The Boeing B-52 Stratofortress was originally designed to supercede the B-36 and carry nuclear weapons for the SAC during the coldwar. It never delivered nuclear weapons in combat, but dropped nearly all the weapons tested in the Pacific during the 50/60's including the first air-deliverable H-bomb in 1956. The B-52 entered service in 1954 and has served in every majot conflict since then. It is not expected to be decomsissioned until at least 2040, an unprecedented service length for a military aircraft.