Free The Secret of Saturn’s Rings by Donald A. Wollheim

motion at differing speeds. Some between Hidalgo and the sun looked like moons of various phases. Others close by loomed large enough to show surface markings. Juno passed fairly closely; this was a big body whose surface was striped almost like one of the big outer planets. Not infrequently a puff of dust on the still surface would indicate the falling of a meteor.
    As the days passed they came clear to the orbit of Jupiter and the bulk of the asteroidal disks disappeared from the sky. Then a new group came into view.
    Garcia, who had gone out with the two spacehands, pointed to a cluster of disks nearly overhead. “See those? They are something really special. They’re what we call the Trojan Asteroids, the Fore-Trojans to be specific, since there is another set of them. They fly around the sun exactly in Jupiter's orbit, at the same speed as Jupiter, but always the same distance ahead of Jupiter. They remain in a cluster fixed forever by the laws of gravity and mathematics.” “Why are they called Trojans?” asked Arpad. “When they were first discovered, astronomers decided to call them all after the heroes of the war between Troy and Athens in very ancient times. So their names are Achilles, Ajax, Agamemnon, Hector, Nestor, and Odysseus. The Aft-Trojans are also named after these ancient heroes.”
    “Any good?” said Arpad, being practical. “I should think maybe they’d make good space stations if we ever develop travel to Saturn as a regular thing.” Garcia chuckled into his space phones. “I imagine you're right. They’ll probably do that in the next hundred years after our trip is a success.” He paused and added:
    “As a matter of fact, I believe there is an astronomical station there now, on Achilles. That would be the biggest one near us. It’ll be passing us by a few hundred miles any minute now. See, you can see the lights and shades of its surface now.”
    They gazed up. It was quite a sight, looming larger for a short time than the moon did in Earth’s sky. They saw patches of brightness and dark spaces. The thought struck Bruce that if indeed there was still an astronomical station up there then it was the nearest they would be getting to other human beings for a long, long time. This lonely Fore-Trojan group would be their farewell point to other human beings. And another memory struck him suddenly.
    “Say,” he murmured, “I seem to remember reading about an asteroid mining base being set up on one of those planets, near the observatory . . . and if I remember right, it was a Terraluna expedition!”
    “Awk!” exclaimed Arpad, while Garcia sucked in his breath. Then the navigator let out a sigh and said, “Perhaps, but I can’t see that that need bother us any. Probably they know nothing about us. Still, I better tell Dr. Rhodes, anyway.”
    He swung off and glided back to the space ship. Bruce and Arpad stood watching the six bodies in the sky above them.
    Arpad nudged Bruce. “A meteor,” he remarked and pointed. A few hundred feet from the space ship there was a small cloud of dust falling back to the surface. Bruce looked. Even as he watched, another such spurt of dust went up in the air about the same distance on the other side of the space ship.
    “That’s strange,” he remarked to Arpad. “Two in succession.”
    “Three,” said Arpad, pointing to a third spurt rising near where the first one had struck.
    Suddenly a cold chill ran through Bruce as it struck him what they were watching. “Those aren’t meteors!” he shouted. “They’re explosions! They’re shells from a cannon! We’re being shot at from Achilles! From the Terraluna base there!”
    They started running wildly back to the ship, calling Dr. Rhodes on their helmet phone. Even as they ran, another shell struck, this time near where they had been standing.
    Bruce shouted the alarm as they neared the ship. Dr. Rhodes called to them to hurry. They