Ascension Island a staging point by the British military during the Falklands War. Ascension Island hosts one of four ground antennas (others are on Kwajalein Island, Diego Garcia, and Cape Canaveral) that assist in the operation of the Global Positioning System (GPS) navigational system. NASA operates a Meter Class Autonomous Telescope (MCAT) on Ascension Island for tracking orbital debris, which is potentially hazardous to operating spacecraft and astronauts, at a facility called the John Africano NASA/AFRL Orbital Debris Observatory. In 1501, the Portuguese navigator Afonso de Albuquerque sighted the island on Ascension Day (which fell on 21 May that year) and named
Afonso de Albuquerque encouraged him to seize power. On 3 February 1509, Almeida fought the naval Battle of Diu against a joint fleet of Mamluks, Ottomans, the Zamorin of Calicut, and the Sultan of Gujarat, regarding it as personal revenge for the death of his son. His victory was decisive: the Ottomans and Mamluks abandoned the Indian Ocean, easing the way for Portuguese rule there for the next century. In August, after a petition from Afonso's former officers with the support of Diogo Lopes de Sequeira claiming him unfit for governance, Afonso was sent in custody to St. Angelo Fort in Cannanore. There