In addition to assembly of weapons, the AFSWP supported nuclear weapons testing. For Operation Sandstone in 1948, Groves ordered Dorland to fill every possible job with his men.[45] He did this so well that Strauss, now an AEC commissioner, became disturbed at the number of AFSWP personnel who were participating, and feared that the Soviet Union might launch a sneak attack on Enewetak to wipe out the nation's ability to assemble nuclear weapons.[46] The successful testing in Operation Sandstone was a major leap forward.[47] The new Mark 4 nuclear bomb that the AEC began delivering in 1949 was a production design that was much easier to assemble and maintain, and enabled a bomb assembly team to be reduced to just 46 men.[48] Kenneth D. Nichols, the wartime commander of the Manhattan District, now "recommended that we should be thinking in terms of thousands of weapons rather than hundreds."[49]