Part 25 (1/2)

The Moons.h.i.+p was in trouble. The sequence and timing of its rocket blasts were worked out on Earth, and checked by visual and radar observation. The computations were done by electronic brains the Moons.h.i.+p could not possibly have carried. And everything worked out. The s.h.i.+p was on course and its firings were on schedule.

But then the unexpected happened. It was an error which no machine could ever have predicted, for which statistics and computations could never have compensated. It was a _human_ error. At the signal for the final acceleration blast, the pilot of the Moons.h.i.+p had fired the wrong set of rockets.

Inexperience, stupidity, negligence, excitement--the reason didn't matter. After years of planning and working and dreaming, one human finger had made a mistake. And the mistake was fatal!

When the mistake was realized, they'd had sense enough to cut loose the still-firing rockets. But the damage had been done. The s.h.i.+p was still plunging on. It would reach the Moon. But it wouldn't land in Aristarchus crater as planned. It would crash. If every rocket remaining mounted on the hull were to be fired at the best possible instant, the Moons.h.i.+p would hit near Copernicus, and it would land with a terminal velocity of 800 feet per second--540 miles an hour.

It could even be calculated that when the Moons.h.i.+p landed, the explosion ought to be visible from Earth with a fairly good telescope. It was due to take place in thirty-two hours plus or minus a few minutes.

11

The others got the s.p.a.ce tug into the platform's lock and did things to it, in the way of loading, that its designers never intended, while Joe was calling Earth for calculations. The result was infuriating. The Moons.h.i.+p had taken off for the Moon on the other side of the Platform's...o...b..t, when it had a velocity of more than 12,000 miles an hour in the direction it wished to go. The Platform and of course the s.p.a.ce tug was now on the reverse side of the Platform's...o...b..t. And of course they now had a velocity of more than 12,000 miles per hour away from the direction in which it was urgently necessary for the s.p.a.ce tug to go.

They could wait for two hours to take off, said Earth, or waste the time and fuel they'd need to throw away to duplicate the effect of waiting.

”But we can't wait!” raged Joe. Then he snapped. ”Look here! Suppose we take off from here, dive at Earth, make a near-graze, and let its gravity curve our course! Like a cometary path! Figure that! That's what we've got to do!”

He kicked off his magnetic-soled shoes and went diving down to the airlock. Over his shoulder he panted an order for the radar-duty man to relay anything from Earth down to him there. He arrived to find Haney and Mike in hot argument over whether it was possible to load on an extra ton or two of ma.s.s. He stopped it. They would.

”Everything's loaded?” he demanded. ”Okay! s.p.a.ce suits! All set? Let's get out of this lock and start blasting!”

He drove them into the s.p.a.ce tug. He climbed in himself. He closed the entrance port. The plastic walls of the lock bulged out, pulled back fast, and the steering rockets jetted. The s.p.a.ce tug came out of the lock. It spun about. It aimed for Earth and monstrous bursts of rocket-trail spread out behind it. It dived.

Naturally! When a s.h.i.+p from the Platform wanted to reach Earth for atmosphere-deceleration, it was more economical to head away from it.

Now that it was the most urgent of all possible necessities to get away from Earth, in the opposite direction to the s.p.a.ce tug's present motion, it was logical to dive toward it. The s.h.i.+p would plunge toward Earth, and Earth's gravity would help its rockets in the attainment of frenzied speed. But the tug still possessed its...o...b..tal speed. So it would not actually strike the Earth, but would be carried eastward past its disk, even though aimed for Earth's mid-bulge. Yet Earth would continue to pull. As the s.p.a.ce tug skimmed past, its path would be curved by the pull of gravity. At the nearest possible approach to Earth, the tug would fire its heaviest rockets for maximum acceleration. And it would swing around Earth's atmosphere perhaps no more than 500 miles high--just barely beyond the measurable presence of air--and come out of that crazy curve a good hour ahead of the Platform for a corresponding position, and with a greater velocity than could be had in any other way. Traced on paper, the course of the tug would be a tight parabola.

The s.h.i.+p dived. And it happened that it had left the Platform and plunged deep in Earth's shadow, so that the look and feel of things was that of an utterly suicidal plunge into oblivion. There was the seeming of a vast sack of pure blackness before the nose of the s.p.a.ce tug. She started for it at four gravities acceleration, and Joe got his headphones to his ears and lay panting while he waited for the figures and information he had to have.

He got them. When the four-gravity rockets burned out, the tug's crew painstakingly adjusted the s.h.i.+p's nose to a certain position. They flung themselves back into the acceleration chairs and Joe fired a six-g blast. They came out of that, and he fired another. The three blasts gave the s.h.i.+p a downward speed of a mile and a half a second, and Earth's pull added to it steadily. The Earth itself was drawing them down most of a 4,000-mile fall, which added to the speed their rockets built up.

Down on Earth, radar-bowls wavered dizzily, hunting for them to feed them observations of position and data for their guidance. Back on the Platform, members of the crew feverishly made their own computations.

When the four in the s.p.a.ce tug were half-way to Earth, they were traveling faster than any humans had ever traveled before, relative to the Earth or the Platform itself. When they were a thousand miles from Earth, it was certain they would clear its edge. Joe proposed and received an okay to fire a salvo of Mark Tens to speed the s.h.i.+p still more. When they burned to the release-point and flashed away past the ports, the Chief and Haney panted up from their chairs and made their way aft.

”Going to reload the firing-frames,” gasped the Chief.

They vanished. The s.p.a.ce tug could take rockets from its cargo and set them outside its hull for firing. No other s.h.i.+p could.

Haney and the Chief came back. There was dead silence in the s.h.i.+p, save for a small, tinny voice in Joe's headphones.

”We'll pa.s.s Earth 600 miles high,” said Joe in a flat voice. ”Maybe closer. I'm going to try to make it 450. We'll be smack over enemy territory, but I doubt they could hit us. We'll be hitting better than six miles a second. If we wanted to, we could spend some more rockets and hit escape velocity. But we want to stop, later. We'll ride it out.”

Silence. Stillness. Speed. Out the ports to Earthward there was purest blackness. On the other side, a universe of stars. But the blackness grew and grew and grew until it neatly bisected the cosmos itself, and half of everything that was, was blackness. Half was tiny colored stars.

Then there was a sound. A faint sound. It was a moan. It was a howl. It was a shriek.... And then it was a mere thin moan again. Then it was not.

”We touched air,” said Joe calmly, ”at six and a quarter miles per second. Pretty thin, though. At that, we may have left a meteor-trail for the populace to admire.”

n.o.body said anything at all. In a little while there was light ahead.

There was brightness. Instantly, it seemed, they were out of night and there was a streaming tumult of clouds flas.h.i.+ng past below--but they were 800 miles up now--and Joe's headphones rattled and he said: