Launch Pad Read Online Free PDF

hope that anything would come out, but the search gave him one hit.
    Astonishingly, the hit was in literature, not physics. The link was to the twentieth century, an ancient science-fiction story that had two men sliding on the surface of a frictionless mirror. He’d always hated classic science fiction. He’d read enough of it in school, before he’d dropped out. The teachers all seemed to love it. But the old authors had always gotten everything so wrong. The characters did amazingly dangerous things, with no safety backups; they were uniformly too stupid to live.
    Things like stealing a snowcat to drive across an alien planet, without telling anybody where they were going? Well, it has seemed like a good idea at the time.
    The databot didn’t have the text of the story, only a brief summary in a survey on 20th century literature. He scanned through it. It wasn’t quite his situation, he realized with mounting disappointment: the characters in the story had far more resources at their disposal. In the story, the two characters were roped together, and they used that fact to pump up rotational speed to allow them to fly apart. The discussion went on to say how the solution in the story wouldn’t work; the author had ignored conservation of angular momentum. No help! Lee would have thrown the book away in disgust, if it had been a physical book, and not just a glow in his heads-up display.
    If only he had a book to throw away! Or anything at all. He could have used the momentum. It was exactly like being adrift in space without a pack. He had no control over his motion.
    See related terms, the summary said. Simple harmonic oscillator, Frictionless motion.
    He queried simple harmonic oscillator, saw that it seemed to be a tutorial about sines and cosines with no obvious application to him, and then flicked over to frictionless motion and scanned the tutorial. Superfluid helium, it said, was the only substance known to support frictionless motion. Well, that was interesting. Could the aliens have found some way to solidify superfluid helium? No, that was ridiculous. But, still, the surface of the mirror was desperately cold, cold enough to make even God shiver. Maybe the mirror was made of some substance that had a thin film of superfluid helium on the surface? Could he possibly heat the mirror, and destroy the effect?
    But no, that was a dead end. Even if it weren’t frictionless, the surface would still be far too smooth for him to be able to climb the slope to the rim. He’d have to carve steps into the slope, and he had no tools to do that. Did the material have any give at all? He kicked at it as hard as he could, but it was like kicking solid granite. His toe hurt, even through the boot, but there had been not the slightest give to the surface. Whatever material it was made of, it was hard.
    A frictionless surface probably had commercial value, even if it only worked when it was cooled nearly to absolute zero. If that bastard Kellerman just knew that one of his workers was slipping along the surface of a material more valuable than any ammonia on the planetoid, rescue would be here soon enough.
    That line of thought didn’t bring him any closer to rescue.
    The rim approached, or rather, he approached the rim. He slid toward it, slowed, hovered frustratingly short of the edge, and then dropped away. Lee checked that his radio was still broadcasting the useless call for help; verified that the toolpack was still out of reach, checked his battery status. No help, no help, no help.
    He was sliding down the slope on his stomach, like riding a sled. He twisted around and then carefully pushed himself up onto his hands and knees. He pushed upright, balancing on his knees, with one hand on the slippery mirror for balance. Wobbly, but after a while he could keep his balance. That wasn’t too hard. He tried getting up onto to his feet, and made it for a moment, his arms windmilling desperately to keep his balance before