Communications Technician Harker took a deep pull at his mug of steaming coffee, blinked his eyes hard at the swimming dials before him, and lit a cigarette. Odysseus warning center was never quiet, even now in the graveyard watch when all other lights were turned low through the great ship's hull. Here in the neat grey room, murmuring, softly-clicking signal equipment was banked against every wall in a gleaming array of dials and meters, heavy power leads, black panels, and intricate sheafs of colored wire. The sonar kept up a sleepy drone, and radar scopes glowed fitfully with interference patterns, and the warning buzzer beeped softly as the radar echoed back to its receivers the rumor of strange planetary forces that radar hadn't been built to filter through. What made the interference, base technicians couldn't tell, but it practically paralyzed radio communication on all bands, and blanketed out even radar warnings. The cigarette burned his finger tips, and Harker jerked awake and tried to concentrate on the letter he was writing home. It would be microfilmed, and go on the next courier rocket. A movement at the Warnings Room door, brought Harker's head up, and he saw Commander Chapman, lean and grey, standing there. "Good evening, sir. Come on in. I've got coffee on." The Communications Technician took a pot from the glow heater at his elbow, and set out another cup. The Commander smiled tiredly, pulled out a stubby metal stool, and sat across the low table from Harker, sipping the scalding coffee cautiously. He looked up after a moment. "What's the good word, Harker? Picked up anything?" Harker ran his fingers through his mop of black hair, and grimaced. "Not a squeak, sir. No radio, no radar. Of course, the interference may be blanketing those. Creates a lot of false signals, too, on the radar screens. But we can't even pick 'em up with long-range sonar. That should get through. We're pretty sure they crashed, all right." "How about our signals, Harker? Do you think we're getting through to them?" Harker leaned back expansively, happy to expound his specialty. "Well, we've been sending radio signals every hour on the hour, and radio voice messages every hour on the half hour. We're sending a continuous sonar beam for their direction-finder. That's about all we can do. As for their picking it up, assuming the rocket has crashed and been totally knocked out, they still have a radio in the whippet tank. It's a transreceiver. And they have a portable sonar set, one of those little twenty-pound armored detection units. They'll use it as a direction finder." Chapman swirled the coffee around in the bottom of his cup and stared thoughtfully into it. "If they can get sonar, why can't we send them messages down the sonar beam? You know, flick it on and off in Morse code?"