Part 23 (1/2)
Rip gave directions as they formed a cylinder of nuc.l.i.te. Kemp spot-welded it, and they pushed it into the hole, forming a lining.
Nunez found a small piece of material in one of the earlier craters. It would provide some neutrons to start the chain reaction. Rip added it to the front of the plutonium wedge along with a piece of beryllium from the bomb, and Kemp welded it in place.
They put the thorium block which contained the plutonium into the hole, the plutonium facing outward. Trudeau rammed it to the bottom with his pole. The neutron source, the neutron reflector, and one piece of fissionable material were in place.
Kemp sliced another round block of thorium out of a near-by crystal and fitted the second wedge of plutonium into it. At first Rip had worried about the two pieces of plutonium making a good enough contact, but Kemp's skillful hand and precision eye removed that worry.
The torchman finished fitting the plutonium and carried the block to the tube opening. He tried it, removed a slight irregularity with his torch, then said quietly, ”Finished, sir.”
Rip took over. He slid the thorium-plutonium block into the tube, took a rocket head from Santos and used it to push the block in farther. When the rocket head was about four inches inside the tube, its wires trailing out, Rip called Kemp. At his direction, the torchman sliced a thin slot up the face of the crystal. Rip fitted the wires into it and held them in place with a small wedge of thorium.
Kemp cut a plug, fitted it into the hole, and welded the seams closed. The tube was sealed. When electric current fired the rocket head, the thorium carrying the plutonium wedge would be driven forward to meet the wedge in the back. And, unless Rip had miscalculated the ma.s.s of the two pieces, they would have their nuclear blast. Rip surveyed the crystal with some anxiety. It looked right.
Dominico already had rigged the timer from the atomic bomb. He connected the wires, then looked at Rip. ”Do I set it, sir?”
”Load the communicator, the extra bomb parts, the rocket launcher and rockets, the cutting equipment, my instruments, and the tubes of fuel,”
Rip ordered. ”Leave everything else in the cave.”
The Planeteers ran to obey. Rip waited until the landing boat was nearly loaded, then told Dominico to set the timer for five minutes. He wondered how they would explode the second charge, since they had only the one timer left, then forgot about it. Time enough to worry when faced with the problem.
”I'll take the snapper-boat,” he stated. ”Santos in the gunner's seat. Koa in charge in the landing boat. Dowst pilot. Let's show an exhaust.”
He fitted himself into the tight pilot seat of the snapper-boat while Santos climbed in behind. Then, handling the controls with the skill of long practice, he lifted the tiny fighting rocket above the asteroid and waited for the landing boat. When it joined up, Rip led the way to safety.
As he cut his exhaust to wait for the explosion, he sighted past the snapper-boat's nose to the asteroid.
He was moving, and the direction of his move told him the sun was already pulling. Its pull was strong, too. He cut his jets back on, just to hold position, and saw Dowst do the same.
Another few miles toward the sun and the landing boat wouldn't have the power to get away from Sol's gravity. A few miles beyond that, even the powerful little snapper-boat would be caught.
Below, the timer reached zero. A mighty fan of fire shot into s.p.a.ce. The asteroid shuddered from the blast, then swerved gradually, picking up speed as well as new direction.
Rip swallowed hard. Now they were committed. They would reach a new perihelion far beyond the limits of safety. P for perihelion and P for peril. In this case, they were the same thing!
CHAPTER FOURTEEN - BETWEEN TWO FIRES
Back on the asteroid, the Planeteers started laying the second atomic charge. Rip selected the spot, found a near-by crystal that would serve to house the bomb, and Kemp started cutting.
The Planeteers knew what to do now, and the work went rapidly. Rip kept an eye on his chronometer. According to the message from Terra base, he had about fifteen minutes before the Consops cruiser arrived.
”We have one advantage we didn't have back in the asteroid belt,” he remarked to Koa. ”Back there they could have landed anywhere on the rock.
Now they have to stick to the dark side. Snapper-boats could last on the sun side, but men in ordinary s.p.a.ce suits couldn't.”
”That's good,” Koa agreed. ”We have only one side to defend. Why don't we put the rocket launcher right in the middle of the dark side?”
”Go ahead. And have all men check their pistols and knives. We don't know what's likely to happen when that Connie flames in.”
Rip walked over to the communicator and plugged his suit into the circuit.