Although intended as a bomber and never before deployed by the USAF to a combat zone, the first B-57s to be deployed to South Vietnam were not operated in an offensive role. The need for additional reconnaissance assets, especially those capable of operating at night, led to the deployment of two RB-57E aircraft on 15 April 1963. The USAF had awarded General Dynamics a contract to modify two B-57E Canberras (55-4243, 55–4245) as all-weather high-altitude strategic reconnaissance aircraft. Under project "Patricia Lynn" these aircraft provided infrared coverage using their Reconofax VI cameras.