Chapter 13. _The Pole of Callisto_

Burl surveyed his position. Judging from the apparent weight of his

body, Boulton was decelerating the ship at a little less than one

gravity. The nylon cord was hooked into a bolt near the center of the

ship. It would be possible for Burl to climb up it and reach a firmer

grip on the outside shell.

There was no time to be lost. An increase in the ship's speed might

increase his weight several times over. He began to climb back, reeling

in the rope, pulling himself up hand over hand, just as he had done many

times in the gymnasium of his high school back home.

Halfway up, Clyde's voice came on his helmet phones. "Will all members

of the crew report their present positions to me? Haines?"

He called each man's name, beginning with the three outside. Haines and

Ferrati were clinging to the surface, on the far--now forward--end of

the ship. The rest of the crew was somewhere in the living sphere.

Lockhart was still unconscious. Burl could hear the faint sounds of a

discussion in the control room, and also thumps as Caton and Shea

continued to try to break open the entry to the generator chambers.

Then Russ spoke again. "Burl, it looks as if you're elected. You seem to

be the only one in the right place. There's a hatchway into the nose of

the ship from the outside. It's just below the central circle. Can you

see it? How close are you to it?"

Burl was almost at the surface now. The circular inset ring that marked

the hatchway entry port was a few feet from where his rope was hooked.

He described it to Russ.

"Can you reach it without losing your grip? If you can, do you think you

can open it?" came the radio voice quickly.

Burl reached the surface and grasped the hook. He studied the circular

panel carefully. "I can reach it all right. There's a holder hook

alongside it. But what will I do when I get there?"

"Open it," Russ ordered brusquely. "It unscrews from either side.

There's a short lock space between the outer shell and the inner

shielding of the generator chamber. Get inside and seal the door after

you. From there you can work your way into the emergency nose door to

the engines. Keep your suit on. While the generators are shielded,

there's no telling what Boulton may have done. The suit will give you

some protection.

"After you go through the door, it's up to you. Boulton will be there.

You'll have to stop him, somehow. Caton says if you can find the tool

kit you may be able to get a wrench to use as a weapon. If you can get

through without his seeing you and open the trap door to us, we'll do

the rest. But it depends on you."

Burl bit his lip. "Okay. Here I go." There was no question of argument.

Everyone's life was at stake, and he happened to be in the strategic

position.

He swung over to the panel, hooked his foot under the handgrip and

grasped the lever inset in the surface. He twisted it. After a brief

moment of resistance, the panel turned slowly. There was a sudden puff

as the air within escaped, and then the hatchway stood open. Burl

climbed inside.

He caught at the open plug, pulled it back and screwed it tightly from

the inside. Now he was in a dark, narrow space. He could feel the flow

of air automatically being pumped back in and heard the humming of the

generators through his suit.

Working his way along the inner wall in darkness, he finally felt the

edge of the metal door that opened into the Zeta-ring chamber itself. He

leaned against it, listening, but there was no sound. He turned the

handle and threw his shoulder against the door.

It gave, then swung open. He stepped cautiously into the engine room.

It was large and circular, fitting neatly within the nose of the ship.

The wide tubes of the A-G generator ring ran around the outside. The

reactors were heavy blocks of ceiling-high metal, shielded, and showing

only the dials that registered their output. Other machines--the rod

storage units and the condensers--were all carefully hidden behind clean

metal shielding.

The panel that controlled the engines was unattended in the center of

the room. Standing by one of the shielded reactors was Boulton, his back

to Burl. He was hammering at the reactor with a bar, evidently trying to

tear away the shielding to get at the guts.

Stealthily, the boy made his way to the locker where the tools were

kept. Just as he opened it, his hand slipped. The door of the locker

clanged against the wall. The burly Marine captain whirled, saw Burl,

and gave a yell of rage.

Burl grabbed a wrench and swung it threateningly. Boulton drew back. His

face was pale, with an odd expression on it, as if he did not recognize

Burl or understand what Burl said. Burl tried to reason with him, but

the glaring eyes were those of a total stranger, or, as it seemed then,

an alien beast.

Boulton cried in anger, dropped his bar, and charged Burl with his hands

outstretched.

Burl swung the wrench, but the strength of the older man tore it from

his grasp, hurling it away. The boy tried to dodge, and then the two

bodies collided.

The instant the two men touched there was a violent flash of light. Burl

felt a shock that left him stunned and reeling. Boulton collapsed in a

heap on the floor.

Burl steadied himself, keeping a wary eye on the captain. Boulton sat up

slowly, putting a hand to his head. "Boy, that was some kickback," he

muttered. He looked at Burl. "Give me a hand up. We've got to get back

to the jeep and scram out of here fast. The A-bomb's already set."

Burl was startled. He realized in a moment, though, that Boulton

recalled nothing of the past few days--his last memory seemed to be of

the blast in the Martian basement. But now, the captain was apparently

himself again.

Boulton got shakily to his feet. He seemed confused. "How'd I get here,

son?" he asked in surprise.

Burl gave a sigh of relief. "I guess you're all right now. But let's get

the trap door to the control room open. Clyde and Caton have got to get

the ship back on course. There'll be time to explain afterward."

Half an hour later, when Lockhart had recovered and resumed command, the

ship was restored to its proper course. Russ filled Boulton in on what

had happened and ventured a guess as to why.

