"What else can we do?" asked Astro.
"Nothing," said Tom bitterly. "Not a space-blasting thing until we get out of here!"
"We've got to have that triple vacuum tube," declared Roger. "That's the only thing that will transmit a voice quickly back to Earth from this fix out in space."
The three boys and Jeff Marshall were back in their quarters after their first week of active duty again. They had surreptitiously begun collecting parts for the communicator and were sorting them out on one of the bunks when Roger mentioned the necessity for the special vacuum tube.
"How quickly?" asked Astro.
Tom explained. "The equipment we have now is strong enough to talk to the Academy, but it'll take about six hours for my voice to reach it. And then another six hours for the Academy's answer to get back to us. At the end of twelve hours we might not be ready to receive and the communications officer might pick up their answer. Then we'd be in the middle of a space hurricane!"
"I see," said Astro. "You've got to be able to talk directly to the Academy, so that when they answer, you'll be ready!"
"Right," said Tom. "We might only get ten or fifteen minutes of free time, when the professor would be away from the observatory."
"Where do you think I could get one of those tubes, besides on the radar bridge, Roger?" asked Jeff. He had been the main source of supply for the equipment used in the communicator. Since getting out of the brig, his movements had not been as restricted as the cadets'.