Rip watched his chronometer. They had plenty of time. When the boat reached a point about ten miles above the asteroid, he ordered, "Stern tube." The boat moved at an angle. He let it go until a sight at the stars showed they were about in the right position, 90 degrees from the line of blast and where they would be behind the asteroid as it moved toward the new course. He looked at his chronometer again. "Two minutes. Line up at the side if you want to watch, but darken your helmets to full protection. This thing will light up like nothing you’ve ever seen before." It was a good thing space cruisers depended on their radar and not on sight, he thought. Usually spacemen opened up visual ports only when landing or taking a star sight for an astro-plot. The clear plastic of the domes had to be shielded from chance meteors. Besides, radar screens were more dependable than eyes, even though they could pick up only solid objects. If the Consops cruiser happened to be searching visually, it would see the blast. But the chance had to be taken. It wasn’t really much of a chance. "One minute," he said. He faced the asteroid, then darkened his helmet, counting to himself. The minute ticked off slowly, though his count was a little fast. When he reached five, brilliant, incandescent light lit up the interior of the boat. Rip saw it even though his helmet was dark. The light faded slowly, and he put his helmet back on full transparent. A mighty column of fire now reached out from the asteroid into space. Rip held his breath until he saw that the little planet was sheering off its course under the great blast. Then he sighed with relief. All was well so far. Someone muttered, "By Gemini! I’m glad we’re out here instead of down there!" The column of fire lengthened, thinned out, grew fainter until there was only a glow behind the asteroid. Rip took his astrogation instruments and made a number of sights. They looked good. The first blast had worked about as predicted, although he wouldn’t be able to tell how much correction was needed until he had taken star sights over a period of five or six days. "Let’s go home," he ordered. Back on the asteroid, a pit that glowed with radioactivity marked the site of the first blast. Rip ordered it covered as much as possible with the thorium that had been taken from the hole. While the men worked, he plotted the lines for the second blast, found the spot, and put Kemp back to work on a new hole. Two hours later the second blast threw fire into space. In another three hours, with the asteroid now speeding on its new course, Rip set off the explosion that blasted straight back and gave extra speed.