Cratered plains: the images were of Mars, clearly enough. But there was a channel cut deeply into what looked like the tough, ancient landscape of the southern hemisphere. There was a crater complex, overlaid by anastomosed channels. There was a crater with a teardrop-shaped, streamlined island, like a gravel bar, collected in its wake; and “downstream” of the crater, there were scour marks, running parallel to the island…

Stone was having trouble making sense of what he saw and heard. “Are you saying that Mars has suffered catastrophic flooding — like the scabland here, in Washington State?”

York hesitated. “I believe so. A lot of us have argued that, since the Mariner pictures came in. I’ve been studying the area you’re looking at, in those photos, since 1973. I guess I’m the leading expert on it, now. And it seems to me the analogy between the terrestrial scabland features and the Martian morphology is too striking to be a coincidence.”

“But not everybody agrees,” Stone hazarded.

“No,” she conceded. “Some say the Martian ‘scabland’ features are too big to have been formed by water. Schumm, for instance.”

“Who?” Bleeker asked.

“Schumm says the Martian channels must have been formed by tensional factors in the planet’s surface. Cracks, modified later, maybe, by vulcanism and the action of the wind.”

“Sounds like an asshole to me,” Stone said, peering at the pictures. “I’m with you, Natalie.”

“But if these Martian channels were formed by flooding,” Bleeker said, “where the hell did the water come from? And where did it go?”

“I’ll bet she has a theory about that, too,” Stone muttered.

“I didn’t copy, EV1.”

“Go ahead, Natalie.”

“Underground aquifers. Contained by tough bedrock below — maybe ten miles deep — and a cap of thick ice in the regolith above. Whatever lifted up Tharsis — a convection process in the mantle, maybe — must have caused the faulting that led to the flooding. The pressure of the water has to exceed the pressure of the rocks. All you’d need would be a breach on the subsurface ice cap for the water to gush to the surface, under high pressure.”

“My God,” Stone said. “Oceans, buried in the Martian rocks. How can we find out if you’re right, Natalie?”

“What we need is for three guys to land there in a MEM, and dig a few deep cores.”

Stone started to see where all this was leading. He leafed through the photos again. “What area are these photos of?”

“That’s one of the most striking outflow channels. It’s Mangala Vallis, Phil. Martian scabland: your landing area.”

Stone grinned. She’s doing it again. Mangala Vallis. On which Natalie York, leading light of the site selection committee and would-be Mars voyager, just happens to be the world’s top expert.

And Adam Bleeker still doesn’t know what anastomosis is. I hope the guy’s watching his back. Mission Elapsed Time [Day/Hr:Min:Sec] Plus 349/11:14:03