However, this left room for higher concentrations, up to somewhat more than normal atmospheric pressure, before there was danger of toxic effects. Lucky let the oxygen pour into his suit.
Then, having done so, he closed the valve under his face-plate entirely and removed the cylinder.
The cylinder was itself a sort of push-gun. It was an unusual push-gun, to be sure. For a person marooned in space to use the precious oxygen that stood between himself and death as motive power, to blow it into space, meant desperation. Or else, a firm resolution.
Lucky cracked the reducing valve and let a blast of oxygen issue out. There was no line of crystals this time. Oxygen, unlike carbon dioxide, froze at very low temperatures indeed and before it could lose sufficient heat to freeze, it had diffused out into space. Gas or solid, however, Newton's third law of motion still held. As the gas pushed out one way, Lucky was pushed in the opposite direction by a natural counterpush.
His spinning slowed. Carefully he allowed the asteroid to come into full view before stopping the spin completely.
He was still receding from the rock. It was no longer particularly brighter than the neighboring stars. Conceivably he had already mistaken his target, but he closed his mind against that uncertainty.
He fixed his eyes firmly on the spot of light he assumed to be the asteroid and let the cylinder blast in the opposite direction. He wondered if he would have enough to reverse the direction of his travel. There was no way of telling at the moment.
In any case, he would have to save some gas. He would need it to maneuver about the asteroid, get on its night side, find Bigman and the ship, unless…
Unless the ship had already been driven away, or destroyed, by the pirates.
It seemed to Lucky that the vibration of his hands, due to the escaping oxygen, was lessening. Either the cylinder was running low, or its temperature was dropping. He was holding it away from his suit so it was no longer absorbing heat from it. It was from the suit that oxygen cylinders gained enough heat to be breathable, and the carbon dioxide cylinders of the push-guns gained enough heat to keep their contents gaseous. In the vacuum of space heat could be lost only by radiation, a slow process, but, even so, the oxygen cylinder had had time to drop in temperature.
He encircled the cylinder in his arms, hugged it to his chest, and waited.
It seemed hours, but only fifteen minutes passed before it seemed to him that the asteroid was growing brighter. Was he approaching the rock again? Or was it imagination? Another fifteen minutes passed and it was distinctly brighter. Lucky felt a deep gratitude to the chance that had shot him out on the sunlit side of the rock so that he could see it plainly as a target.
It was getting harder to breathe. There was no question of carbon dioxide asphyxiation. That gas was removed as it was formed. Still, each breath also removed a small fraction of his precious oxygen. He tried to breathe shallowly, close his eyes, rest. After all, he could do nothing more until he had reached and passed the asteroid. There on the night side, Bigman might still be waiting.
Then, if he could get close enough to Bigman, if he could call him on his limping radio before he passed out, there might yet be a chance.
* * *
The hours had passed slowly and torturously for Bigman. He longed to descend, but dared not. He reasoned with himself that, if the enemy existed, he would have shown himself by now. Then he argued it out bitterly and came to the conclusion that the very silence and motionlessness of space meant a trap, and that Lucky was caught.
He put Lucky's personal capsule before him and wondered about its contents. If only there were some way of bursting it, of reading the thin roll of microfilm within. If he could do that, he could radio it to Ceres, get it off his hands, and be free to go slamming down to the rock. He would blast them all, drag Lucky out of whatever mess he was in.
No! In the first place he dared not use the sub-etherics. True, the pirates could not break the code, but they would detect the carrier wave and he had been instructed not to give away the location of the ship.
Besides, what was the use of thinking of breaking into a personal capsule. A solar furnace could melt and destroy it, an atom blast could disintegrate it, but nothing could open it and leave its message intact except the living touch of the person for which it had been "personalized." That was that.
More than half of the twelve-hour period had passed when the gravities gave their entirely distinctive warning.
Bigman roused himself out of his frustrated reverie and stared with shocked surprise at the Ergometer. The pulsations of several ships were blending themselves into complicated curves that melted snakelike from one configuration to another.
