Tubes of ordinary rocket fuel were placed in these and fired, and the thrust moved the asteroid slightly, just enough to make the corrections Rip needed. It was not necessary to take to the landing boat for these blasts. The Planeteers retired to their cave, which was now lined with nuclite as a protection against radiation.
Rip watched his dosimeter climb steadily as the radiation dosage mounted. Then he took the landing boat to the Scorpius, talked the problem over with the ship’s medical department, and arranged for his men to take injections that would keep them from getting radiation sickness.
They left the asteroid belt far behind and passed within ten thousand miles of Mars. The Scorpius sent its entire complement of snapper-boats to the asteroid for protection, in case Consops made another try, then flamed off to Marsport to put in new supplies to replace those damaged when Rip had forced sudden and disastrous acceleration.
The asteroid had reached Earth’s solar orbit before the cruiser returned, though Earth itself was on the other side of the sun. Rip ordered a survey and found the best place on the dark side to make a new base. The Planeteers cut out a cave with the torch, lined it with nuclite, and moved in the supplies. It would be their base to the end of the trip.
The sun was very hot now. On the sunny side of the asteroid the temperature had soared far past the boiling point of water. But on the dark side, Rip measured temperatures close to absolute zero.
When the Scorpius returned, he arranged with Commander O’Brine for the Planeteers to take turns going to the cruiser for showers and decent meals.
The asteroid approached the orbit of Venus, but the bright planet was some distance away, at its greatest elongation to the east of the sun. Mercury, however, loomed larger and larger. They would pass close to the hot planet.
O’Brine recalled Rip to the Scorpius and handed him a message.
Asteroid now within protection reach of Mercury and Terra bases. Your escort no longer required. Proceed immediately Titan, take on cargo and personnel.
The commander sighed. “Looks like I’ll never get to Earth long enough to see my family.”
Rip sympathized. “Tough, sir. Perhaps the cargo from Titan will be scheduled for Terra.”
“That’s what I hope,” O’Brine agreed. “Well, here’s where we part. Is there anything you need?”
Rip made a mental check on supplies. He had more than enough. “The only thing we need is a long-range communicator, sir. We’ll need one to contact the planet bases.”
“I’ll see that you get one.” The Irishman thrust out his hand. “Stay out of high vack, Foster. Too bad you didn’t join us instead of the Planeteers. I might have made a decent officer out of you.”
Rip grinned. “That’s a real compliment, sir. I might return it by saying that you have the makings of a Planeteer officer yourself.”
O’Brine chuckled. “All right. Let’s declare a truce, Planeteer. We’ll meet again. Space isn’t very big.”
A short time later Rip stood in front of his asteroid base and watched the great cruiser drive into space. A short distance away a snapper-boat was lashed to the landing boat. O’Brine had left it, with a word of warning.
“These Connies are plenty smart. I don’t like leaving you unprotected, even within reach of Mercury and Terra, but orders are orders. Keep the snapper-boat, and you’ll at least be able to put up a fight if you bump into trouble.”
The asteroid sped on its lonely way for two days, and then a cruiser came out of space, its nuclear drive glowing. The Planeteers manned the rocket launcher, and Rip and Santos stood by the snapper-boat, just in case, but the cruiser was the Sagittarius, out of Mercury.
Capt. Go Sian-tek, a Chinese Planeteer officer, arrived in one of the cruiser’s boats with three enlisted men.
Captain Go greeted Rip and his men, then handed over a plastic stylus plate ordering Rip to deliver six cubic meters of thorium for use on Mercury. While Koa supervised the cutting of the block, Rip and the captain chatted.
The Mercurian Planeteer base was in the twilight zone, but the Planeteers always worked on the sun side, wearing special alloy suits to mine the precious nuclite that only the hot planet provided.
At some time during its first years, Mercury had been so close to the sun that its temperature was driven high enough to permit a subatomic thermonuclear reaction. The reaction had shorn some elements of their electrons and left a thin coating of material composed almost entirely of neutrons. The nuclite was incredibly dense. It could be handled only in low gravity because of its weight. But nothing else provided the shielding against radiation and meteors half so well, and it was in great demand.
