Chapter 7: Earthbound!

There was something else that Rip didn’t add, although he knew the Planeteers would realize it in a few minutes. Probably some of them already had thought of it.

To move the asteroid into a new orbit, they were going to fire nuclear bombs. Most of the highly radioactive fission products would be blown into space, but some would be drawn back by the asteroid’s slight gravity. The craters would be highly radioactive, and some radioactive debris was certain to be scattered around, too. Every particle would add to the problem.

“Is there anything we can do, sir?” Koa asked.

Rip shook his head inside the transparent bubble. “If you have a good luck charm in your pocket, you might talk to it. That’s about all.”

Nuclear physics had been part of his training. He read the gamma meter again and did some quick calculations. They would be exposed for the entire trip, at a daily dosage of--

Koa interrupted his train of thought. Evidently the sergeant major had been doing some calculations of his own. “How long will we be on this rock, sir? You’ve never told us just how long the trip will take.”

Rip said quietly, “With luck, it will take us a little more than three weeks.”

He could see their faces faintly in the dim sunlight. They were shocked. Spaceships blasted through space between the inner planets in a matter of hours. The nuclear drive cruisers, which could approach almost half the speed of light, had brought even distant Pluto within easy reach. The inner planets could be covered in a matter of minutes on a straight speed run, although to take off from one and land on the other meant considerable time used in acceleration and deceleration.

The Planeteers were used to such speed. Hearing that it would take over three weeks to reach Earth had jarred them.

“This piece of metal isn’t a spaceship,” Rip reminded them. “At the moment, our speed around the sun is just slightly more than ten miles a second. If we just shifted orbits and kept the same speed, it would take us months to reach Terra. But we’ll use one bomb for retrothrust, then fire two to increase speed. The estimate is that we’ll push up to about forty miles a second.”

Koa spoke up. “That’s not bad when you think that Mercury is the fastest planet, and it only makes about thirty miles a second.”

“Right,” Rip agreed. “After the asteroid is kicked out of orbit, it will fall toward the sun. At our closest approach to the sun, we’ll have enough velocity to carry us past safely. Then we’ll lose speed constantly until we come into Earth’s gravitational field and have to brake.”

It was just space luck that Terra was on the other side of the sun from the asteroid’s present position. By the time they approached, it would be in a good place, just far enough from the line to the sun to avoid changing course. Of course, Rip’s planned orbit was not aiming the asteroid at Earth, but at where Earth would be at the end of the trip.

“That means more than three weeks of radiation, then,” Corporal Santos observed. “Can we take it, sir?”

Rip shrugged, but the gesture couldn’t be seen inside his space suit. “At the rate we’re getting radiation now, plus what I estimate we’ll get from the nuclear explosions, we’ll get the maximum safety limit in just three weeks. That leaves us no margin, even if we risk getting radiation sickness. So we have to get shielding pretty soon. If we do, we can last the trip.”

Private Dominico saluted and moved forward. “Sir, may I ask a question?”

Rip turned to face the Planeteer, still worrying over the problem. He nodded and said, “What is it, Dominico?”

“Sir, I think we can’t worry too much about this radiation, eh? You will think of some way to take care of it. What I want to ask, sir, is when do we let go the bombs? I do not know much about radiation, but I can set those bombs like you want them.”

Rip was touched by the Planeteer’s faith in his ability to solve the radiation problem. That was why being an officer in the Special Order Squadrons was so challenging. The men knew the kind of training their officers had, and they expected them to come up with technical solutions as the situation required.

“You’ll have a chance to set the bombs in just a short while,” he said crisply. “Let’s get busy. Koa, load all bombs but one ten KT on the landing boat. Stake the rest of the equipment down. While you’re doing that, I’ll find the spots where we plant the charges. I’ll need two men now and more later.”

He went back to his instrument, putting the radiation problem out of his mind--a rather hard thing to do with the colorimeter glowing pink next to his shoulder. Koa detailed men to load the nuclear bombs into the landing craft, left Pederson to supervise, and then brought Santos with him to help Rip.

“The bombs are being put on the boat, sir,” Koa reported.

“Fine. There isn’t too much chance of the blasts setting them off, but we’ll take no chances at all. Koa, I’m going to shoot a line straight out toward Alpha Centauri. You walk that way and turn on your belt light. I’ll tell you which way to move.”

He adjusted his sighting rings while the sergeant major glided away. Moving around on a no-weight world was more like skating than walking. A regular walk would have lifted Koa into space with every step. Of course, the asteroid had some gravity, but so little that it hardly mattered.

Rip centered the top of the instrument’s vertical hairline on Alpha Centauri, then waited until Koa was almost out of sight over the asteroid’s horizon, which was only a few hundred yards away.

He turned up the volume on his helmet communicator. “Koa, move about ten feet to your left.”

Koa did so. Rip sighted past the vertical hairline at the belt light. “That’s a little too far. Take a small step to the right. That’s good ... just a few inches more ... hold it. You’re right in position. Stand where you are.”

“Yessir.”

Rip turned to Santos. “Stand here, Corporal. Take a sight at Koa to get your bearings, then hold position.”

Santos did so. Now the two lights gave Rip one of the lines he needed. He called for two more men, and Trudeau and Nunez joined him. “Follow me,” he directed.

Rip picked up the instrument and carried it to a point ninety degrees from the line represented by Koa and Santos. He put the instrument down and zeroed it on Messier 44, the Beehive star cluster in the constellation Cancer. For the second sighting star he chose Beta Pyxis as being closest to the line he wanted, made the slight adjustments necessary to set the line of sight, since Pyxis wasn’t exactly on it, then directed Trudeau into position as he had Koa. Nunez took position behind the instrument, and Rip had his cross fix.

He called for Dowst, then carried the instrument to the center of the cross formed by the four men. Using the instrument, he rechecked the lines from the center out. They were within a hair or two of being exactly on, and a slight error wouldn’t hurt, anyway. He knew he would have to correct with rocket blasts once the asteroid was in the new orbit.

“X marks the spot,” he told Dowst. He put his toe on the place where the crosslines met.

Dowst used a spike to make an X in the metal ground.

“All set,” Rip announced. “You four men can move now. Let’s have the cutting equipment over here, Koa.”

The Planeteers were all waiting for instructions now. In a few moments the equipment was ready, fuel and oxygen bottles attached.

“Who’s the champion torchman?” Rip asked.

Koa replied, “Kemp is, sir.”

Kemp, one of the two American privates, took the torch and waited for orders. “We need a hole six feet across and twenty feet deep,” Rip told him. “Go to it.”

“How about direction, sir?” Kemp asked.

“Straight down. We’ll take a bearing on an overhead star when you’re in a few feet.”

Dowst inscribed a circle around the X he had made and stood back. Kemp pushed the striker button and the torch flared. “Watch your eyes,” he warned. The Planeteers reached for belt controls and turned the rheostats that darkened the clear bubbles electronically. Kemp adjusted his flame until it was blue-white, a knife of fire brighter by far than the light of the sun at this distance.

Koa stepped behind Kemp and leaned against his back, because the flame of the torch was like an exhaust, driving Kemp backward. Kemp bent down, and the torch sliced into the metal of the asteroid like a hot knife into ice. The metal splintered a little as the heat raised it instantly from almost absolute zero to many thousands of degrees.

When the circle was completed, Kemp adjusted his torch again, and the flame lengthened. He moved inside the circle and cut at an angle toward the perimeter. His control was quick and certain. In a moment he stood aside, and Koa lifted out a perfect ring of thorium. It varied from a knife edge on the inner side to eighteen inches on the outer side.