demanded Roger of Spears.

"A blip is never a slip. It is constant with the eye of the beholder, and constant with the constant that is always--" Spears faltered, his face flushing with embarrassment.

"Always what?" hounded Roger.

"I--I don't know," stammered the fledgling helplessly.

"_You don't know?_" yelled Roger. He looked at Tom and Astro, shaking his head. "He doesn't know." The two cadets frowned at the quivering boy and Roger faced him again. "For your information, Mr. Spears," he said at his sarcastic best, "there are five words remaining in that sentence. And for each word, you will spend one hour cleaning this room. Is that clear?"

Spears could only nod his head.

"And for your further information," continued Roger, "the remaining words are 'constantly alert to constant dangers'! Does that help you, Mister?"

"Yes, Cadet Manning," gulped Spears. "You are very kind to give me this information. And it will be a great honor to clean your room."

Astro stepped forward to take his turn. He towered over the remaining cadet candidate and glowered at the thoroughly frightened boy. "So," he roared, "I guess this means you're going to handle the power deck in one of our space buckets, eh?"

"Yes, very well," came the quavering, high-pitched reply.

"Give me the correction of thrust when you are underway in a forward motion and you receive orders from the control deck for immediate reversal."

Coglin closed his eyes, took a deep breath, and the words poured from his lips. "To go forward is to overtake space, and to go sternward is to retake space already overtaken. To correct thrust, I would figure in the beginning of my flight how much space I intended to take and how much I would retake, and since overtake and retake are both additional quotients that have not been divided, I will add them together and arrive at a correction." The cadet candidate stopped abruptly, gasping for breath.

Secretly disappointed at the accuracy of the reply, Astro grunted and turned to Tom and Roger. "Any questions before they blast off on their solo hop?" he growled.

The two cadets shook their heads and Roger quickly lined three chairs in a row. Tom addressed the frightened boys solemnly. "This is your spaceship. The first chair is the command deck; second, radar deck; third, power deck. Take your stations and stand by to blast off."

Spears, Coglin, and Duke jumped into the chairs and Tom walked around them eying them coldly. "Now, Misters," he said, "you are to blast off, make a complete circle of the Earth, and return to the Academy spaceport for a touchdown. Is that clearly understood?"

"All clear," chorused the boys.

"Stand by to raise ship!" bawled Tom.

"Power deck, check in!" snapped Duke from the first chair. "Radar deck, check in!"

"Just one moment, Mister," interrupted Roger. "When you issue an order over the intercom, I want to see you pick up that mike. I want to see all the motions. It's up to you, Misters, to make us believe that you are blasting off!"