“Things aren’t so bad,” Go told Rip. “The base is comfortable, and we only work a two-hour shift out of each ten. We’ve had a plague of silly dillies recently. They got into one man’s suit while we were working, but mostly they’re just a nuisance.”
Rip had heard of the creatures. They were like Earth armadillos, except that they were silicon animals and not carbon like those of Earth. They were drawn to oxygen like iron to a magnet, and their diamond-hard tongues, used for drilling rock in order to get the minerals on which they lived, could drive right through a space suit. Or, if these animals worked undetected for a while, they could drill through the shell of a space station.
Scralabus primus was the scientific name of the creature, but the fact that it looked like a silicon armadillo had given it the popular name of “silly dilly.” Apart from its desire for oxygen, it was harmless.
Koa reported, “Sir, the block of thorium is ready. We’ve hung it on a line behind the landing-boat. The blast won’t hurt it, and it’s too big to get inside the boat.”
“Fine, Koa. Well, Captain, that does it.”
The Mercurian Planeteers got into their craft and blasted off, trailing the block of thorium in their exhaust. Rip watched the cruiser take the craft and thorium aboard, then drive toward Mercury, brilliant sunlight reflecting from its sleek sides. The planet was only a short distance away by spaceship. It was the largest thing in space, except for the sun, as seen from the asteroid.
Past the orbit of Mercury, the sun side of the asteroid grew dangerously hot for men in space suits. Rip and the Planeteers stayed in the bitter cold of the dark side, which ceased to be entirely dark. The temperature rose somewhat. They were close enough to the sun that the prominences, great flaming tongues of hydrogen that sped many thousands of miles into space, gave them light and enough heat to register on Rip’s instruments.
Mercury was left far behind, and Earth could not be seen because of the sun. There was nothing to do now but ride out the rest of the trip as comfortably as possible, until it was time to throw the asteroid into a series of ever-tightening elliptical orbits around Earth, known as braking ellipses. The method would use Earth’s gravity to slow them down to the proper speed. A single atomic bomb and a half dozen tubes of rocket fuel remained.
Then, as Rip was enjoying the comfort of air during his off-watch hour in the boat compartment, Koa beat an alarm on the door.
Rip and the Planeteers got into suits and opened up.
“It’s Terra base calling on the communicator, sir,” Koa reported. “Urgent message, they said, and they want to talk to you personally.”
Rip hurried to the cave. The communicator indicator light was glowing bright red. He plugged in his helmet circuit and said, “This is Lieutenant Foster. Go ahead.”
A voice crackled across space from Earth. “This is Terra base. Foster, a Consops cruiser has apparently been hiding behind the sun waiting for you. Our screens just picked it up, heading your way. We’ve sent orders to the Sagittarius on Mercury to give you cover, and the Aquila has taken off from here. But get this, Foster. The Consops cruiser will reach you first. You have about one hour. Do you understand?”
Rip understood all right. He understood too well. “Got you,” he said shortly. “Now what?”
The communicator buzzed. “Take any appropriate action.
You’re on your own. Sorry. Sending the cruisers is all we can do. We’ll stand by for word from you. If you think of any way we can help, let us know.”
Rip asked, “How long before the cruisers arrive?”
“You’re too close to us for them to move fast. They’ll have to use time accelerating and decelerating. The Sagittarius should arrive in something less than two hours and the Aquila a few minutes later.”
The communicator paused, then continued. “One thing more, Foster. The Connies know how badly we want that asteroid, but they also know we don’t want it enough to start a war. Got that?”
“Got it,” Rip stated wryly. “I got it good. Thanks for the warning, Terra base. Foster off.”
“Terra base off. Stay out of high vack.”
Fine advice, if it could be taken. Rip stared up at the brilliant stars, thinking fast. The Connie would have almost an hour’s lead on the space-patrol cruisers. In that hour, if the Connie were willing to pay the price in blasted snapper-boats, Consops would have the asteroid. And Terra base had made it clear that the space patrol would not try to blast the Connie cruiser, because that would mean war.
