Rip Foster Rides the Gray Planet, Harold L. Goodwin [red white royal blue .txt] 📗

This particular bomb design used five pieces of plutonium which were driven together to form a ball. Rip made a quick estimate. Two were enough to form a critical mass. He would use two to blast into the sun and three to blast out again. He would need the extra kick.

There was only one trouble. The pieces were wedge shaped. They would have to be mounted in[pg 177] thorium in order to keep them rigid. Only Kemp could do that. They had no cutting tool but the torch.

Santos appeared, carrying a rocket head under each arm. They had wires wound around them, ready to be attached to an electrical source.

Rip hurried back to where Kemp was at work. The private was using a cutting nozzle that threw an almost invisible flame five feet long. In air, the nozzle wouldn't have worked effectively beyond two feet, but in space it cut right down to the end of the flame. Kemp had his arm inside the hole and was peering past it as he finished the cut.

"Done, sir," he said, and adjusted the flame to a spout of red fire. He thrust the torch into the hole and quickly withdrew it as pieces of thorium flew out. A stream of water hosed into the tube would have washed them out the same way.

Rip took a block of plutonium from Dominico and handed it to Kemp. "Cut a plug and fit this into it. Then cut a second plug for the other piece. They have to match perfectly, and you can't put them together to try out the fit. If you do, we'll have fission right here in the open."

Kemp searched and found a piece he had cut in making the tube. It was perfectly round, ideal for the purpose. He sliced off the inner side where it tapered to a cone, then, working only by eye estimate, cut out a hole in which the wedge of fission[pg 178] material would fit. He wasn't off by a thirty-second of an inch. Skillful application of the torch melted the thorium around the wedge and sealed it tightly.

Koa was ready with a sheet of nuclite. Trudeau arrived with a long pole he had made by lashing two crate sticks together.

Rip gave directions as they formed a cylinder of nuclite. 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 mass 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 space. 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!