Part 10 (1/2)

”Get me the radiation detection instruments,” he ordered.

Koa sensed the urgency in his voice and got the instruments himself. Rip switched them on and read the illuminated dial on the alpha counter.

Plenty high, as was natural. But no danger there--alpha particles couldn't penetrate the s.p.a.ce suits. Then, his hand clammy inside the s.p.a.ce glove, he switched on the other meter. The gamma count was far below the alpha, but there were too many of the rays around for comfort.

Inside the helmet his face turned pale.

There was no immediate danger. It would take many days to build up a dose of gamma that could hurt them. But gamma was not the only radiation. They were in s.p.a.ce, fully exposed to equally dangerous cosmic radiation.

The Planeteers had gathered while he read the instruments. Now they stood watching him.

They knew the significance of what he had found.

”I ought to be busted to recruit,” he told them. ”I knew this asteroid was thorium and that thorium is radioactive. If I had used my head, I would have added nuc.l.i.te s.h.i.+elding to the list of supplies the _Scorpius_ provided. We could have had enough of it to protect us while around our base, even if we couldn't be protected while working on the charges. That would at least have kept our dosage down enough for safety.”

”No one else thought of it, either, sir,” Koa reminded him.

”It was my job to think of it, and I didn't. So I've put us in a time squeeze. If the _Scorpius_ gets back soon, we can get the s.h.i.+elding before our radiation dosage has built up very high. If the s.h.i.+p doesn't come back, the dosage will mount.”

He looked at them grimly. ”It won't kill us, and it won't even make us very sick. I'll have the s.h.i.+p take us off before we build up that much dosage.”

Santos started. ”But, sir! That means--”

”I know what it means,” Rip stated bitterly. ”It means the s.h.i.+p has got to return in time to give us some nuc.l.i.te s.h.i.+elding, or we'll be the laughingstock of the Special Order Squadrons--the detachment that started a job the s.p.a.cemen had to finis.h.!.+”

CHAPTER SEVEN

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 s.p.a.ce, 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.

s.p.a.ces.h.i.+ps blasted through s.p.a.ce 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 s.p.a.ces.h.i.+p,” Rip reminded them. ”At the moment, our speed around the sun is just slightly more than ten miles a second. If we just s.h.i.+fted 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.”