The Arzachel lunar base is a moon base in the series Gundam SEED Destiny.
After the Ptolemaeus lunar base was destroyed at the end of the First Alliance-PLANT War in CE 71 by ZAFT's GENESIS superweapon, a new base was needed. As a result the Earth Alliance built a new base in the Arzachel crater, fittingly naming the new base the Arzachel lunar base. As with its predecessor, the new base became the headquarters of the EA space fleet, housing a large number of ships, Mobile weapons and equipment.
After the "Break the World" incident, the Earth Alliance, under influence of the secret society Logos, declared war on PLANT, thus starting the Second Alliance-PLANT War. Shortly thereafter, a large spacefleet launched from the Arzachel base, carrying a large complement of nuclear weapons, to bring a swift end to PLANT. The nuclear attack was however repelled by ZAFT using the new Neutron Stampeder. The 8th EA Mobile Fleet was stationed here, and was instrumental in distracting the ZAFT forces during the Requiem superweapon attack on PLANT. However after Gilbert Durandal's speech of his Destiny Plan, ZAFT used the captured Requiem weapon to destroy the base, killing the president of the Atlantic Federation, Joseph Copeland, in this process.
The crater is named after Al-Zarqali (in full Abu Ishaq Ibrahim ibn Yahya Al-Zarqali, "Arzachel" to Latin Europe), a leading Arab mathematician and the foremost astronomer of his time.