The Jet Propulsion Laboratory was a jumble of rectangular blocks perched on a still-green hillside. As the bus wheezed to a stop he heard chanting and saw three New Sons handing out literature and buttonholing at the main gate. He took one of their handouts and crumpled it up after a glance. It seemed to him their promotional field work was getting worse; overtly mystical appeals wouldn’t work with JPL’s staff.

He passed through three sets of guards, grudgingly showed his badge—the Lab was a prime target for the bombers, but it was a nuisance nonetheless—and made his way down chilly, neon-bleached corridors. When he reached his office he found Kevin Lubkin, Mission Coordinator, already waiting for him. Nigel moved some issues of Icarus, the scholarly journal, out of a chair for Lubkin, pushed them into the heap of papers on his desk and raised the blinds of his window to let one pale blade of light lance across the opposite wall. He worked in a wing without air conditioning and it was a good idea to get some cross-ventilation going as soon as possible; the afternoon was unforgiving. Then, too, he adjusted the blinds each morning as a ritual beginning of work, and so uttered nothing more than a greeting to Lubkin until it was done.

“Something wrong?” he asked then, summoning up an artificial alertness.

Kevin Lubkin, distracted, closed a folder he had been reading. “Jupiter Monitor,” he said tersely. He was a burly, red-faced man with a smooth voice and a belly that had recently begun to bulge downward, concealing his belt buckle.

“Malfunction?”

“No. It’s being jammed.”

He flicked a blank look at Nigel, waiting.

Nigel raised an eyebrow. An odd tension had suddenly come into the room. He might still be relaxed from breakfast, but he wasn’t so slow that he could be taken in by an office sendup. He said nothing.

“Yeah, I know,” Lubkin said, sighing. “Sounds impossible. But it happened. I called you about it but—”

“What’s the trouble?”

“At two this morning we got a diagnostic report from the Jovian Monitor. The graveyard shift couldn’t figure it out, so they called me. Seemed like the onboard computer thought the main radio dish was having problems.” He took off his creamshell glasses to cradle them in his lap. “That wasn’t it, I decided. The dish is okay. But every time it tries to transmit to us, something echoes the signal back after two minutes.”

“Echoes?” Nigel tilted his chair, staring at titles on his bookshelves while he ran the circuit layout of the J-Monitor’s radio gear through his mind. “Two minutes is far too long for any feedback problem—you’re right. Unless the whole program has gone sour and the transmissions are being retaped by Monitor itself. It could get confused and think it was reading an incoming signal.”

Lubkin waved a hand impatiently. “We thought of that.”

“And?”

“The self-diagnostics say no—everything checks.”

“I give up,” Nigel said. “I can tell you’ve got a theory, though.” He spread his hands expansively. “What is it, then?”

“I think J-Monitor is getting an honest incoming signal. It’s telling us the truth.”

Nigel snorted. “How did you muddle through to that idea?”

“Well, I know—”

“Radio takes nearly an hour to reach us from Jupiter at this phase of the orbit. How is anyone going to send Monitor’s own messages back to it in two minutes?”

“By putting a transmitter in Jupiter orbit—just like Monitor.”

Nigel blinked. “The Sovs? But they agreed—”

“No Soviets. We checked on the fastwire. They say no, they haven’t shot anything out that way at all in a coon’s age. Our intelligence people are sure they’re leveling.”

“Chinese?”

“They aren’t playing in our league yet.”

“Who, then?”

Lubkin shrugged. The sallow sagging lines in his face told more than his words. “I was kind of thinking you might help me find out.”

There was a faint ring of defeat in the way the man said it—Nigel noted the tone because he had never heard it before. Usually Lubkin had an aspect of brittle hardness, a cool superior air. Now his face was not set in its habitual aloof expression; it seemed open, even vulnerable. Nigel guessed why the man had come in himself at 2

A.M., rather than delegating the job—to show his people, without having to tell them in so many words, that he could do the work himself, that he hadn’t lost the sure touch, that he understood the twists and subtleties of the machines they guided. But now Lubkin hadn’t unraveled the knot. The graveyard shift had departed into a gray dawn, so now he could safely ask for help without being obvious.

Nigel smiled wryly at himself. Always calculating, weighing the scales.

“Right,” he said. “I’ll help.”

The solar system is vast. Light requires eleven hours to cross it. Scattered debris—rock, dust, icy conglomerates, planets—circles the ordinary white star, each fragment turning one face to the incandescent center, receiving warmth, while the other faces the interstellar abyss.

The craft approaching the system in 2031 did not know even these simple facts. Swimming in black vastness, it understood only that it was once again nearing a commonplace type of star and that the familiar ritual must begin again.

Though it was carrying out a long and labored exploration of this spiral arm, it had not chosen this particular star at random. Long before, cruising at a sizable fraction of light speed somewhat below the plane of the galaxy, it had filtered through the whispering radio noise a brief signal. The message was blurred and garbled. There were three common referents the craft could piece together, however, and these resembled an ancient code it had been taught to honor. The machine began to turn in a great arc which arrowed toward a grouping of stars; the jittery message had not lasted long enough to get a precise fix.

Much later, during the approach, a stronger radio burst peaked through the sea of hydrogen emission. A distress call. Life system failure. A breach in the hull, violation of the vital integrity indices—

There it ended. The signal’s direction was clearer. But did it come from this system ahead, or from some much more distant source lying behind it? In such circumstances the craft fell back on its habitual patterns.

Its first duty was simple. It had already decelerated until interstellar dust would no longer plow into it with blistering, destructive velocity. The craft could now safely cut off the magnetic fields encasing it and begin to extend sensors. A port opened to the utter cold and peered ahead. A blinder drew across the image of the nearing star, so that tiny flecks of light nearby could register.

The telescope employed was 150 centimeters in diameter and did not differ markedly from those used on Earth; some facets of design, bounded by natural law, are universal. The craft crept along at far below light speed. Isotopes met with a low mumble in the throat of its exhaust. Fingers of magnetic fields, extended forward, plucked the proper atoms from the interstellar gas and funneled them in. Only this carving of a cylinder in the dust disturbed the silent reaches.

The craft watched patiently. Any planets orbiting the star ahead were still far away, and picking out their movements against the speckled background of stationary stars was difficult. At four-tenths of a light-year away, the activated circuits and their consultation backup agreed: a yellow-brown patch near the white star was a planet. Higher functions of the computers felt the prickly stirrings of activity and heard of the discovery. A background library of planetary theory was consulted. The blurred, dim disk ahead shimmered as the ship swept through a whisper-thin cloud of dust, while the machine bracketed and measured its objective in methodical detail.