Cities in Flight

—to concentrate—

“Three.”

—on anything—

‘Two.”

—else but

“One.”

—actual—

“Zero.”

—take-off hit him with the abrupt, bone-cracking, gut-wrenching impact of all ferry take-offs. There was nothing you could do to ameliorate it but let the strong muscles of the arms and legs and back bear it as best they could, with the automatic tetanus of the Seyle GA reaction, and concentrate on keeping your head and your abdomen in exact neutral with the acceleration thrust. The muscles you used for that were seldom called upon on the ground, even by weight-lifters, but you learned to use them or were invalided out of the service; a trained spaceman’s abdominal muscles will bounce a heavy rock, and no strong man can make him turn his head if his neck muscles say no.

Also, it helped a little to yell. Theoretically, the yell collapses the lungs—acceleration pneumothorax, the books call it—and keeps them collapsed until the surge of powered flight is over. By that time, the carbon dioxide level of the blood has risen so high that the breathing reflex will reassert itself with an enormous gasp, even if crucial chest muscles have been torn. The yell makes sure that when next you breathe, you breathe.

But more importantly for Paige and every other spaceman, the yell was the only protest he could form against that murderous nine seconds of pressure; it makes you feel better. Paige yelled with vigor.

He was still yelling when the ship went into free fall.

Instantly, while the yell was still dying incredulously in his throat, he was clawing at his harness. All his spaceman’s reflexes had gone off at once. The powered-flight period had been too short. Even the shortest possible take-off acceleration outlasts the yell. Yet the ion-rockets were obviously silenced. The little ship’s power had failed—she was falling back to the Earth—

“Attention, please,” the intercom box said mildly. “We are now under way. Free fall will last only a few seconds. Stand by for restoration of normal gravity.”

And then …. And then the hammock against which Paige was struggling was down again, as though the ship were still resting quietly on Earth. Impossible; she couldn’t even be out of the atmosphere yet. Even if she were, free fall should last all the rest of the trip. Gravity in an interplanetary vessel—let alone a ferry—could be re-established only by rotating the ship around its long axis; few captains bothered with the fuel- expensive maneuvre, since hardly anybody but old hands flew between the planets. Besides, this ship—the Per Aspera— hadn’t gone through any such maneuvre, or Paige would have detected it.

Yet his body continued to press down against the hammock with an acceleration of one Earth gravity.

“Attention, please. We will be passing the Moon in one point two minutes. The observation blister is now open to passengers. Senator Wagoner requests the presence of Miss Abbott and Colonel Russell in the blister.”

There was no further sound from the ion-rockets, which had inexplicably been shut off when the Per Aspera could have been no more than 250 miles above the surface of the Earth. Yet she was passing the Moon now, without the slightest sensation of movement, though she must still be accelerating. What was driving her? Paige could hear nothing but the small hum of the ship’s electrical generator, no louder than it would have been on the ground, unburdened of the job of RF-heating the electron-ion plasma which the rockets used. Grimly, he unsnapped the last gripper from his harness, conscious of what a baby he evidently was on board this ship, and got up.

The deck felt solid and abnormal under his feet, pressing against the soles of his shoes with a smug terrestrial pressure of one unvarying gravity. Only the habits of caution of a service lifetime prevented him from running forward up the companionway to the observation blister.

Anne and Senator Wagoner were there, the dimming moonlight bathing their backs as they looked ahead into deep space. They had been more than a little shaken up by the take-off, that was obvious, but they were already almost recovered; compared to the effects of the normal ferry take-off, this could only have ruffled them; and of course the sudden transformation to the impossible one-gravity field would not have bollized their untrained reflexes with anything like the thoroughness that it had scrambled Paige’s long-conditioned reactions. Looked at this way, space-flight like this might well be easier for civilians than it would be for spacemen, at least for some years to come.

He padded cautiously toward them, feeling disastrously humbled. Shining between them was a brilliant, hard spot of yellow-white light, glaring into the blister through the thick, cosmics-proof glass. The spot was fixed and steady, as were all the stars looking into the blister; proof positive that the ship’s gravity was not being produced by axial spin. The yellow spot itself, shining between Wagoner’s elbow and Anne’s upper arm, was—

Jupiter.

On either side of the planet were two smaller bright dots; the four Galilean satellites, as widely separated to Paige’s naked eye as they would have looked on Earth through a telescope the size of Galileo’s.

While Paige hesitated in the doorway to the blister, the little spots that were Jupiter’s largest moons visibly drew apart from each other a little, until one of them went into occultation behind Anne’s right shoulder. The Per Aspera was still accelerating; it was driving toward Jupiter at a speed nothing in Paige’s experience could have prepared him for. Stunned, he made a very rough estimate in his head of the increase in parallax and tried to calculate the ship’s rate of approach from that.

The little lunar ferry, humming scarcely louder than a transformer for carrying five people—let alone ten—as far as SV-1, was now hurtling toward Jupiter at about a quarter of the speed of light.

At least forty thousand miles per second.

And the deepening color of Jupiter showed that the Per Aspera was still picking up speed.

“Come in, Colonel Russell,” Wagoner’s voice said, echoing slightly in the blister. “Come watch the show. We’ve been waiting for you.”

CHAPTER TEN: Jupiter V

That is precisely what common sense is for, to be jarred into uncommon sense. One of the chief services which mathematics has rendered the human race in the past century is to put ‘common sense’ where it belongs, on the topmost shelf next to the dusty canister labeled ‘discarded nonsense.’

—ERIC TEMPLE BELL

THE SHIP that landed as Helmuth was going on duty did nothing to lighten the load on his heart. In shape it was not distinguishable from any of the short-range ferries which covered the Jovian satellary circuit, carrying supplies from the regular SV-1-Mars-Belt-Jupiter X cruiser to the inner moons—and, sometimes, some years-old mail; but it was considerably bigger than the usual Jovian ferry, and it grounded its outsize mass on Jupiter V with only the briefest cough of rockets.

That landing told Helmuth that his dream was well on its way to coming true. If the high brass had a real anti- gravity, there would have been no reason why the ion-streams should have been necessary at all. Obviously, what had been discovered was some sort of partial gravity screen, which allowed a ship to operate with far less rocket thrust than was usual, but which still left it subject to a sizable fraction of the universal G, the inherent stress of space.

Nothing less than a complete, and completely controllable gravity screen would do, on Jupiter.

And theory said that a complete gravity screen was impossible. Once you set one up—even supposing that you