More missiles were fired carefully--not to do damage, but to discourage the intruders; the latter were held at bay for another twelve hours. Copeland and Brinker left radio commands and threats unanswered, so it was hard for their opponents to get a fix on their position in the whirling nucleus. Explosions blazed around them, but never very close. Masses of iron and stone were shattered and half vaporized, cooling subsequently to fine dust. The nucleus of Brulow's Comet expanded a bit under the battering that went on within it. At an opportune moment, Copeland and Brinker clung to one of their jet-tubes and, gunning it very lightly, rode it from the central core-mass of the nucleus to a lesser meteor, and hid in a cleft. A dust-poll had concealed their change of position. And now, with so many other large meteors around them, they would be almost impossible to find. They glimpsed the Patrol craft invading the heart of the comet. Men poured forth, struggling to set up jets in the hope of still deflecting this juggernaut from the Moon. But the comet was already much too close; before the setting-up was half completed it had to be abandoned. Still, the ships remained almost to the last. Copeland wondered tensely if they'd ever go. His withered palms perspired. "We could still yell for help--have them take us off," Brinker suggested when they had left. He spoke by sound-channel contact. The Moon loomed huge and ugly ahead. Copeland gave it a scared glance, and then laughed grimly. "Ironic, that would be," he snapped, "No--we've got this jet to ride, and we're still at liberty." From space, lashed to the flaming propulsion tube, they saw the crash happen. It was a terrific spectacle. Copeland's hopes now had jagged cracks of worry. The comet seemed to move slowly, its coma flattening over the Moon's spaceward hemisphere. There were blinding flashes as the chunks of its nucleus bit into the lunar crust, their energy of velocity converting largely to heat. Then dust masked the region of impact. The comet's tail collapsed over the Moon like a crumbling tower. Copeland gulped. He saw that Brinker had gone limp--fainted. Weakness was enough to cause that; but the fact of a plan carried out had a shock in it, too. Copeland worked the jury-rigged controls of the jet, continuing to decelerate. At spotty intervals, under the terrible thrust of reducing speed, he was unconscious, too. * * * * * There was no such thing as picking a landing-spot. Checking velocity soon enough, so close to the Moon, took all of the propulsion tube's power--so he just followed the comet down. Almost at a stand-still at last, balanced on a streamer of flame, he toppled into hot dust Feebly he worked to unlash himself from the tube. Brinker, jolted back to semi-consciousness, managed to do the same. Weakened and spent, they could not even lift themselves against the slight lunar gravity for a while.