Prometheus was the code name for the experimental X-303 project, despite O'Neill's preference for the name "Enterprise." Following the X-301 and X-302, the X-303 was the third in a series of human designed interstellar ships that incorporated key systems and technology of alien origin. Built as a countermeasure to the Goa'uld mothership, the Prometheus was the first of several such vessels planned, and was constructed at Area 51 over a period of approximately two years in a project that was so secret the government appropriated the budget of several billion dollars without the usual congressional oversight. When the experimental craft became a part of Earth's fleet, it became officially known as the battle cruiser BC-303, the United States Air Force Vessel Prometheus.

The ship was constructed of a trinium alloy and naquadah, and many of its key systems used crystal technology rather than wires and chips. The Prometheus was designed to carry a complement of eight F-302 fighters, and it used advanced scanning and weapons technology. It was equipped with a ring transporter which could be used to enter and exit the vessel as it hovered above a planet, and it was also able to land on a planet's surface. The ship was capable of reaching orbit in less than 30 seconds, and inertial dampeners and artificial gravity limited the effect of G-forces and zero gravity. Using sub-light engines, the ship could accelerate to more than half the speed of light at 110,000 miles per second, and it was designed with a naquadria powered hyperdrive for interstellar travel.

Before the ship was completed, however, it became the target of a hijacking plot by rogue NID agents who planned to use the ship to reach a cache of weapons and technology described in an Ancient text. Using the cover story of a media leak, four rogue NID operatives commandeered the ship and obtained the release of Colonel Simmons and Adrian Conrad. Their plot was thwarted by SG-1, and Simmons and Conrad were killed, however the Prometheus was left stranded in space 1200 light years from Earth when Thor unexpectedly beamed aboard. Despite the advanced technology of Prometheus, the ship was vastly inferior to Asgard technology, which made it ideally suited to enter Replicator-dominated space. At the request of Thor, SG-1 flew the Prometheus to Hala to repair a time-dilation device that would contain the Replicators. As a token of thanks, Thor added Asgard shields and weapons to the design of the Prometheus.

SG-1 participated in the shakedown cruise of the USAF Vessel Prometheus under the command of Colonel Ronson. However, on the mission to P7X-009, an intense gravity wave from a collapsing star caused a massive power surge in the naquadria powering the hyperdrive engines, damaging the buffer and shutting down the engines. Prometheus dropped out of hyperspace 40.62 light years short of its target and was forced to divert to Tagrea instead, using short bursts of the hyperdrive engines to travel the additional .38 light years. The naquadria reactor went critical, and was jettisoned and destroyed, and SG-1 relied on the Tagrean stargate to return home and to obtain the necessary materials to repair the ship.

The Prometheus was fitted with a hyperdrive engine taken from an alkesh, a ship one-tenth its size, making it possible to return the ship to Earth by using short bursts of the hyperdrive engines and stopping approximately every 49 light years for regularly scheduled cool-down points. Carter was accompanying Colonel Ronson and his crew for the return voyage when the ship came under attack from an unknown alien vessel and was forced to take cover in a gaseous nebula-like cloud. Carter sustained a head injury during the attack, and awoke to find the crew had vanished. Neither sub-light nor hyperdrive engines could be engaged within the cloud, and the corrosive effects of the gases would breach the hull within hours. By engaging minimal power to the hyperdrive emitter, Carter was able to cause a partial shift into hyperspace, essentially taking the ship out the cloud's space-time long enough to eliminate its effects on the sub-light engines, which allowed the sub-light engines to engage and to draw both the Prometheus and the alien vessel from the cloud in exchange for the return of the Prometheus crew. Following the recovery of the Prometheus, the Asgard installed new hyperdrive engines to the ship as well as Asgard beam technology, however without Asgard sensors the transport beam required a locator beacon to pinpoint a specific target.

After its return to Earth, the Prometheus was called upon several times to defend the planet. Under the command of General Hammond, and with Colonel Kirkland at the helm, Prometheus and its fleet of F-302s engaged Anubis's fleet in battle above Antarctica, allowing SG-1 time to complete their mission and to launch the Ancient defense weapon. When negotiations with the Goa'uld System Lords broke down, the Prometheus was launched under the command of Colonel Lionel Pendergast, however the anticipated Goa'uld attack force never arrived. Colonel Pendergast also commanded the mission to intercept the alkesh in Earth's orbit that was being used as a base of operations by the Trust, who had stolen the stargate from the SGC. Pendergast succeeded in rescuing SG-1 and recovering the stolen stargate, however the alkesh escaped. When members of the Trust were compromised by the Goa'uld and used the alkesh to return to Earth, Colonel Pendergast was once again at the helm as the Prometheus engaged the Goa'uld alkesh in battle and destroyed it.

