With the exception of the Douglas A-3 Skywarrior, the North American A-5 Vigilante was the heaviest aircraft accepted for use aboard US Navy aircraft carriers. The design originated to meet a Navy requirement in 1955 and was intended as a high performance attack aircraft with all-weather capability. The first prototype flew in 1958, and the first operational unit began to receive their Vigilantes in June 1961. The RA-5C was an unarmed reconnaissance version of the A-5 with a large array of electronic and visual reconnaissance equipment in the space previously occupied by the bomb bay. This equipment  included side-looking airborne radar, vertical, oblique and split-image cameras, and active and passive ECM equipment. The prototype RA-5C flew in June 1962, with operational RA-5Cs being first received in June 1964.
(source: United States Navy Aircraft since 1911 by Gordon Swanborough and Peter Bowers)