Retractable mast with shape memory alloy. A mast is suggested based on a flattened polygonal tube section with the sides made of conventional material (metal or compound) and the corners made of shape memory alloy (SMA), joined at the aforesaid sides by adhesives. The mast is made in its extended form. It is then flattened, all the corners being deformed plastically, and rolled up for storage. It will remain in this state until the alloy of the corners is heated above its transition temperature, when it regenerates its original extended mast form. The process may be repeated on hundreds of occasions.<IMAGE>