 Due to the limitations of the Mark III Fat Man , a nuclear strike would have been a formidable undertaking in the 1940s . The lead @-@ acid batteries that powered the fuzing system remained charged for only 36 hours , after which they needed to be recharged . To do this meant disassembling the bomb , and recharging took 72 hours . The batteries had to be removed in any case after nine days or they corroded . The plutonium core could not be left in for much longer , because its heat damaged the high explosives . Replacing the core also required the bomb to be completely disassembled and reassembled . This required about 40 to 50 men and took between 56 and 72 hours , depending on the skill of the bomb assembly team , and in June 1948 the Armed Forces Special Weapons Project had only three teams . The only aircraft capable of carrying the bomb were Silverplate B @-@ 29s , and the only group equipped with them was the 509th Bombardment Group at Walker Air Force Base in Roswell , New Mexico . They would first have to fly to Sandia Base to collect the bombs , and then to an overseas base from which a strike could be mounted . 
