He covertly watched Nagel, wondering if his prowling was a form of escape, an effort to forget his fears. He was beginning to understand the stark reality of Nagel's terror. It had been mirrored in his face, a naked, horrible dread, during the recent emergency. No ... he wasn't the saboteur type. Larkwell, maybe. Perhaps Prochaska. But not Nagel. A saboteur would have iron nerves, a cold, icy fanaticism that never considered danger. But supposing the man were a consummate actor, his fear a mask to conceal his purpose?

He debated the pros and cons. In the end he decided it would not be politic to forbid Nagel to handle the gear during flight. He was, after all, their oxygen equipment specialist. He contented himself with keeping a sharp watch on Nagel's activities—a situation Nagel seemed unmindful of. He seemed to have lost some of his earlier fear. His face was alert, almost cheerful at times; yet it held the attitude of watchful waiting.

Despite his liking for Prochaska, Crag couldn't forget that he had failed to find the time bomb in a panel he had twice searched. Still, the console's complex maze of wiring and tubes had made an excellent hiding place. He had to admit he was lucky to have found it himself. He tried to push his suspicions from his mind without relaxing his vigilance. It was a hard job.

By the third day the enemy missile had become a prime factor in the things he found to worry about. The intruder rocket had drawn closer. Alpine warned that the race was neck and neck. It had either escaped earth at a higher speed or had continued to accelerate beyond the escape point. Crag regarded the reason as purely academic. The hard fact was that it would eventually overtake the still decelerating Aztec. Just now it was a pip on the analog, a pip which before long would loom as large as Drone Able, perhaps as close. He tried to assess its meaning, vexed that Alpine seemed to be doing so little to help in the matter.

Later Larkwell spotted the pip made by the East's rocket on the scope. That let the cat out of the bag as far as Crag was concerned. Soberly he informed them of its origin. Larkwell bit his lip thoughtfully. Nagel furrowed his brow, seemingly lost in contemplation. Prochaska's expression never changed. Crag assessed each reaction. In fairness, he also assessed his own feeling toward each of the men. He felt a positive dislike of Nagel and a positive liking for Prochaska. Larkwell was a neutral. He seemed to be a congenial, open-faced man who wore his feelings in plain sight. But there was a quality about him which, try as he would, he could not put his finger on.

Nagel, he told himself, must have plenty on the ball. After all, he had passed through a tough selection board. Just because the man's personality conflicted with his own was no grounds for suspicion. But the same reasoning could apply to the others. The fact remained—at least Gotch seemed certain—that his crew numbered a ringer among them. He was mulling it over when the communicator came to life. The message was in moon code.

It came slowly, widely spaced, as if Gotch realized Crag's limitations in handling the intricate cipher system evolved especially for this one operation. Learning it had caused him many a sleepless night. He copied the message letter by letter, his understanding blanked by the effort to decipher it. He finished, then quickly read the two scant lines:

"Blank channel to Alp unless survival need."

He studied the message for a long moment. Gotch was telling him not to contact Alpine Base unless it were a life or death matter. Not that everything connected with the operation wasn't a life or death matter, he thought grimly. He decided the message was connected with the presence of the rocket now riding astern and to one side of the Aztec and her drone. He guessed the Moon Code had been used to prevent possible pickup by the intruder rather than any secrecy involving his own crew.

He quietly passed the information to Prochaska. The Chief listened, nodding, his eyes going to the analog.