"Why?" asked Mike.
"Because," Ishie explained, "when we reach the top of our course northward, then the thrust of the Confusor and Earth's gravity come into conflict, moving our entire orbit off-center and bringing us closer to the pole. In not too many orbits, that eccentricity in our orbit might pull us into the Van Allen belt. We can't afford that. Now, if we reverse the thrust at the right time, our orbit will be enlarged and we stay out of troubled spaces."
Mike was still puzzled. "I don't see how that works," he said. "Why wouldn't we just go off in a spiral on our present thrust?"
"The acceleration of Earth is a much greater influence," Ishie tried to make it clear, "than our little mosquito here. As long as they work together, things go well. But when Earth dictates that we will now swing south, be it ever so few degrees south, our mosquito is overpowered and can only drag us clear to Earth-center on a closing spiral, which would eventually lead us to crash somewhere in the southern hemisphere, a good many orbits from now.
"I hope," he said, "reversing the magnetic field will indeed reverse our little mosquito's thrust." He moved toward the Confusor.
"Hold it," said Mike. "The displacement in orbit won't be very much, at least on the first few go-arounds, will it? and if we switch it now, somebody'll start getting suspicious of this magneto-ionic effect. The effect that's doing all this. A sudden reversal might not be in its character, if it had a character. And anyhow, we don't want to give another jerk on Hot Rod. We might jerk something loose this time. We've already wiped out Thule Base—and there's no use adding scalps to an already full belt."
"O.K.," said Ishie. "Then now, I think it is time that we presented our formal drawings to the captain; and I think that when we present them we will suggest that we start work immediately on construction, even while he is checking out our drawings through his experts, so that the project will not be delayed."
On the bridge, the captain received the drawings with relief.
"Thank you, gentlemen. If these prove out, you may have saved the satellite by the rapidity of your work. Dr. Kimball calculated that our present acceleration will take us dangerously close to the Van Allen belt in about three orbits, and I need not tell you what that would mean."