Free Space by Stephen Baxter Page A

processes like magma electrolysis or pyrolysis. The same processes could be used for oxygen production. In the case of magma electrolysis the main slag component would be ferrosilicon. From a pyrolysis process we would expect to find traces of elemental iron and silicon, or perhaps slightly oxidized forms..."
    We are crawling across a slag heap, Maura thought, trying to figure out what was made here. But are we being too anthropomorphic? Would a Neandertal conclude that we must be unintelligent because, searching our nuclear reactors, she could find no chippings from flint cores?
    But what else can we do? How can we test for the unknowable?
    The asteroid's second lobe had all but "risen" above the horizon now. It was a ball of rock, black and battered, that hung suspended over the land, as if in some Magritte painting. She could even see a broad band of crushed, flattened rock ahead, where one flying mountain rested against the other.
    The second lobe was so close it seemed Maura could see every fold in its surface, every crater, even the grains of dust there. How remarkable, she thought.
    The probe's mode of travel had changed now, she noticed; the pitons were applying small sideways or braking tweaks to an accelerating motion toward the system's center of gravity, that contact zone. The gravitational tug of the rock below must be decreasing, balanced by the equal mass of rock above, so that the net force was becoming more and more horizontal, and the probe was simply pulled across the surface.
    Now the second lobe was so close, in this virtual diorama, it was over her head. Its crumpled inverted landscape formed a rocky roof. It was dark here, with the Sun occluded, and the slices of starlight in the gap between the worlds were growing narrower.
    Lamps lit up on the probe, and they played on the land beneath, the folded roof above. She longed to reach up and touch those inverted craters, as if a toy Moon had been hung over her head, a souvenir from some Aristotelian pocket universe.
    "I think we have something," Xenia said quietly.
    Maura looked down. Her field of view blurred as the interpolation routines struggled to keep up.
    There was something on the ground before her. It looked like a blanket of foil, aluminum or silver, ragged-edged, laid over the dark regolith. Aside from a fringe a meter or two wide, it appeared to be buried in the loose dirt. Its crumpled edges glinted in the low sunlight.
    It was obviously artificial.
     
    Brind had next met Malenfant a few months later, at Kennedy Space Center.
    Malenfant found KSC depressing; most of the launch gantries had been demolished or turned into rusting museum pieces. But the visitors' center was still open. The shuttle exhibit -- artifacts, photographs, and virtuals -- was contained within a small geodesic dome, yellowing with age.
    And there, next to the dome, was Columbia, a genuine orbiter, the first to be flown in space. A handful of people were sheltering from the Florida Sun in the shade of her wing; others were desultorily queuing on a ramp to get on board. Columbia 's main engines had been replaced by plastic mock-ups, and her landing gear was fixed in concrete. Columbia was forever trapped on Earth, he thought.
    He found Brind standing before the astronaut memorial. This was a big slab of polished granite, with names of dead astronauts etched into it. It rotated to follow the Sun, so that the names glowed bright against a backdrop of sky.
    "At least it's sunny," he said. "Damn thing doesn't work when it's cloudy."
    "No." The granite surface, towering over them, was mostly empty. The space program had shut down, leaving plenty of room for more names.
    Sally Brind was short, thin, intense, with spiky, prematurely gray hair; she was no older than forty. She affected small round black glasses that looked like turn-of-the-century antiques. She seemed bright, alert, engaged. Interested, he thought, encouraged.
    He smiled at her. "You got any answers for me?"
    She