Zewbriski," said Strong coldly, "is a human
being like you and we don't budge until we find him!"

At that moment the bell began to ring, indicating that the outer hatch
to the air lock was opening.

"By the craters of Luna," said Tom, "that must be Astro now!"

"But if it is," said Roger, "how did he get out there?"

From behind them, the hatch to the inner air lock opened and Al James
stepped through.

"Captain Strong," he said excitedly, "you've got to come quickly. Some
of the crewmen have broken into your arms locker and taken paralo-ray
guns. They threaten to leave you here if you don't return to the ship
within five minutes. They're afraid the _Venus_ might blow up and damage
the _Polaris_ at this close range." The young skipper, his red-brown
uniform torn and dirty, looked at the Solar Guard captain with wild-eyed
desperation.

"They can't leave us here," whimpered Zewbriski. "We'll all be blown to
bits!"

"Shut up!" barked Strong. He turned to Tom and Roger. "I can do one of
two things," he said. "I can order you to return to the _Polaris_ now,
with James and myself, or you can volunteer to stay behind and search
for Astro."

Without looking at Roger, Tom answered, "We'll stay, sir. And we won't
have to search for him. I think I know where he is."

"Now that I think about it," replied Strong, "I guess there is only one
place he could be."

"Yes, sir," said Tom, "down on the power deck trying to save this wagon!
Come on, Roger! Let's get him!"

CHAPTER 15

"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