"So what?"
"So the satellite Mimas, the one we're heading for, travels around Saturn in twenty-four hours."
"Again, so what?"
"All the particles in the ring are pulled this way and that by the satellites as they and the satellites move about Saturn. Mimas does most of the pulling because it is the closest. Mostly the pulls are in one direction now and in another direction an hour from now, so that they cancel out. If there were gravel in Cassini's division, however, every second time it completed its rotation it would find Mimas in the same spot in the sky, pulling in the same old direction. Some of the gravel is constantly pulled ahead, so that it spirals outward into the outer ring; and some of it is pulled back, so that it spirals inward into the inner ring. They don't stay where they are; a section of the ring empties of particles and bingo-you have Cassini's division and two rings."
"Is that so?" said Bigman weakly (he felt reasonably certain Wess was giving him the correct story). "Then how come there is some gravel in the division? Why isn't it all moved out by now?"
"Because," said Wess with a lofty air of superiority, "some is always being pushed in or pulled in by random gravitational effects of the satellites, but none of it ever stays long… And I hope you're taking notes on all this, Bigman, because I may ask questions on this later."
"Go fry your skull in a mesonic blast," muttered Bigman.
Wess returned to his mass detectors again, smiling. He fiddled with them a moment, then with no trace of the preceding banter left on his leathery face, he bent down closely.
"Lucky!"
"Yes, Wess?"
"The rings aren't masking us."
"What?"
"Well, look for yourself. The Sirians are getting closer. The rings aren't bothering them at all."
Lucky said thoughtfully, "Why, how can that be?"
"It can't be blind luck that's converging eight ships on our orbit. We've made a right-angle bend and they've adjusted their orbits to suit. They must be detecting us."
Lucky stroked his chin with his knuckles. "If they're doing it, then, Great Galaxy, they're doing it. There's no use in reasoning out the fact that they can't do it. It might mean that they have something we don't have."
"No one ever said the Sirians were dummies," said Wess.
"No, but sometimes there's a tendency among us to act as though they were; as though all scientific advance comes out of the minds of the Council of Science and that unless the Sirians steal our secrets they have nothing. And sometimes I fall into that particular trap too… Well, here we go."
"Where do we go?" demanded Bigman sharply.
"I told you already, Bigman," said Lucky. "Mimas."
"But they're after us."
"I know. Which just means we've got to get there faster than ever… Wess, can they cut us off before we get to Mimas?"
Wess worked quickly. "Not unless they can accelerate at least three times faster than we can, Lucky."
"All right. Giving the Sirians all the credit in the world, I can't believe they can have that much more power than the Shooter. So we'll make it."
Bigman said, "But, Lucky, you're crazy. Let's fight or get out of the Saturnian system altogether. We can't land on Mimas."
Lucky said, "Sorry, Bigman, we have no choice. We've got to land on Mimas."
"But they've got us spotted. They'll just follow us down to Mimas and we'll have to fight then, so why not fight now while we can maneuver with our Agrav and they can't?"
"They might not bother to follow us down to Mimas."
"Why shouldn't they?"
"Well, Bigman, did we bother to go into the rings and pull out what was left of The Net of Space?"
"But that ship blew up."
"Exactly."
There was silence in the control room. The Shooting Starr streaked through space, curving slowly away from Saturn, then more quickly, slipping out from under the outermost ring and into open space. Ahead of it now lay Mimas, a glittering world seen in tiny crescent. It was only 320 miles in diameter.
Still far away were the converging ships of the Sirian fleet.
Mimas grew in size, and finally The Shooting Starr's forward thrust burst into action and the ship began a deceleration.
But to Bigman it seemed incredible that the space-wise Lucky could have so miscalculated. He said tightly, "Too late, Lucky. We'll never slow up enough for a landing. We'll have to go into a spiral orbit until we lose enough velocity."
"No time for spiraling Mimas, Bigman. We're heading straight in."
"Sands of Mars, we can't! Not at this speed!"
"That's what I hope the Sirians will decide."
"But, Lucky, they'd be right."
Wess put in slowly, "Hate to say it, Lucky, but I agree with Bigman."
"No time to argue or explain," said Lucky. He bent over the controls.
Mimas expanded crazily in the visiplate. Bigman licked his lips. "Lucky, if you think it's better going out this way than letting the Sirians get us, okay. I can go along. But, Lucky, if we're going to go, can't we go out fighting? Can't we maybe get one of the cobbers first?"
Lucky shook his head and said nothing. His arms were moving quickly now, so that Bigman could not make out exactly what he was doing. Deceleration was still proceeding too slowly.
For a moment Wess extended his hands as though to remove Lucky forcibly from the controls, but Bigman placed his hand quickly on the other's wrist. Bigman might be convinced they were going to their death, but his stubborn faith in Lucky somehow remained.
They were slowing, slowing, slowing, in what would have been body-crushing deceleration in any ship other than The Shooting Starr, but with Mimas filling the visiplate now and hurtling at them, the slowing was not enough.
Flashing down at deadly speed, The Shooting Starr struck the surface of Mimas.
7. On Mimas
And yet didn't.
Instead, there was a keening hiss that was familiar to Bigman. It was that of a ship striking atmosphere.
Atmosphere?
But that was impossible. No world the size of Mimas could possibly have an atmosphere. He looked at Wess, who was suddenly sitting back on the blanket, looking worn and pale but somehow satisfied.
Bigman strode up to Lucky, "Lucky… "
"Not now, Bigman."
And suddenly Bigman recognized what it was that Lucky was doing at the controls. He was manipulating the fusion beam. Bigman ran back to the visiplate and focused it dead ahead.
There was no doubt of it, now that he finally grasped the idea. The fusion beam was the most magnificent "heat ray" ever invented. It was designed mainly as a weapon at close range, but surely no one had ever used one as Lucky was using it now.
The jet of deuterium, snaking out forward of the ship, was pinched in by a powerful magnetic field and, at a point miles ahead, was heated to nuclear ignition by a surge of power from the micro-piles. Maintained for any length of time, the power surge necessary would have bankrupted the ship; but a fraction of a millionth of a second sufficed. After that the deuterium fusion reaction was self-sustaining and the incredible fusion flame that resulted burned in a heat of three hundred million degrees.
That spot of heat ignited before the surface of Mimas was touched and bored into the body of the satellite as though it were not there, puncturing a tunnel into its vitals. Into that tunnel whizzed The Shooting Starr. The vaporized substance of Mimas was the, atmosphere that surrounded them, helping to decelerate them, but bringing the temperature of the ship's outer skin to dangerous redness.
Lucky watched the skin-temperature dial and said, "Wess, put more punch in the vaporization coils."