twelve companies responded during november 1958 to the invitations for bids to construct the airframe of little joe. the technical evaluation of these proposals was carried on in much the same manner as for the spacecraft, except that langley research center itself carried the bulk of the administrative load. the missile division of north american aviation won the contract on december 29, 1958; and began work immediately in downey, california, on its order for seven booster airframes and one mobile launcher.