When requested in writing by a duly authorized representative of the United States to provide the site for an aircraft control and warning station to be operated by the federal government in the vicinity of the city, any city in this state may acquire, by purchase, gift or condemnation, not more than 50 acres of land suitable for such aircraft control and warning station, and thereafter may, for a nominal consideration convey such land in fee simple to the United States of America for use as such aircraft control and warning station. Such land shall be purchased only after a resolution directing such purchase has been adopted by the governing body of the city, and no contracts or conveyances relative to acquiring or disposing of the land shall be valid unless signed by the officer or officers designated to perform such duty in the resolution.