Added together, the facts said just one thing: They had one hour in which to think of some way to hold off the Connies for an additional hour.
The Planeteers were clustered around him. Rip asked grimly, “Any of you ever study the ancient art of magic?”
The Planeteers remained silent and tense.
“Magic is what we need,” Rip told them. “We have to make the whole asteroid disappear, or else we have to conjure up a space cruiser out of the thorium. Otherwise, we have barely an hour till we’re either prisoners or dead!”
CHAPTER 13
Peril!
Sergeant major Koa asked thoughtfully, “Sir, would it do the Connie much good to launch boats this close to the sun? They’d have to use too much fuel just keeping position.”
“You could be right,” Rip said slowly. Koa had a point! To counter gravitational attraction took velocity, which meant consumption of fuel. Maneuvering boats meant rapid velocity changes. Against the sun’s terrific gravity at this distance, it also meant maximum thrust and maximum fuel flow most of the time. The asteroid, in a planned orbit with the correct velocity, was safe enough, and the Connie cruiser would simply match the asteroid’s orbit. But boats, which had to maneuver, were another matter.
Rip figured quickly. In accordance with Newton’s Law, gravitational attraction increased rapidly on approaching a body. If he could put the asteroid even closer to the sun, the boat problem would become worse, until even a small velocity change in the wrong direction could leave a boat in the terrible position of not having enough thrust for a long enough time to keep from being drawn into the sun.
But to change the asteroid’s orbit was dangerous! It meant losing just enough velocity to be drawn closer to the sun, and then picking up a much higher velocity to get free again!
Rip got his instruments and pulled out a special slide rule designed for use in space. He had Koa stand by with stylus and computation board and take down his figures.
He recalculated the safety factor he had used when deciding how close to the sun to put the asteroid, then took quick star sights to determine their exact position. They were within a few miles of perihelion, the point at which they would be closest to Sol.
Rip tapped gloved fingers on his helmet absently. If they could blast out of the orbit and drive into the sun.… He estimated the result. A few miles per second of less speed would let them be pulled so far within the sun’s field of gravity that, within an hour or so, small boats would venture into space only at their peril.
He reviewed the equipment. They had tubes of rocket fuel, but the tubes wouldn’t give the powerful thrust needed for this job. They had one atomic bomb. One wasn’t enough. Not only must they drive toward the sun, but also they must keep reserve power to blast free again. If only they had a pair of nuclear charges!
He called his Planeteers together and outlined the problem. Perhaps one of them would have an idea. But no useful suggestions were forth-coming—until Dominico spoke up. “Sir, why don’t we make two bombs from one?”
“I wish we could,” Rip said. “Do you know how?”
“No, Lieutenant. If we had parts, I could put bombs together. I can take them apart, but I don’t know how to make two out of one.” The Italian Planeteer looked accusingly at Rip. “I thought maybe you knew, sir.”
Rip grunted. If they had parts, he could assemble nuclear bombs, too. Part of his physics training had been concerned with fission and its various applications. But no one had taught him how to make two bombs out of one.
The theory behind this particular bomb design was simple. Two or more correctly sized pieces of plutonium or uranium isotope, when brought together, formed what was known as a critical mass, which would fission. The fissioning released energy and produced the explosion.
But there was a wide gap between theory and practice. A nuclear bomb was actually pretty complicated. It had to be complicated to keep the pieces of the fissionable material apart until a chemical explosion drove them together fast and hard enough to create a fission explosion. If the pieces weren’t brought together rapidly enough, the mass would fission in a slow chain reaction with no explosion.
Rip was trained in scientific analysis. He tackled the problem logically, considering the design of a nuclear bomb and the reasons for it.
Atomic bombs had to be carried. That meant an outer casing was necessary. The casing had a lot to do with the design. Suppose no casing were required? What would be needed?
