transponders, and dead reckoning, and visual fixes, peering down anxiously in the dawn twilight to spot the next airstrip in the wilderness. Once it took them well into the morning to find a strip near Dao Vallis. After that Yeli began to follow pistes, flying low through the night and watching the silvery ribbon snake below them through the starlight, checking transponder signals against the maps.
And so they managed to fly down in the broad lowland of Hellas Basin, following the piste to Low Point Lakefront. Then in the horizontal red light and long shadows of sunrise, a sea of shattered ice came over the horizon into view. It filled the whole western part of Hellas. A sea!
The piste they had been following ran right into ice. The frozen shoreline was a jagged tangle of ice plates that were black or red or white or even blue, or a rich jade green—all piled together, as if a tidal wave had crushed Big Man’s butterfly collection, and left it strewn over a barren beach. Beyond it the frozen sea stretched right over the horizon.
After many seconds’ silence, Ann said, “They must have broken the Hellespontus aquifer. That was a really big one, and it would drain down to Low Point.”
“So the Hellas mohole must be flooded!” Yeli said.
“That’s right. And the water at the bottom of it will heat up. Probably hot enough to keep the surface of the lake from freezing. Hard to say. The air is cold, but with the turbulence there might be a clear spot. If not, then right under the surface it will be liquid for sure. Must be some strong convection currents in fact. But the surface …”
Yeli said, “We’ll see pretty soon, we’re going to fly over it.”
“We should be landing,” Nadia observed.
“Well, we will when we can. Besides, things seem to be calming down a bit.”
“That’s just a function of being cut off from news.”
“Hmm.”
As it turned out they had to fly all the way across the lake, and land on the other side. It was an eerie morning, flying low across a shattered surface reminiscent of the Arctic Sea, except here the ice flows were frosting like an open freezer door, and they were colored across the whole spectrum, heavy on the reds of course, but this only made the occasional blues and greens and yellows stand out more vividly, the focal points of an immense, chaotic mosaic.
And there at its center—where, even flying as high as they were, the ice sea still extended to the horizon in every direction—there was an enormous steam cloud, rising thousands of meters into the air. Circling this cloud cautiously, they saw that the ice underneath it was broken into bergs and floes, floating tight-packed in roiling, steaming black water. The dirty bergs rotated, collided, turned turtle and caused thick walls of red-black water to splash upward; when these walls fell back down, waves expanded out in concentric circles, bobbing all the bergs up and down as they passed.
There was silence in the two planes as they stared down at this most un-Martian spectacle. Finally, after two mute circumnavigations of the steam column, they flew on westward over the shattered waste. “Sax must be loving this revolution,” Nadia said as she had before, breaking the silence. “Do you think he’s part of it?”
“I doubt it,” Ann said. “He probably wouldn’t risk his Terran investment. Nor an orderly progression to the project, or some kind of control. But I’m sure he’s evaluating it in terms of how it affects the terraforming. Not who’s dying, or what’s getting wrecked, or who’s taking over here. Just how it affects the project.”
“An interesting experiment,” Nadia said.
“But hard to model,” Ann said. They both had to laugh.
• • •
Speak of the devil—they landed west of the new sea (Lakefront was drowned), and spent the day resting, and the next night as they followed the piste northwest toward Marineris, they flew over a transponder that was blinking SOS in Morse code. They circled the transponder until dawn, and landed on the piste itself, just beyond a disabled rover. And next to it was Sax, in a walker, fiddling with the transponder to send his manual SOS.
Sax climbed into their plane and slowly took off his helmet, blinking and purse-mouthed, his usual bland self. Tired, but looking like the rat that ate the canary, as Ann said to Nadia later. He said little. He had been stuck on the piste in the rover