As the rumble of the main rockets started again, Tom waited for the ship's descent to be checked, and sudden concern welled up within him as the ship failed to respond.

"Thirty-five thousand feet," reported Roger from the radar deck.

"Full thrust, Astro," called Tom, anxiously watching the approaching surface of Roald. He checked his instruments again and his heart jumped up into his throat. The needles of all the gauges and meters were dancing back and forth as though they were being flicked with invisible fingers.

Tom grabbed the intercom and shouted wildly. "Astro! Emergency s.p.a.ce speed! We've got to get out of here!" Tom whirled around to face Vidac and Hardy. "You'd better call Professor Sykes up here, right away," he declared.

"Why? What's the matter?" stuttered Hardy.

"Something's interfering with our whole electrical system, sir," replied the cadet.

"What's that, Corbett?" snapped Sykes, stepping quickly through the hatch into the control room. Tom was about to repeat his statement when suddenly the rockets blasted loudly, and the ship tossed and rocked, throwing everyone off his feet. Astro had applied emergency power to his reactors, sending the _Polaris_ hurtling back into the safety of s.p.a.ce.

"By the rings of Saturn," bawled Sykes, after he had adjusted to the sudden acceleration, "I'll have that s.p.a.ce-brained idiot court-martialed for this!"

"It's not his fault, Professor," said Hardy, getting to his feet again.

"If Corbett hadn't ordered emergency s.p.a.ce speed, we'd all be smeared across that plain down there." He pointed to the scanner screen where the surface of Roald could be seen receding rapidly.

"Umph!" snorted Sykes, "let me take a look at that control board."

Quickly and surely, the professor tested every major circuit in the giant panel. Finally he straightened up and turned to face Hardy.

"Governor," he said quietly, "I'm afraid you'll have to forget about landing on Roald until I can find the reason for the disturbance."

"Then it's not caused by any malfunction aboard the ship?" Vidac broke in.

Sykes shook his head. "Whatever force field caused those instruments to react the way they did came from Roald. You'll have to stand off until I can go down and make a complete investigation."

"Well, what do you think it is?" asked Hardy.

"It might be one of a hundred things," replied the professor. "But I wouldn't attempt to land down there until we know what's causing the interference and can counteract it."

"s.p.a.ce gas!" exploded Vidac. "Is this another of your tricks, Corbett?"

"Tricks, sir?" asked Tom stupidly, so incredible did the lieutenant governor's question seem.

"Yes, _tricks!_" roared Vidac. "Get out of the way. I can take this ship down." He sat down in the pilot's chair and called Roger on the radar bridge. "Notify all the other ships they are to stand off until we have made a secure touchdown!"

"Yes, sir!" replied Roger.

"Professor," whispered Tom, "do something!"

Sykes looked at Tom a moment and then turned to leave the control deck.

He paused in the hatch to call back in a low voice, "What can you do with a madman?"

Helplessly, Tom turned to appeal to Governor Hardy but changed his mind and stood beside Hardy, crossing his fingers.

At the controls Vidac gripped the acceleration lever and called into the intercom, "Stand by for touchdown. Power deck, cut all thrust!"

"Power deck, aye, sir," reported Astro.

As the main rockets were cut out again and the _Polaris_ slipped back through s.p.a.ce toward the surface of Roald once more, Tom stood behind Vidac with Hardy and watched the instruments begin their strange gyrations again. The cadet glanced at Hardy, whose face was impa.s.sive.

"Sir," asked Tom quietly, "isn't there something we can do?"

"Keep quiet, Corbett," snapped Hardy. "That's what you can do!"

"Yes, sir," replied Tom. He turned away to climb into the nearest acceleration chair and strap himself in. He knew it was possible for the _Polaris_ to land successfully. He felt sure he could have made a touchdown on the satellite without trouble, but his first thought had been for the safety of the others aboard the ship. Now it was out of his hands and he grudgingly admired the way Vidac was handling the giant rocket cruiser.

"Twenty-five thousand feet to touchdown," reported Roger.

So far, Vidac had kept the ship dropping at a steadily decreasing rate.

But the tension on the control deck mounted as the surface of Roald loomed closer and closer.

"Fifteen thousand feet," reported Roger.

Governor Hardy walked to a near-by acceleration chair and strapped himself in.

"Ten thousand feet!" yelled Roger.

"Power deck, give me three-quarters thrust!" ordered Vidac. Tom heard the whine of the rockets on the power deck increase with a sharp surge.

"Seven thousand feet," reported Roger.

Vidac remained cool, staring at the control board. Tom wondered what it was he was watching, since there wasn't one instrument that registered properly.

"Five thousand feet!" screamed Roger. "s.p.a.ceman's luck!"

[Ill.u.s.tration: _The_ Polaris _landed safely on the surface of the satellite_]

Immediately Vidac ordered Astro to apply full thrust to the main rockets. The great ship bucked under the sudden acceleration, and Tom could feel the tug of war between the cruiser's thrust and the satellite's gravity. The ship continued to drop at slightly lessened speed, but still too fast to land safely.

Tom waited for Vidac to order emergency thrust to counter the pull of the satellite. They were dropping too fast. He watched Vidac and waited for the only order that would save the ship. If he doesn't do it now, thought Tom, it will be too late.

"Vidac!" yelled Tom. "Emergency power! We're falling too fast!"

Vidac didn't answer. "Vidac!" screamed Tom again. "Emergency power!"

The man didn't move. He sat in front of the control panel as though paralyzed. Tom slipped off the straps of the acceleration chair and raced to the intercom. Vidac made no attempt to stop him.

"Astro! Full emergency thrust! Hit it!"

In immediate reply, a jolting burst of power blasted through the tubes, jerking the ship convulsively and throwing Tom to the deck. A loud, crashing sound filled the ship, followed by a strange stillness. Dimly Tom realized that the rockets had been cut and they were safely on the surface of the satellite.

He picked himself up and turned to face Vidac. The lieutenant governor was unstrapping himself from the pilot's chair. His face was ashen. He stalked out of the control deck without a word.

"Touchdown!" screamed Roger from the radar deck. "We made it. We're on Roald!"

Tom heard the blond-haired cadet, but his unit mate's excitement did not register. He was staring at the open hatch. "He lost his nerve," said Tom aloud, half to himself and half to Governor Hardy who was unstrapping himself from the acceleration chair. "He quit cold!"