of three gravities continued. Joe's chest muscles ached with the exertion of breathing over so long a period. Six gravities for fourteen seconds had been a ghastly ordeal. Three gravities for minutes built up to something nearly as bad. Joe's heart began to feel fatigue, and a man's heart normally simply doesn't ever feel tired. It became more and more difficult to see clearly.
But he had work to do. Important work. The take-off rockets were solid-fuel jobs, like those which launched the Platform. They were wire-wound steel tubes lined with a very special refractory, with unstable beryllium and fluorine compounds in them. The solid fuel burned at so many inches per second. The refractory crumbled away and was hurled astern at a corresponding rate—save for one small point. The refractory was not all exactly alike. Some parts of it crumbled away faster, leaving a pattern of baffles which acted like a maxim silencer on a rifle, or like an automobile muffler. The baffles set up eddies in the gas stream and produced exactly the effect of a rocket motor's throat. But the baffles themselves crumbled and were flung astern, so that the solid-fuel rockets had always the efficiency of gas-throated rocket motors; and yet every bit of refractory was reaction-mass to be hurled astern, and even the steel tubes melted and were hurled away with a gain in acceleration to the ship. Every fraction of every ounce of rocket mass was used for drive. No tanks or pumps or burners rode deadhead after they ceased to be useful.
But solid-fuel rockets simply can't be made to burn with absolute evenness as a team. Minute differences in burning-rates do tend to cancel out. But now and again they reinforce each other and if uncorrected will throw a ship off course. Gyros can't handle such effects. So Joe had to watch his instruments and listen to the tinny voice behind him and steer the ship against accidental wobblings as the Earth fell away behind him.
He battled against the fatigue of continuing to live, and struggled with gyros and steering jets to keep the ship on its hair-line course. He panted heavily. The beating of his heart became such a heavy pounding that it seemed that his whole body shook with it. He had to do infinitely fine precision steering with hands that weighed pounds and arms that weighed scores of pounds and a body that had an effective weight of almost a quarter of a ton.
And this went on and went on and on for what seemed several centuries.
Then the voice in the speaker said thickly: "Everything is in the clear. In ten seconds you can release your rockets. Shall I count?"
Joe panted, "Count!"
The mechanical voice said, "Seven … six … five … four … three … two … one … cut!"
Joe pressed the release. The small, unburnt stubs of the take-off rockets went hurtling off toward emptiness. They consumed themselves as they went, and they attained an acceleration of fifty gravities once they were relieved of all load but their own substance. They had to be released lest one burn longer than another. It was also the only way to stop acceleration by solid-fuel rockets. They couldn't be extinguished. They had to be released.
From intolerably burdensome heaviness, there was abruptly no weight at all in the ship. Joe's laboring heart beat twice with the violence the weight had called for, though weight had ended. It seemed to him that his skull would crack open during those two heart-beats. Then he lay limply, resting.
There was a completely incredible stillness, for a time. The four of them panted. Haney was better off than Joe, but the Chief was harder hit. Mike's small body had taken the strain best of all, and he would use the fact later in shrill argument that midgets were designed by nature to be the explorers of space for their bulkier and less spaceworthy kindred.
The ending of the steady, punishing drag was infinitely good, but the new sensation was hardly pleasant. They had no weight. It felt as if they and the ship about them were falling together down an abyss which must have a bottom. Actually, they were falling up. But they felt a physical, crawling apprehension—a cringing from an imaginary imminent impact.
They had expected the sensation, but it was not the better for being understood. Joe flexed and unflexed his fingers slowly. He stirred and swallowed hastily. But the feeling persisted. He unstrapped himself from his seat. He stood up—and floated to the ceiling of the cabin. But there was of course no ceiling. Every way was up and every way was down. His stomach cramped itself in a hard knot, in the instinctive tensity of somebody in free fall.
He fended himself from the ceiling and caught at a hand-line placed there for just this necessity to grip something. In his absorption, he did not notice which way his heels went. He suddenly noticed that his companions, with regard to him, were upside down and staring at him with wooden, dazed expressions on their faces.
He tried to laugh, and gulped instead. He pulled over to the quartz-glass ports. He did not put his hand into the sunlight, but shifted the glare shutters over those ports which admitted direct sunshine. Some ports remained clear. Through one of them he saw the Earth seemingly at arm's length somewhere off. Not up, not down. Simply out from where he was. It filled all the space that the porthole showed. It was a gigantic mass of white, fleecy specks and spots which would be clouds, and between the whiteness there was a muddy dark greenish color which would be the ocean. Yet it seemed to slide very, very slowly past the window.
He saw a tanness between the clouds, and it moved inward from the edge of his field of view. He suddenly realized what it was.
"We've just about crossed the Atlantic," he said in a peculiar astonishment. But it was true the ship had not been aloft nearly as much as half an hour. "Africa's just coming into sight below. We ought to be about 1,200 miles high and still rising fast. That was the calculation."
He looked again, and then drew himself across to the opposite porthole. He saw the blackness of space, which was not blackness because it was a carpet of jewels. They were infinite in number and variations in brightness, and somehow of vastly more colorings than one noticed from Earth.
He heard the Chief grunt, and Haney gulp. He was suddenly conscious that his legs were floating rather ridiculously in mid-air with no particular relationship to anything. He saw the Chief rise very cautiously, holding on to the arms of his seat.
"Better not look at the sun," said Joe, "even though I've put on the glare-shields."
The Chief nodded. The glare-shields would keep out most of the heat and a very great deal of the ultraviolet the sun gave off. But even so, to look at the sun directly might easily result in a retinal sunburn which could result in blindness.
The loudspeaker behind Joe's chair clattered. It had seemed muted by the weight of its diaphragm at three gravities. Now it blasted unintelligibly, with no weight at all. Mike threw a switch and took the message.
"Communications says radar says we're right on course, Joe," he reported nonchalantly, "and our speed's okay. We'll reach maximum altitude in an hour and thirty-six minutes. We ought to be within calculated distance of the Platform then."
"Good," said Joe abstractedly.
He strained his eyes at the Earth. They were moving at an extraordinary speed and height. It had been reached by just four human beings before them. The tannishness which was the coast of Africa crept with astonishing slowness toward the center of what he could see.
Joe headed back to his seat. He could not walk, of course. He floated. He launched himself with a fine air of confidence. He misjudged. He was floating past his chair when he reached down—and that turned his body—and fumbled wildly. He caught hold of the back as he went by, then held on and found himself turning a grandly dignified somersault. He wound up in a remarkably foolish position with the back of his neck on the back of the chair, his arms in a highly strained position to hold him there, and his feet touching the deck of the cabin a good five feet away.
Haney looked greenish, but he said hoarsely:
"Joe, don't make me laugh—not when my stomach feels like this!"
The feeling of weightlessness was unexpectedly daunting. Joe turned himself about very slowly, with his legs floating indecorously in entirely unintended kicks. He was breathing hard when he pulled himself into the chair and strapped in once more.
"I'll