"What's the reading on the Geiger counter now?" asked Tom.

Roger looked down at the face of the radioactive measuring device and answered, "She's been dropping for the last five minutes, Tom. Looks like the mass in number three is cooling off. Fourteen hundred and ten now."

"That's not fast enough," said Astro, straightening up from tightening a nut on the lead baffle. "She's still plenty hot. That mass should have been dumped out of the rocket exhaust right away. Now the whole tube control box is so hot with radiation, it'd burn you to a crisp if you opened the hatch."

"Good thing you brought along those tools from the Polaris," said Tom.

"Yeah, greaseball," said Roger, "you used your head for once. Now let's see you use it again and pile out of this hunk of junk!"

"Fifteen hundred on the counter is the danger mark, Roger, and as long as we keep it under that, I'm going to try and save this wagon!" replied Astro.

"Why? To get yourself a Solar Medal?" asked Roger sarcastically.

"What do you think made this tub act up like this, Astro?" asked Tom, ignoring Roger's remark.

"Using special reactant feed, Tom," replied Astro. "This is a converted chemical burner—with an old-type cooling pump. It's touchy stuff."

"Well, couldn't we drive boron rods into the mass and slow down the reaction?" asked Tom.

"No, Tom," answered Astro, "the control for the rods are inside the tube control box. We can't reach it."

There was a sudden loud ticking from the Geiger counter.

"Astro!" cried Roger. "The mass is building!"

"Here, lemme see!" shouted Astro. He took the instrument in his big hand and watched the clocklike face intently.

" ... fourteen hundred thirty—fourteen hundred fifty—fourteen hundred seventy—" He faced his unit-mates. "Well, that does it. The mass is maintaining a steady reaction without the energizing pumps. It's sustaining itself!"

"But how is that possible?" asked Tom.

"It's one of those freaks, Tom. It's been known to happen before. The fuel is just hot enough to sustain a steady reaction because of its high intensity. Once that baffle worked loose, the mass started wildcatting itself."

"And if it doesn't stop?" asked Roger tensely.

"It'll reach a point where the reaction comes so fast it'll explode!"

"Let's pile out of here!" said Roger.

The three boys made a dash for their space suits and the jet boat. Inside the air lock, they adjusted their oxygen valves and waited for pressure to equalize so they could blast off.

"Blast it," said Astro, "there must be some way to get to that rocket tube and dump that stuff!"

"Impossible, Astro," said Roger. "The release controls are in the control box, and with all that radiation loose, you wouldn't last half a minute!"

Tom walked over to the valve that would open the outside hatch.

"Wonder how Captain Strong is making out with those tough babies on the Polaris?" asked Tom.

"I don't know," replied Roger, "but anything would be better than sitting around waiting for this thing to blow up!"

"Ah—stop griping," said Astro, "or I'll shove you up a rocket tube and blast you from here all the way back to Atom City!"

"Hey, wait a minute!" shouted Tom. "Astro, remember the time we were on the ground crew as extra duty and we had to overhaul the Polaris?"

"Yeah, why?"

"There was one place you couldn't go. You were too big, so I went in, remember?"

"Yeah, the space between the rocket tubes and the hull of the ship. It was when we were putting in the new tube. So what?"

"So this!" said Tom. "When they converted this tub, they had standard exhausts, so it must have the same layout as the Polaris. Suppose I climb in the main exhaust, between the tube and the outer hull, and cut away the cleats that hold the tube to the ship?"

"Why, then everything would come out in one piece!" Astro's face lit up. "Reactant mass, tube, control box—the works!"

"Say, what are you two guys talking about?" asked Roger.

"Saving a ship, Roger," said Tom. "Dumping the whole assembly of the number-three rocket!"

"Ah—you're space happy!"

"Maybe," said Tom, "but I think it's worth trying. How about it, Astro?"

"O.K. by me, Tom," replied Astro.

"Good. You get the cutting torches rigged, Astro. Roger, you give him a hand and keep your eye on the counter. Then feed the torches to me when I get inside the tube. I'm going outside to get rid of a bad rocket and save a five-million-credit spaceship!"

Before Astro or Roger could protest, Tom opened the hatch and began to climb out on the steel hull toward the rocket tubes, main exhaust.

His magnetic-soled shoes gripping the smooth steel hull, the cadet made his way aft to the stern of the ship and began the climb down around the huge firing tubes and into the tubes themselves.

