As a preliminary, they cut a cavern in the central mass of the nucleus with Martian blasters, and fitted it with a crude airlock. The cavern would be better to live in than the interior of a ship meant for alien beings. They moved Martian apparatus and supplies into it: Air-rejuvenators, moisture-reclaimers, cylinders of oxygen and water, and containers of nourishment--all millions of years old. Their remaining supply of Earthly food in their packs was now very short. It was weird--eating what had been preserved so long ago, on another world, for beings just barely close enough to human for their food to be edible. Gelatins, sectional fragments of vegetation, and what might have been muscle-tissue. Copeland and Brinker both gagged often. It wasn't the bland, oily taste so much, but the idea.... Some of it, Copeland decided, was not native Martian. It was more like terrestrial fish. And slabs of coarse meat might have been flesh of the last dinosaurs! Martians surely must have visited Earth briefly, though evidence there had long since weathered away. * * * * * While the still-distant sun sent thin light into the comet, Brinker and Copeland removed the propulsion-tubes from the ship and welded them to the central chunk of the nucleus. They had a number of other spare jet-tubes. These they fastened to lesser masses. Whenever, in the slow swirling of the nucleus, tubes pointed in the calculated proper direction at right angles to the comet's course, they were fired in long bursts. Thus, slowly, like a perfectly-balanced bank vault door moved by a finger, the mass of the comet--slight by volume, but still measuring many thousands of tons--was deflected in the opposite direction. Astrogation-instruments showed the shift. Copeland had expected such coarse deflection to be possible; still, it startled him--this was the moving of a celestial body! "Just a little--for now, Cope," Brinker said. "We'll leave the fine aiming for later. Meanwhile we've got to pass the time, stay as well as we can, and keep our heads on straight." Sure--straight! If Brinker hadn't turned foolish before they had come, they wouldn't be out here at all. In a month they were already thinning down from malnutrition and strain. At first, thinking coldly, Copeland was sure they'd wilt and die long before they got near the Moon. Then, as they managed to steady themselves some by the diversions of playing cards, and studying the intricacies of Martian equipment, he began to fear once more that Brinker might succeed in his efforts--but fail terribly in result. Many times Copeland went over the same arguments, struggling to speak calmly, and without anger: "I wonder if you realize it, Brinker--with enough velocity one large meteor carries more energy than a fission bomb. A whole comet would affect thousands of square miles of the lunar surface, at least. Smash equipment, kill men. And if the comet happened to miss the Moon and hit Earth--"