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This article concerns the Strangereal superweapon. For the superweapon from Ace Combat Infinity, see Stonehenge (Infinity).
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SPOILER WARNING: This article or section contains spoilers from Ace Combat 7: Skies Unknown. Proceed at your own discretion.

"Is the distance to the target correct? Holy... that thing is huge!"
ISAF pilot upon seeing Stonehenge[1]

Stonehenge (ストーンヘンジ), also known as the Spaceguard Turret Network (STN),[2] is a planetary defense railgun complex constructed in the Hatties Desert in western Usea. It was the primary weapon developed at the end of the 20th century to address the threat of the Ulysses 1994XF04 asteroid.

The former Federal Republic of Erusea captured Stonehenge in 2003, compelling the Federation of Central Usea and its allies to form the Independent State Allied Forces (ISAF). Erusea utilized Stonehenge as an anti-aircraft weapon against ISAF throughout the ensuing Continental War until Mobius 1 destroyed the seven operational railguns in April 2005; power to the eighth railgun was previously disabled by a Ulysses meteorite.

In 2019, the Osean Ground Defense Force reactivated the eighth railgun during the Lighthouse War. It was used in Operation Dragon Breath to destroy one Arsenal Bird, Liberty.



STN Overhead

After the discovery of Ulysses in late 1994 and the determination of its trajectory, news of the impending impact was kept secret in order to avoid widespread panic. Finally, on April 20, 1996, FCU President Robert Sinclair disclosed the existence of the asteroid to the world in a public news conference.[3] That same day, FCU Secretary of State Stateson attended an emergency assembly of the Central Usea Treaty Organization (UTO), wherein various defense proposals were made, including the creation of a "National Missile Defense" system within UTO member nations.[4]

The Stonehenge complex—known internally as the STN program[5]—was later conceived by the FCU under the Defense Initiative plan. Construction took place in Area 26021-3, a site in the desert region south of San Salvacion. The weapon's development was overseen by the Project STN Committee and security was provided by UTO coalition troops and a fighter squadron, whose roster included John Herbert, a veteran of the Usean coup d'état.

STN Construction

Construction crews assembling Stonehenge

Numerous governments, private sector corporations, and scientists from around the world participated in the construction effort; at least one Belkan scientist, David Hartmann, was known to have been involved.[6] Osea and Yuktobania initially considered joining the project, but declined on account of post-Belkan War reconstruction efforts.[7][8] The main STN site was completed in June 1998, while the rest of the railgun system remained under construction for several more months.[5]

In the same month, the International Astronomical Union released an updated report on Ulysses' projected impact area, sparking protests in Anea against the FCU over the northern hemisphere's lack of protection against the asteroid. By that time, however, Stonehenge had reached a point in its development where no further modifications could be made.[9]

Ulysses Day and Erusean takeover

On July 3, 1999, Stonehenge went online and commenced operations against Ulysses, limiting damage across the Usean continent during the planetfall event.[10] Despite being the only successful weapon of its type during the disaster, Stonehenge could not prevent all of the carnage; over 500,000 civilians perished in the first two weeks of the planetfall.[11][12] In addition, one of Stonehenge's eight cannons was disabled by a nearby meteorite impact[13] and remained out of commission for the rest of the STN's existence.[1]

Stonehenge Soldiers

Erusean soldiers occupying Stonehenge

In the aftermath of Ulysses Day, Erusea was overwhelmed by an influx of refugees, compelling Erusean officials to restrict the issuing of visas to refugees.[14] As tensions escalated with the international community, the Erusean military, without warning, invaded San Salvacion in the summer of 2003 and captured Stonehenge. The weapon's capture, together with the invasion of San Salvacion, caused great worry within the international community. In an official statement, Erusea declared that STN ground patrols and staff were being kept "under protection" by its troops; twelve UTO aircraft disappeared during the incident.[15]

On August 22, 2003, Erusea sent an ultimatum to Robert Sinclair, threatening attacks against the Federation and its allies if he refused to withdraw the FCU forces from San Salvacion's borders before September 9.[16] Sinclair responded by threatening to declare war if the occupation troops in both San Salvacion and Stonehenge were not removed before September 14.[17] The standoff led to the formation of the Independent State Allied Forces,[18] which dispatched an elite squadron to perform a surprise attack on Stonehenge on September 14; the effort, however, was soundly defeated by the Federal Erusea Air Force's infamous Yellow Squadron.[12]

