The colors leached out of the big clunky control panel in front of her, and walls of darkness closed in around her vision. It was hard even to blink, to relieve the dryness of her eyes. Her mouthpiece felt like an iron bar being forced against her jaw. Unable to see a chronometer, she tried to count, to reduce this experience to a finite time that must pass. A thousand and one. A thousand and two…

She couldn’t concentrate. She lost count. She wasn’t even able to maintain the rhythm of the count.

Starved of blood and oxygen, her brain was closing down. The darkness at the fringe of her vision closed in, like sweeping curtains.

Then, as suddenly as it had mounted, the pressure faded. The weight on her chest was lifted off. She sucked in air, her chest expanding against emptiness.

The glow of the plasma was fading. Beyond Jitterbug’s window there was a rusty orange glow. Already she was deep within the air-ocean of this drowned moon; above her was a hundred miles of murky aerosol haze, a hundred miles of cigarette smoke.

For the first time in six years, Mott’s sky was no longer black.

The fiery entry phase was already over. The G meter read nought point one four — Titan gravity, one-seventh of a G. Three minutes after leaving orbit she was falling, alone, towards a hidden landscape, at nine hundred miles an hour.

Now, the first drogue parachute should deploy. It would burst from the parachute compartment in Jitterbug’s nose with a pyrotechnic bang, blowing away the apex cover of the compartment, and then open with a snap…

Nothing happened.

She checked her mission timer and G-meter against the checklist, still fixed to the control panel before her.

The drogue should have opened by now. If the drogue didn’t open, neither would the main chutes.

Shit, she thought. What did I miss?

She punched the manual drogue deploy button.

After a few seconds she heard the bang of the drogue’s pyrotechnics. The drogue chute hauled at the capsule, jolting her hard into her couch.

Jitterbug’s velocity slowed — in thirty seconds and five miles — to three hundred feet per second, well below the speed of sound.

A hundred miles up, the air temperature outside was minus 120 degrees C.

Another bang. That had to be the mains, the three eighty-footer ringsails which would lower Jitterbug gently to the surface of Titan. Through the little docking windows above her Mott could see the main chutes as they unfolded, streaming upwards lazily in the thickening air. The chutes were unbleached, to save weight; they were yellow, like three big dirty jellyfish.

Jitterbug became a huge pendulum, swinging on a wide, slow path, suspended beneath the mains, in Titan’s feeble gravity taking all of forty-five seconds to complete a cycle; it was a slow, comforting rocking.

She felt her heartbeat slow, the moment of panic over.

What did I miss?

The Command Module was supposed to be controlling its own sequence of operations, now, as it went through its cycle of pyrotechnic explosions and parachute deployment. The main Arming Timer fired the pyrotechnics in a hard-wired sequence keyed to deceleration measured by a G-switch. The idea was to improve reliability, to provide a hardware-managed timelining that was independent of the Command Module’s computer processor and software.

That was the idea, anyhow. She scanned back up her checklist.

…Oh.

She had been supposed to enable the whole system by throwing a couple of switches, to start the Titan landing system and disable the reaction control shutdown. She should have done that just after emerging from the heavy deceleration of the entry phase.

She hadn’t. Maybe if she hadn’t been alone, she wouldn’t have missed it.

So far it all seemed to be working, however. Except for her human error. Everything — her life — depended on how robust the reworked systems now proved to be, in the face of that mistake.

She heard a rattle of solenoids; the capsule jerked about, startling her.

It was the reaction control thrusters. They were still firing, trying to damp oscillations in the vehicle’s attitude, their action futile so deep in the atmosphere. It shouldn’t be happening. The RCS should have been disabled, at the start of the auto sequence that she’d missed.

She snapped the RCS switch to OFF. The solenoid rattle died immediately.

The fact was, she was off the nominal program, now.

By failing to enter that command to start the new customized automated sequence, she was having Jitterbug follow fallback paths.

Fifty-year-old logic paths, designed, originally, for entry into Earth’s comparatively benign atmosphere. And although those logic paths had been tested out, there was no way they could have been made as safe as the primary path…

She felt a flicker of unease.

For fifteen minutes Jitterbug drifted under its main chutes, its speed gradually dropping. It was as if she was suspended above the surface of Titan in the metallic gondola of some balloon.

She monitored the Command Module’s clunky systems, waiting for the next glitch, the next anomaly.

She tried the periscope display. This was an oval piece of glass about a foot across set in the middle of the instrument panel before her. The periscope gave her a fish-eye view of the surface, looking down past the scorched white tiles of the hull:

A layer of thin white cloud, like cirrus, came ballooning up around her. Methane ice. Once through that, she looked down on a rolling, unbroken layer of thick, dark methane-nitrogen clouds, hiding the murky ground below. The clouds were almost Earthlike: fat, fluffy cumuli…

She could turn the periscope this way and that, with a little joystick in front of her. She imagined the tiny lens poking out of the hull and swivelling, above her head. The periscope had actually been cannibalized from an antique Mercury capsule, one of the original production run, which had been designed without windows; the periscope had been installed after protests from the astronauts to give them a view.

Even the effort of twisting the joystick seemed to deplete the muscles of her hand. It was going to take her a good while after landing before she had acclimatized enough to clamber out of her couch and try cracking the hatch.

After fifteen minutes the Command Module’s velocity was reduced to a hundred and twenty feet per second, and she was ninety miles above the surface. Now, with a crack of pyrotechnics above her, the main chute was jettisoned.

For an instant she was falling freely.

And then the final chute, the paraglider, opened up; and she was joked back into her couch once more.

She let out her breath. She was through another command sequence which hadn’t gone wrong. Maybe she would live through this yet.

The paraglider was just a shaped canopy, marginally steerable. It was another old idea, that had been tried out for Gemini. Thus, a Gemini paraglider and a Mercury periscope should let Mott fly an Apollo capsule, like Dumbo, down to the wreck of a Shuttle orbiter, a billion miles from home…

Fifty miles above the ground, Jitterbug was immersed in thickening orange petrochemical haze. But the sun was still plainly visible as a brilliant disc, surrounded by an aureole, a yellow-brown halo. Mott swivelled her periscope until Saturn was fixed at the center of her oval window. But already the water-color yellow wash of Saturn’s surface was becoming fainter, obscured by the uniform brown smear of the smog. She stared into the periscope until at last the planet’s fat, elliptical outline was lost, as if fading out on a poorly tuned TV screen, and the cloud closed over.

The sun, she saw, had vanished too. She had watched her last dawn, her last sunset. She was stuck down here, for good or ill.