The doctor and a medic were carrying out Stevens when he came back a few seconds later. Dan was slipping on the welder's helmet. "Keep everyone away from the control-room level," he said to Rawlins. "And you better have the crash trucks and the flame quenchers standing by on the field." Rawlins stared at him. "And what happens to you?" Dan licked his lips. "I--I don't know. I'm going to try something." Rawlins smiled. He reached out his hand. "Good luck, Dan," he said. He clapped him on the shoulder. When they were gone, Dan dropped the helmet over his face. He walked slowly across the room with his hands in front of him like a blind man. Finally he lifted up across the room with his hands in front of the helmet and knocked out the dark glass in the eye slot. Then he slipped it back on. From one of the drawers in a small desk beside the control table he lifted out a small rectangular object and slipped it in his pocket. He seated himself before the control table. The dials on the edge of the table glowed dimly. In the center of the flat top was a large circular graph with white lines that pulsed like a network of capillaries. He looked across the table through the big window. Everything except one nearby tower was hidden in swirling mists. The speaker at his side clicked on. He heard Rawlins' voice. "I picked 'em up Dan. They're coming in at minimum speed--seventy point two nine five degrees. I didn't mention the freighter." Dan flicked a small switch on the table edge. A straight white line of light shot out across the graph, then swung slowly back and forth through an arc of ten degrees like a searching feeler. Suddenly it steadied and an orange bead appeared at its terminus. Dan watched the bead travel down the line, across the pulsing capillaries. He reached out and grasped a small lever sticking out of the table top. As he pressed the lever to one side, the line moved around the graph like a pointer, carrying the orange bead with it. He watched it till the bead reached the center of the graph, and then glanced up through the window. Above the far end of the field he could discern the dim orange glow of a rocket's keel jets. Suddenly he jerked back his head. A beam of purple light was playing back and forth across the table. It swept over his gloved hands, across his arms and chest, and moved upward toward his face. He jumped up, keeping hold of the lever and studied the angle of the small beam. The reflection on the dark cloth of his jacket was making him dizzy. He reached into his pocket.... [Illustration: _Suddenly ... a beam of purple light!_] From the observation tower Rawlins watched the rocket sweep toward the field with keel jets blazing. As it reached the strip it seemed to falter and dip. Rawlins clenched his hands and swore. Then it steadied and slid in to a perfect landing. The intercommunication telaudio flashed on. He saw Dan Kearns' haggard face under the uplifted welder's helmet.