"Nothing yet, as far as contact goes," he said. "We've heard from the spotter station in Topeka; they missed it at the same time we did—1702 hours, two seconds."

MacIlheny glanced at the chronometer on the wall. The satellite had been missing for nearly four minutes now.

"Get the Long Island Observatory; tell 'em to keep an eye peeled for Number Four. It ought to be out of Earth's shadow," MacIlheny ordered. "And start a sweep search with the radar. Cover the whole area. Get a prediction from the Orbit Division; find the cone of greatest probability and search it carefully. Unless the damned thing just blew up, it's got to be up there somewhere!"

"I've already called Orbits," Blake said. "I'll get Long Island on the line." He headed for the phone.

MacIlheny went over to one of the control boards and looked over the instruments. He swept his eyes across them, reading them as a group, in the same way an ordinary man reads a sentence. Satellite Number Four had vanished, as far as the Beam Controls were concerned. Data from the electronic brain indicated that the acceleration of the satellite had been something terrific, but whether it had slowed down or speeded up was something the brain couldn't tell yet.

A thin, sandy-haired man at a nearby board said: "What do you think, Mac?"

"There's only one thing could have done it, Jackson," MacIlheny said. "A meteor."

"That's what we figured. It must have been a doozie!"

"Yeah. But which direction did it hit from? If it hit from the side, Number Four will be twisted around; its new orbit will be at an angle to the old one. If it overtook the satellite from behind, the additional velocity will lift it into a newer, higher orbit. If it was hit from the front, it'll be slowed down, and it may hit the atmosphere."

"Not much chance of its being overtaken," Jackson said. "A meteor would have to be hitting it up at a pretty good clip to shove Four ahead that fast!"