21: POLE.

The Discovery plowed its way through a half-meter thickness of carbon dioxide snow. The fragile dry-ice stuff sublimated before the rovers heat, so they drove into a blinding mist, and even beyond the mist it was a murky dark. Nobody said anything, the poker players continuing their endless tournaments. Bisesa just had to put up with the unnerving drive alone.

Then, through the gloom, she saw bright green lights, brilliant sparks. The rover slowed to a halt. The rest of the crew hurried forward.

A vehicle of some kind sat on the ice, with big balloon wheels and straddled by two spacesuited occupants. Their helmets were illuminated, but Bisesa couldnt make out their faces. When they caught the rovers lights they waved.

Thats a tricycle, Myra said, wondering. Actually, Paula said mildly, they call it a General Utility Vehicle. For operations close to the pole station I want one.

Alexei tapped a softscreen. Yuri. Is that you?

Hi, Alexei. We cleared a path for you with the sublimation blade. The snows heavier than usual this season.

Appreciated.

Discovery, just follow us and youll be fine. Eleven, twelve hours or so and well be home with no trouble. See you at Wells. The vehicle turned and drove ahead. Mist burst around it in a spray, brightly illuminated by the floods.

With Discovery following easily, the little convoys speed soon passed forty kilometers an hour.

As they roared on into the dark, the hard ground under the snow began to change. It was layered, alternating light and dark in strata as thick as Bisesas arm, like a vast sedimentary bed. And it looked polished, with a fine patina that glistened in the trucks lights.

After a couple of hours of this they crunched up onto a firmer, paler surface, a grimy white tinged with Mars red.

Water ice, Paula announced. Mostly, anyhow. This is the permanent ice cap, the residue thats left after the carbon dioxide snow sublimes away every spring. Here at the edge were about five hundred klicks from Wells Station, which is near the geographic pole. The drive will be smoother now. The rovers wheels are reconfigurable for different surface types.

Bisesa said, Im surprised Discovery isnt lowering a set of skis. Alexei looked at her, a bit pained. Bisesa, this is Mars. The temperature out there is the freezing point of dry iceat this pressure, thats about a hundred fifty K. She worked that out. A hundred and twenty degrees below freezing. Right, Paula said. At these temperatures water ice is so hard it would be like skiing on basalt. Bisesa was chagrined. Youve given this little lecture a dozen times, havent you? You didnt have time for the usual orientation. Dont worry about it.

Now that they were on the ice Bisesa expected a smooth, straight ride on to the pole. But the lead truck soon turned aside from its dead-straight northern track, and embarked on a grand, sweeping detour, turning clockwise. Peering out of the left-hand window, Bisesa glimpsed a canyon.

She swallowed her pride and asked Paula about it.

Paula said it was a spiral canyon, one of many gouged into the ice cap. She pulled up an image of the whole cap, taken from space in the summer, when the dry ice snow wasnt there to obscure it. The ice cap looked like a twisting storm system, with those spiral canyons twisting in from the edge and reaching almost to the pole. It was astounding, like nothing Bisesa knew of on Earth. But after her jaunt across the solar system there wasnt much wonder left in her soul.

As they drove on the snow grew deeper, until they were driving along a path between two walls of snow heaped up maybe two meters deep. The snow looked compact, harder than snow on Earth, denser maybe.

She was relieved when she saw a cluster of lights ahead, and the rounded shoulders of living modules.

A row of green lights stretched off into the distance, as if they were driving down a runway. As the rover rolled closer Bisesa saw that the lights were on poles maybe four meters high, perhaps to keep above the snow. Glancing back, she saw that looking the other way the lights were bright whiteso, in the murk of a Martian blizzard, you could always tell if you were heading toward or away from the base.

The structures that loomed out of the dark, lifted up off the ground on stilts, were not domes but flattened pie-shapes, round above and below. They were colored bright green, and huddled close together, interlinked by short tunnels. Bisesa saw that these big hab modules were in fact mounted on wheels, and had been tied down to the ice by cables fixed to pitons. They were like monstrous caravans, she thought.

As the rover neared the station, the walls of dry ice snow thinned away, until the rover was driving over an ice surface almost clear of snow but covered with an open black mesh. Heating elements, perhaps, designed to keep off the dry ice. The rover nuzzled up to a low dome at the foot of one of the stilts. Two station vehicles were already parked here, heavy-looking, smaller than the rover from Lowell.

Paula led them through the hatch, and Bisesa found herself facing a staircase, roofed over with blue-green plastic, that evidently led up to the nearest of the stilted habs. Alexeis suitcase couldnt climb the stairs and had to be hauled up on a plastic rope.

At the top of the stairs, the station crew were waiting for the newcomers. There were four of them, two women, two men, Mars-spindly in the limbs though a little heavy in the belly. All were pretty young, Bisesa guessed, none older than forty. Their coveralls were clean but well-patched, and they all smelled faintly greasy. None of them had cheek ident tattoos.

They stared at Bisesa, and stood a little too close together.

One burly twenty-five-year-old came forward and shook Bisesas hand. Youll have to forgive us. We dont get too many visitors up here. He had a big, blotchy drinkers nose, grimy black hair pulled back into a ponytail, and a mass of curly beard. His accent was indistinct, like American but laced with longer European vowels.

Youre Yuri, right? You were on the ice bike.

Yes. We exchanged a wave. Yuri ORourke. Resident glaciologist, climatologist, what have you. Briskly he introduced the rest of the base crew: Ellie von Devender, a physicist, Grendel Speth, a doctor-biologist, and Hanse Critchfield, an engineer responsible for power, transport, and essential systems, but also a specialist in the drilling rig, the bases main scientific function. Although we all multitask, Yuri said. Were all trained paramedics, for instance...

Ellie von Devender approached Bisesa. The physicist was maybe thirty, stocky in her jumpsuit, with her hair tightly pulled back. She wore thick-rimmed spectacles, an affectation that hid her eyes and made her look hostile.

Bisesa said curiously, I guess I would have expected a glaciologist, a biologist. But a physicist?

Ellie said, The glaciology is the reason the base is here, along with Grendel and her wet lab. I am the reason youre here, Ms. Dutt.

Yuri clapped Bisesa on the shoulder. Come see the place. He led them briskly through the hab. This is what we call Can Six, he said. The EVA port...

Can Six was a bubble of fabric, the walls colored a bright sea-green with an eye-deceiving wave pattern. It had a honeycomb floor that straddled its interior at the widest point, and looking down Bisesa could see stores stacked up in the underfloor space. There were no spacesuits in evidence, but there were odd hatches in the walls that might have led to externally-mounted suits, like the rovers. Equipment was stacked up here, what looked like spare parts and other gear for the rovers, and also a small science lab, and a medical area, a single bed surrounded by equipment, sealed off from the rest by a zippered plastic curtain. It was dark, and felt cold and dusty, as if not much used.

Yuri hurried them through a small airlock to another module: Can Five, science, he said. Here there was another, more comprehensive lab suite, and a larger hospital area, and what looked like a small gym. It was brighter, with glowing panels plastered to walls that seemed to be decorated with scenes of mountains and rivers.

Bisesa murmured to Myra, Why two lab suites, two medical bays?

Myra shrugged. To avoid contamination maybe. You come in from EVA, and can process your samples and treat injuries without breaking the seals to the rest of the base.

Contamination of the crew by Martians?

Or of Martians by the crew.

In Can Five, Grendel Speth, small, neat, slim, her black hair speckled with gray, briskly took blood, urine, and cheek-swab samples from each of the visitors. Just so the station can keep you healthy, she said. Testing for allergies, nutritional genomics, that sort of thing. Our food comes from freeze-dried stores from Lowell, and homegrown vegetables from our garden. Well add supplements to make sure your specific nutritional needs are met. You wont even know they are there...

Now Yuri hurried them through a third moduleCan Three, evidently a sleeping area, divided up into pie-slice bedrooms, dark, evidently not used. They came to another module, Can Two. Bizarrely this module had been fitted out to simulate a city-center hotel called the Mars-Astoria. But many of the internal partitions here had been torn down to give a more open, shared space, though the core section was dedicated to a small galley and a shower-toilet. There were four beds in this round space, with small cupboards and chairs beside them, all of them cluttered with clothes and other gear. Softscreens had been plastered over the unregarded urban landscape, cycling through what looked like personal images of families, pets, domestic landscapes.

Myra said curiously, Youre not using this as the makers intended, are you?

Yuri said, Wells was built for ten; there are only four of us. The nights are long here, Myra. We prefer living like this, together.

After that, Yuri apologetically led them down another staircase to a small surface dome, and then down steps cut into the ice. Sorry about this. You can see we only have the four beds set up, and weve pretty much shut down the modules we dont use. We generally put up visitors down here, in our radiation storm shelter...If youre not comfortable we can open up another of the cans.

Bisesa glanced around as she descended. The cavern in the ice was a squat cylinder, sliced up by partitions into pie-shaped segments. She recognized a galley, a comms station, a shower block, a cluttered space that looked like a lab or a medical station. The place was lived-in. There were ruts in the floor around the galley and the shower block, the walls and metal surfaces looked scuffed and polished with use and reuse, and there was a faintly stale smell, of air that had been cycled too often.

Some of the cavern wall was exposed, and she saw it was decorated with an odd design, a thin band marked with faint bars and a more general meter-scale wash of dark and light. This barcode frieze wrapped itself all around the walls curving surface like the flayed skin of a tremendous snake.

The room Myra and Bisesa were to share was just a truncated pie-slice, big enough for bunk beds, a table, a couple of chairs. Its back wall was ice, layered over with translucent plastic, and decorated with that odd barcode design that passed across the length of wall, from one side to the other.

As they sorted themselves out Yuri sat on the bunk. He took up a lot of space in the little room. Its kind of cozy up here at Wells, but we survive. Actually the polar cold doesnt make much difference. On Mars, if you stepped outdoors at high noon in midsummer on the equator, youd still freeze your butt off. The main issue up here is the darkhalf a Martian year at a time, twelve Earth months. Polar explorers on Earth had the same challenges. We did learn a lot of lessons from those guys. Though more from Shackle-ton than from Scott.

Myra said, Yuri, Im having trouble placing your accent.

My mother was Russian like my forename, my father Irish like my surname. Im officially a citizen of Ireland, so of Eurasia. He grinned. But that doesnt count for much up here. Things get kind of mixed up, away from Earth. He turned to Bisesa. Look, Ms. Dutt Bisesa. Bisesa. I know youre here for the thing in the Pit. Bisesa eyed Myra. What thing? What Pit?

But you need to know what were really doing here. He passed a hand along the striped designs on the wall. The lines were faint, of irregular widths and colors. It did look like a barcode, or a spectrograph. Look at this. This is why I came here. This wallpaper is an image of the most complete core weve yet been able to extract.

Myra nodded. An ice core from Mars.

Right. We drilled right down from here, from the top of the ice dome, and we got all the way down to two and a half klicks deepHanse Critchfield is going to enjoy showing off his rig. Of course it would have been three klicks if not for the sunstorm burning the top ice layers away. He shook his head. Damn shame.

Myra ran her finger along the record. And you can interpret this, the way they read ice cores from Earth?

Surely. The cap is built up layer by layer, year on year. And each year it captures a snapshot of the conditions at the timeclimate, dust, cosmic, whatever. Just as on Earth. Of course the detail is different here. In Greenland, say, you get an annual snowfall tens of centimeters thick. Here the residual water-ice layer is less than a seventh of a millimeter, annually.

Look here. He stood by the wall, where the long winding strip came to an end. This is the top of the strip; the most recent layers are at the top, the last deposited, yes? This upper bit of the record was collected by the Aurora crew before the sunstorm. A few centimeters corresponds to decades in time. These fine brown stripes He marked them with his thumbnail. They correspond to global dust storms. And that band corresponds to the washout Mariner 9 found when it arrived in orbit in 1971, the whole planet swathed in dust...

On Mars, events occurring on different timescales were marked by different levels in the ice core. Ten centimeters down was to be found the trace of radiation washed over the planet by the Crab supernova a thousand years earlier. Every meter or so was a significant layer of micrometeorites, droplets of once-molten rock; every ten or a hundred thousand years Mars was hit by an object massive enough to spread debris even to the poles. And the big meter-scale striping corresponded to the most dramatic event in Marss current astronomical cycling, a nodding of its polar tilt that occurred every hundred thousand years.

Yuri said, You can even find traces of Earth in this Martian icemeteorites blasted off the home world, just as Mars meteorites find their way to the Earth. He grinned. Im still looking for traces of the dinosaur killer.

Myra studied him. You love your work, dont you? She sounded envious, Bisesa thought. She always had been drawn to people with missions, like Eugene Mangles.

I wouldnt be stuck in this ice coffin otherwise. But were not concentrating any more. After what we found under the ice, nobody cares about all this stuff. The ice cap, the cores. Its all just in the way.

Bisesa thought that over. Im sorry.

He laughed shortly. Its not your fault.

Myra asked, So what did you find?

Youre about to find out. If youre done, Im supposed to take you in to a council of war. He stood up.

22: APPROACH.

The Liberator sailed toward the Q-bomb, a spear of ice and fire. On the flight deck, Edna Fingal and John Metternes were in their pressure suits, helmets on, visors open.

Though it was still invisible to the naked eye, they were already seeing the Q-bomb through its tug of gravity, its knot of magnetic energy, and the mist of exotic particles it emitted as it cruised through the solar system.