The Shooting Starr's shield, which had been glimmering routinely at a strength sufficient to ward off casual "debris" (the usual space term for wandering meteorites an inch or less in diameter) stiffened to maximum. Bigman heard the soft purr of the power output grow strident. One by one, he let the short-range visiplates glow into life, bank on bank of them.
His mind churned. The ships were rising from the asteroid, since none could be detected further away. Lucky must be caught, then; dead, probably. He didn't care now how many ships came at him. He would get them all, every single one of them.
He sobered. The first Sun glint had caught in one of the visiplates. He maneuvered the cross hairs and centered them. He then depressed something that looked like a piano key and, caught in an invisible burst of energy, the pirate ship glowed.
The glow was not due to any action upon its hull, but was rather the result of the energy absorption of the enemy screen. It glowed brightly and more brightly still. Then it dimmed as the enemy turned tail and put distance between them.
A second ship and a third were in view. A projectile was making its way toward the Shooting Starr. In the vacuum of space there was no flash, no sound, but the Sun caught it and it was a little sparking spot of light. It became a little circle in the visiplate, then a larger one, until finally it moved out of the plate's field.
Bigman might have dodged, flashed the Shooter out of the way, but he thought, Let it hit. He wanted them to see what they were playing with. The Shooter might look like a rich man's toy, but they weren't going to put it out of action with a few slingshooters.
The projectile struck and slogged to a halt against the Shooting Starr's hysteretic shields, which, Bigman knew, must have flashed momentarily into brilliance. The ship itself moved smoothly, absorbing the momentum that had leaked past the shield.
"Let's return that," Bigman muttered. The Shooting Starr carried no projectiles, explosive or otherwise, but its store of energy projectors was varied and powerful.
His hand was hovering over the blaster controls when he saw in one of the visiplates something that brought a scowl to his small, determined face, something that looked like a man in a space-suit.
It was strange that the space-ship was more vulnerable to a man in a space-suit than to the best weapons of another ship. An enemy ship could be easily detected by gravities at a distance of miles and by Ergometers at a distance of thousands of miles. A single man in a space-suit could only be detected by a gravitic at a hundred yards and by an Ergometer not at all.
Again, a hysteretic shield worked the more effectively the greater the velocity of the projectile. Huge lumps of metal tearing at miles per second could be stopped cold.
One man, however, drifting along at ten miles an hour was not even aware of the existence of the shield except for a tiny warming of his suit.
Let a dozen men creep toward a ship at once and only great skill could bring them all down. If two or three penetrated and succeeded in blasting open the air-lock with hand weapons, the ship they attacked was seriously crippled.
And now Bigman caught the little speck that could only mean the advance guard of such a suicide squadron. He brought one of the secondaries to bear. The single figure was centered and Bigman was ready to fire when his radio receiver sounded.
&nbs
p; For a moment he was startled. The pirates had attacked without warning and had not tried to communicate, to call for surrender, to offer terms, anything. What now?
He hesitated and the sounding became a word, repeated twice, "Bigman… Bigman… Bigman…"
Bigman jumped from his seat, ignoring the suited man, the battle, everything. "Lucky! Is that you?"
"I'm near the ship… Space-suit… Air… nearly gone."
"Great Galaxy!" Bigman, white-faced, maneuvered the Shooting Starr nearer the figure in space, the figure whom he had nearly destroyed.
* * *
Bigman watched over Lucky, who, helmet off, was still gulping air. "You'd better get some rest, Lucky."
"Later," said Lucky. He climbed out of his suit. "Have they attacked yet?"
Bigman nodded. "It doesn't matter. They're just breaking their teeth on the old Shooter."
"They've got stronger teeth than any they've shown," said Lucky. "We've got to get away and fast. They'll be bringing out their heavy craft, and even our energy stores won't last forever."
"Where are they going to get heavy craft from?"
"That's a major pirate base down there! The major base, perhaps."
"You mean it isn't the hermit's rock?"
"I mean we've got to get away."
He took the controls, face still pale from his ordeal. For the first time the rock below them moved from its position on the screens. Even during the attack Bigman had heeded Lucky's parting order to stay put for twelve hours.
The rock grew larger.
Bigman protested. "If we've got to get away, why are we landing?"