g 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."

[Illustration: _A low muted roar pulsed through the ship_]

"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