Free Marooned! by Brad Strickland, THOMAS E. FULLER

around Jupiter, then spiral inward toward the sun and toward Mars. After a long time, they crash near the Martian south pole. But what happens if the gun isn’t aimed right?”
    “Then the meteors miss Mars, I guess,” Sean said.
    “Yeah, or they come smashing right into the middle of Marsport. So twice a year we do a Bradbury run to the South Pole. We take readings on the trajectories of incoming meteorites. If we have toadjust the mass driver, the signal has to be sent right now—it takes years for those meteorites to get to us, and if they start to creep north of where they’re supposed to land, we have to correct that right away. Otherwise, the meteorites miss us altogether, which is bad, or they hit us, which could be a little bit worse.”
    “It’s a lot of fun, flying to the pole. So what do you say, Sean? You coming with us?” Alex asked.
    “What do I have to do?”
    Mickey gave a triumphant squawk of laughter, leaned back in his chair, and clapped his hands. “Not much, Doe. Just pull out a 3.75 or better!”
    Sean groaned. That was an A average on schoolwork. Exams were coming up. At the moment, Sean had a 3.9 in English and history, but only a 3.5 in life sciences. Even worse, Mickey was right about Sean’s two borderline subjects. His math grade was only a 2.4 and his physical science score a barely passing 2.0. “I’ll never make it!”
    “You don’t have to have an
overall
average of3.75,” Alex said, shooting a look at Mickey. “You just have to average that high on the exams. With a little intensive cramming, you can do it. Look, Sean, you probably have like a 3.2 right now. You’ll just have to study extra hard for the math and the science, and you’ve got it.”
    “Give it up, Benford,” Mickey said. “A slow-brain like Doe? He’ll never do it.”
    And right then and there, Sean determined that he
would
do it, if only to prove Mickey wrong.
    That started several days of exhaustive studying, drilling, and memorization. Jenny helped a lot, going over and over his life sciences assignments with him until he had the basics down cold. And Nickie, who was very good in math, was glad to step up her tutoring. Sean began to feel as if he was just a learning machine, packing facts, equations, theories, definitions, and more into his brain. But it wasn’t easy, not at all, and Sean never felt truly confident. Despite the extra work he put in, he still struggled with math, and he doubted that he’d everreally understand chemistry and physics. But now and then a little light glimmered.
6.2
    Exam week arrived. A tired but triumphant Sean breezed through English with a perfect 4.0, and came close in history, missing only one item on a long and exhausting test for a 3.99. Jenny had drummed more biology into his head than he thought it could hold, and he didn’t do badly on his life sciences exam, winding up with a respectable 3.74. Through the three-hour math test, Sean sweated almost as much as he had climbing the windmill towers, and learned at last that Nickie’s tutoring had paid off: He scored a 3.66. That left only natural sciences, Ellman’s exam.
    Jenny whispered, “You’ve just got to get a 3.36. You can doit!”
    Dr. Ellman had made out twenty different exams,one for each of his students. He sat at the central desk and gave them all the signal to begin.
    Sean turned on his computer and felt his heart sink. The exam was heavily weighted toward chemistry—his worst subject. But he waded in, trying desperately to remember the chart of the elements, ionic potentials, and what a mole was. Some of it came floating back to his consciousness as he worked through the test. He had to skip some of the more difficult problems, rushing ahead to answer the easier questions, then going back to concentrate on the puzzlers.
    An hour left. Then thirty minutes. Sean feverishly worked to solve chemical equations, tried to come up with definitions for terms that he was shaky on, took a few guesses when