Its just as Professor Carel predicted, John reported, scrolling through softscreen summaries. Exactly like the spectrum you get from the evaporation of a mini black hole. Clearly a cosmological artifact There, Edna whispered. She pointed at the window.

The Q-bomb was a blister of distorted starlight, a droplet of water rolling down the face of the heavens. Edna felt chilled to the bone actually to see this thing.

Thats an Eye, John reported. A perfectly reflective sphere, a ball bearing a hundred meters across. All the classic signs: the distorted geometry, the anomalous Doppler shifts from the surface. The radiation spectrum isnt quite what was recorded of the Eyes found in the Trojans during the sunstorm, however.

So this thing isnt just an observer. I guess we knew that already.

Five kilometers out and closing, Libby said softly.

Edna glanced at John. She knew he had showered only an hour ago, but even so sweat stood out on his brow and pooled at his neck. Ready?

As Ill ever be, cobber.

Well follow the agreed strategy. Libby, you got that? Four passes. And if anything changes We gun for home, Libby said. It will be just as we rehearsed. Three kilometers to closest approach. Edna?

Yes, Libby? History is watching. Oh, Jesus, John muttered.

23: THE PIT.

The four base crew, plus Bisesa, Myra, and Alexei, sat in a circle on chairs and upturned boxes in Can Two, the Hotel Mars-Astoria. Paula, it seemed, was sleeping off the journey.

And here at the Martian north pole, under a hood of carbon dioxide snow, about as remote and secure a place as you could find in the solar system, Bisesa was told the truth at last.

It seemed a relief to Alexei as he finally revealed what various Spacer factions had discovered through various routes: that something unknown and menacing was sliding through the inner solar system. Theyre calling it a Q-bomb. Best guess remains that it is a Firstborn artifact, here to do us harm. The navy have launched some kind of mission to take it out. They may even succeed. But if not You have a plan of your own. Thats right. Bisesa looked around the ring of faces, all of them so much younger than her and Myrabut then, Spacers were young by definition. This is covert. Youre obviously some kind of faction. Running around, hiding from the Earth cops. Having fun, are you? Do you have a leader?

Yes, Alexei said.

Who?

We cant tell you that. Not yet. Nobody here.

And you brought me here because of something you found under the ice.

Thats right.

Then show me.

Grendel Speth, astrobiologist and doctor, faced Bisesa. You only just arrived. Youre sure you dont need to rest?

Bisesa stood. Ive been resting for nineteen years, and traveling for weeks. Lets go. One by one the others stood, following her lead.

To reach the Pit, they would have to suit up.

They went back to Can Six, and then down another flight of steps to a small dome on the ice. Here Bisesa, Myra, and Alexei had to strip out of their coveralls. Knowing the Martian night-winter was only meters away, Bisesa felt illogically cold in her bare skin.

Doctor Grendel gave her a brisk physical check. Aside from having your system systematically ruined in a Hibernaculum for two decades, youre doing fine.

Thanks.

Bisesas skin was briskly oiled. She had to don a bio-vest, a rather prickly waistcoat that clung to her bare skin, providing an interface to the biometric systems that would monitor her bodys performance during this jaunt. Then she put on an undersuit, bright green and clinging, with a helmet, boots, and gloves and a small backpack. This was a complete spacesuit in itself, Grendel told her, effectively pressurized by the tension of its elastic fabric, and would keep her alive for minutes, maybe an hour if there were an emergency, like a module breach.

But this undersuit was only the innermost layer in a double spacesuit design. She was going to have to climb into one of those Captain Ahab external suits.

She was walked to a small hatchway in the dome wall, which led to her outer suit, fixed to the exterior of the dome. She was helped into the suit legs first, then her arms into the sleeves, then her torso and head. Her visor was opaque. The suit was made of rigid sections; it was like climbing into a suit of armor. But the suit seemed to help her by adjusting itself this way and that as she wriggled into it; she heard the hum of servo motors. The trickiest part was getting her helmeted head through the hatch without banging it, and then interfacing it with the larger helmet structure of the oversuit.

Grendel called, How are you feeling? These things arent custom-made. Fine. How do I get out of it?

The suit will tell you when you need to know.

At last Grendel snapped closed the panel at the back. The suit popped off the dome wall, and Bisesa staggered a little.

Her visor cleared. Framed by Martian winter dark, all she could see was the round, helmeted face of the support engineer, whose name was Hanse, he said, smiling. Just checking your suits functioning properly. When you get into the rhythm of this youll learn to check mine; we work on a buddy system...Suit Five? Whats your status?