“Fine, but try to keep some perspective on it! What the hell, you could have stayed back on Earth and been a plumber! You didn’t have to come all this way to drive a goddamn bulldozer! Just how long are you going to go on grubbing away here, installing toilets, programming tractors?”
“All right, all right,” Nadia said, thinking of Maya and all the rest. The square of vaults was almost finished, anyway. “I could use a vacation.”
They took off in three big long-range rovers: Nadia and five of the geologists, Ann, Simon Frazier, George Berkovic, Phyllis Boyle, and Edvard Perrin. George and Edvard were friends of Phyllis’s from their NASA days, and they supported her in advocating “applied geological studies,” meaning prospecting for rare metals. Simon on the other hand was a quiet ally of Ann’s, committed to pure research and a hands-off attitude. Nadia knew all this even though she had spent very little time alone with any of these people, except for Ann. But talk was talk; she could have named all the allegiances of everyone at base if she had to.The expedition rovers were each composed of two four-wheeled modules, coupled by a flexible frame; they looked a bit like giant ants. They had been built by Rolls-Royce and a multinational aerospace consortium, and had a beautiful sea-green finish. The forward modules contained the living quarters and had tinted windows on all four sides; the aft modules contained the fuel tanks, and sported a number of black rotating solar panels. The eight wire-mesh wheels were two-and-a-half meters high, and very broad.
As they headed north across Lunae Planum they marked their route with little green transponders, dropping one every few kilometers. They also cleared rocks from their path that might disable a robot-driven rover, using the snowplow attachment or the little crane at the front end of the first rover. So in effect they were building a road. But they seldom had to use the rock-moving equipment on Lunae; they drove northeast at nearly their full speed of thirty kilometers an hour, for several days straight. They were heading northeast to avoid the canyon systems of Tempe and Mareotis, and this route took them down Lunae to the long slope of Chryse Planitia. Both these regions looked much like the land around their base camp, bumpy and strewn with small rocks, but because they were heading downhill they often had much longer views than they were used to. It was a new pleasure to Nadia, to drive on and on and see new countryside continually pop over the horizon: hillocks, dips, enormous isolated boulders, the occasional low round mesa that was the outside of a crater.
When they had descended to the lowlands of the northern hemisphere, they turned and drove straight north across the immense Acidalia Planitia, and again ran straight for several days. Their wheel tracks stretched behind them like the first cut of a lawnmower through grass, and the transponders gleamed bright and incongruous among the rocks. Phyllis, Edvard and George talked about making a few side trips, to investigate some indications seen in satellite photos that there were unusual mineral outcroppings near Perepelkin Crater. Ann reminded them irritably of their mission. It made Nadia sad to see that Ann was nearly as distant and tense out here as she was back at base; whenever the rovers were stopped she was outside walking around alone, and she was withdrawn when they sat together in Rover One to eat dinner. Occasionally Nadia tried to draw her out: “Ann, how did all these rocks get scattered around like this?”
“Meteors.”
“But where are the craters?”
“Most are in the south.”
“But how did the rocks get here, then?”
“They flew. That’s why they’re so small. It’s only smaller rocks could be tossed so far.”
“But I thought you told me that these northern plains were relatively new, while the heavy cratering was relatively old.”
“That’s right. The rocks you see here come from late meteor action. The total accumulation of loose rock from meteor strikes is much greater than what we can see, that’s what gardened regolith is. And the regolith is a kilometer deep.”
“It’s hard to believe,” Nadia said. “I mean, that’s so many meteors.”
Ann nodded. “It’s billions of years. That’s the difference between here and Earth, the age of the land goes from millions of years to billions. It’s such a big difference it’s hard to imagine. But seeing stuff like this can help.”
Midway across Acidalia they began running into long, straight, steep-walled, flat-bottomed canyons. They looked, as George noted more than once, like the dry beds of the legendary canals. The geological name for them was fossae, and they came in clusters. Even the smallest of these canyons were impassable to rovers, and when they came on one they had to turn and run along its rim, until its floors rose or its walls drew together, and they could continue north over the flat plain again.