"This rock will take more nuclear blasts than we have," he assured Koa. He turned his communicator back on and went to the edge of the hole for a look at Kemp’s progress. He was far down, now. Pederson was holding one end of a measuring tape. The other end was fastened to Kemp’s shoulder strap. The Swedish corporal showed Rip that he had only about eight feet of tape left. Kemp was almost down. Rip called, "Kemp. When you reach bottom, cut toward the center. Leave an inverted cone." "Got it, sir. Be up in two more cuts." Dominico had connected cable to the bomb terminals and was attaching a timer to the other end. Without the wooden case, the bomb was like a fat, oversized can. It had been shipped without a combat casing. "Koa, make a final check. You can untie the landing boat, except for one line. We’ll be taking off in a few minutes." "Right, sir." Koa glided toward the landing boat, which was out of sight over the horizon. It was nearly time. Rip had a moment’s misgiving. Had his figures or his sightings been off? His red hair prickled at the thought. But the ship’s computer had done the work, and it was not capable of making a mistake. Kemp tossed up the last section of thorium and then came out of the hole himself, carrying his torch. Rip inspected the hole, saw with satisfaction it was in almost perfect alignment, and ordered the bomb placed. He bent over the edge of the hole and watched Trudeau pay out wire while Dominico pushed the bomb to the bottom. The Italian made a last minute check, then called to Rip. "Ready, sir." He dropped into the hole and inspected the connections himself, then personally pulled the safety lever. The bomb was armed. When the timer acted, it would go off. Back at ground level, he turned up his communicator. "Koa, is everything ready at the boat?" "Ready, sir." The Planeteers had already carried away the torch and its fuel and oxygen supplies. The area was clear of pieces of thorium. Rip announced, "We’re setting the explosion for ten minutes." He leaned over the timer, which rested near the lip of the hole, took the dial control in his glove and turned it to position ten. He held it long enough to glance at his chronometer and say, "Starting now!" Then he let it go. Wasting no time, but not hurrying, he and Dominico returned to the landing boat. The Planeteers were already aboard, except for Koa, who stood by to cast off the remaining tie line. Rip stepped inside and counted the men. All present. He ordered, "Cast off." As Koa did so and stepped aboard, he added, "Pilot, take off. Straight up." The landing boat rose from the asteroid. Rip counted the men again, just to be sure. The boat seemed a little crowded, but that was because the rear compartment took up quite a bit of room.