<hi style=afpcap>The B-52B was the first operational version of the Stratofortress with deliveries to the 93rd Bombardment Wing at Castle Air Force Base, California taking place from June 1955 onwards. The unit also received the RB-52B version, which was equipped with a four cameras mounted in a pod located in the bomb bay. Eight 93rd BW B-52Bs completed a 17,000 mile flight over North America in November 1956 lasting 32 hours as a preliminary for a round the world flight in January 1957. The mission was performed by three aircraft in 45 hours and 19 minutes with air refuelling provided by KC-97s. The B-52B also dropped the first airborne hydrogen bomb test in May 1956, from a height of 50,000 feet over Bikini Atoll. </hi>
