One approach to building

an expandable torus

pressure hull

A torus is a commonly used pressure hull shape in space habitat concept designs. The most technically challenging​ aspect of designing a growth-capable space habitat is growing the pressure hull. One method of growing a torus shaped pressure hull is illustrated in the animation shown here. In this method a new folded pressure hull is constructed inside the existing pressure hull. When the new hull has been pressure tested, the existing hull is removed and the material recycled. The new pressure hull is then expanded by a controlled release of the restraining cables. The animation shows one way of folding the new pressure hull to enable proportional growth where every facet of the torus grows by the same proportion, resulting in a uniformly scaled expansion.

Habitable real estate for the human future in space