Part 5

"We might beam a wide-dispersion affair at them," continued Channing. "But it would be pretty thin by the time it got there. And, having no equipment, they couldn't hear us."

"May we amend that?" asked Franks. "They are equipped with radio. But the things are used only in landing operations where the distance is measured in miles, not Astronomical Units."

"O.K.," smiled Channing. "It's turned off during flight and we may consider the equipment as being non-existent."

"And, according to the chart, we've got to contact them before the turnabout," offered Arden. "They must have time to deflect their course to Terra."

"You think of the nicest complications," said Channing. "I was just about to hope that we could flash them, or grab at 'em with a skeeter. But we can't wait until they pass us."

"That will be the last hope," admitted Franks. "But say! Did any bright soul think of shooting a fast ship after them from Canalopsis?"

"Sure. The answer is the same as Simple Simon's answer to the Pieman: 'Alas, they haven't any!'"

"No use asking why," growled Franks. "O.K., Don, we'll after 'em. I'll have the crew set up a couple of mass detectors at either end of the station. We'll triangulate, and calculate, and hope to hit the right correction factor. We'll find them and keep them in line. You figure out a means of contacting them, huh?"

"I'll set up the detectors and _you_ find the means," suggested Don.

"No go. You're the director of communications."

Don sighed a false sigh. "Arden, hand me my electronics text," he said.

"And shall I wipe your fevered brow?" cooed Arden.

"Leave him alone," directed Franks. "You distract him."

"It seems to me that you two are taking this rather lightly," said Arden.

"What do you want us to do? Get down on the floor and chew the rug? You know us better than that. If we can find the answer to contacting a spaceship in flight, we'll add another flower to our flag. But we can't do it by clawing through the first edition of Henney's 'Handbook of Radio Engineering.' It will be done by the seat of our pants, if at all; a pair of side-cutters, and a spool of wire, a hunk of string and a lump of solder, a--"

"A rag, a bone, and a hank of hair?" asked Franks.

"Leave Kipling out of this. He didn't have to cover the entire Solar System. Let's get cooking."

Don and Walt left the office just a trifle on the fast side. Arden looked after them, out through the open door, shaking her head until she remembered something that she could do. She smiled and went to her typewriter, and pounded out a message back to Keg Johnson at Interplanet. It read:

"CHANNING AND FRANKS AT WORK ON CONTACTING THE EMPRESS OF KOLAIN. WILL DO OUR BEST.

VENUS EQUILATERAL."

* * * * *

Unknowing of the storm, the _Empress of Kolain_ sped silently through the void, accelerating constantly at one G. Hour after hour she was adding to her velocity, building it up to a speed that would make the trip in days, and not weeks. Her drivers flared dull red no more, for there was no atmosphere for the ionic stream to excite. Her few portholes sparkled with light, but they were nothing in comparison to the starry curtain of the background.

Her hull was of a neutral color, and though the sun glanced from her metal flanks, a reflection from a convex side is not productive of a beam of light. It spreads according to the degree of convexity and is lost.

What constitutes an apparent absence? The answer to that question is the example of a ship in space flight. The _Empress of Kolain_ did not radiate anything detectable in the electromagnetic scale from ultralong waves to ultra-high frequencies; nothing at all that could be detected at any distance beyond a few thousand miles. The sweep of her meteor-spotting equipment would pass a spot in micro-micro-seconds at a hundred miles; at the distance from Venus Equilateral the sweep of the beam would be so fleeting that the best equipment ever known or made would have no time to react, thus missing the signal.

Theorists claim a thing unexistent if it cannot be detected. The _Empress of Kolain_ was invisible. It was undetectable to radio waves. It was in space, so no physical wave could be transmitted to be depicted as sound. Its mass was inconsiderable. Its size as cosmic sizes go was comparatively sub-microscopic, and therefore it would occult few, if any, stars. Therefore, to all intents and purposes, the _Empress of Kolain_ was non-existent, and would remain in that state of material-non-being until it came to life again upon its landing at Venus.