"Hey, Astro," he yelled into the spacephone, "I'm inside the tubes. How about those torches?" The cadets had adjusted the wave length so that all could hear what was said.

"Take it easy, spaceboy," said Roger, "I'm leaving the hatch now. You and your fatheaded friend from Venus are so hopped up for getting a Solar Medal—"

"Knock it off, Manning!" said Astro from inside the ship. "And for your information, I don't want a medal. I don't want anything except for you to stop griping!"

Roger reached the end of the ship and began to climb down inside the tube where Tom was waiting for him.

"O.K., spaceboy," said Roger, "here're your cutting torches." He started moving back. "I'll see you around. I don't mind being a little hero for saving people and all that stuff. But not for any ship. And the odds against a big hero staying alive are too big!"

"Roger, wait," shouted Tom. "I'll need...." And then the curly-headed cadet clamped his teeth together and turned back to the task at hand.

He made adjustments on the nozzle of the cutting torch, and then, focusing his chest light, called to Astro.

"O.K., Astro," he said, "shoot me the juice!"

"Coming up, Tom!" answered Astro. "And wait till I get my hands on that Manning! I'm going to smear that yellow space crawler from one corner of the universe to another!"

"Never mind the talk," snarled Roger, who at the moment was re-entering the tube. "Just get that juice down to this torch and make it fast!"

Tom turned to see Roger crawling back into the tube and adjusting a cutting torch.

"Glad to have you aboard, Roger," said Tom with a smile that Roger could not see in the darkness of the tube. The two boys went to work.

Suddenly the torches came to life. And immediately Tom and Roger began to cut away at the cleats that held the tube lining to the skin of the ship. Steadily, the cadets worked their way up toward the center of the ship, cutting anything that looked as though it might hold the giant tube to the ship.

"Boy," said Tom, "it's getting hot in here!"

From inside the ship, Astro's reassuring voice came back in answer. "You're getting close to the reactant-mass chamber. The last cleat is up by one of the exhaust gratings. Think you can last it?"

"Well, if he can't," snarled Roger, "he's sure to get that medal anyway!" He inched up a little. "Move over, Corbett, I'm skinnier than you are, and I can reach that cleat easier than you can."

Roger slipped past Tom and inched his way toward the last cleat. He pulled his torch up alongside and pulled the trigger. The flame shot out and began eating the steel. In a moment the last cleat was cut and the two boys started their long haul down the tube to the outside of the ship.

As they walked across the steel surface, back to the air lock, Tom stuck out his hand.

"I'm glad you came back, Roger."

"Save it for the boys that fall for that stuff, Corbett," said Roger sarcastically. "I came back because I didn't want you and that Venusian hick to think you're the only ones with guts around here!"

"No one has ever accused you of not having guts, Roger."

"Ah—go blast your jets," snarled Roger.

They went directly to the power deck where Astro was waiting for them, the Geiger counter in his hand.

"All set to get rid of the rotten apple?" he asked with a smile.

"All set, Astro," said Tom. "What's the count?"

"She seems to have steadied around fourteen hundred ninety—and believe me, the ten points to the official danger mark of fifteen hundred is so small that we could find out where the angels live any moment now!"

"Then what're we waiting for," said Tom. "Let's dump that thing!"

"How?" snarled Roger.

Tom and Astro looked at him bewilderedly. "What do you mean 'how'?" asked Astro.

"I mean how are you going to get the tube out of the ship?"

"Why," started Tom, "there's nothing holding that tube assembly to the ship now. We cut all the cleats, remember? We can jettison the whole unit!"

"It seems to me," drawled Roger lazily, "that the two great heroes in their mad rush for the Solar Medal have forgotten an unwritten law of space. There's no gravity out here—no natural force to pull or push the tube. The only way it could be moved is by the power of thrust, either forward or backward!"

"O.K. Then let's push it out, just that way," said Astro.

"How?" asked Roger cynically.

"Simple, Roger," said Tom, "Newton's Laws of motion. Everything in motion tends to keep going at the same speed unless influenced by an outside force. So if we blasted our nose rockets and started going backward, everything on the ship would go backward too, then if we reversed—"

Astro cut in, "Yeah—if we blasted the stern rockets, the ship would go forward, but the tube, being loose, would keep going the other way!"

