Cell-based space systems with nested-ring structures that interlock and can change configuration to support a mission are provided. The cells may self-assemble into a larger structure to carry out a mission. Multiple rotatable rings may be included in a cell, with a payload/control section in the center. The rings may provide power and/or data to trams that move about the rails. Trams may interlock with other cells, carry sensors or other devices, etc. Cells may be stowed in a cell stack that is deployable. Such cell-based systems may have various applications in space, on Earth, other celestial bodies, and underwater.