Once the test flights for the new Asgard hyperdrive had been completed successfully, the Prometheus became capable of intergalactic travel and was prepared for a journey to the Pegasus Galaxy to rendezvous with the Atlantis expedition. Daniel joined the team under the command of General Hammond for the mission to Atlantis, however the ship was still well inside the Milky Way Galaxy when it responded to an apparent distress signal and diverted approximately 50 light years off the designated route, a journey of about 20 minutes. The ship was boarded and hijacked by Vala, who left only Daniel aboard after transporting the entire crew to her disabled alkesh, claiming that she required the Prometheus to rescue her people from the Goa'uld. Vala was apprehended, but later escaped, and the Prometheus, which engaged a fleet of alkesh and death gliders in battle, sustained hull damage and returned to Earth for repairs before making another attempt at an extended journey through hyperspace.

During the mission to locate Merlin's treasure hidden at Avalon, Prometheus remained in Earth orbit, and its advanced Asgard sensors were able to map the area around an energy distortion field, technology that would have normally fooled deep-ground sonar, in order to locate a previously undiscovered underground entrance to Glastonbury Tor. Unable to penetrate a half mile below ground with the Asgard transport beam, SG-1 used Prometheus's rings to transport into the secret chamber beneath the Tor.

Under the command of Colonel Pendergast, Prometheus also countered the first attempt by the Ori to establish a supergate in the Milky Way. Unable to dial the stargate at Kallana because of an active wormhole from the Ori galaxy, SG-1 gated instead to P4C-452, where they were able to rendezvous with Prometheus for the journey to Kallana. Using the ship's Asgard beam technology, SG-1 was able to beam into the force field that was intended to collapse the planet. Although Vala's actions prevented the formation of a supergate, the Prometheus suffered a hull breach during a partial collision with the components that arranged themselves to form the Ori gate.

Following repairs to the ship, Colonel Pendergast again commanded Prometheus with Mitchell and Teal'c aboard as they scanned for signs of Gerak's mothership in the vicinity of Earth, and they located a ha'tak on the far side of the moon, from which Gerak's Jaffa had been launching incursions on Earth to capture Ba'al. When it was determined that Ba'al had sabotaged the Halcyon Tower in Seattle, Prometheus beamed Carter directly from a stakeout near Bethesda to Seattle, however, the explosion of the Tower could not be prevented, and Prometheus beamed the entire Halcyon Tower building into space where it detonated harmlessly. Prometheus also aided in the search for Mitchell, after he was lost on the Sodan world, by running surface scans on the nearby planets and moons.

When a subspace rupture caused a ripple effect through several alternate realities, SG-1 and a team from an alternate universe embarked on a mission aboard Prometheus in an attempt to seal the rupture by releasing an explosive device into the singularity that had bridged the multiple realities. The alternate team attempted to commandeer the ship, however, hoping to reach Atlantis, but SG-1 regained control of the ship and scrapped the mission, returning to Earth with an alternate plan to reverse the time-space rupture.

Colonel Pendergast was once again in command of the Prometheus when SG-1 traveled to Tegalus with the intention of preventing a global war by destroying Rand's Ori-designed satellite weapon. Two missiles were fired, but they were ineffective against the satellite's defenses, and when the satellite returned fire, its Ori weapons easily pierced Prometheus's Asgard shields. Prometheus returned fire with its forward rail guns, and in response Mitchell scrambled Blue Squadron, a fleet of six F-302s. Prometheus was severely damaged, however, and Pendergast attempted to negotiate a surrender, but President Nadal of Rand ordered the ship's destruction. The crew began evacuating by beaming down to Caledonia, but as the satellite weapon fired once more, the Prometheus was completely destroyed. Colonel Pendergast lost his life aboard the ship, and of his crew of 115, only 76 survived.

At the time of the Prometheus's destruction, production had already begun on the next generation of interstellar vessel, the BC-304 Daedalus-class ship. The Odyssey, the newly completed sister ship to the Daedalus, replaced the Prometheus as Earth's main interstellar defense in this galaxy.

Cross Reference: Alternate Reality - Ripple Effect, Antarctica, Area 51, Asgard, Asgard Transport Beam, Ashwan, Atlantis, BC-303, Bosworth, Adrian Conrad, Crystals, Daedalus, Paul Davis, Peter DeLuise, Julia Donovan, F-302, Force Field, Erin Gant, Glastonbury, Grace, Hala, Halcyon Tower, George Hammond, Hyperspace, Jones, Kalfas, Kallana, Colonel Kirkland, Locator Beacon, Vala Mal Doran, Major Marks, Al Martell, Naquadah, Naquadria, Nebula, NID Rogue Operation, Lindsey Novak, Odyssey, Ori Satellite Weapon, Lionel Pendergast, Replicators, Colonel Reynolds, Ring Transporter, William Ronson, Frank Simmons, Smith, Supergate, Tagrea, Tagreans, Tegalus, Thor, Time Dilation Device, Trinium, Trust, Catherine Womack, X-303

Episode Reference: Prometheus, Unnatural Selection, Memento, Grace, Lost City, New Order, Endgame, Prometheus Unbound, Full Alert, Avalon, Beachhead, Ex Deus Machina, Ripple Effect, Ethon