Yet the _Empress of Kolain_ existed in the minds of the men who were to find her. Like the shot unseen, fired from a distant cannon, the _Empress of Kolain_ was coming at them with ever-mounting velocity, its unseen course a theoretical curve.

And the ship, like the projectile, would land if the men who knew of her failed in their purpose.

* * * * *

Don Channing and Walt Franks found their man in the combined dining room and bar--the only one in sixty million miles. They surrounded him, ordered a sandwich and beer, and began to tell him their troubles.

Charles Thomas listened for about three minutes. "Boy," he grinned, "being up in that shiny, plush-lined office has sure done plenty to your think-tank, Don."

Channing stopped talking. "Proceed," he said. "In what way has my perspective been warped?"

"You talk like Burbank," said Thomas, mentioning a sore spot of some months past. "You think a mass detector would work at this distance? Nuts, fellow. It might, if there were nothing else in the place to interfere. But you want to shoot out near Mars. Mars is on the other side of the Sun--and Evening Star to anyone on Terra. You want us to shoot a slap-happy beam like a mass detector out past Sol; and then a hundred and forty million miles beyond in the faint hope that you can triangulate upon a little mite of matter; a stinking six hundred-odd feet of aluminum hull mostly filled with air and some machinery and so on. Brother, what do you think all the rest of the planets will do to your piddling little beam? Retract, or perhaps abrogate the law of universal gravitation?"

"Crushed," said Franks with a sorry attempt at a smile.

"_Phew!_" agreed Channing. "Maybe I should know more about mass detectors."

"Forget it," said Thomas. "The only thing that mass detectors are any good for is to conjure up beautiful bubble dreams, which anyone who knows about 'em can break with the cold point of icy logic."

"What would you do?" asked Channing.

"Darned if I know. We might flash 'em with a big mirror--if we had a big mirror and they weren't heading into the Sun."

"Let's see," said Franks, making tabulations on the tablecloth. "They're a couple of hundred million miles away. In order that your mirror present a recognizable disk, it should be about twice the diameter of Venus as seen from Terra. That's eight thousand miles in--at the least visibility--say, eighty million or a thousand-to-one ratio. The _Empress of Kolain_ is heading at us from some two hundred million miles, so at a thousand-to-one ratio our mirror would have to be twenty thousand miles across. Some mirror!"

Don tipped Walt's beer over the edge of the table, and while the other man was busy mopping up and muttering unprintables, Don said to Thomas: "This is serious and it isn't. Nobody's going to lose their skin if we don't, but a problem has been put to us and we're going to crack it if we have to skin our teeth to do it."

"You can't calculate their position?"

"Sure. Within a couple of hundred thousand miles we can. That isn't close enough."

"No, it isn't," agreed Chuck.

Silence fell for a moment. It was broken by Arden, who came in waving a telegram. She sat down and appropriated Channing's glass, which had not been touched. Don opened the sheet and read: "Have received confirmation of your effort. I repeat, spare no expense!" It was signed: "Keg Johnson, Interplanet."

"Does that letter offer mean anything to you?" asked Arden.

"Sure," agreed Don. "But at the same time we're stumped. Should we be doing anything?"

"Anything, I should think, would be better than what you're doing at present. Or does that dinner-and-beer come under 'expenses'?"

Arden stood up, tossed Channing's napkin at him, and started toward the door. Channing watched her go, his hand making motions on the tablecloth. His eyes fell to the table and he took Franks' pencil and drew a long curve from a spot of gravy on one side of the table to a touch of coffee stain on the other. The curve went through a bit of grape jelly near the first stain.

"Here goes the tablecloth strategist," said Franks. "What now, little man?"

"That spot of gravy," explained Don, "is Mars. The jelly is the _Empress of Kolain_. Coffee stain is Venus, and up here by this cigarette burn is Venus Equilateral. Get me?"

"Yop, that's clear enough."

"Now it would be the job for seventeen astronomers for nine weeks to predict the movements of this jelly spot with respect to the usual astral standards. But, fellows, we know the acceleration of the _Empress of Kolain_, and we know her position with respect to Mars at the instant of take-off. We can correct for Mars' advance along her--or his--orbit. We can figure the position of the _Empress of Kolain_ from her angular distance from Mars! That's the only thing we need know. We don't give a ten-dollar damn about her true position."

