Voyager 2 was launched from Cape Canaveral on August 20 1977, and made its closest approach to Saturn on August 25, 1981, to Uranus on January 24, 1986, and to Neptune on August 25, 1989. The spacecraft was a 10-sided aluminum framework ring about 18 inches (45 cm) high and 70 inches (179 cm) across. The ring contained 10 electronic packaging compartments. Above the ring was a high-gain antenna dish, measuring 12 feet (3.7 m) in diameter and capable of transmitting and receiving at two frequencies in the S and X bands. Voyager 2 was powered by three radioisotope thermoelectric generators located on a boom deployed shortly after launch.