Continental War

Stonehenge Espionage Mission Intel

A reconnaissance photo of a Stonehenge railgun turret

"Stonehenge is responsible for the loss of many aces."
AWACS SkyEye[1]

After its retreat from the mainland and the relocation of its headquarters to North Point, the ISAF began making retaliatory strikes in preparation for a counterattack. Shortly after the capture of Stonehenge, the Erusean government announced its plan to produce X-02 Wyverns to serve as the superweapon's protectors, sparking debate within the Erusean Parliament over their cost and efficacy, which eventually halted the X-02's production.[16]

During the ISAF's counteroffensive operations within mainland Usea, Erusea used Stonehenge to attack the ISAF with limited success. In March 2005, several engineers and scientists responsible for designing the weapon, who had been detained by Erusea under the pretext of "security purposes", escaped with their families on-board Air Ixiom Flights 701 and 702. In exchange for protection and amnesty, the engineers offered to provide ISAF with crucial information regarding Stonehenge's defensive systems. ISAF ace Mobius 1 was dispatched to escort and defend the airliners from Erusean fighters until their safe arrival within ISAF territory.[16][19]

Stonehenge Cannons

The Stonehenge railgun turrets ready to fire

A month later, on April 2, the ISAF launched a second aerial attack on Stonehenge. The effort, Operation Stone Crusher, resulted in the complete destruction of the seven operational railguns due to Mobius 1's intervention. Yellow Squadron scrambled from nearby San Salvacion to intercept the ISAF squadrons, but was forced to retreat after Mobius 1 shot down Yellow 4.[1][16]

Lighthouse War

Stonehenge Power Trucks

Stonehenge being powered by Osean generator trucks

During the Lighthouse War, the Cyclops and Strider Squadrons were tasked with reconnaissance on Stonehenge and its surroundings.[20]

Later in the war, forces from the Osean Ground Defense Force, led by Major Deanna McOnie and Warrant Officer Lehmann, secretly reactivated the eighth railgun that was previously disabled by a Ulysses meteorite impact. This operation was undertaken with the intention of eliminating at least one of the Arsenal Birds. Instead of using the facility's power circuit damaged by the meteorite impacts, multiple trucks carrying power banks were used to power the railgun.[21]

During the operation, multiple Osean Air Defense Force and OGDF units defended the railgun from invading Erusean forces. The Arsenal Bird Liberty later entered the airspace. As the battle progressed, the survey team was killed by an Erusean agent, forcing the team to visually aim the railgun. Trigger and Cyclops 1 were also tasked with destroying the main propellers in order for the Arsenal Bird to slow down, giving the railgun a clear shot. As the Arsenal Bird activated its shield, the railgun was fired, penetrating the shield and splitting Liberty in half, crashing in the vicinity of Stonehenge. Upon successfully firing, the railgun broke down, effectively rendering the entirety of Stonehenge inoperable.[21]


One of humanity's foremost projects built to combat the threat of Ulysses, Stonehenge was based on a circular design divided into eight sections, each of which housed a railgun turret.[5] The weapons, officially called the "120cm dual-use anti-air-and-surface, gunpowder-and-electromagnetic hybrid acceleration system, semi-automatic fixed guns", operated on a hybrid energy principle using gunpowder to initially propel projectile shells, and then accelerate them to maximum velocity with electromagnetic energy.[5]

The cannons were considered "electromagnetic launchers" by their creators instead of true railguns, due to the combination of propellants utilized. Capable of accelerating projectiles to a velocity of six kilometers per second (about 17-18 times the speed of sound), Stonehenge's hybrid propellant system was chosen to prevent excess heat from warping the barrels and lower the cost of its electricity consumption. The weapons were originally planned to be locomotive, but the idea was quickly abandoned because a capacitor suited for such operations was technologically unfeasible.[5]

Stonehenge (Complex Illustration)

Concept art of the STN facility

Stonehenge's turrets were directed by a synthesized control network beneath the facility formed by a complex of 8,192 supercomputers split into 1,024 sets of eight; each was capable of performing nine billion floating point arithmetic operations per second. Stonehenge was capable of performing a total of 100 trillion operations per second using all of its computational power. The system also employed data gathered from orbiting satellites, observatories around the globe, and weather models of Usea's atmospheric conditions to calculate an asteroid's destined point of impact. The computers aiming the cannon(s) would then plot the asteroid's trajectory, track the target, and fire.[5]

