"I'll make him hard to catch," he answered, pulling his stumpy blaster from the holster at his back, and testing the spring to see if it was wound up to maximum capacity. The blaster was spring actuated, and hurled an explosive pellet about the size of a buckshot, which was really a tiny atomic bomb. Where that pellet hit, there was big trouble immediately, but the pellets in rare instances had been known to explode in the gun, in which case the person who had hold of the gun was never heard of again, so that blasters were not a favored weapon. Andy had picked this one up at a bargain from a technician whose nerves had gone bad from space strain and who no longer had enough guts to shoot it. Blasters were not used on Jupiter or Saturn. Too much atmosphere and gravity for even the most powerful spring to hurl the pellet far enough for the shooter to be safe.
Andy poked one eye around the top of the boulder and squinted for a target. He was in the edge of the glow zone. Off yonder, 216,000 miles away, the mighty rim of Jupiter was visible. The sun was on the other side of Io, but reflected light from the planet supplied illumination much better than the best terrestrial moonlight.
Twisted, tumbled, torn and shattered rocks met his eye. Mosses, lichens, a few tough, low-growing plants. It looked like a picture of hell, but it was a prospector's paradise, for the rocks of Io were shot through with veins of gold, silver, platinum, iridium, not to mention the more common iron and copper, which were not sought for because transportation back to earth was too expensive to pay profits.
"Off to the right," Oscar whispered.
The glint of Jove-glow on a polished sight up the ravine gave Andy an aiming point and he snapped the blaster in that direction. He over-estimated the weak gravity of Io and the pellet hit on top of a high ridge beyond. A most satisfactory explosion took place there. Rocks split and tumbled in every direction. Andy lowered his sights and blasted again. Another brilliant explosion illuminated the landscape, far to the left this time.
"You shoot like a rocket-man," Oscar commented.
"Shut up," Andy growled. The men who tended the rockets lived in atmosphere of constant hammering from the explosion of the driving charges. A few years handling rockets and a man was unable to hold his hands still, so that old rocket-men always looked like they had well-developed cases of paralysis agitans. To tell a navigator, who had to have sure nerves and steady hands, that he resembled a rocket-man was a supreme insult.
"Duck, Boss, he's drawing a bead on you," came Oscar's hurried whisper, and Andy jerked his head down behind the boulder just in time to avoid a ray that frothed across the top of the stone. No warning shot, that one. The unknown marksman had fired that shot with honest intentions of doing damage.
The ray skipped back and forth across the boulder, went over the top and burned into the bluff beyond. Andy watched it, and wondered what in hell all the shooting was about. Io, by order of the Interplanetary Council, was free territory, with the exception of commercial developments, but any straggler was always welcome there, for the sake of his companionship. Andy did not know whether he had stumbled into a space-pirate's lair, or whether some cracked prospector was using him for a target.