"[Osea and Yuktobania] were building a 'bridge of peace' that would span into outer space. Not anymore."
Kei Nagase[1]

A mass driver is a catapult launch system powered by electromagnetic energy.[2] Mass drivers are mainly used to launch spacecraft into orbit,[1] though they can also be used to simply propel aircraft at high speeds or to launch massive aircraft.[2][3][4] They are a key component in single-stage-to-orbit launches.[1]

Mass drivers in the Ace Combat franchise have only appeared in the Strangereal universe. The Osean Federation is the only country known to develop mass drivers, and only two are known to exist: one at Basset Space Center in Osea[1] and one at Tyler Island on the Usean continent.[4]


The mass driver at Basset Space Center

Osea's mass drivers appear as bridge-like structures, each measuring 12 kilometers (7.5 mi) in length.[2][5] The start of the mass driver accelerates the vehicle through a series of checkpoints. The end of the launch ramp curves upward into the sky and allows the accelerated vehicle to gain altitude at a high velocity.[1]

While mass drivers are normally used for unmanned launches,[1][4] they can also safely launch vehicles carrying humans.[6]


Basset Space Center

Wardog Squadron fighters flying near Basset's mass driver

Osea formerly kept its development concept for a mass driver as a closely-guarded state secret. Following the Yuktobanian Peace Treaty in 1996, Osea's Aerospace Bureau and Yuktobania's National Space Agency collaborated to build a mass driver at Basset Space Center.[6] The project was considered to be the first step towards realizing an international space station,[1] and the facility would also later support the Arkbird.[6] With the mass driver designed to run east-west, the space center was split in half: Osean facilities south of the mass driver; and Yuktobanian facilities, including its prioritized development area, to the north.[7]

The mass driver was not completed until after the 2004 election of President Vincent Harling, who redirected some military spending to go to the mass driver project.[1] In August 2008, the Basset mass driver launched an SSTO craft carrying delegates and reporters from various countries to board the Arkbird for the G7 Summit.[6]

In the early stages of the Circum-Pacific War, President Harling directed the Arkbird to be used against Yuktobania's Scinfaxi.[8] Basset Space Center prepared a laser module to be launched to the Arkbird via SSTO. Wardog Squadron launched from McNealy Air Force Base to defend the launch from a Yuktobanian attack. Despite Yuktobania's use of airborne tanks and cruise missiles to invade the facility and destroy the mass driver, respectively, the SSTO craft launched and docked with the Arkbird.[1] The laser module was then used to sink the Scinfaxi.[9]

Nastasya Vasilievna Obertas revealed to Albert Genette that the Basset mass driver was sending shipments to space, even after Razgriz Squadron destroyed the Arkbird. She supposed that they were the Grey Men supplying the Strategic Orbital Linear Gun.[10]

Tyler Island

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SSTO supply ships near Tyler Island's mass driver

Sometime before 2019, a mass driver was also built on Tyler Island, Usea, by Osea to support the Arsenal Birds protecting the ISEV. This mass driver was built at an IUN airbase, itself a former rocket launch facility for a federation of Usean nations.[11]

Unlike the Basset Space Center however, Tyler Island's mass driver is solely intended for the launching of resupply ships to both Arsenal Birds.[11] In addition to resupply duties, Tyler Island was also the site of the construction and launch process for both Arsenal Birds. Launched via the mass driver, their extreme weight (100,000 tons when empty) necessitated the use of additional solid-fuel rocket boosters to provide the required propulsion.[3]

The last known use of the catapult was in the Lighthouse War where the Erusean radical faction launched SSTOs carrying Helios missiles for the last Arsenal Bird. Both vehicles were shot down by Trigger.[4]