During the Battle For Earth, the AIF lacked a proper Aerospace Fleet, causing then AIF Fleet Admiral Preston J. Cole to design an easy to produce warship. He decided to use the idea of a high powered coilgun to fight the prometheus ships, but would need a ship to carry it. The idea for the Halcyon then came up, a simple, yet powerful design to use.
Service in the AIF
The Halcyon-class would be put into production immediatly once the first ship came out. By the time Prometheus began the main assault, there was only a small number of them, but would be helped by the AIF XAW-1799. During the battle, half of the halcyons would be destroyed, with the AIF struggling to produce as many as possible. By the end of the conflict, the numbers were extremely low and that was the time Preston J. Cole decided to form the United Aerospace Command
Service in the UAC
About 5 Halcyons and 15 Paris-class heavy frigates would be taken by Preston J. Cole to Ceres to form the United Aerosapce Command. These would be the first few ships to become part of the UAC Navy. Since they proved to be very reliable, they would remain in production from the beginning of the UAC to present day, despite there being superior ships that could replace it.One ship in the class, the Pillar of Autumn, became the ship that served in many of the SPARTAN-II Program's missions against the IRF. The ship recieved critical damage during the Battle of Neviston when a Federation kinetic bombardment station fired at three UAC ships including the Infinity, Over the Rainbow, and the Autumn. The United States took the three ships to their base on Luna where they were repaired and given some upgrades, courtesy of the North American Aerospace Defense Command. After weeks of repairs and reforging of her titanium armor, the ship was relaunched along with the Infinity and returned to active service.
The Halcyon's primary weapon was a MarK-2 Magnetic Accelerator Cannon, a coilgun that used magnetic coils to propel a tungsten slug at extremely high speeds, relying on the kinetic impact to damage the ship and not the actual explosive. This weapon proved its usefulness during the Battle for Earth, and would become the primary weapon for most UAC ships. Her secondaries included 192 Archer missiles, a missile system similar to modern day missiles, only they are designed to be used effectivelly in space. 32 missiles would be stored inside a "pod" and are very effective in massive numbers too. Her defesive systems include 20 12.7cm poind defense guns, a rapid fire gun in a dual turret that can fire 240 rounds a minute, but uses high explosive rounds as they are designed to counter enemy aircraft and missile systems, and are extremely deadly against infantry and light armor. The are controlled by the ship's AI and it makes them very accurate comaperd to a manned system.