In the pressurized cabin, Furness' voice was more nearly audible. But this was the first of two moments of truth. Here and now McCauley had to perform, as the act of a man, what highly complicated machines would later compute he should have done. He had to get the X-21 into a three-dimensional relationship to the gravitational field of Earth. He had to point the ship not only laterally but vertically in the exact direction that the exact timing of rocket thrust would convert into an orbit. An error of half a degree would immediately be fatal. An even smaller error could make the ship's course so eccentric that when he got back into air it would be with a velocity that would burn ship and men together as a meteor some fifty miles high. He sweated, in absolute absorption in his task. Not only did the ship have to point exactly when he fired the rocket engine, but it had to be stationary, so it would not move past that point. It had to be settled dead center on an imaginary optimum or the rocket thrust would change direction as the ship's nose turned. He flung his hand against a switch. The ramjets died. There was a vast, furry stillness--the deafness produced by the past din. McCauley spoke and barely heard his own voice. He shouted to Furness: "Settle back for rocket fire!" Furness nodded. He looked cadaverous. His eyes seemed filled with a peculiar, tragic despair. But his lips moved. McCauley knew that he was saying: "Ramjets off. Maneuvering for course prior to rocket firing. Over." But he did not stir in his seat. His left hand stayed pressed against his side. The ship would be coasting downward now. Its wings still gave some support, and its wingtips had some effect, but not enough. Now was the time to use the steam-jets on the fins. McCauley played them tensely as if they were a musical instrument. He struck balances of opposing thrusts as if they were chords. The nose of the ship steadied, steadied, steadied.... The timer button was set at one minute. He struck the rocket-firing button. He was hurled back in his seat with a sort of vicious and unreasonable violence. He was caught in a vise of twelve gravities pressure which held him motionless against the seat back and tried to flatten out his legs and body and prevent his breathing. But his flight suit was designed to prevent exactly this. It squeezed also. His legs were tightened unbearably. His arms were constricted past endurance. His chest, his stomach--he was confined in the most horrible of strait jackets. He felt his tongue curling back down his throat to strangle him. With an utterly herculean effort he managed to turn his head to one side. Then he could breathe, and the grav-pressure air protected his chest from collapse, and he endured and endured and endured.