They couldn’t avoid a big crater, maybe two hundred yards wide. As they approached the rim Geena slowed down; they had to thread their way through an apron of ejecta a couple of hundred yards deep, sharp-edged, scattered blocks up to four or five yards in size, dug out of the Moon and thrown up here.

From above, Henry knew, this blanket would form the crater’s ray system, the scattering of ejecta around the central wound, like a splash of blood around a bullet-hole. It gave him a thrill to know that he was here, actually driving among the rays of a lunar crater. A hell of a thing.

Here at last was the lip of the crater. They went over the rim into the basin. It was strewn with blocks ranging from a yard across to maybe fifteen yards, with a few yards separating the blocks, wide enough for them to drive through, as if passing through some miniature city block.

Crossing the crater floor there was an ejecta ridge, a rough, loose structure made of highland dust and mare basalt fragments, churned up together. It must be part of the ray system that came radiating away from the impact that created the younger Aristarchus. He noticed a piece of rock that sparkled with glass beads. It was possible that after the impact, so many billions of years ago, this chunk had been thrown thousands of miles into space, smashed, molten, cooling, before falling back to the Moon, to land here, and, after waiting as long as it had taken for life to evolve on the Earth, here it was for him to see.

Now they drove through a dune field — as he thought of it, in defiance of lunar geology — pitching over a uniformly corrugated ground, ridges and troughs. Here, he thought, was a place they could easily get lost. But the sun hung in the sky above them, unmoving, a beacon.

He thought about that. Morning would be a week long, on the Moon.

For seven days that sun was going to climb up the black sky. For seven days the shadows, of rocks and craters and two human beings, would shrink, vanishing at local noon. The rocks would get as hot as two hundred degrees Fahrenheit. Then the sun would start to sink, sliding at last under the western horizon, and the two-week-long lunar night would cut in. The temperatures then would get down as far as two hundred degrees below zero.

Four hundred degree temperature swings, every month. On Earth, on a field trip in the desert, you could get swings of more than a hundred degrees, and at night you would sometimes hear distant, muffled crumps: rocks, exploding under the pressure of the endless contractions and expansions.

But there would be no shattering rocks here. Maybe there had been such incidents once, but every rock that was going to shed layers had done it a hundred million years ago, or more; and there was no volcanism to push up mountains and deliver fresh rocks to the air, no frost to work into rock cracks. After aeons of erosion the Moon was smooth. The mountains of Aristarchus, on the horizon, were like fluid sculptures, rounded and smooth, set out under the black sky, majestic in their own way. If he looked towards the sun’s glare, they were partly silhouetted, their forms delineated by smooth crescents of sunlit terrain, like sand dunes at dawn.

And the mountains weren’t grey or brown as he had expected, but a pale gold, in the low lunar morning light. Rounded, dust-covered, they reminded him of ski slopes — maybe in the mountains of Colorado, high above the timber line. And that golden sheen gave them a feeling of warmth, for him; they seemed to cup the Rover like an open hand.

He could, he realized, get to feel at home here. You could set down your lander almost anywhere on the Moon and expect to find a reasonable surface to work with.

And it had its own antique beauty, he found, subtle and unexpected. A place where time ran slow, where morning was a week long. But he wished he could see the stars. He imagined walking here in the lunar night, with the stars above: a huge canopy of them, reaching down to the horizon, undiminished by even the slightest trace of dust or mist.

But it would take all of twenty-eight days for a star to circle around the sky — and the stars here didn’t turn around Polaris, that great hinge in the skies of northern Earth, because the Moon’s axis was tipped compared to Earth’s.

…But, even as the stars slowly worked around the sky, the Earth would hang above you, fixed forever. That unmoving Earth would spook you, hanging there in the sky, blue and white, forty times as bright as a full Moon: winding through its remorseless phases, like an immense, blinking, unwavering eye.

To an inhabitant of the Moon, Earth was the blue eyeball of God, he thought.

They stopped every few hundred yards, so Henry could emplace seismometer stations. The little moving-coil devices, jug-shaped and trailing wires, were placed three at a time, to pick up the ground’s movement in three dimensions. He even had some experimental lightweight gravimeters, little stainless-steel cans, that were capable of getting down to an accuracy of ten milligals or so.

Henry was wiring the Moon.

Here and there, he also laid down small explosives. His intention was to do a little active seismography, using the explosives to send shock waves through the Moon’s interior, to be picked up by the seismos. The larger the net of sensors he could cast, the better the image of the interior of the Moon he would be able to build up; in a way the messages of the little seismometers were likely to be more significant than anything he would see, at the rille.

As they approached the rille, still following the old Apollo tracks, they had to drive up an incline. It was an outcrop of Cobra Head, the old volcanic dome here, the source of the lava which had gouged out the rille.

The thirty-year-old Rover performed impressively on the slope, seeming to carry them without effort. But, a hundred yards short of the edge of the rille, they stopped. The old Rover tracks snaked on further up the incline, but Geena was reluctant to risk taking the aged car any further.

When Henry tried to get up, he could barely raise his suited body out of the seat, and when he got to stand, he felt as if he might slip down the slope. The steepness here was deceptive.

“Henry. Help me.”

“What?”

“I think this damn thing is going to run downhill.”

Geena was holding onto the Rover. Henry could see one of its wheels was lifting off the surface.

Henry grabbed onto the Rover; it was so light he felt he could support it easily.

He pointed out an eroded old crater they could park in, and when Geena drove forward, they found the Rover was left almost level.

Henry turned to look back. He was three hundred feet high now, and the view was staggering. The sloping land swept away, obviously a sculpture of craters: craters on craters, young on old, small and sharp and cup-shaped on old and eroded and subtle. And he could see that big rubble-strewn crater they had driven through, looking as fresh as if it was dug out of the plain yesterday. Its sharp rim was a ring of dazzling white, and rays of boulders, black and white, clean and sharp, were scattered across the landscape for miles in all directions.

Further out the slope’s broad flank swept down and merged with a bright, undulating dust plain that was pocked with the gleaming white rims of craters, all of it diamond sharp, under a black sky. It was a wilderness, suspended beneath that starless interplanetary sky above.

And it was crossed by just two, closely paralleled, human-made car tracks.

Geena was already working on the Rover, carefully wiping Moon dust from its new batteries.

Henry took his equipment from the sample bags in back of the Rover, and from beneath its seats. They both had big Beta-cloth bags they loaded up with gear, and then slung over their shoulders. Geena had a coil of nylon rope she looped over one arm. And they both had torches, taped to their helmets.