"There's only one thing wrong," said Roger. "That mass is so hot now, if any booster energy hit it, it would be like a trigger on a bomb. It'd blow us from here to the next galaxy!"

"I'm willing to try it," said Tom. "How about you, Astro?"

"I've gone this far, and I'm not quitting now."

They turned to face Roger.

"Well, how about it, Roger?" asked Tom. "No one will think you're yellow if you take the jet boat and leave now."

"Ah—talk again!" grumbled Roger. "We always have to talk. Let's be original for a change and just do our jobs!"

"All right," said Tom. "Take an emergency light and signal Captain Strong. Tell him what we're going to do. Warn him to stay away—about two hundred miles off. He'll know if we're successful or not within a half hour!"

"Yeah," said Roger, "then we'll send him one big flash to mean we failed! Bon voyage!"

Fifteen minutes later, as the Lady Venus drifted in her silent but deadly orbit, Tom, Roger and Astro still worked feverishly as the Geiger counter ticked off the increasing radioactivity of the wildcatting reaction mass in number-three rocket tube.

"Reading on the counter still's going up, Astro," warned Roger. "Fifteen-O-five."

"Hurry it up, Astro," urged Tom.

"Hand me that wrench, Tom," ordered Astro. The big cadet, stripped to the waist, his thick arms and chest splattered with grease and sweat, fitted the wrench to the nut and applied pressure. Tom and Roger watched the muscles ripple along his back, as the big Venusian pitted all of his great strength against the metal.

"Give it all you've got," said Tom. "If we do manage to jettison that tube, we've got to keep this part of the power deck airtight!"

Astro pulled harder. The veins standing out on his neck. At last, easing off, he stood up and looked down at the nut.

"That's as tight as I can get it," he said, breathing heavily.

"Or anyone else," said Tom.

"All the valve connections broken?" asked Astro.

"Yep," replied Roger. "We're sealed tight."

"That's it, then," said Tom. "Let's get to the control deck and start blasting!"

Astro turned to the power-deck control board and checked the gauges for the last time. From above his head, he heard Tom's voice over the intercom.

"All your relays to the power deck working, Astro?"

"Ready, Tom," answered Astro.

"Then stand by," said Tom on the control deck. He had made a hasty check of the controls and found them to be similar enough to those on the Polaris so that he could handle the ship. He flipped the switch to the radar deck and spoke into the intercom.

"Do we have a clear trajectory fore and aft, Roger?"

"All clear," replied Roger. "I sent Captain Strong the message."

"What'd he say?"

"The rebellion wasn't anything more than a bunch of badly scared old men. Al James just got hysterical, that's all."

"What did he have to say about this operation?"

"I can't repeat it for your young ears," said Roger.

"So bad, huh?"

"Yeah, but not because we're trying to save the ship."

"Then why?" asked Tom.

"He's afraid of losing a good unit!"

Tom smiled and turned to the control board. "Energize the cooling pumps!" he bawled to Astro over the intercom.

The slow whine of the pumps began to build to a shrieking pitch.

"Pumps in operation, Tom," said Astro.

"Cut in nose braking rockets," ordered Tom.

A low muted roar pulsed through the ship.

"Rockets on—we're moving backward, Tom," reported Astro.

And then suddenly Astro let out a roar. "Tom, the Geiger counter is going wild!"

"Never mind that now," answered Tom. "Sound off, Roger!" he yelled.

"Ship moving astern—one thousand feet a second—two thousand—four thousand—"

"I'm going to let her build to ten, Roger," yelled Tom. "We've only got one chance and we might as well make it a good one!"

"Six thousand!" yelled Roger. "Seven thousand!"

"Astro," bellowed Tom, "stand by to fire stern rockets!"

"Ready, Tom," was Astro's reply.

"Eight thousand," warned Roger. "Spaceman's luck, fellas!"

The silver ship moved through space away from the Polaris.

"Nine thousand," reported Roger. "And, Astro, I really love ya!"

"Cut nose braking rockets!" ordered Tom.

There was a sudden hush that seemed to be as loud as the noise of the rockets. The huge passenger ship, Lady Venus, was traveling through space as silent as a ghost.

"Nine thousand five hundred feet a second," yelled Roger.

"Stand by, Astro, Roger! Hang on tight, and spaceman's luck!"

"Ten thousand feet a second!" Roger's voice was a hoarse scream.

"Fire stern rockets!" bawled Tom.