructions and a schematic diagram in the time machine to enable his 1955 counterpart to repair it using components from that era — which included vacuum tubes — before burying it in a mine, and sending Marty a letter via several generations of the Western Union.

A replica of the DeLorean time machine's Mr. Fusion Home Energy Reactor

The Mr. Fusion Home Energy Reactor is the name of a power source used by the DeLorean time machine in the Back to the Future trilogy. It can be seen for the first time at the end of Back to the Future when "Doc" Emmett Brown pulls into the McFly's driveway after a trip to the year 2015. It is a parody of Mr. Coffee machines, which were very popular at the time of filming.[10] The appliance from which the prop was made was actually a Krups "Coffina" model coffee grinder.

The Mr. Fusion Home Energy Reactor converts household waste to power for the time machine's flux capacitor and time circuits using nuclear fusion, presumably cold fusion. In the film, Mr. Fusion allows the DeLorean time machine to generate the required 1.21 gigawatts needed to travel to any point in time. The energy produced by Mr. Fusion replaces plutonium as the primary power source of the DeLorean's time travel, allowing the characters to bypass the arduous power-generation requirements upon which the plot of the first film hinges. The plutonium fission reactor was most likely left installed underneath Mr. Fusion as a backup power source.[3][4]

The Mr. Fusion can provide enough power to the flux capacitor and the time circuits, but is not used to power up the DeLorean itself, which makes use of an ordinary gasoline combustion engine to reach the 88 mph speed necessary for it to time travel, a limitation that proved itself crucial in the third movie when Doc and Marty find themselves stuck in 1885 and unable to return with the DeLorean out of gas (due to a fuel leak). The vehicle's hover system is powered by Mr. Fusion and is capable of bringing the DeLorean up to the required 88 mph; the combustion engine was also probably left on board as a backup. However, the flight systems were destroyed as a result of a lightning strike, leaving Marty to rely on the original combustion engine, which in turn was disabled.

The time circuits in a replica time machine

In the films, the DeLorean time machine is a licensed, registered vehicle in the state of California, where the films take place. The vanity license plate used in the film reads "OUTATIME", a deliberate anomaly, as the maximum number of symbols on California plates is seven characters.[3] When Doc returns from 2015, it is a barcode license plate,[3][4] which implies that by that year license plates have moved to other more sophisticated means of tracking and registering. There is also an alarm clock that sits in the cockpit (having been placed there by 1955 Doc in the first movie), which is set to ring when it is time for Marty to speed towards the clock tower to return to 1985. The clock remains in the DeLorean for the rest of the series.

In The Animated Series, Doc builds another DeLorean into a time machine, restoring most of its features, including Mr. Fusion and the hover conversion (Doc either rebuilds the one destroyed at the end of Part III or he simply builds a new one). He also seemingly adds the capability to travel through space in addition to time (i.e., appear at a different location from the one it departed), similar to the TARDIS from Doctor Who. The cartoon DeLorean time machine has many add-ons, including a back seat in normal two-door mode, the ability to transform into a four-door, a pop-out covered wagon top, a blimp, a rear video screen, and a voice activated time input.

Back to the Future: The Game features a chronal duplicate of the original DeLorean, which Doc Brown recovered from the timestream after the destruction of the original. This DeLorean is created at the end of Back to the Future Part II, when the original time machine was struck by lightning: while the DeLorean itself is sent to 1885, a fully functional duplicate appears (apparently unmanned and undamaged) in 2025, where Doc retrieves it with the Time Train. He later traveled to 1931 and sent the Clone DeLorean to 1986 to get Marty to rescue him from 1931 before he can be killed. This Clone DeLorean is effectively the same as the Part II one, including the occasional glitches in the time circuits (mostly affecting the last time departed time display), but with a new automatic retrieval feature that automatically brings the Clone DeLorean to a set time and location of Doc's choosing every time Doc Brown doesn't return to the car in a fixed amount of time.[12]

This DeLorean is later badly damaged (after returning to 1986, Marty crashes the Clone DeLorean into a billboard and after Marty gets out, the Clone DeLorean falls through the billboard and crashes onto the ground) and then restored by an alternate version of Doc Brown who has never developed time travel technology, having access to limited notes about the flux capacitor. As such, the time circuits of the alternate Clone DeLorean become even more glitchy following their return to 1931, accumulating errors as severe as the interval of time traveled, with increasing damage with every attempt: as such, Citizen Brown, the alternate version of Doc, has to install a diagnostic console made of materials available in 1931 (appearing as a plywood box with a lightbulb and three similar bulbs placed on the coils on the outer body).[13]

Apparently, part of the problem is chromium parts becoming unstable during time travel, according to Citizen Brown. This DeLorean is later stolen by Edna Strickland, one of the game's main villains. The original Doc arrives in the original Clone DeLorean as Citizen Brown disappears from existence due to earlier events in the game; i.e., because Marty restored the original timeline, the original Clone DeLorean was brought back into existence. Officer Danny Parker nearly arrests Marty and Doc for allegedly having the car that Edna got away in. After they explain to him that there is more than one DeLorean, Marty explains to Doc that the alternate Clone DeLorean had malfunctioning time circuits. To make matters worse, the entire town of Hill Valley disappears around them; Edna had unwillingly time traveled to 1876. They go to "Mary Pickford's" house and see that the alternate Clone DeLorean had been destroyed. After they get information from Mary, who was really Edna, they go to 1876. After they stop the fire that would've burned down Hill Valley, they chase down Edna, who is trying to get away in the alternate Clone DeLorean. Marty hoverboards to Edna's DeLorean and synchronizes the two DeLoreans by attaching signal dishes called flux synchronizers over the diagnostic lightbulbs on Edna's DeLorean and pointing them at the receiving dish on Doc's DeLorean, which is flying behind the one that Edna is driving. They all travel back to 1931, with Edna's DeLorean vanishing because of the time ripples catching up with them, causing "chronal decay" (i.e., since Citizen Brown's timeline ceased to exist, the alternate Clone DeLorean was erased from existence). Marty and Doc return to 1986, where three DeLoreans (one normal, one blue, and one black) suddenly arrive with different versions of Marty. The duo leave the Martys argue before departing to an unknown time in their own DeLorean.[14]