Channing began to write equations on the tablecloth. "You see, they aren't moving so fast in respect to us. The course is foreshortened as they are coming almost in line with Venus Equilateral, curving outward and away from the Sun. Her course, as we see it from the station here, will be a long radius-upward curve, slightly on the parabolic side. Like all long-range cruises the _Empress of Kolain_ will hoist herself slightly above the plane of the ecliptic to avoid the swarm of meteors that follow about the Sun in the same plane as the planets, lifting the highest at the point of greatest velocity.

"I get it," said Franks. "We get the best beam controller we have to keep the planet on the cross hairs. We apply a spiral cam to advance the beam along the orbit. Right?"

"Right." Don sketched a conical section on the tablecloth and added dimensions. He checked his dimensions against the long string of equations, and nodded. "We'll drive this cockeyed-looking cam with an isochronic clock, and then squirt a beam out there. Thank the Lord for the way our beam transmitters work."

"You mean the effect of reflected waves?" asked Chuck.

"Sure," grinned Don. "There's plenty of radar operating at our transmitting frequencies or near by. So far, no one has ever tried to radar anything as small as a spacecraft at that distance, though getting a radar signal from a planet is duck soup. Yet," he reflected cheerfully, "there are a couple of things we have handy out here, and one of them is a plethora of power output. We can soup up one of our beam transmitters and use it with a tightened beam to get a radar fix off of the _Empress of Kolain_."

"And then?" asked Franks.

"Then we will have left the small end, which I'll give to you, Walt, so that you can have part of the credit."

Walt shook his head. "The easy part," he said uncheerfully. "By which you mean the manner in which we contact them and make them listen to us?"

"That's her," said Don with a cheerful smile.

"Fine," said Thomas. "Now what do we do?"

"Clear up this mess so we can make the cam. This drawing will do, just grab the tablecloth."

Joe, the operator of Venus Equilateral's one and only establishment for the benefit of the stomach, came up as the three men began to move their glasses and dishes over to an empty table. "What makes with the tablecloth?" he asked. "Want a piece of carbon paper and another tablecloth?"

"No," said Don nonchalantly. "This single copy will do."

"We lose lots of tablecloths that way," said Joe. "It's tough, running a restaurant on Venus Equilateral. I tried using paper ones once, but that didn't work. I had 'em printed but when the solar system was on 'em, you fellows drew schematic diagrams for a new coupler circuit. I put all kinds of radio circuits on them, and the gang drew plans for antenna arrays. I gave up and put pads of paper on each table, and the boys used them to make folded paper airplanes and they shot them all over the place. Why don't you guys grow up?"

"Cheer up, Joe. But if this tablecloth won't run through the blueprint machine, we'll squawk!"

Joe looked downcast, and Franks hurried to explain: "It isn't that bad, Joe. We won't try it. We just want to have these figures so we won't have to run through the math again. We'll return the cloth."

"Yeah," said Joe at their retreating figures. "And for the rest of its usefulness it will be full of curves, drawings, and a complete set of astrogating equations." He shrugged his shoulders and went for a new tablecloth.

Don, Walt and Chuck took their improvised drawing to the machine shop, where they put it in the hands of the master mechanic.

"This thing has a top requirement," Don told him. "Make it as quick as you can."

Master Mechanic Warren took the cloth and said: "You forgot the note. You know, 'Work to dimensions shown, do not scale this drawing.' Lord, Don, this silly looking cam will take a man about six hours to do. It'll have to be right on the button all over, no tolerance. I'll have to cut it to the 'T' and then lap it smooth with polishing compound. Then what'll you test it on?"

"Sodium light interferometer. Can you do it in four hours?"

"If nothing goes wrong. Brass all right?"

"Anything you say. It'll only be used once. Anything of sufficient hardness for a single usage will do."

