Forty miles high, Jitterbug fell out of the condensate haze, into a layer of clearer air. Then, at thirty miles, it penetrated the fat methane clouds. The temperature was close to its minimum here, at minus two hundred degrees Centigrade. The clouds were dark, brooding, as if stormy. Deep within the clouds, the cabin grew dark, and the lights of the instruments on the panel before her seemed to glow brighter.

Suddenly the altimeter kicked in. She was at a hundred and fifty thousand feet, it said. Feet, not miles: the measure of an aircraft, ballooning down through Titan’s atmosphere.

Jitterbug emerged from the base of the clouds, which now hid the orange sky.

Gradually, through mist and scattered cloud, for the first time, Titan’s surface became visible to human eyes.

…Fluffy clouds of ethane vapor lay draped over glimmering circular lakes, which were cupped in continents of water ice. The liquid in those lakes was black to her vision, the round ponds puncturing the red-brown carcass of Titan like neat bullet-holes. It might have been a high-altitude view of Earth’s surface, though rendered in sombre, reds and browns, a twilit panorama…

She reached out and took hold of a handset on the panel in front. of her. The handset controlled the paraglider, by tweaking at its cables. Using this she ought to be able to fly the Command Module right in to the orbiter, with an accuracy of — the designers had told her — a hundred yards or so. And in the limited VR sims they’d set up, she’d consistently scored better than that, getting down to within thirty or forty feet of the target.

But first she had to spot her target, the orbiter on the surface. She peered anxiously into the periscope. The surface of Titan — in the fish-eye view, bulging towards her — was resolving into a landscape of mud and crater lakes. The smaller lakes, a couple of miles across, were simple circles. But she could see central peaks protruding from the centers of some of the larger lakes, their shores washed clean of muddy slush.

And now Jitterbug drifted over a pair of giant craters, each perhaps fifty miles across. In one of these the central peak seemed to have broadened into a dome, so that the ethane pool was contained in a thin ring around a central island. But she could see a pit at the center of the dome, itself containing a small pool, so the whole structure had a bull’s-eye shape, with the solid circle and band of dark fluid contained by the circular crater rim. And in the second of the big craters, the outer annulus of fluid seemed to be heaped up against one wall of the crater — perhaps by some tidal effect — so that the lake was in the form of a semicircular horseshoe. The landscape was strange, even the shape of the lakes bizarre. This is Titan, she reminded herself with a shiver. You are a billion miles from home. And there’s nothing in human experience to guide you as to what you’ll find here. The Command Module shuddered, the hull groaning. She gripped her seat, hard. She could feel the hard metal frame through the thickness of her pressure suit gloves. The Command Module felt fragile around her; it was like being inside some flimsy aluminum bathysphere, descending into this murky orange ocean. Now she was suspended over a mountain range, wrinkles in the glimmering surface. The peaks were exposed, dark grey water ice bedrock, and the uniform orange coating of the lower ground lay in streaks that followed the contours of the mountain, like snow runs. The area looked familiar from Rosenberg’s Cassini maps. She turned the periscope, jerking it from one side of the ship to the other.

There.A little way away from the range was a crater lake, the muddy liquid pooled in the shape of a cashew nut.

It was Clear Lake: just like the radar images. And Mount Othrys must be somewhere in that range below her.

…She caught a glimpse of white, embedded on the dried-blood surface like a splinter of bone protruding from a wound.

It was a delta-shape. Discovery.

She grinned fiercely, her spirits rising for the first time since Saturn had disappeared. She wouldn’t even have to steer the paraglider much; now all she had to do was glide her way down this last ten thousand feet and—

There was a snap, somewhere in the wall high above her.

Murky air billowed into the cabin, above her face. There was a stink, of swamps and marshes and…

And methane. Titan air. And, mixed in with it, the sharp tang of nitrogen tetroxide, oxidizer from the RCS.

She couldn’t believe it; she sat staring as the orange mush billowed down towards her. Following some antique command, the cabin pressure relief valve had opened. The valve was a two-inch nozzle designed to let in warm Pacific air, for returning Moon voyagers. It was not supposed to open on the way down to Titan.

It was the failure she had been waiting for. This had to be some consequence of her failing to follow the correct automation sequence earlier. Another untested logic path. But why the hell hadn’t that damn valve simply been welded shut?

It was a multiple failure. Multiple failures always got you, in the end.

And while she lay here and thought about it, she had sucked in a lungful of freezing, toxic Titan air…

She closed her mouth and eyes and pulled her faceplate down. It snapped into place, and she felt a cool blue blast of oxygen on her face. She breathed out, trying to empty her lungs. But that, she realized, was only going to start the methane and nitrogen tet circulating in her life support.

The stink of swamp gas was overwhelming. And the nitrogen tet seemed to be burning at her lungs and eyes; she could barely see.

She considered trying to find some way to close that relief valve. But now she could barely see the instrument panel.

Anyhow, maybe it was better for the oxygen in the cabin to be overwhelmed by Titan air. If that methane caught a spark, Jitterbug would explode.

She was coughing, her throat and lungs aching.

The descent was nearly over, anyhow.

The cold air of Titan wrapped over her limbs. She found herself shivering already. When she got to the ground, she’d have to move quickly to get to the heated EVA suit. She rehearsed the moves she would make. Stand up, as best she could, and reach under the couch for the big net bag there; haul out the suit…

Jitterbug crashed into the tholin slush.

The fall was no more severe than if Jitterbug had been dropped on Earth from five or six feet. But to Mott it felt like a huge impact, an astonishing eruption of agony throughout her bruised body.

…And now the Command Module tipped to the right. She could feel the roll, see the orange-black landscape wheel past the windows. Perhaps the paraglider hadn’t come loose, and was dragging Jitterbug over. Or perhaps she had landed on some kind of slope, a crater wall maybe, and was rolling.

Orange-brown mud splashed across the glass of the windows to her right, and turned them dark. Mott found herself hanging there in her straps, with cabin trash raining down around her: bits of paper, urine bags, discarded washcloths. The Stable 2 position, she thought. Upside down. One whole side of Jitterbug must be buried in the icy slush of Titan.

For a moment there was stillness, a cramped creaking as the hull cooled.

Then a window to her right cracked in two. Orange-black slush forced its way into the cabin, flowing, viscous.

Mott, suspended, began coughing again.

She was stuck in her seat. She couldn’t move. She was going to freeze. Help was two hours away, or a billion miles, depending on how you looked at it.

When the Titan slush lapped against her legs, she could feel the cold of it seep into her bones.

No footprints and flags for me, after all. But I got here. I got to touch Titan.