Free Marsquake! by Brad Strickland, THOMAS E. FULLER Page A

case someone called them. Sean shuffled over to see what she meant.
    She had found a small branch tunnel opening. It didn’t look like a lava tube though. More like a cave cut by running water. The opening was only about three meters tall, and it had a different shape from the oval lava tubes. This tunnel’s cross-section had the shape of a spade in a deck of cards: sharp top, almost a crevice, but a fairly broad body.
    Jenny squeezed through the opening, and Sean followed. “Don’t go far,” he warned her. “Ellman will notice if we’re away for a long time.”
    “I’m just taking some pictures.” Her camera snapped four or five times. The passage opened up slightly as they explored it, though Sean thought that Mickey would have collapsed from claustrophobia astep or two into this confining space. He felt the surface underfoot shifting. “Back on sand again,” he said.
    “All the minerals drained down into the main passage, I guess,” Jenny said. “Some of these crystals are really pretty.” Her camera flashed again.
    Sean squinted at a dark streak on the wall. “This doesn’t look like a mineral,” he said, sweeping his glove across it. “It’s more like—ouch!”
    “What happened?”
    “Stuck my finger. Went right through my glove,” Sean said, pointing to a sharp little crystal spike, dull gray and not more than a couple of centimeters long.
    “You need medical aid?” Jenny sounded panicky.
    “Just a pinprick. I’ll check the glove before we head back up, though, to make sure I don’t have a leak. This is small enough that it should seal itself without—hey, look at this.”
    He held up his fingers, rubbing the tips of them together. Jenny shone her light on the glove. “What is that?”
    “Feels like … but it can’t be.” On the fingers ofSean’s glove was a dark orange-brown substance, a blobby smear that spread as he rubbed his fingers. It was almost like … “Mud?” he asked.
    Sean turned his light onto the rock wall again. The dark streak led from the crack overhead down to the sandy floor. He prodded at the sand with the toe of his right boot, and it behaved strangely, clumping together like snow. “Jenny, look at this stuff. This is wet!” he said.
    He heard Jenny gulp. “The air pressure is high enough. Liquid water! That hasn’t existed naturally on Mars for—Sean, do you realize how big this might be? Come on, we’ve got to tell them!”
    If Miles’s discovery hadn’t caused an uproar, Sean’s more than made up for it. Everyone had to come and see, and even Rormer got involved, taking samples of the sand, scrapings from the trickle, storing everything in biotight containers. It didn’t amount to much, more dampness than wetness. Rormer couldn’t even get a single drop of clear water from the orange-brown slime, though he tried hard enough. Miles himself supervised, excitedly speculating that perhaps, a little farther underground, just perhaps, there might beenough liquid water for some lingering Martian bacteria to have survived—
    But Ellman cut through his excitement with a flat statement: “That will have to wait for a later expedition. Our orders are to finish up and start our return trip today. We’re going to do so. Hurry up with your samples, tell our photographers what they should record, and make sure everything is secured. We’ve got two hours, and then we’re starting back.”
    Rormer, kneeling, said suddenly, “Look at this!” He had dug down into the wet sand and had uncovered a scattering of tiny little blue crystals. He scooped some up on a sampling trowel and held them under his helmet light. Sean, remembering his job, snapped a picture.
    What Rormer held looked like BB pellets packed into the sand, though if anything, they were even smaller than that—tiny round spheres, their surfaces glowing a brilliant sapphire blue in the helmet light.
    “Blueberries!” Miles said exultantly. “That’s what those are. They’ve only been found in