Exterior view of a Stanford torus. Bottom center is the non-rotating primary solar mirror, which reflects sunlight onto the angled ring of secondary mirrors around the hub. Painting by Donald E. Davis.Interior of a Stanford torus, painted by Donald E. DavisCollage of figures and tables of Stanford Torus space habitat, from Space Settlements: A Design Study book. Charles Holbrow and Richard D. Johnson, NASA, 1977.