The original membership of the Board, totaling twenty-five, consisted of the chairman of the eleven technical advisory panels in the Office of the Assistant Secretary of Defense (Research and Development), the chairmen of the senior advisory committees of the Army, Navy, and Air Force, the Directors of the National Science Foundation, the National Bureau of Standards, and the National Advisory Committee for Aeronautics (predecessor of the National Aeronautics and Space Administration), the President of the National Academy of Sciences, and seven members-at-large drawn from the scientific and technical community.