"I'll use brass then. Or free-cutting steel may be better. If you make it soft you have the chance of cutting too much off with your lapping compound. We'll take care of it, Don. The rest of this stuff isn't too hard. Your framework and so on can be whittled out and pasted together from standard girders, right?"

"Sure. Plaster them together any way you can. And we don't want them painted. As long as she works, phooey to the looks."

"Fine," said Warren. "I'll have the whole business installed in the Beam Control Room in nine hours. Complete and ready to work."

"That nine hours is a minimum?"

"Absolutely. After we cut and polish that screwball cam, we'll have to check it, and then you'll have to check it. Then the silly thing will have to be installed and its concentricity must be checked to the last wave length of cadmium light. That'll take us a couple of hours, I bet. The rest of the works will be ready, checked, and waiting for the ding-busted cam."

"Yeah," agreed Franks. "Then we'll have to get up there with our works and put the electricals on the mechanicals. My guess, Don, is a good, healthy twelve hours before we can begin to squirt our signal."

* * * * *

Twelve hours is not much in the life of a man; it is less in the life of a planet. The Terran Standard of Gravity is so small that it is expressed in feet per second. But when the two are coupled together as a measure of travel, and the standard Terran G is applied for twelve hours steady, it builds up to almost three hundred miles per second, and by the end of that twelve hours, six million miles have fled into the past.

Now take a look at Mars. It is a small, red mote in the sky, its diameter some four thousand miles. Sol is eight hundred thousand miles in diameter. Six million miles from Mars, then, can be crudely expressed by visualizing a point eight times the diameter of the Sun away from Mars, and you have the distance that the _Empress of Kolain_ had come from Mars.

But the ship was heading in at an angle, and the six million miles did not subtend the above arc. From Venus Equilateral, the position of the _Empress of Kolain_ was more like two diameters of the Sun away from Mars, slightly to the north, and on the side away from Sol.

It may sound like a problem for the distant future, this pointing a radio beam at a planet, but it is no different from Galileo's attempts to see Jupiter through his Optik Glass. Of course, it has had refinements that have enabled man to make several hundred hours of exposure of a star on a photographic plate. So if men can maintain a telescope on a star, night after night, to build up a faint image, they can also maintain a beamed transmission wave on a planet.

All you need is a place to stand; a firm, immobile platform. The three-mile-long, one-mile-diameter mass of Venus Equilateral offered such a platform. It rotated smoothly, and upon its "business" end a hardened and highly polished set of rails maintained projectors that were pointed at the planets. These were parabolic reflectors that focussed ultra-high-frequency waves into tight beams which were hurled at Mars, Terra, and Venus for communication.

And because the beams were acted upon by all of the trivia in the Solar System, highly trained technicians stood their tricks at the beam controls. In fifty million miles, even the bending of electromagnetic waves by the Sun's mass had to be considered. Sunspots made known their presence. And the vagaries of land transmission were present in a hundred ways due to the distance and the necessity of concentrating every milliwatt of available power on the target.

This problem of the _Empress of Kolain_ was different. Spaceships were invisible, therefore the beam-control man must sight on Mars and the mechanical cam would keep the ship in sight of the beam.

The hours went past in a peculiar mixture of speed and slowness. On one hand the minutes sped by swiftly and fleetingly, each tick of the clock adding to the lost moments, never to be regained. Time, being precious, seemed to slip through their fingers like sifting sand.

On the other hand, the time that must be spent in preparation of the equipment went slow. Always it was in the future, that time when their experiment must either prove a success or a failure. Always there was another hour of preparatory work before the parabolic reflector was mounted; and then another hour before it swung freely and perfectly in its new mounting. Then the minutes were spent in anticipation of the instant that the power stage of transmitter was tested and the megawatts of ultra-high-frequency energy poured into the single rod that acted as a radiator.

It was a singularly disappointing sight. The rod glowed not, and the reflector was the same as it was before the rod drew power. But the meters read and the generators moaned, and the pyrometers in the insulators mounted as the small quantity of energy lost was converted into heat. So the rod drew power, and the parabolic reflector beamed that power into a tight beam and hurled it out on a die-true line.

