t of the mechanism."

"Looks that way," mused Connel. "But there is still the possibility that
it was an accident, as the professor said."

Strong looked at Connel questioningly and then back to the wreckage. The
unit had been hurled from the upper deck of the spaceship, down to the
main deck, and it looked as if someone had trampled on its delicate
works.

[Illustration]

"I'll have a crew put right to work on this," said Hemmingwell.

"Commander," Connel suddenly announced, "I'm going ahead with my trip to
Mars to inspect the testing receivers. I don't think this incident is
serious enough for me to delay leaving, and if Professor Hemmingwell and
his men can get this unit back in operation in twelve hours, then
there's very little time lost and we can go ahead with the tests on
schedule."

"All right, Lou," said Walters. "Do whatever you think best. I'll have a
ship made ready for you at the Academy spaceport any time you want to
leave."

Connel nodded his thanks. "I think I'll take the _Polaris_, with Cadet
Corbett along as second pilot," he said. "I'm getting too old to make a
solo hop in a scout all the way to Mars. I need my rest." He grinned
slyly at Walters.

"Rest," Walters snorted. "If I know you, Lou Connel, you'll be up all
night working out standard operational procedures for the space
projectiles." He turned to Strong. "He's so sure this will work that
he's already writing a preliminary handbook for the enlisted personnel."

Strong turned and looked at the major, amazed. Every day he learned more
and more about the space-hardened veteran.

Connel turned to Strong. "Will you give Corbett the order to be ready at
0600 hours tomorrow morning, Steve?" he asked.

"Certainly, Lou," replied Strong.

As the major turned away, Walters called after him, "Take it easy."

Leaving Hemmingwell and Barret to take care of clearing away the
wreckage, Strong and Walters climbed out of the ship, left the hangar,
and headed for the Academy.

"Do you think it was sabotage, sir?" asked Strong, as they rode on the
slidewalk.

"I don't know, Steve," said the commander. "If that special unit of
Hemmingwell's had been damaged, I would say it might have been an
accident. But the things that were damaged would have put the whole
works out of commission if we didn't have that unit."

"Yes, sir," said Strong grimly. "So the man who did it thought he was
doing a complete job."

"Right," said Walters. "Assuming tha