Around this south polar hub-lock, which would rotate with the wheel, was the stationary anchor ring on which rode free both the stat-walk and the anchor tubes for the smaller satellites that served as distant components of the mother ship.
Kept rigid by air pressure, any deviation corrected by pressure tanks in the stationary ring, the tubes served both to keep the smaller bodies from drifting too close to Space Lab One, and prevented their drifting off.
The anchor tubes were just over one foot in diameter, weighing less than five ounces to the yard—gray plastic and fiber, air-rigid fingers pointing away into space—but they could take over two thousand pounds of compression or tension, far more than needed for their job, which was to cancel out the light drift motion caused by crews kicking in or out, or activities aboard. Uncanceled, these motions might otherwise have caused the baby satellites to come nudging against the space lab; or to scatter to the stars.
There had been talk of making them larger, so that they might also provide passageway for personnel without the necessity for suiting up; but as yet this had not been done. Perhaps later they would become the forerunners of space corridors in the growing complex that would inevitably develop around such a center of man's activities as this laboratory in its thirty-six hour orbit.
At the far end of the longest anchor tube, ten miles away and barely visible from here, was located the unshielded, remote-controlled power pile that supplied the necessary energy for the operation of the wheel. Later, it was hoped, experimental research now in progress would make this massive device unnecessary. Solar energy would make an ideal replacement; but as yet the research was not complete, and solar energy had not yet been successfully harnessed for the high power requirements of the Lab.
Inside this anchor tube ran the thick coaxial cable that fed three-phase electric power from the atomic pile to the ship.
At the far end of the second anchor tube, five miles off in space, was Project Hot Rod, the latest in the long series of experiments by which man was attempting to convert the sun's radiant energy to useful power.
At the end of the third anchor tube, and comparatively near the ship, was the dump—a conglomeration of equipment, used and unused booster rocket cases, oddments of all sorts, some to be installed aboard the wheel, others to be used as building components of other projects; and some oddments of materials that no one could have given a logical reason for keeping at all except that they "might be useful"—all held loosely together by short guidelines to an anchor ring at the tube's end.
Carefully, Mike checked the servo-motor that would maintain the stationary position of the ring with clocklike precision against the drag of bearing friction and the spin of the hub on which it was mounted; then briefly looked over the network of tubes before entering the air lock.