The Martin B-57E Canberra is an American-built, twinjet tactical bomber and reconnaissance aircraft that entered service with the United States Air Force (USAF) in 1953. The B-57 was a license-built version of the British English Electric Canberra; the Glenn L. Martin Company later modified the design to produce several different variants. The Canberra was the first U.S. jet bomber to drop bombs during combat.[3] Its retirement in 1983 ended the era of the tactical bomber that had its beginning with the British World War I De Havilland DH-4 bomber. The three remaining flightworthy WB-57Fs are technically assigned to the NASA Johnson Space Center, next to Ellington Field in Houston, as high-altitude scientific research aircraft,[1] but are also used for testing and communications in the U.S. and Afghanistan.[4] From Wikipedia Ag-1 to drop all 50 dumb bombs ag-2 to drop all 25 dumb bombs ag-3 to drop cluster bomb ag-4 to fire all the infernos and ag-5 to drop infernos pod