The radiation environment on the Moon's surface is highly hazardous to astronauts. Space radiation comes in two forms: galactic cosmic rays, with a gradual, cumulative effect on the body according to exposure time; and solar storms composed of solar flares and coronal mass ejections. These are lethal to unprotected astronauts in a matter of hours. Substantial radiation shielding is essential for lunar bases, whatever their design. The space community had yet to address this issue seriously in lunar base visions of the early 1980s and this Future Systems study was one of the first to do so. At the time, it was thought that a one-metre thick layer of loose lunar regolith (soil) would provide sufficient shielding. In one-sixth lunar gravity, the mass is roughly equivalent to 150mm of terrestrial sand. This design explores a lightweight, tent-like superstructure of composite posts and beams supporting a layer a regolith deposited over a finely-woven graphite fibre mesh attached along the beam edges. The mesh sags gradually with the regolith load transferred to the beams and posts. Lunar regolith is highly abrasive and the elevated structure ensures that it is kept off the surfaces of pressurized modules. The support posts are telescopic and mechanically operated, enabling the entire structure to be assembled and filled at ground level before being cranked up into position in a step-by-step sequence.