It is implied that the Time Train stays with Clara, Jules and Verne, passingly mentioned as enjoying the same nomadic life around the time-stream of Doc, but it is never seen in the game. The ending introduces a blue DeLorean and a black DeLorean, but it is unknown how these DeLoreans were created.[12][14]

In Back to the Future: The Ride, Doc, who now lives in a lab called the Institute of Future Technology, had created an 8-passenger DeLorean that can fly just like the original DeLorean (which can be seen in the ride and in the outside display) and the Time Train (which can only be seen in display outside of the attraction). Unlike the original DeLorean, the flux capacitor is in the front of the cockpit along with a small screen, the time circuits, and the speedometer. The original DeLorean is equipped with a sub-ether time-tracking scanner that allows Doc to pinpoint its location in time. It is also shown to have its original "OUTATIME" license plate instead of the bar code license plate, but it could just mean that this DeLorean is actually a new one being built into a time machine. In the attraction, Biff Tannan (who stowed away in one of the institute's time machines that had recently visited 1955) steals the original DeLorean, prompting Doc to send the riders to the 8-passenger DeLorean and use it to go after Biff. After following Biff to 2015 Hill Valley, the Ice Age (where the 8-passenger DeLorean experiences a temporally engine failure), and the Cretaceous Period, Biff's DeLorean gets damaged by a T-Rex and lands in a volcano. The 8-passenger DeLorean follows Biff and bumps into him after both DeLoreans go over a cliff, sending them back to 1991. In a post-credits scene, Clara Clayton, who has built the Time Train with Doc, reveals to have currently repaired the DeLorean and travels back to 1947 to a farm.

In Doc Brown Saves the World, there was a repaired DeLorean time machine which included new replacement parts from 2015. The DeLorean is also seen in a video promoting Doc Brown Saves the World, and it is unknown as to whether or not a flux capacitor was inside.

Inside the cabin facing front

Inside the cabin facing rear

The time machine went through several variations during production of the first film, Back to the Future. In the first draft of the screenplay, the time machine was a laser device that was housed in a room. At the end of the first draft the device was attached to a refrigerator and taken to a nuclear bomb test. Director Robert Zemeckis said in an interview that the idea was scrapped because he did not want children to start climbing into refrigerators and getting trapped inside. In the third draft of the film the time machine was a car, as Zemeckis reasoned that if you were going to make a time machine, you would want it to be mobile.[15] The specific choice of vehicle was a DeLorean for the purposes of it looking like an alien spaceship[16] due to its characteristic gullwing doors (which were inspired by the Mercedes-Benz 300 SL). The original ending of the 1985 film Back to the Future was to have Marty outrun a nuclear explosion at a test site to power the DeLorean's flux capacitor in order to travel back to 1985. However, during the movie's filming, it went overbudget and behind schedule, and Universal refused to grant the producers any more money, as it couldn't afford the desert location to shoot such scenario. Ultimately, the power source was changed to the lightning strike at the clock tower in Hill Valley as a result.[17]

When the filmmakers arrived at the point where the time machine would be built into a car, the art department was instructed to come up with designs for the DeLorean. Andrew Probert was the first artist to explore the subject (before Ron Cobb joined the production), but his designs were deemed "too perfect" for the look the producers wanted, which was to make it look as if it had been built in a garage by Doc Brown. The idea was that it had been constructed with parts found in a hardware and electronics store, so it couldn't look too sophisticated. It also had to look dangerous, as Producer Bob Gale noted in the DVD commentary for Back to the Future.[16] The task was undertaken by Ron Cobb who added the coils to the back of the vehicle. The nuclear reactor was also a design choice made by Cobb. This choice proved to be important, given the direction the script had taken. Cobb complemented the nuclear reactor with one vent on the back of the car, since it was generally known at the time that nuclear reactors had vents. Once Cobb had left the production, the producers wanted to balance the design with another vent, keeping a symmetrical aesthetic. Probert was asked to step in and he brought the design to its final form. At the end of the first film of the trilogy these vents become the propulsion system for the improved DeLorean, which now had hovering abilities and could reach the time-traveling speed of 88 miles per hour flying. The production design team added other buttons and lights inside the car to make it look more appealing and complex in order for the audience to have something attractive to look at.

Different parts from three 1982 DeLoreans were used in the first film. Liquid nitrogen was poured onto the car for scenes after it had travelled through time to give the impression that it was cold. The base for the nuclear reactor was made from the hubcap from a Dodge Polara. Aircraft parts and blinking lights were added for effect. In one of the first scenes, carbon dioxide extinguishers were hidden inside the DeLorean to simulate the exhaust effect.[18] Ultimately, five real DeLoreans were used in the filming of the trilogy, plus one "process" car built for interior shots. In the off-road scenes in the third film, a modified-for-off-road VW Beetle frame was fitted to the DeLorean with the whitewall tires and baby Moon hubcaps.[19] A seventh DeLorean was also used in the filming; however, this one was merely a full-sized, fiberglass model used for exterior shots where the vehicle hovers above the set as well as when the actors interact with the vehicle.[20]

Rather than use the sound of the stock V-6 DeLorean engine in the film, the sound of a DeLorean with a Legend Twin Turbo VIN 530 was used.