The precipitous rocky sides rose above them, and suddenly they were in darkness. Immediately, the plane's cooling system became more effective as Ferrati guided the rocket through the shadowy depths away from the blazing sunbeams. Burl saw, by means of the radar, that the bottom of the heat crack was many miles down. They raced along the crevice until they reached the mountain chain. Here, Ferrati abruptly raised the nose of the plane and they shot upward, popping out of the shadow into the sunlight. Before them loomed the hard unbroken walls of the Sun-tap station. The rocket plane came to a stop a hundred feet away. As soon as it had halted, Burl and Ferrati leaped out, with white sheets thrown over their suits to afford some extra protection from the Sun's rays. Between them they carried a long, awkward affair of poles and plastic. Burl's feet touched the ground; through the cushioned leather of his thick boots he felt the heat just as if he had stepped on a hot stove. He moved quickly, and as they had rehearsed, he and the explorer slapped the rig together and set up a gleaming plastic skin sunbreak to shield the rocket plane. The plastic sheets reflected the Sun's heat and cut off a fair portion of the direct radiation which would otherwise have rendered the rocket plane inoperable and uninhabitable in short order. While they were assembling the sunbreak, Haines and Boulton unloaded a portable antitank rocket launcher. With no wasted motion, Boulton aimed the launcher at the wall, and Haines thrust a long, wicked-looking rocket projectile into the tube. There was a flash of soundless fire and a line of dissipating white smoke. Nothing could be heard in the airlessness. Burl felt the shock through the ground as the shell hit. A chunk of the wall ripped apart and collapsed. As quickly as he saw it, Burl acted. Haines's voice rang in his ear, but already Burl was in action. Back into the rocket plane, out again with--an umbrella! He made a flying leap toward the Sun-tap station. He felt terrifically strong in the slight gravity, and the leap carried him thirty feet forward. As he slid through the space above the surface, he opened the umbrella. Its outer side had been painted white, and partly shielded him from the direct heat. He made the station in five leaps and climbed through the broken wall. Boulton followed him with another umbrella and a pack under his arm. Inside the station it was cool--the walls had been high enough to create shade within. It was like the station in the Andes, but bigger, much bigger. Boulton joined him, folded his umbrella calmly, and yanked an air-compression pistol from his belt. "See anyone?" he asked. "No." Burl remembered then that there could possibly be a living guard at this station. They searched carefully, but there was no sign of life. Boulton was doing a soldier's job, that was all.