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 to each of the fields in the Portuguese coat-of-arms, Afonso being one of the wings of the griffin headed by Henry the Navigator, the other wing being King John II. A variety of mango that he used to bring on his journeys to India has been named in his honour. Numerous homages have been paid to Afonso; he is featured in the Padrão dos Descobrimentos monument; there is a square carrying his name in the Portuguese capital of Lisbon, which also features a bronze statue; two Portuguese Navy ships have been named in his honour: the sloop NRP "Afonso de