Wilson's feet took him a few steps toward the Bar, as though they were dragging the rest of him. Then he said, "Nah! I better not."

Ten minutes to zero time.

It had been Lucky Starr's idea. He had been in Con-way's home office the day the news arrived that the T.S.S. Waltham Zachary had been gutted by pirates, its cargo gone, its officers frozen corpses in space and most of the men captives. The ship itself had put up a pitifully futile fight and had been too damaged to be worth the pirate's salvage. They had taken everything movable though, the instruments, of course, and even the motors.

Lucky said, "It's the asteroid belt that's the enemy. One hundred thousand rocks."

"More than that." Conway spat out his cigarette. "But what can we do? Ever since the Terrestrial Empire has been a going concern, the asteroids have been more than we could handle. A dozen times we've gone in there to clean out nests of them, and each time we've left enough to breed the troubles again. Twenty-five years ago, when-"

The white-haired scientist stopped short. Twenty-five years ago Lucky's parents had been killed in space and he himself, a little boy, had been cast adrift.

Lucky's calm brown eyes showed no emotion. He said, "The trouble is we don't even know where all the asteroids are."

"Naturally not. It would take a hundred ships a hundred years to get the necessary information for the sizable asteroids. And even then the pull of Jupiter would be forever changing asteroidal orbits here and there."

"We might still try. If we sent out one ship, the pirates might not know it was an impossible job and fear the consequences of a real mapping. If the word got out that we had started a mapping survey, the ship would be attacked."

"And then what?"

"Suppose we sent out an automatic ship, completely equipped, but with no human personnel."

"It would be an expensive thing to do."

"It might be worth it. Suppose we equipped it with lifeboats automatically designed to leave the ship when its instruments recorded the energy pattern of an approaching hyperatomic motor. What do you suppose the pirates would do?"

"Shoot the lifeboats into metal drift, board the ship, and take it to their base."

"Or one of their bases. Right. And if they see the lifeboats try to get away, they won't be surprised at finding no crew aboard. After all, it would be an unarmed survey ship. You wouldn't expect the crew to attempt resistance."

"Well, what are you getting at?"

"Suppose further that the ship is wired to explode once its temperature is raised to more than twenty degrees absolute, as it certainly would if it were brought into an asteroid hangar."

"You're proposing a booby trap, then?"

"A gigantic one. It would blow an asteroid apart. It might destroy dozens of pirate ships. Furthermore, the observatories at Ceres, Vesta, Juno, or Pallas might pick up the flash. Then, if we could locate surviving pirates, we might get information that would be very useful indeed."

"I see."

And so they started work on the Atlas.

The shadowy figure in the recess leading to the Moon's surface worked with sure quickness. The sealed controls of the air-lock gave under the needle beam of a micro-heatgun. The shielding metal disc swung open. Busy, black-gloved fingers flew for a moment. Then the disc was replaced and fused tightly back by a wider and cooler beam from the same heatgun.

The cave door of the lock yawned. The alarm that rang routinely whenever it did so was silent this time, its circuits behind the tampered disc disarranged. The figure entered the lock and the door closed behind him. Before he opened the surface door that faced out into the vacuum, he unrolled the pliant plastic he carried under his arm. He scrambled into it, the material covering him wholly and clinging to him, broken only by a strip of clear silicone plastic across his eyes. A small cylinder of liquid oxygen was clamped to a short hose that lead to the headpiece and was hooked on to the belt. It was a semi-space-suit, designed for the quick trip across an airless surface, not guaranteed to be serviceable for stretches of more than half an hour.

Bert Wilson, startled, swiveled his head. "Did you hear that?"

Bigman gaped at the sentry. "I didn't hear anything."

"I could swear it was a lock door closing. There isn't any alarm, though."

"Is there supposed to be?"

"Sure. You've got to know when one door is open. It's a bell where there's air and a light where there isn't. Otherwise someone is liable to open the other door and blow all the air out of a ship or corridor."

"All right. If there's no alarm, there's nothing to worry about."

"I'm not so sure." With flat leaps, each one covering twenty feet in the Moon's baby gravity, the sentry passed up the corridor to the air-lock recess. He stopped at a wall panel on the way and activated three separate banks of ceiling Floressoes, turning the area into a noonday of light.

Bigman followed, leaping clumsily and in perpetual danger of overbalancing into a slow nose landing.

Wilson had his blaster out. He inspected the door, then turned to look up the corridor again. "Are you sure you didn't hear anything?"

"Nothing," said Bigman. "Of course, I wasn't listening."

Five minutes to zero time.

Pumice kicked up as the space-suited figure moved slow-motion toward the Atlas. The space-ship glittered in the Earthlight, but on the Moon's airless surface the light did not carry even an inch into the shadow of the ridge that hemmed in the port.

In three long leaps the figure moved across the lighted portion and into the pitchy shadow of the ship itself.

He moved up the ladder hand over hand, flinging himself into an upward drift that carried him ten rungs at a time. He came to the ship's air-lock. A moment at the controls and it yawned open, then closed.

The Atlas had a passenger. One passenger!

The sentry stood before the corridor air-lock and considered its appearance dubiously.

Bigman was rattling on. He said, "I been here nearly a week. I'm supposed to follow my side-kick around and make sure he doesn't get into trouble. How's that for a space wrangler like me. I haven't had a chance to get away-"

The anguished sentry said, "Give it a rest, friend. Look, you're a nice kid and all that, but let's have it some other time.

For a moment he stared at the control seal. "That's funny," he said.

Bigman was swelling ominously. His little face had reddened. He seized the sentry by the elbow and swung him about, almost overbalancing himself as he did so.

"Hey, bud, who're you calling a kid?"

"Look, go away!"

"Just a minute. Let's get something straight. Don't think I let myself get pushed around because I'm not as tall as the next fellow. Put 'em up. Go ahead. Get your fists up or I'll splatter your nose all over your face."

He was sparring and slipping about.

Wilson looked at him with astonishment. "What's got into you? Stop being foolish."

"Scared?"

"I can't fight on duty. Besides, I didn't mean to hurt your feelings. I've just got a job to do and I haven't got any time for you."

Bigman lowered his fists. "Hey, I guess the ship's taking off."

There was no sound, of course, since sound would not travel through a vacuum, but the ground under their feet vibrated softly in response to the hammer blows of a rocket exhaust lifting a ship off a planet.