The planet was like a sculpture of glass, two or three feet across, held at arm’s length. Saturn itself was a fat ball of milky yellow crystal, at the heart of a plate of shining rings. The rings — contained well within the orbit of Titan — were tipped up, from Mott’s perspective; they emerged from darkness on the face of the planet, and formed a thin, banded ellipse. Looking along the rings, Mott could see other moons, a string of glowing crescent-beads.

Under the clouds of Titan the sky would be hidden. It was going to be hell to know that Saturn itself was suspended above the clouds, as motionless as Earth in the black sky of the Moon, and yet forever invisible.

The hatch opened. Benacerraf and Rosenberg came bustling onto the flight deck, up the tunnel from the orbiter’s mid deck. Through the open access-way to the mid deck — through the airlock and the connecting tunnel to the hab module — Mott could hear the aimless crooning of Bill Angel, blind and alone. His gull-like cries were diminished by distance; sound didn’t carry well in the reduced pressure of the hab module. Mott said, “What do you want?”

“We have to talk,” Rosenberg said. Benacerraf looked at Mott and shrugged.

Mott, reluctantly, released her restraints and pulled herself across the cabin.

Rosenberg said, “We have to discuss Bill. How in hell are we going to get him to the surface?”

Benacerraf sighed. “Damn your logical mind, Rosenberg.”

But it’s a non-question, Mott thought. She avoided the eyes of the others; she stared at the dull ochre Titan highlights on the instrument panels. She said, “Logical, maybe, but he’s starting from an assumption.”

“What assumption?”

“That we take Bill down at all.”

There was a long silence.

The three of them drew closer together — like conspirators, Mott thought, their hair drifting in the sluggish currents of the air. They were gaunt, withered by years of microgravity and a lousy diet and canned air; they must look like three witches, gathered around some spell-book, plotting the fate of another human being.

Benacerraf said at last, “There is nowhere to leave him. We’re taking Discovery down too, remember.”

“I know,” Mott said. “That doesn’t alter the suggestion.”

Rosenberg raised greying eyebrows. “Right. And you’ll be the one who will shove him out the airlock.”

Mott opened her mouth to reply.

Benacerraf said, “This isn’t doing us any good. Niki, Bill Angel didn’t ask to finish up as he has. He’s just turned out to be the weakest of us, is all. It could have been any of us. And now, he’s a billion miles from the nearest person who can help him. Save for us. So we take him down.”

“Anyhow,” Rosenberg said, “you know what Houston says. Maybe being returned to a stable gravity environment will help bring Bill out of this. He’s always going to be disabled, of course. But he was a competent astronaut. Maybe he can still be useful.”

“And you believe that?” Mott said mildly.

“Enough,” Benacerraf snapped.

Mott thought about pushing it.

After six years, she was sick of Benacerraf’s peevish bossiness. One day, perhaps, she was going to have to challenge the authority that Benacerraf assumed so easily. But now wasn’t the time.

“Which returns me to my original question,” Rosenberg said. “How do we get him to the surface?”

Benacerraf frowned. “Each Apollo can hold one, two, three — even all four of us if it has to. Logically, we ought to split evenly between the capsules: two and two.”

Rosenberg shook his head. “I got to advise against that. We know little enough about this Titan entry as it is, and we’re not sure how the Apollos will behave, after a couple of decades in store and six years of space soak. Anything could happen. Who would want to be alone in a failing Command Module with Bill Angel?”

“Even if he was sedated?”

“Even so. Paula, the entry is going to take hours, remember.”

Mott said, “We could all four of us ride down in the one capsule. It wouldn’t be comfortable, but with a couch installed in the lower equipment bay—”

“Again, bad idea,” Rosenberg said. “We ought to go down separately. If one Apollo has a bad landing, we only hurt half the crew; the rest are on hand to help.”

“But,” Benacerraf said, evidently irritated, “that logic leaves us with only one combination. One and three: one person alone, and two of us sandwiching Angel. Hardly an ideal.”

“Well,” Mott said angrily, “it might not be what we planned. But it’s what we’re left with. We never planned for Siobhan to get herself killed—”

“Nicola. The one alone. It has to be you.”

“That hadn’t occurred to Mott. Tell me why,” she said.

“You’re the nearest thing to a pilot we have left. I could trust you to fly that Apollo down alone, but not myself or Rosenberg.”

To fly down to the surface of Titan, a new world, alone… She felt an odd mixture of exhilaration and sheer, unadulterated fear.

It would be the first time the crew had been separated, since the launch day.

The three of them gathered a little closer, watching each other, as if in awe of how far they had travelled together, of what they were planning now.

“All right,” Mott said. “I’ll do it.”

Both Rosenberg and Benacerraf, simultaneously and apparently on impulse, reached out towards her. Physical contact had become a major taboo for them all; but now they held onto each other’s arms, feebly hugging.

Benacerraf said, “We don’t have anything to fear. We can do this. We’ll be there for you when you land.”

“Sure,” said Mott. “See you in the mud.”

Rosenberg tugged at his wispy beard. “We need another name. A call-sign for the base camp, the landing site of the orbiter… You know, in Greek mythology the Titans were a family of giants, the children of Uranus and Gaia, the sky and the Earth. Before the gods, they sought to rule the heavens. You’ll know some of their names: Rhea, Tethys, Iapetus, Hyperion, Phoebe. And others — Cronos, the leader, Rhea, Oceanus, Coeus, Crius, Mnemosyne. Their stronghold was Mount Othrys, a counterpart of Mount Olympus.”

“Oh,” Benacerraf said. “Hence the Geological Survey name for our friendly ice mountain down there. So what happened to the Titans?”

“Cronos overthrew Uranus, his father. But then there was a ten-year battle, between the Titans and the gods. Zeus beat out Cronos by bringing in Hundred-armed Giants — the Hecatoncheires — as his allies. Then the Titans were imprisoned, for eternity, in Tartarus. They were locked behind huge bronze doors, and the Hundred-armed Giants were appointed jailers—”

“Tartarus? Where’s that?”

Rosenberg pulled a face. “You don’t want to know. A place as far below Hades as Hades is below Heaven.”

Mott stabbed a finger at Titan. “Then that’s the name for our colony. Where we’re going to have to live out the rest of our lives. Underneath all that orange shit. Tartarus.”

Nobody disagreed.

The rusty light of Titan, washing from the hab module’s multiple monitors, made their skin look old, pallid.

Mott lay on her back in the center couch of Apollo Command Module CM-115, now known as Jitterbug.

She was alone in here. She was wearing her orange pressure suit. Cool air washed over her face, inside her helmet, bringing with it a smell of plastic and metal; all around her the fans and pumps of the Command Module clicked and whirred. It was a mundane, comforting noise, louder than a Shuttle orbiter or the hab module, somehow more obviously mechanical; it was like being inside some huge, elaborate clock.

She looked ahead, through the small docking windows set in Jitterbug’s nose.

She was sailing backwards over the orange-brown cloud-sea of Titan. She was in Titan’s shadow, but some light was diffused forward by the thick atmosphere, so that the clouds before Jitterbug were a blanket of rusty oranges and browns, fading into curved darkness far ahead of her.