The Ringworld Engineers

Chmeee said, “Perhaps the sun has become unstable recently. This could explain why the Ringworld is off center.”

“It may be. Lying Bastard’s records show a flare during your approach to the Ringworld, but for most of that year the sun was quiet.” The Hindmost’s heads poised above his instrument board. “Odd. The magnetic patterns—”

The black disc slid behind the black edge of the rim wall.

“The magnetic patterns of that star are most unusual,” the Hindmost continued.

Louis said, “So go back for another look.”

“Our mission does not permit the collection of random data.”

“No curiosity?”

“No.”

From under ten thousand miles away, the black wall seemed straight as a ruled line. Darkness and speed blurred all detail. The Hindmost had the telescope screen set for infrared light, but it did little good … or did it? There were shadows along the bottom of the rim wall, triangles of coolness thirty to forty miles tall, as if something on the i

Chmeee asked politely, “Are we boarding or merely hovering?”

“Hovering, to assess the situation.”

“The treasure is yours. You may leave without it if it pleases you.”

The Hindmost was restless. His legs gripped the pilot’s bench hard. Muscles twitched in his back. Chmeee was relaxed; he seemed pleased with himself. He said, “Nessus had a kzin for his pilot. There were times when he could give way to total fear. You dare not. Can the automatics land Needle for you while you hide in stasis?”

“What if an emergency developed? No. I did not anticipate this.”

“You must land us yourself. Do it, Hindmost.”

Needle turned nose down and accelerated.

It took nearly two hours to accelerate to the Ringworld’s seven hundred and seventy miles per second. By then, hundreds of thousands of miles of the dark line had raced past them. The Hindmost began to ease them closer—slowly, so slowly that Louis wondered if he would back out. He watched without impatience. He wasn’t under the wire, and by his own choice. Nothing else could be that important.

But where was Chmeee’s patience coming from? Was Chmeee feeling his oncoming youth? A human reaching his first century could feel that he had all the time in the world, for anything. Would a kzin react that way? Or … Chmeee was a trained diplomat. Perhaps he could hide his feelings.

Needle balanced on belly thrusters. .992 gravities of thrust warped its path into the Ringworld’s curve; left to itself, the ship would have flung itself outward toward interstellar space. Louis watched the puppeteer’s heads darting and weaving to check the dials and meters and screens around him. Louis couldn’t read them.

The dark line had become a row of rings set well apart, each ring a hundred miles across, drifting past. During the first expedition, an old recording had shown them how ships would position themselves fifty miles from the rim wall and wait for the rings to sweep them up and accelerate them from free fall to Ringworld rotational speed and then dump them at the far end, on the spaceport ledge.

To left and right the black wall converged at vanishing points. It was close now, a few thousand miles away. The Hindmost tilted Needle to coast along the linear accelerator. Hundreds of thousands of miles of rings … but the Ringworlders had lacked gravity generators. Their ships and crews would not tolerate high accelerations.

“The rings are inactive. I find not even sensors for incoming ships,” a puppeteer head turned to tell them, and then turned quickly back to work.

Here came the spaceport ledge.

It was seventy miles across. There were tall cranes built in beautiful curves, and rounded buildings, and low, wide flatbed trucks. There were ships: four flat-nosed cylinders, of which three had been damaged, the curve of the hulls broken.

“I hope you brought lights,” Chmeee said.

“I do not want to be noticed yet.”

“Do you find any sign of awareness? Will you land us without lights?”

“No and no,” said the Hindmost. The spotlight flared from Needle’s nose, tremendously powerful: an auxiliary weapon, of course.

The ships were vast. An open airlock was a mere black speck. Thousands of windows glittered on the cylinders precisely like candy flecks sprinkled on a cake. One ship seemed intact. The others had been torn open and ca

“Nothing attacks, nothing warns us,” the puppeteer said. “The temperature of the buildings and machinery is as that of the ledge and the ships, 174° Absolute. This place is long abandoned.”

A pair of massive toroids, copper-colored, ringed the waist of the intact ship. They must have been a third the mass of the ship itself, or more. Louis pointed them out. “Ramscoop generators, maybe. I studied the history of spaceflight once. A Bussard ramjet generates an electromagnetic field to scoop up interstellar hydrogen and guide it into a constriction zone for fusion. Infinite fuel supply. But you need an inboard tank and rocket motor for when you’re moving too slow for the ramscoop. There.” Tanks were visible within two of the rifled ships.

And on all three of the rifled ships, the massive toroids were missing. That puzzled Louis. But Bussard ramjets commonly used magnetic monopoles, and monopoles could be valuable in other contexts.

Something else was bothering the Hindmost.

“Tanks to carry the lead? But why not simply plate it around the ship, where it would serve as shielding before it need be transmuted into fuel?”

Louis was silent. There had been no lead.

“Availability,” Chmeee said. “Perhaps they had to fight battles. Lead could be boiled from the hull, leaving the ship without fuel. Land us, Hindmost, and we will seek answers in the unharmed ship.”

Needle hovered.

“Easy to depart,” Chmeee insinuated. “Ease us off the ledge and turn off the thrusters. We fall to flat space, activate the hyperdrive and rush for safety.”

Needle settled on the spaceport ledge. The Hindmost said, “Take your place on the stepping discs.”

Chmeee did. He was … not chuckling, but purring as he vanished. Louis stepped after him and was elsewhere.

Chapter 6

“Now Here’s My Plan …”

The room felt familiar. He’d never seen one exactly like it, but it looked like the flight deck on any small interplanetary spacecraft. You always needed cabin gravity, a ship’s computer, thrust controls, attitude jets, a mass detector. The three control chairs were recliners equipped with crash webs, controls in the arms, urinal tubes, and slots for food and drink. One chair was much larger than the others, that was all. Louis felt he could fly the lander blindfolded.

There was a broad strip of wraparound window above a semicircle of screens and dials. Through the window Louis watched a section of Needle’s hull swing out and up. The hanger was open to space.

Chmeee glanced over the larger knobs and switches set before his own chair. “We have weapons,” he said softly.

A screen blinked and showed a foreshortened puppeteer head, which said, “Descend the steps to reach your vacuum equipment.”

The lander’s stairs were broad and shallow, made for a kzin’s tread. Below was a much larger area, living space, with a water bed and sleeping plates and a kitchen the duplicate of the one in their cell. There was an autodoc big enough for a kzin, with an elaborate control console. Louis had been an experimental surgeon once. Perhaps the Hindmost knew it.

Chmeee had found the vacuum equipment behind one of an array of locker doors. He encased himself in what looked like an assortment of transparent balloons. He was edgy with impatience. “Louis! Gear yourself!”