Rip felt sudden weight against his feet. The green point on the screen moved downward below center. The feeling of weight ceased. He knew what had happened, of course. Around the hull of the ship, set in evenly spaced lines, were a series of blast holes through which steam was fired. The steam was produced instantly by running water through the heat coils of the nuclear engine. By using groups or combinations of steam tubes, the control officer could move the ship in any direction or set it rolling, spin it end over end or whirl it in an eccentric pattern. "How do you decide which tubes to use?" Rip asked. "Depends on what’s happening. If we were ducking missiles from an enemy, I’d get orders from the commander. But to duck asteroids, there’s no problem. I go over them by firing the steam tubes along the bottom of the ship. That way, you feel the acceleration on your feet. If I fired the top tubes the ship would drop out from under those who were standing. They’d all end up on the ceiling." Rip watched for a while longer, then wandered back to Commander O’Brine. He was getting anxious. At first, the task of capturing an asteroid and moving it back to earth had been rather unreal, like some of the problems he had worked out while training on the space platform. Now he was no longer calm about it. He had faith in the Terra base Planeteer specialists, but they couldn’t figure everything out for him. Most of the problems of getting the asteroid back to earth would have to be solved by Lieutenant Richard Ingalls Peter Foster. A junior space officer suddenly called, "Sir, I have a reading at two seventy degrees, twenty-three degrees eight minutes high." Commander O’Brine jumped up so fast that the action shot him to the ceiling. He kicked down again and leaned over the officer’s ’scope. Rip got there by pulling himself right across the top of the chart table. The green point of light on the ’scope was bigger than any other he had seen. "It’s about the right size," O’Brine said. There was excitement in his voice. "Correct course. Let’s take a look at it." All hands gripped something with which to steady themselves as the cruiser spun swiftly onto the new course. The control officer called, "I have it centered, sir. We’ll reach it in about an hour at this speed." "Jack it up," O’Brine ordered. "Heave some neutrons into it. Double speed, then decelerate to reach it in thirty minutes." The control officer issued orders to the engine control room. In a moment acceleration plucked at them. O’Brine motioned to Rip. "Come on, Foster. Let’s see what Analysis makes of this rock." Rip followed the commander to the deck below where the technical analysts were located. His heart was pounding a little faster than usual, and not from acceleration, either. He found himself wetting his lips frequently and thought, "Get hold of it, boy. You got nothing to worry about but high vacuum."