“Comm check?” Rikki asked.
“Sure.” He tapped his headset. “Comm check, Endeavour. We’re ready to head out.”
“Endeavour,” a gravelly voice answered. The mother ship hung nearby in orbit and Blake hardly noticed the delay. “You’re…up early.”
According to shipboard time, perhaps. Here the sun had already climbed above the ridge he and Rikki would be climbing. Though basic astronomy said this was local spring, snowpack sparkled along the crest.
“Lots to do,” Rikki said. “How are you today, Antonio?”
“Fine.”
“How’s our day going to be?” Blake asked.
“Cold.”
That much Blake already knew. “Can you give me something more to go on?”
“When I…can…you’ll be the first…to know.” (Antonio’s speech was like that, all unnatural pauses, rhythms, and emphases—unless he got lost in his thoughts. When that happened, all anyone got from him was monosyllables.) “I don’t…understand…the weather here…yet.”
For matters unrelated to astrophysics, that was a speech. Unless you happened upon one of Antonio’s hot buttons….
Back when they still knew where they were, Rikki had inadvertently set their shipmate talking about food. A monologue on cooking or favorite breakfasts, Blake could have handled. Maybe, even, a monologue on pancake preferences. But fifteen minutes on the virtues of different blueberry types in pancakes? That was a bit much, because they had no blueberries.
But except for Antonio, they would all be dead.
“Okay,” Blake said. “If you spot anything, let us know.”
“All right.”
“Who else is awake?” Rikki asked hopefully.
“No…one.”
“We should get going,” Blake said. “We’ll call in when we reach the cave.”
“Fine,” Antonio said.
“Shall we?” Blake asked Rikki. He tapped off his headset.
She shrugged to reposition her knapsack. “Sure.”
Long shadows spilled across the desolate terrain. Along the rock-strewn shore, wavy bands of jade-green sludge marked recent storm and tidal surges. Last night’s gale had torn fissures in the algae mats, or whatever the drifting sludge was, that half-covered the inland sea. Their shuttle, looking tiny, perched five meters beyond the highest of the high-water marks.
The topo map on his specs showed a blinking dot scarcely two klicks away. An easy enough hike—if their way wasn’t all uphill. If the oxygen even here, near sea level, wasn’t already marginal and the carbon-dioxide concentration almost toxic. If gravity wasn’t forty percent beyond standard, and the temperature just above freezing, and the rocky incline everywhere slick with melting hoarfrost.
If the fate of—everything—did not burden every decision they made, every step they took.
“If it had been safe to land closer,” Rikki said, “I know you would have.” She patted his arm before slipping on her breather mask. Leaning forward, she started up the hill.
Two klicks, Blake kept telling himself as he followed, ready to catch her if she fell. Nothing to it.
A thirty-degree average upslope was quite doable—on Mars. Here they were panting after fifty meters. Angling back and forth, improvising switchbacks, he guessed their two kilometers would end up closer to…six. They detoured around boulders and mounds of dust-speckled snow. Twice he feigned interest in stony outcroppings, giving Rikki a rest while he chipped away with his rock hammer. As the day warmed, they stepped across more and more trickles of snowmelt, the water-slicked rock shimmering like fresh tar. They seldom spoke, saving their energy for the climb.
He wasn’t a hiker or a climber, but none of them was. No one on Endeavour was a spelunker, either. Or a geologist, or a meteorologist, or a….
Quit whining, he told himself. Keep walking.
“How about we break for lunch?” Rikki wheezed.
They had at least an hour until local noon. She must be beat. Still, they were almost to the cave entrance. They had done a good morning’s work.
“Sounds good,” he told her.
His mask dangling about his neck, Blake chugged most of a bottle of water. When he forgot to breathe deeply, even just sitting, he felt lightheaded. By virtue of their climb, the already low atmospheric pressure would have dropped by about a tenth.
No longer fixated on where next to set down his boots, the terrain seemed bleaker than ever. The shuttle looked puny, and the shelter beside it very inviting. There was nothing like a tree or a shrub to be seen, not as much as a scraggly weed. Life on Dark had yet to make the great leap to dry land.
“Are you cold?” he asked.
“Freezing, at the moment,” Rikki said. “I’m okay when we’re moving.”
“Yeah. Me, too.”
He had his back to the wind, but his bare face already tingled from the cold. The higher altitude alone could explain the temperature drop, or the weather might be changing on them.
He tapped his headset. “Endeavour, I see a line of clouds bearing down on us from the west. A weather front?”
“Yes,” Antonio said, the connection crackling with static.
Almost certainly the hiss was in the low-power link between Blake’s headset and the shuttle, not the shuttle’s radio link to orbit. They were at the limits of the headsets’ range; Blake had expected to set down much nearer to the caves.
“Rain?” Rikki wondered.
“I don’t know,” Antonio said.
Where Blake had grown up, a sky like this was ominous. On Dark, a green sky might be the norm. “Can you make a guess?”
Antonio finally answered, “Snow flurries, based on Earth and…Mars weather models.”
“What good are those here?” Blake asked. Rikki gave him a dirty look.
Antonio took no offense. “Those models are…all we have. In time…we’ll adapt them.”
Shading his eyes with a hand, Blake looked uphill. He and Rikki were not far below the shadowed cave entrance. “Keep an eye on things. Let us know if conditions get worse.”
“Will do.”
Rikki was already stowing the remains and wrappings of their lunches. “Best not dawdle.”
“Right,” he told her. “I don’t like that sky, so only a quick look around today. If the caves show promise, we’ll come back up.”
He pretended not to notice her wince.
An uninterrupted thirty-minute climb delivered them, both panting, to the cave mouth. A warm, steady draft poured from the opening. He heard water trickling.
The orbital radar survey had revealed a system of caves beneath this