As a whole, Stonehenge's firing range encompassed a radius of 1,200 kilometers,[5] spanning from Erusea's capital of Farbanti on the western tip of Usea to the Faith Park region. The cannons could launch a variety of ammunition, including armor-piercing explosive rounds and a special type of shell suited for large fragments, whose use was limited under a special measures act.[5]



  • The names "Stonehenge" and "Spaceguard Turret Network" have previously been combined by fans to create the name "Stonehenge Turret Network". However, no official material uses this name.
  • In-universe material cites similarities between the weapon and the real-life monument, Stonehenge, being the reason for the weapon's nickname.[5] Considering that Ace Combat 04 took place in a version of Strangereal that bore many similarities to our world, the Stonehenge monument may have been present somewhere in the Ace Combat 04 world outside of Usea.
  • Within Ace Combat 04 and its promotional media, Stonehenge is frequently referred to as a single gun.
  • The Meson Cannon complex in Ace Combat X is similar in appearance to the Stonehenge facility; the differences being that the Meson Cannon surrounded a city, fired lasers, and may not have had radar jamming (depending on whether or not the player destroyed the Nevera Jammer first).
  • The jamming facility in the center of Stonehenge may have provided inspiration for the nuclear missile silo doors in the mission "Sanctify" from Ace Combat: Joint Assault.
  • The air base next to the turret network is a photo-exact replica of Edwards Air Force Base northeast of Palmdale, CA. Both Edwards AFB and the base next to Stonehenge share the same desert terrain and layout.


  1. 1.0 1.1 1.2 1.3 Stonehenge Offensive, Ace Combat 04: Shattered Skies.
  2. Hasegawa 1/72 "F-22A ACE COMBAT Mobius 1" (plastic model) description.
  3. "FCU President Makes Announcement To Ambassadors And Their Respective Nations", Asteroid On Collision Course With Earth. Retrieved January 30, 2017.
  4. "Secretary Of State Expresses Support For NMD Proposal", Asteroid On Collision Course With Earth. Retrieved January 30, 2017.
  5. 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 Titan Guns. Retrieved on August 9, 2017.
  6. Assault Records #046: David Hartmann, Ace Combat Zero: The Belkan War.
  7. Aces At War: A History, page 136.
  8. "Entwining Destiny", Arkbird Declaration: Summit 2008. Retrieved January 30, 2017.
  9. "Wider Damage Range than Estimated", Last Christmas. GAZE. Retrieved January 30, 2017.
  10. "Introduction", War?. GAZE. Retrieved January 30, 2017.
  11. Ace Combat 04: Shattered Skies - Perfect Guide, page 007.
  12. 12.0 12.1 World, AC04Web. Retrieved January 30, 2017.
  13. "Erusea's Aggression", War?. Retrieved 25 July 2018.
  14. "Friction Comes to the Surface of the Refugee Problem", War?. GAZE. Retrieved January 30, 2017.
  15. "The Rash Act of Erusea", War?. GAZE. Retrieved January 30, 2017.
  16. 16.0 16.1 16.2 16.3 Aces At War: A History, page needed.
  17. "The Acquirement of the Country", War?. GAZE. Retrieved January 30, 2017.
  18. "Countries Unite to Counter Erusea; 'ISAF' Established", War?. GAZE. Retrieved January 30, 2017.
  19. Escort, Ace Combat 04: Shattered Skies.
  20. "First Contact", Ace Combat 7: Skies Unknown.
  21. 21.0 21.1 "Stonehenge Defensive", Ace Combat 7: Skies Unknown.

Start a Discussion Discussions about Stonehenge (Strangereal)

  • Ulysses intel on the AC 4 training book

    4 messages
    • Hang on, is this the French manual for ''Ace Combat: Distant Thunder'', or is this from a book about more than just Ace Combat?
    • French manual , i have never see this manual in another language .  It is pretty strange to the translator have do this kind of mistake . I ...
  • Stonehenge Turret Network: The Civics Project

    17 messages
    • There is also Megalith, altough it was only for pinpoint the meteor fragments for the cruiser missiles.
    • wrote:There is also Megalith, altough it was only for pinpoint the meteor fragments for the cruiser missiles. Cruiser missiles...