In the picture, "home" is to be found within the spherical portion. There is more than meets the eye: the visible surface is an outer shell which shields the habitat from cosmic rays and solar flares. This shell is accumulated from the slag of industrial processes, which are carried out using lunar surface material as input. Inside the shell, an inner sphere, almost a mile in circumference, rotates to provide "gravity" comparable to that of the Earth. Residents' homes stand upon the inside surface of the inner sphere.

The structure at the two ends of the axial portion are docking areas and the sites of zero-gravity manufacturing. The flat, paddle-like fixtures radiate away the waste heat of the habitat into the cold of outer space. Nearer to the sphere, the stacked rings are agricultural areas, helping provide for the needs of the workforce. Here agricultural crops, far less sensitive to radiation than humans would be, are grown in the intense sunlight of space. The simulated "gravity" in these areas is about 0.7 that of the Earth; the atmospheres are optimized for the growth of various crops.

The slightly curved plates, arranged in a circle surrounding the sphere, are the second stage in a series of mirrors which bring sunlight into the habitat at controlled hours. At a locus outside the picture, the mirrors of the first stage govern the "day-night" cycle. The second-stage mirrors pass the light at a desired angle to the ring-shaped mirrors capping the sphere. From these last, finally, the sunlight is directed into the interior of the sphere.

In the 1976 NASA Study on Space Manufacturing, habitats of this type, very efficient in their use of materials for shielding, are thought of as next steps beyond more utilitarian structures. An earlier stage of development would involve shielded versions of the agricultural areas shown here.

The habitat design shown here, made visual by NASA artist R. Guidice, is known as a "Bernal Sphere." Houses, lawns, trees, people, and all – a community of some 10,000 people – rest upon the interior surface of a large sphere, nearly a mile in circumference. The entire sphere rotates at about 1.9 RPM, producing centrifugal force as a substitute for gravity. At the equator, this simulated "gravity" is of about Earth-normal intensity. Away from the equator, it tapers off, diminishing gradually to zero at the poles. This offers the inhabitants some unusual recreational opportunities: human-powered flight, for example, and zero-gravity sports.

Near the equator of the rotating habitat wanders a small river whose shores are made of lunar sand. Natural sunshine is brought in through external mirrors. Inhabitants can have the "weather" they prefer, without worrying about its effect upon the crops: agriculture is conducted in neighboring edifices, outside the spherical portion of the habitat.

For the short distances within the space habitat, automobiles would be unnecessary, and transport would be on foot or bicycle. A climb from the equator past the small villages on the hillsides, to the rotation axis where gravity would be zero, would take about twenty minutes. A corridor at the axis would permit floating in zero-gravity out to external structures, such as the agricultural areas, the observatories, the docking ports, and contiguously located industries. Part of the workforce would take various means of conveyance to more remote worksites, such as a satellite solar power station, some kilometers off in space.