"What caused it, Tom?" Bud asked as they paused to sip the fruit drink.

"Good question," Tom replied. "Frankly, I don't know." But he was
wondering if the set might have been sabotaged.

Tom was still eager to get in touch with his father and telephoned the
electronics department to bring another set to his laboratory. Chow left
just as the new set arrived.

Tom hooked it up quickly, donned a set of goggles, and tuned to the
space-station frequency. Then he picked up the microphone and stepped
well back from the set, waving Bud out of range at the same time.

"Tom Swift calling Outpost!... Come in, please!"

A moment later came another explosion! _The new set had also blown up!_

"Good night!" Bud gasped in a stunned voice. "Don't tell me that's just
a coincidence!"

Tom shrugged. "We can certainly rule out the possibility that anything
was wrong with the radio itself. Every set is checked before it leaves
the electronics department."

"So where does that leave us?" Bud persisted.

Tom shook his head worriedly as he took off the goggles. "Both times it
seemed to happen just as the reply was coming through from the space
station. There is no possibility that their signal was too strong--in