He slid into the chair, taking care to smooth the clothing under his back and legs. On the surface of the star a crease of cloth could cut like a knife. A red light flashed on the control panel, casting sombre shadows, and the base of the cabin slid aside with a soft grind. The ancient machinery worked with a chorus of scrapes and squeaks; the drum turned and the cable began to pay out.

With a jolt Rees dropped through the station floor and into the dense cloud. The chair was pulled down the guide cable; the guide continued through the mist, he knew, for four hundred yards to the surface of the star. The familiar sensation of shifting gravity pulled at his stomach like gentle hands. The Belt was rotating a little faster than its orbital velocity — to keep the chain of cabins taut — and a few yards below the Belt the centripetal force faded, so that Rees drifted briefly through true weightlessness. Then he entered the gravity well of the star kernel and his weight built up rapidly, plating over his chest and stomach like iron.

Despite the mounting discomfort he felt a sense of release. He wondered what his workmates would think if they could see him now. To choose to descend to the mine during an off-shift… and what for? To talk to a digging machine?

The oval face of Sheen floated before him, intelligent, skeptical and pragmatic.

He felt a flush burn up through his cheeks and he was suddenly glad that his descent was hidden by the mist.

He dropped out of the mist arid the star kernel was revealed. It was a porous ball of iron fifty yards wide, visibly scarred by the hands and the machines of men. The guide cable — and its siblings, spread evenly around the Belt — scraped along the iron equator at a speed of a few feet each second.

His descent slowed; he imagined the winch four hundred yards above him straining to hold him against the star's clutching pull. Weight built up more rapidly now, climbing to its chest-crushing peak of five gees. The wheels of the chair began to rotate, whirring; then, cautiously, they kissed the moving iron surface. There was a bump which knocked the breath out of him. The cable disengaged rapidly, whipping backwards and away through the mist. The chair rolled slowly to a halt, carrying Rees a few yards from the trail of the cable.

For a few minutes Rees sat in the silence of the deserted star, allowing his breathing to adjust. His neck, back and legs all seemed comfortable in their deep padding, with no circulation-cutting folds of flesh or cloth. He lifted his right hand cautiously; it felt as if bands of iron encased his forearm, but he could reach the small control pad set into the chair arm.

He turned his head a few degrees to left and right. His chair sat isolated in the center of an iron landscape. Thick rust covered the surface, scoured by valleys a few inches deep and pitted by tiny craters. The horizon was no more than a dozen yards away; it was as if he sat at the crest of a dome. The Belt, glimpsed through the layer of cloud around the star, was a chain of boxes rolling through the sky, its cables hauling the cabins and workshops through a full rotation every five minutes.

Rees had often worked through in his head the sequence of events which had brought this spectacle into being. The star must have reached the end of its active life many centuries earlier, leaving a slowly spinning core of white-hot metal. Islands of solid iron would have formed in that sea of heat, colliding and gradually coalescing. At last a skin must have congealed around the iron, thickening and cooling. In the process bubbles of air had been trapped, leaving the sphere riddled with caverns and tunnels — and so making it accessible to humans. Finally the oxygen-laden air of the Nebula had worked on the shining iron, coating it with a patina of brown oxide.

The star kernel was probably cold all the way to its center by now, but Rees liked to imagine he could feel a faint glow of heat from the surface, the last ghost of star fire—

The silence was lanced through by a whine, far above him. Something glittering raced down breakthrough the air and hit the rust with a small impact a yard from Rees's chair. It left a fresh crater a half-inch across; a wisp of steam struggled to rise against the star pull.

Now more of the little missiles fizzed through the air; the star rang with impacts.

Rain. Metamorphosed by its fall through a five-gee gravity well into a hail of steaming bullets.

Rees cursed and reached for his control panel. The chair rolled forward, each bump and valley in the landscape jarring the breath from him. He was a few yards still from the nearest entrance to the mine works. How could he have been so careless as to descend to the surface — alone — when there was danger of rain? The shower thickened, slamming into the surface all around him. He cringed, pinned to his chair, waiting for the shower to reach his head and exposed arms.

The mouth of the mine works was a long rectangle cut in the rust. His chair rolled with agonizing slowness down a shallow slope into the depths of the star. At last the roof of the works was sliding over his head; the rain, safely excluded, spanged into the rust.

After pausing for a few minutes to allow his rattling heart to rest, Rees rolled on down the shallow, curving slope; Nebula light faded, to be replaced by the white glow of a chain of well-spaced lamps. Rees peered up at them as he passed. No one knew how the fist-sized globes worked. Apparently the lamps had glowed here unattended for centuries — most of them, anyway; here and there the chain was broken by the dimness of a failed lamp. Rees passed through the pools of darkness with a shudder; typically his mind raced through the years to a future in which miners would have to function without the ancient lamps.

After fifty yards of passageway — a third of the way around the circumference of the star — the light of the Nebula and the noise of the rain had disappeared. He reached a wide, cylindrical chamber, its roof about ten yards beneath the surface of the star. Rust-free walls gleamed in the lamplight. This was the entrance to the mine proper; the walls of the chamber were broken by the mouths of five circular passageways which led on into the heart of the star. The Moles — the digging machines — cut and refined the iron in the passageways, returning it in manageable nodules to the surface.

The real function of humans down here was to supplement the limited decision-making capabilities of the digging machines — to adjust their quota, perhaps, or to direct the gouging of fresh passageways around broken-down wheelchairs. Few people were capable of more… although some miners, like Roch, were full of drunken stories about their prowess under the extreme gravity conditions.

From one passageway came a grumbling, scraping sound. Rees turned the chair. After some minutes a blunt prow nosed into the light of the chamber, and — with painful slowness — one of the machines the miners called the Moles worked its way over the lip of the tunnel.

The Mole was a cylinder of dull metal, some five yards long. It moved on six fat wheels. The prow of the Mole was studded with a series of cutting devices and with handlike claws which worked the star iron. The machine's back bore a wide pannier containing several nodules of freshly cut iron.

Rees snapped: "Status!"

The Mole rolled to a halt. It replied — as it always replied—"Massive sensor dysfunction." Its voice was thin and flat, and emanated from somewhere within its scuffed body.

Rees often imagined that if he knew what lay behind that brief report he would understand much of what baffled him about the world.

The Mole extended an arm from its nose. It reached to the panniers on its back and began lifting head-sized nodules down to a pile on the floor of the chamber. Rees watched it work for a few minutes. There were crude weld marks around the prow devices, the wheel axles and the points where the panniers were fixed; also, the skin of the Mole bore long, thin scars showing clearly where devices had been cut away, long ago. Rees half-closed his eyes so that he could see only the broad cylindrical shape of the Mole. What might have been fixed to those scars on the hull? With a flash of insight he imagined the jets that maintained the Belt in its orbit attached to the Mole. In his mind the components moved around, assembling and reassembling in various degrees of implausibility. Could the jets really once have been attached to the Mole? Had it once been some kind of flying machine, adapted for work down here?