He took the stylus and computation board from Koa and jotted down the parts required. First, two or more pieces of plutonium large enough to form a critical mass. Second, a neutron source—the type of radioactivity that produced neutrons—to accelerate the reaction. Third, some kind of neutron reflector. And fourth, explosive to drive the pieces together.
Did they have all those items? He checked them off. Their single five KT bomb contained at least enough plutonium for two critical masses, if brought together inside a good neutron reflector. Each mass should give about a two kiloton explosion. And they did have a good neutron reflector—nuclite. There wasn’t anything better.
“What have we got for a neutron source?” he asked aloud. He was really asking himself, but he got a quick answer from Koa.
“Sir, some of the stuff left in the craters from the other explosions gives off neutrons.”
“You’re right,” Rip agreed instantly. A small piece from one of the craters, when combined with half of the neutron source in the bomb, should be enough. As for the explosive, they had exploding heads on their attack rockets.
In other words, he had what he needed—except for a method of putting all the pieces together to create a bomb.
If only they had a tube of some sort that would withstand the chemical explosion—the one that brought the critical mass together!
He told the Planeteers what he had been thinking, then asked, “Any ideas for a tube?”
“How about a tube from the snapper-boat?” Santos suggested.
Rip shook his head. “Not strong enough. They’re designed to withstand the slow push of rocket fuel, not the fast rap of an explosion. When I say slow, I mean slow-burning when compared with explosive. Any more ideas?”
Kemp, the expert torchman, said, “Sir, I can burn you a tube into the asteroid.”
Rip grabbed the Planeteer so hard they both floated upward. “Kemp, that’s wonderful! That’s it!” The details took form in his mind even as he called orders. “Dominico, tear down that bomb. Santos, remove two heads from your rockets and wire them to explode on electrical impulse. Kemp, we’ll want the tube just a fraction of an inch wider than a rocket head. Get your torch ready.”
He took the stylus and began calculating. He talked as he worked, telling the Planeteers exactly what they were up against. “I’m figuring out where to put the charge so it will do the m
ost good, but my data isn’t complete. If our homemade bomb goes off, I don’t know exactly how much power it will give. If it gives too much, we’ll be driven so close to the sun we’ll never get free of its gravity.”
Bradshaw, the English Planeteer, said mildly, “Don’t worry, Lieutenant. If it isn’t the solar frying pan, it’s Connie fire.”
A chorus of agreement came from the other Planeteers. “What a crew!” Rip thought. “What a great gang of space pirates!”
He finished his calculations and found the exact place where Kemp would cut. A few feet away from the spot was a thick pyramid of thorium. That would do, and they could cut into it horizontally instead of drilling straight down. He pointed to it. “Let’s have a hole straight in for six feet. And keep it straight, Kemp. Allow enough room for a lining of nuclite. Koa, cut a sheet of nuclite to size.”
Kemp’s torch already was slicing into the metal. Rip asked, “Can you weld with that thing, Kemp?”
“Just show me what you want, sir.”
“Good.” Rip motioned to Trudeau. “Frenchy, we’ll need a strong rod at least eight feet long.”
The French Planeteer hurried off. Rip consulted his chronometer. Less than ten minutes had passed since the call from Terra base.
He went over his plan again. It had to work! If it didn’t, asteroid and Planeteers would end up as subatomic particles in the sun’s photosphere, because he had calculated his blast to drive the asteroid past the limit of safety. It was the only way he could be sure of putting them beyond danger from Connie landing boats or snapper-boats. The Connie would have only one chance—to bring his cruiser down.
If he tried that, Rip thought grimly, he would get a surprise. The second nuclear charge would be set, ready to be fired. The Connie cruiser was so big that no matter how it pulled up to the asteroid, some part of it would be close enough to the charge to be blown into space dust. No cruiser could survive an atomic explosion within five hundred yards, and the Connie would have to get closer to the nuclear charge than that.
The Tom Corbett Space Cadet Megapack: 10 Classic Young Adult Sci-Fi Novels Page 126