Invisible power that could be used in communications.

Then the cam was installed. The time went by even slower then, because the cam must be lapped and polished to absolute perfection, not only of its own surface but to absolute concentricity to the shaft on which it turned.

But eventually the job was finished, and the men stood back, their eyes expectantly upon Don Channing and Walt Franks.

Don spoke to the man chosen to control the beam. "You can start any time now. Keep her knifed clean, if you can."

The man grinned at Channing. "If the devils that roam the void are with us we'll have no trouble. We should all pray for a phrase used by some characters in a magazine I read once: 'Clear ether!' We could use some right now."

He applied his eyes to the telescope. He fiddled with the verniers for a brief time, made a major adjustment on a larger handwheel, and then said, without removing his eye from the 'scope, "That's it, Dr. Channing."

Don answered: "O.K., Jim, but you can use the screen now. We aren't going to make you squint through that pipe for the next few hours straight."

"That's all right. I'll use the screen as soon as you can prove we're right. Ready?"

"Ready," said Channing.

Franks closed a tiny switch. Below, in the transmitter room, relays clicked and heavy-duty contacts closed with blue fire. Meters began to climb upward across their scales, and the generators moaned in a descending whine. A shielded monitor began to glow, indicating that full power was vomiting from the mouth of the reflector.

And out from the projector there went, like a spear-head, a wave-front of circularly polarized microwaves. Die-true they sped, crossing the void like a line of sight to an invisible spot above Mars and to the left. Out past the Sun, where they bent inward just enough to make Jim's job tough. Out across the open sky they sped at the velocity of light, and taking sixteen minutes to get there.

A half-hour passed. "Now," said Channing. "Are we?"

Ten minutes went by. The receiver was silent save for a constant crackle of cosmic static.

Fifteen minutes passed.

"Nuts," said Channing. "Could it be that we aren't quite hitting them?"

"Could be," admitted Franks. "Jim, waggle that beam a bit, and slowly. When we hit 'em, we'll know it because we'll hear 'em a half-hour later. Take it easy and slowly. We've used up thirteen of our fifty-odd hours. We can use another thirty or so just in being sure."

Jim began to make the beam roam around the invisible spot in the sky. He swept the beam in microscopic scans, up and down, and advancing the beam by one-half of its apparent width at the receiver for each sweep.

Two more hours went by. The receiver was still silent of reflected signals.

It was a terrific strain, this necessary wait of approximately a half-hour between each minor adjustment and the subsequent knowledge of failure. Jim gave up the 'scope because of eyestrain, and though Don and Walt had confidence that the beam-control man was competent to use the cross-ruled screen to keep Mars on the beam, Jim was none too sure of himself, and so he kept checking the screen against the 'scope.

At the end of the next hour of abject failure, Walt Franks began to scribble on a pad of paper. Don came over to peer over Franks' shoulder, and because he couldn't read Walt's mind, he was forced to ask what the engineer was calculating.

"I've been thinking," said Franks.

"Beginner's luck?" asked Don with a wry smile.

"I hope not. Look, Don, we're moving on the orbit of Venus, at Venus' orbital velocity. Oh, all right, say it scientifical: We are circling Sol at twenty-one point seven five miles per second. The reflected wave starts back right through the beam, remember?"

"I get it," shouted Channing in glee. "Thirty-two minutes' transmission time at twenty-one point seven five miles per second gives us--ah--"

Walt looked up from his slide rule. "Fifty-two thousand, two hundred and twenty-four miles," he said.

"Just what I was about to say," grinned Don.

"But why do you always get there second with your genius?" complained Walt with a pseudo-hurt whine. "So how to establish it?"

"Can't use space radar for range," grunted Channing. "That would louse up the receiver. We've got everything shut off tight, you know. How about some visual loran?"

"Yipe!" exploded Walt. "How?"

"I'd suggest an optical range finder excepting that the base-line of three miles--the length of Venus Equilateral--isn't long enough to triangulate for that fifty-two thousand--"

"Two hundred and twenty-four miles," finished Walt with a grin. "Proceed, genius, with caution."