Free The Sunborn by Gregory Benford

testosterone seemed to drive guys onward.
    They got it rigged surprisingly quickly. Viktor was never happier than when he was tinkering, trying something new. Come to think of it, so was she. They attached long black shielded leads to two nearby strata, only a few meters away. Viktor drilled short holes into the stone and sank stub contacts into them. She suspected he had thought of this experiment before, else why bring just the right gear? But let it go. The red bands were of some basaltic iron-oxide-rich layers, probably over 3 billion years old—or so said one of the team, the geo guy.
    Following protocol, Julia alerted Gusev about what they were trying. Gusev objected right away and pointed out that none of this had even been discussed in preplanning meetings. She told them they were going to do it, anyway. The Gusev operations officer—the OO , whose always-seeing-trouble motto was “oh-oh”—started sputtering.
    Viktor called out on their comm line that ran up the monofilament to the winch. Reception was good, another vast improvement over the relay system in the first expedition. He went through Expedition Control and alerted the satellite superintendent to focus their orbiting arrays on the vent area. Those had originally picked up the odd low-frequency emissions during a routine orbital scan of the whole planet. Again objections. “Now Gusev acts like Earthside,” Viktor said, grimacing.
    Julia nodded, having fun. “Everything in triplicate.” More like playing hooky from school than research, yes.
    Viktor told them to just do it. Then he turned the capacitor system voltage to the max. Daphne asked why. “Big losses in strata, resistive load, have to overcome. Prob’ly won’t work. Get nothing. Still—” and he closed the switch.
    No drama. Some sparking for a second at the lower connection, then nothing but the hum of the electromotor discharge. Viktor kept it on for ten seconds, off for five, on for ten, then started a more complex pattern.
    “What’s the point of this pulse pattern?” Julia asked.
    “Just trying things.”
    “You really hadn’t thought of this before, had you?”
    He grinned, lines crinkling deeply around his eyes. “You always say I’m tinkerer. So I do.”
    He kept this up for minutes, watching the pulser readouts intently, and they got a heads-up call from the OO . Julia was off checking on the team, and when she came back over to his “experiment,” Viktor said, “Orbital low-frequency antenna is picking up emission. From here.”
    Julia felt a thrill, plus confusion. “Why? What’s going on?”
    “Stimulate a system maybe.”
    Julia frowned. “Some sort of—what?”
    A team member said over comm, “How about some kind of induced resonance?”
    Julia had no idea what that meant. Viktor said carefully, “More likely, somebody answering.”
    It took a moment for her to get her head around the idea. Viktor started switching the settings on the pulser. “I’ll run a sequence, move around the parameter space,” he muttered to her. She could not keep up with his moving hands, the readings for volts and amps. “System has high inductance.”
    “Which means?”
    “Responds slowly. So I go to longer pulses, see what high voltage gets us.”
    He held the pulser to thirty-second sine waves. Minutes passed. The OO called through: higher emissions from the satellite antenna, also now in thirty-second waves. “Is echoing,” Viktor said triumphantly.
    “What’s echoing?” Julia asked. “Do you think the mat has some capacity to—”
    Crackling came from the stub contacts. Julia looked toward them and saw some vapor steaming out from the rock. “What?”
    Viktor quickly turned down both volts and amps. “Funny. We are not putting much power through—”
    The crackling got louder. Sparks at the contacts.
    “Breakdown voltage?” Viktor asked, staring at the vapor now boiling from the contacts. “Our pulser, we’re not near that level. Must be coming in.