- Stark: "I think we should take another look into arc reactor technology."
- Stane: "Come on. The arc reactor, that's a publicity stunt! Tony, come on. We built that thing to shut the hippies up!"
- Stark: "It works."
- —Stark urges Obediah Stane to look into arc reactor technology[src]
An arc reactor is a clean source of energy, first proposed and unsuccessfully designed in a joint effort of Howard Stark and Anton Vanko. It was later perfected to a working extent by Howard's son Tony Stark, who also used a miniature version of it to power his armored suits.
Howard Stark, founder of the Stark Industries originally designed and developed the arc reactor with the help of Russian physicist Anton Vanko, father of Ivan Vanko. But the project never got to its full potential and remained only as a theoretical idea, due to the technological limitations of Howard's era. Howard had envisioned to use the arc reactor to provide a clean source of energy to people, while Anton had other nefarious plans. Howard, finding about Anton's plans fired him and had him exiled back to Russia. The original arc reactor, while incapable of providing energy to vast crowd, provided sufficient energy to power Stark Industries.
Tony Stark's versionEdit
When Tony Stark was abducted by the Afghan terrorist group Ten Rings and was ordered to make a Jericho missile for them, Tony with the Ho Yinsen instead used the time and resources to create a miniature version of the arc reactor powering his company back in the USA. This first reactor, created by using 1.6 grams of Palladium and capable of generating three gigajoules per second, was not only allegedly capable of powering the electromagnet protecting Tony's heart from the shrapnel for fifty lifetimes on its own but also capable of powering the Mark Isuit, also designed and assembled in the captivity, for approximately 15 mins. Stark was successful in fleeing from the base camp using his armor powered by the arc reactor. After returning home Stark developed a more efficient reactor that he used to power the Mark II and Mark III suits as well.
The new arc reactor was later stolen by Obadiah Stane to power his Iron Monger suit, also made by the blueprints of the first Tony's Mark I suit. As a result, Tony had to revert back the original arc reactor created during his captivity to primarily keep himself alive and to power his Mark III suit in order to face Obediah. The original reactor had great difficulty providing enough power to the Mark III suit, being depleted to around a fifth of its power supply simply by flying Stark from his home to Stark Industries, with the last 20% being exhausted during his fight with Stane in the Iron Monger armor.
But the Palladium core in the arc reactor that kept Stark alive and powered the armor was slowly poisoning and killing him, with Stark unable to find a substitute for it. But later when Nick Fury handed him some of his father's old material; Tony found a hidden message in the diorama of the 1974 Stark Expo proves to be a diagram of the structure of a new element that proved to be the perfect substitute for Palladium, with no fear of poisoning. With the aid of his computer JARVIS, Stark synthesized it - revealing the element to be Vibranium, the same material used by Howard Stark to make Captain America's shield. Stark then had a new suit (Mark VI) developed, capable of channeling the power of the small, yet extremely powerful, new reactor.
Stark later also had a large scale version of the reactor built to power the Stark Tower in New York City. The arc reactor also prevented Loki to take control of Stark using his staff, with the reactor seeming neutralizing the staff's effect.
The Whiplash's versionEdit
With Senator Stern demanding that Stark turn over the "Iron Man technology" to the government, Stark refused, claiming that foreign nations and business competitors were decades away from successfully recreating his achievements, and that the armor is in fact his own property.
Meanwhile, after the death of his father Anton, Ivan Vanko a.k.a. the Whiplash decided to make an arc reactor of his own with the help of his father's blueprints, to power whip-like weapons. He succeeded in making one and attacked Tony Stark while racing in the a Grand Prix at the Circuit de Monaco, but was defeated in Stark and sent to prison.
Following his escape from prison with help of Justin Hammer, Vanko again creates the arc reactor to power his new, heavily upgraded armor of suit.