been performing theirtasks for many years. Astronauts had come and gone, testing, checking,probing however briefly; bravely clawing their way up the sides of thelong gravitic well that separated Earth from space.
The moon project that had originally been forecast for immediateaccomplishment had met with delay. As yet there was no base on themoon, though men had been there, and this was bound to occur.
But the lab was not here so much as a stepping stone to the moon as itwas to provide information for the future manned trips out towardsMars and the asteroids; and in towards Venus and the sun.
Besides research, the big wheel would provide living quarters for menbuilding other projects; would provide a permanent central for thenetwork of communications beams that was gradually encompassing man'sworld and would eventually spread to the other planets as well.Cooperating with this master communications central, other satellites,automatic so far, occupied the same orbit, leading and lagging by onehundred twenty degrees.
A twenty-four hour orbit would have been more advantageous from thepoint of view of communications, except for the interference thatwould have been occasioned by the vast flood of electrons encirclingEarth in the outer Van Allen belt. These electrons, trapped by Earth'smagnetic field from the solar wind of charged particles escaping thesun, unfortunately occupied the twenty-four hour orbit, and, as theirorbit expanded and contracted under the influence of the shiftingmagnetic field and solar flares, could produce tremendous havoc evenin automatic equipment, so that it had been deemed economicallyimpractical to set up the originally-postulated three satellites instationary twenty-four orbits as communications terminals.
As the next best choice, the thirty-six-hour orbit had been selected.It gave a slow rate of angular displacement, since the satelliteitself moved ten degrees an hour, while Earth moved 15 deg., for adifferential rate of only five degrees an hour, making fairly easytracking for the various Earth terminals of the communications net;and making possible a leisurely view of more than ninety per cent ofEarth's surface every seventy-two hours.
The other two power and communications stations which led and laggedSpace Lab One by 120 deg. each, would combine to command a complete viewof Earth, lacking only a circle within the arctic regions, so thatthey could provide power and communications for the entire world--afact which had been the political carrot which had united Earth in theeffort to create the labs with their combined technologies.
The danger of such powerful instruments as Hot Rod, concentratingmegawatt beams of solar energy for relay to earth, and which couldalso be one of man's greatest weapons if it fell into unscrupuloushands, had been carefully played down, and also carefully countered inthe screening by the Security Forces of U.N. of the personnel board.
* * * * *
T minus three and counting.
On the zero signal Mike in the engineer's quarters would change thenow idly-bubbling air jets in the rim-rivers over to thefully-directional drive jets necessary to spin the fluid incounter-rotation through the rim tanks.
The suiting-up and strapping down were probably unnecessary, Mikethought, but in space you don't take chances.
"T minus two and counting." Bessie's voice rang over the com circuitin officially clipped clarity.
From the physics lab came a rather oddly pitched echo. "Allee allee infree fallee! Hold it, please, as Confusion would say! Paul forgot tosecure the electrolite for the ECM equipment. Can't have thesefive-gallon bottles bouncing around!"
"And we can't have you bouncing around either, Dr. Chi Tung. Get thatsoup under wraps quick. How much time do you need?" came the captain'svoice from his console angled over Bessie's head.
Clark's voice could be heard murmuring into his Earth-contact phone."T minus two. Holding."
Less than two minutes later, Dr. Chi released the hold by announcingbriefly, "Machine shop and physics department secure."
"T minus two and counting...."
"T minus one and counting...." Bessie continued officially. "Fifty,forty, thirty, twenty...."
The faint whine of high-speed centrifugal compressors could be heardthrough the ship.
"Ten...." The jets that had previously bubbled almost inaudibly tookon the sound of a percolating coffee pot.
"... Four, three, two, one, mark."
The bubbling became a hiss that settled into a soft susurrus ofbackground noise, as the jets forced air through the river of water inthe circular tanks of the rim.
The water began to move. By reaction, the wheel took up a slow,circular motion in the opposite direction.
Then, gently, the wheel shook itself and settled into a complacentlyoff-center motion that placed Bessie somewhere near the actual centerof rotation.
"We're out of balance, Mr. Blackhawk," said the captain, one hand onthe intercom switch.
"Bessie, ask the Cow what's off balance." It was Mike's voice fromengineering control. "Thought we had this thing trued up like awatch."
But the computer had already taken over, and was controlling the flowof water to the hydrostatic balance tank system, rapidly orienting theaxis 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 disappearedand Space Lab One rolled true.
Slowly Mike inched the jet power up, and the speed and "gravity" ofthe rim rose--from 0.009 to 0.039 to the pre-scheduled 0.15 of agravity--two RPM--at which she would remain until a thorough testschedule over several days had been accomplished. Later tests wouldput 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 thesoft lullaby-sound that the wheel would always sing as she rolled.
* * * * *
New, experimental, her full complement of six hundred scientists andservice personnel so far represented by only one hundred sixty-threeaboard, the big wheel that was Space Lab One rotated majestically ather hydrodynamically controlled two revolutions per minute.
She gave nearly half her mass to the water that spun her--huge riversof water, pumped through the walls of the wheel's rim, forming asix-foot barrier between the laboratories within the rim and thecosmic and solar radiations of outer space.
Arguments on Earth had raged for months over the necessities--or lackof them--for the huge mass of water aboard, but the fluid mass servedmany purposes better than anything else could serve those purposes.
As a radiation shield, it provided sufficient safety against cosmicradiations of space and from solar radiations, except for solar flareconditions, to provide a margin of safety for the crew over the threemonths in which they would do their jobs before being rotated back toEarth for the fifteen-month recovery period.
The margin was nearly enough for permanent duty--and there were thosewho claimed it was sufficient--but the claim had not beensubstantiated, and the three months maximum for tour was mandatory.
Originally, shielding had not been considered of vital importance, butexperience had proven the necessity. The first construction personnelhad been driven back to Earth after two weeks, dosimeters in the red.The third crew didn't make it. All five died of radiation exposurefrom a solar flare. An original two weeks' limit was raised as moreshielding arrived--three weeks, four, five--now the shadowy edge ofthe theoretic ninety-day recovery rate from radiation damage and theninety days required to get the maximum safe dosage overlapped--butsafety procedures still dictated that a red dosimeter meant a quickreturn to Earth whether the rate of recovery overlapped or not.
The question was still open whether more shielding would be brought upto make the overlap certain, or whether it would be best to maintain apersonnel rotation policy indefinitely. Some factions on Earth seemeddetermined that rotation must remain not only a procedural but anactual requirement--their voices spoke plainly through the directivesand edicts of U.N. Budget Control--but from what s
ource behind thisbureaucratic smokescreen it would have been difficult to say.
As a heat sink, the water provided stability of temperature that wouldhave been difficult to achieve without it. Bathed in the tenuous solaratmosphere that extends well beyond the orbit of Earth, and with atemperature over 100,000 C, maintenance of a livable temperature onboard the big wheel was not the straight-forward balancing ofradiation intercepted/radiation outgoing that had been originallyanticipated by early writers on the subject.
True, the percentage of energy received by convection was smallcompared to that received by radiation; but it was also wildlyvariable.
As a biological cultural medium, the hydraulic system provided a basisfor both air restoration and food supplies. When the proper balance ofplankton and algae was achieved, the air jets that gave the ship itsspin would also purify the ship's air, giving it back in a