“I get it now!” piped up Joe Spinzo, a bright—
18 COSMIC ASTRONAUTS
eyed eight-year-old. “We need the string pulling on the kite, too, to make it fly.”
“Smart thinking, Joe!” Tom approved. “You see, there are three things that happen when a kite goes up in the air. Watch.”
Tom picked up a stick and drew a diagram on the ground. “First,” he pointed out, “there’s the force of gravity which tries to pull the kite down. Second, the wind blows along the field and pushes the kite away from you. Third, you pull on the string into the wind, which makes the kite move upward in a curved arc. The string enables the kite to make use of the wind force so as to overcome the force of gravity.”
“Gee, that’s simple the way you explain it, Tom!” said Billy.
Tom grinned. “Actually, when you pull on the kite string you supply the force needed to keep the kite up-in the same way an aircraft engine supplies the force to keep the plane up. No engine, no flight-no string, no flight.”
After chatting with the boys a few minutes longer, Tom asked them what they wanted to be when they grew up.
“Space pilots!” the trio chorused.
“Glad to hear that, fellows,” Tom said. “It’s one of the best jobs in the world.”
He waved good-by and resumed his homeward stroll. He found himself wondering if the boys’ dreams would ever come true.
THE INVISIBLE STRING 19
“Not if we can’t beat the cost factor in space travell” Tom reflected ruefully.
“Kite flying is sure cheaper!”
Kites! The word exploded in Tom’s mind. He stopped short as an exciting idea struck him full force. Instead of regarding cosmic rays as a dangerous drawback to space flight, why not make use of them just as a kite makes use of the wind?