CHAPTER XV
The Empty Boat
The Swiss torsion clock on Steve Ames's fireplace mantle read 6:49. Rick and Scotty, in slacks, shirts, and moccasins, sat in armchairs and tried to stay awake. The small rocket, cleaned and dried, rested on a newspaper on Steve's table.
"Rockoon," Rick said. "That explains the funny antenna, the presence of the electronics expert, and why the stingarees are launched."
"Not to me, it doesn't," Scotty retorted. He sipped steaming coffee. "What was that word you used? Grain?"
Rick nodded sleepily. "That's what solid rocket fuel is called. It's poured into the casing around a form. The form is withdrawn after the fuel hardens. The shape is designed to give maximum burning surface. Since the solid fuel is grainy, it's called grain."
"Logical," Scotty replied with a languid wave of his hand. "All perfectly logical. I also understand that a rockoon is a combination of a rocket and a balloon. The balloon carries the rocket up to where the air is less dense, then the rocket fires and breaks away. How does the rocket know when to fire?"
"Two ways. A barometric switch can be installed that will act at a certain altitude, or a signal can be sent from the ground."
"The antenna," Scotty said. "It can send a signal."