"You must have been given some sort of charge by that globe in the Mars

Sun-tap station," Russ said. "It turned you into a sort of robot--a

human body running on a charge of alien energy that responded to the

commands of the Sun-tap outfit. Apparently, it took a long time before

the charge had complete control of your body. Obviously, it then could

act only in some general way--telling you to wreck the ship.

"Now, Burl, your body received a charge a long time ago. Whatever its

nature, it counteracted or shorted Boulton's when you came into

contact."

Both Boulton and Burl thought that made sense. "But," Burl conjectured,

"isn't it possible that the charge in my own body has also been

shorted?"

Russ shrugged. "Maybe. We'll find out at the next stop. And,

incidentally, that's not going to be on Jupiter itself, but on its moon

Callisto. We've traced the line of distortions."

"That's good news," said Burl. "I had the feeling you were worried about

Jupiter. The planet's so huge it would have meant real trouble trying to

land. The books say its atmosphere is thick, unbreathable, and moves in

gale velocity around it."

Russ nodded. "With Jupiter almost 89,000 miles in diameter, it would

have been a tough problem to maneuver outside this ship ... in fact,

impossible, not to mention the fact that the atmosphere, mostly ammonia

and other frigid gases, moves in several independent belts. However,

Callisto should be okay."

"That's something we know about our opponents, anyway," said Burl, "They

must have physical limitations enough like ours to rule out places where

we couldn't move, either."

Boulton showed no further effects from his experience. In time, the

_Magellan_ drew near Jupiter. Callisto, its fifth satellite outward,

moved about the mighty planet at a distance of 1,170,000 miles. It was a

large satellite as they go, 3,220 miles in diameter, larger, in fact,

than Mercury. But, as Russ explained, it was a queer place in its own

fashion.

For despite its size, Callisto was apparently not a solid body as we

think of it. Its density totaled only a little more than that of water,

its mass half that of the Earth's Moon--a notoriously porous body.

They bore down on Callisto, matching their speed to its, and swung close

to its surface. It had almost no atmosphere, just a thin layer of the

heavier gases. It was a belted world, without clearly defined continents

or surface markings. Its equatorial zone was one vast, featureless belt

of darkish-gray. Its temperate zones were white, with patches of yellow

here and there. But its poles were gray again.

"The satellite's like a huge ball of thin mud that's never hardened,"

said Burl as they studied the strange terrain.

"The equator's the softest--it seems to be a river of muddy water,

hundreds of miles wide--only it can't be water. Probably semisolidified

gases holding dust and grains of matter in suspension," said Russ. "The

temperate zones are the same stuff, only colder, and therefore more

stable. A thin crust of frozen gases over a planet-wide ocean of

semiliquid substance."

"The Sun-tap station's on the southern pole," said Burl. "That must be

solid."

It was. The poles of Callisto were actually two continent-sized islands

of shell. Dry, mudlike stuff, hard as rock, floating on the endless seas

of the semiliquid planet.

The station, a ringed setup quite like the one on Earth, stood in the

geographic center of the south pole. The _Magellan_ hovered over it

while a landing party went down in the four-man rocket plane.

Clyde, Haines and Burl were the landing party. This time, only Burl

entered the station after a hole had been blasted in the outer shell.

While the redheaded astronomer took samples and made observations,

Haines kept watch. Nobody knew what type of defense awaited them here.

Burl found the controls easily enough. He was afraid that he might have

lost his physical charge, but it was not so. The controls functioned,

the Sun-tap station died. The effect was not very noticeable, for

Callisto was already far from the Sun and the thin atmosphere could not

diminish the dark sky of outer space. What the great masts caught must

have been only the relay from other stations--or perhaps the invisible

rays of the distant Sun.

Burl saw no reason to linger, and the three of them gathered up their

equipment. As they started back toward the rocket plane, they heard an

ominous rumble in the ground.

A sudden spurt of blazing gas shot up from the center of the station.

"Duck!" yelled Haines, and they fell flat on the ground. Burl held his

hands protectively over his head, as an explosion shook the building.

There was no rain of rocks. Whatever the blast, Callisto's gravity was

too weak to attract the debris that flew high above the station.

"It was an atomic explosion!" Haines shouted into his helmet mike. "They

mined the station. Run for it!"

They raced for the rocket plane. As they ran, Burl felt the ground

quiver beneath him, and huge cracks began to spread, rippling through

the hard ground.

They reached the plane and piled in. Russ took off just as the surface

cracked open in a thousand places like an ice sheet breaking in an

Arctic thaw.

As they rocketed back to the _Magellan_, the whole polar cap, an area

hundreds of miles around the Sun-tap station, split apart. Great spurts

of liquid magma, the liquid gas-dust from the heart of the planet, shot

up like fountains. Parts of the shell-like polar continent were

disappearing beneath this new ocean.

"Their little atomic bomb shattered the thin crust. The whole polar

island will probably sink," said Russ. "It was a clever trap. They knew

what would happen."

"Saturn next," said Burl. "What'll they have set up there?"

They reached the _Magellan_, loaded the rocket plane aboard, and pulled

out, setting their course for the ringed planet. But even as they did

so, something was coming from Saturn to meet them.