The clock flashed a red light and made a buzzing sound. It was a reminder that now, according to the figure evolved on the ground before take-off, McCauley might begin the attempt at skip landing, the improbable but still least implausible procedure for getting the ship on to the ground in not more than two or three pieces. It should begin with a rocket-driven dive into the atmosphere. He was expected to have enough fuel for that. With downward velocity established, he should bleed out all the remaining nitric acid to emptiness. After it had been completely expelled, and not before, he should wait the number of seconds which would be equivalent to five hundred miles, and then jettison the hydrazine. By that time the ship should hit the outermost fringes of air. He should dive into it until the ship's skin temperature began to rise--a matter of fractions of seconds--and then let the ship bounce out again. It would have lost some velocity and would no longer be capable of remaining in an orbit. So it would come down into the air again, after an interval in which it would cool off, and again it would bounce out like a stone skipping across the surface of a pond until it has lost enough speed to settle quietly to the bottom. If McCauley attempted such a landing system, his place of entry into the air for a dead-stick landing would not be less than one thousand miles from the point of the first bounce, and it might be three thousand. It could not be calculated. Fractions of seconds and seconds of arc would apply, so McCauley might start his skip-stop descent out above the Pacific Ocean, and the X-21 might finally ditch in the Atlantic somewhere off Newfoundland. Furness tried to speak. "Report," he said faintly. "I should report." McCauley threw the switch for him. Furness summoned what seemed to be his last reserve of strength. "X-21 reporting," he said almost naturally. "We are well past Hawaii and approaching the continent. Altitude...." He was halfway through when green solid ground with very few clouds lay directly below, and the Rocky Mountains were a little way ahead. He could not quite detect their height, but the pattern of the soil was distinctive. McCauley flipped on his own throat-mike and said: "I interrupt. Here is the situation. My fuel tanks read...." He snapped off the readings. "I'm going to swing the ship end for end and burn my remaining rocket fuel to kill velocity. Then I'll adopt such skip-stop practices as the situation requires. I doubt it will require them. We were lucky enough to get a nearly circular orbit. In consequence our velocity is lower than if we'd had to make an eccentric one. We saved fuel unexpectedly in getting into space, and I'm going to use it getting out. Over."