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
4th Portuguese India Armada (Gama, 1502) discovered the previous year by João da Nova's Third Armada). Vasco da Gama's main fleet arrives in Lisbon in September, 1503. Gama delivers his report, noting his failure to bring the Zamorin of Calicut to terms, and urging the immediate outfitting of a strong fleet to establish strong permanent Portuguese garrisons to protect the allied cities of Cochin and Cannanore. Gama arrives too late to affect the outfitting of the 5th Armada, which had already departed in April, 1503 under the command of Afonso de Albuquerque. But his recommendation will guide the formation of the next one, the 6th Armada,