Then, gently, the wheel shook itself and settled into a complacently off-center motion that placed Bessie somewhere near the actual center of rotation.
"We're out of balance, Mr. Blackhawk," said the captain, one hand on the intercom switch.
"Bessie, ask the Cow what's off balance." It was Mike's voice from engineering control. "Thought we had this thing trued up like a watch."
But the computer had already taken over, and was controlling the flow of water to the hydrostatic balance tank system, rapidly orienting the axis of spin against the true axis of the wheel.
The wobble became a wiggle; the wiggle became the slightest of sways; and under the computer's gentle ministrations, the sways disappeared and Space Lab One rolled true.
Slowly Mike inched the jet power up, and the speed and "gravity" of the rim rose—from 0.009 to 0.039 to the pre-scheduled 0.15 of a gravity—two RPM—at which she would remain until a thorough test schedule over several days had been accomplished. Later tests would put the rim through check-out tests to as high as 1.59 gee, but "normal" operation had been fixed at two RPM.
In the background, the susurrus of the air jets rose slightly to the soft lullaby-sound that the wheel would always sing as she rolled.
New, experimental, her full complement of six hundred scientists and service personnel so far represented by only one hundred sixty-three aboard, the big wheel that was Space Lab One rotated majestically at her hydrodynamically controlled two revolutions per minute.
She gave nearly half her mass to the water that spun her—huge rivers of water, pumped through the walls of the wheel's rim, forming a six-foot barrier between the laboratories within the rim and the cosmic and solar radiations of outer space.