It would, no doubt, be conceivable to design technical equipment that make possible staying in empty space despite the absence of all materials; however, even the absence of gravity would (at least in a physical sense, probably otherwise also) not present any critical obstacle to the sustenance of life, if the various peculiarities resulting from space conditions are taken into consideration in the manner previously indicated.
However, since the weightless state would be associated in any case with considerable inconveniences and could even perhaps prove to be dangerous to health over very long periods of time, artificial replacement of gravity is provided for in the space station. In accordance with our previous discussion, the force of gravity, being an inertial force, can only be influenced, offset or replaced by an inertial force, more specifically, by centrifugal force if a permanent (stabile) state is to result. This very force allows us to maintain the space station in its vertiginous altitude, so to speak, and to support it there. However, since the latter also leads at the same time to complete compensation of the gravitational state in the space station itself, the centrifugal force now is used again (however, in a different manner) to replace the missing gravitational state.
Basically, this is very easy to accomplish: only those parts of the station in which the centrifugal force and consequently a gravitational state are to be produced must be rotated at the proper speed around their center of mass (center of gravity). At the same time, it is more difficult to satisfy the following requirement: the space traveller must be able to exit and enter the station, connect cables and attach large concave mirrors simply and safely when some parts of the station are rotating. Another requirement is that it be possible also to reposition the entire station not only relative to the sun's rays, but also according to the demands of remote observations.
These conditions lead to a partitioning of the space station into three individual entities: first, the "habitat wheel," in which a manmade gravitational state is continually maintained through rotation, thus offering the same living conditions as exist on Earth; it is used for relaxing and for the normal life functions; second, the "observatory"; and third, the "machine room." While retaining the weightless state, the latter two are only equipped in accordance with their special functions; they provide the personnel on duty with a place for performing their work, but only for a short stay.
However, this partitioning of the space station makes it necessary to apply special procedures in order to compensate for the mutual attraction of the individual objects, because even though this is very slight due to the relative smallness of the attracting masses, the mutual attraction would nevertheless lead to a noticeable approach over a longer period (perhaps in weeks or months) and finally even to the mutual impact of individual objects of the space station. The individual objects, therefore, must either: be positioned as far as possible from one another (at several hundred or thousand meters distance), so that the force of mutual attraction is sufficiently low; from time to time the approach that is occurring nonetheless can be compensated for by means of thrusters, or; be as close as possible to one another and be mutually braced in a suitable manner to keep them separated. In this study, we decided on the first alternative (Figure 94).