Missile silo

A missile silo is an underground vertical container and launcher for intermediate-range ballistic missiles (IRBMs) or intercontinental ballistic missiles (ICBMs). This structure stores a missile some distance below ground and protects it with a reinforced barrier on ground level. When the silo receives a launch order, the barrier opens and the missile begins its boost phase.

Missile silos appear as enemy units in most Ace Combat games, usually in a dedicated mission involving destroying the silos before an enemy missile launch. In some cases, the player may perform a canyon flight or a tunnel flight within a large launch facility containing one or more silos.

Development
Missile silos were first developed in the Strangereal universe prior to or during the Cold War. Both the Union of Yuktobanian Republics and the Osean Federation built many strategic missile silos in tandem with advanced developments in ICBM technology. Osea further designed anti-missile silo weapons, including conventional deep-penetration bombs that could be equipped on B-2A Spirit bombers. Osea also developed the Strategic Orbital Linear Gun, which would have used Kinetic Energy Weapons to destroy silos, but this was later abandoned.

As the Cold War progressed, the threat of Osea's anti-silo weapons led to Yuktobania designing mobile missile carriers instead, such as the Scinfaxi. Other countries continued to develop missile silos and, by the 1990s, silos were present in Belka's Avalon Dam and in multiple locations across Usea, including Faith Park Gorge and Sierraplata.

Other universes
The Joint Assault, Assault Horizon, and Infinity universes all take place on a version of Earth more like our own. Missile silos are prominent in all three related games when players enter Russian or former Soviet Union territory.

In the Joint Assault universe, the Valahia took control of a former Soviet missile silo facility in Romania. Missiles still inside the facility were equipped with nuclear warheads, empowering the Valahia to threaten the United States of America and European countries. Antares Squadron made their way to the launch facility and Antares One flew into the facility's tunnels, destroying the launch control devices and causing the facility to explode.