Mike wasn’t there, of course, or anywhere within five hundred miles of her. He was losing himself in the NERVA developments. As Ben had hinted, that damned project was slipping again.

Anyway, she realized, things hadn’t been quite the same between the two of them since that day in 1969 when she’d gone out to Jackass Flats with Mike and Ben.

She’d tried to talk it through with Mike. It had gone beyond a simple argument for her, beyond the kind of sparky debating exercise they’d enjoyed so many times in the past. NERVA seemed to symbolize, to her, a lot of her unease about the way the country was being run. And eventually that seemed to get through to Mike. Impatiently, he’d shown her schemes to trap the venting hydrogen, to bury the expended cores more deeply…

Somehow that didn’t help. Obviously Mike was smart enough to understand the issues that concerned her, but it was pretty clear he didn’t care; not as much as he cared about a successful project, anyhow.

She loved Mike, she believed. And he loved her. But, she thought, their disparate lives, their different perspectives over the value of projects like NERVA, all of it was steadily pulling them apart.

They’d gone out to Jackass Flats, she recalled, just six months after they’d met. And that was all of three years ago. Maybe she should start regarding those first happy six months as the anomaly, not the norm.

Meanwhile, in March — four months into Mariner’s orbital survey — the first detailed maps of Mars had begun to appear from the U.S. Geological Survey people at Flagstaff. York had gotten hold of copies of those and pored over them.

Mars was very different from what anyone had expected.

Mars was asymmetrical. The whole of the southern hemisphere was swollen, the land lifted well above the datum level and heavily cratered. The northern hemisphere was mostly below the datum, and was a lot smoother than the south… but the north had Tharsis.

Tharsis was a bulge in the planet the size of southern Africa. It was as if a quarter of the whole surface of Mars had been lifted up by some colossal event. The bulge was surrounded by an array of cracks and grooves: to the east of Tharsis, in the Coprates region, a huge canyon system stretched nearly a quarter of the way around the circumference of the planet.

The ancient cratered terrain in the south was cut by gullies and channels which seemed to have been incised by running water. York was entranced by images of Moonlike craters, eroded by flash floods. But there was no sign of water on the surface, in the quantities needed to cut the gullies; maybe the water had escaped from the atmosphere, or was trapped under the surface.