Benacerraf hauled Angel’s PLSS — his Personal Life Support System, his backpack — up from storage lockers under the couches. The pack was a big, massive box coated in Beta-cloth. Here it weighed just twenty pounds, but she could feel the mass of the pack, its Newton’s-laws inertia undiminished; she had to handle it carefully to avoid battering the control panels. Rosenberg leaned Angel forward, and Benacerraf lifted the backpack over him and strapped it in place round him. The packs were adapted Shuttle technology, with lightweight batteries for power, air and water circulation pumps and fans, and lithium hydroxide canisters for scrubbing out carbon dioxide. Not much more advanced than the packs which had sustained men on the Moon. The suits would support EVAs of seven or eight hours, if they were lucky.
Next came the fitting of Angel’s umbilicals, hoses for air and water for the heating system. Rosenberg and Benacerraf worked across Angel’s chest, locking each hose into place, double-checking each other’s progress. “Locks checked, blue locks. Locks checked, red locks. Purge locks, double-locked…”
The surface of Titan represented a new challenge for EVA suit designers.
All previous EVAs — in Earth orbit, or on the Moon — had been in a vacuum. And the main challenge had been to surround the astronaut with an atmospheric pressure which, if not equivalent to Earth’s, was at least sufficient to sustain life. So the astronauts wore pressure garments, bubbles inflated with oxygen.
On Titan, it was different. On Titan, the air was thick — thicker, in fact, than on Earth. The air wasn’t breathable, and the astronauts still needed an Earth-equivalent air supply. But there was no need for pressurization against vacuum; the suits in that respect were a little more like deep-diving suits.
There was another novelty.
In the vacuum of space, the problem was keeping the astronaut’s body cool. Solar heat could be reflected by white overgarments, and sufficient heat of the astronaut’s own body could be retained by insulating layers; the trick was to wrap the body in a cooling garment — tubes of water to carry body heat away, and then radiate it into the vacuum.
Here on Titan, there was no vacuum. In the thick air conduction I and convection would work rapidly to carry away heat. The main problem on Titan, in fact, was the deadly cold. If that frigid slush or the thick, sluggish air above it came into anything close to direct contact with an astronaut’s flesh, life heat would be sucked away with frightening speed.
To combat the cold, the Titan suit was built on a Heating Garment — a sexless, skintight piece of clothing laced with wires and water pipes. The wires would heat the flesh, and the air which ran over it. It was like wearing an electric blanket. And the water in the tubes had high heat capacity; it would form a heat-retaining shell around the body. And over the heating suit the astronauts would wear layers of soft, insulating clothing.
The final outer garment was crude — much more primitive than the pressure suit — just layers of white Beta-cloth, fiberglass filaments coated with Teflon, with heat-retentive insulating material between, the chest unit studded with umbilical connectors and controls.
She fixed on Angel’s Snoopy hat, his flight helmet with its radio earphones and microphone, and over the top of that Rosenberg lifted Angel’s hard helmet with its visor, and twisted it into place against the seal at the neck. The last pieces of the suit were the gloves; these were close-fitting, and snapped onto rings at Angel’s wrist.
Now Rosenberg flicked a switch on Angel’s chest panel. Benacerraf could hear the soft, familiar hum of the pumps and fans in Angel’s backpack, the whoosh of the oxygen-nitrogen mix inside his helmet.
Rosenberg and Benacerraf worked through suit checks. There was a panel on the front of Angel’s chest which gave a digital readout of oxygen and carbon dioxide and pressure levels, and various malfunction warning lights. She could see Angel’s oxygen pressure level stabilizing.
Rosenberg nodded, satisfied.
Benacerraf sat back on the cabin’s right hand couch and peered into Angel’s helmet. Once again, they had got Bill sealed away, locked into his own self-contained world, as if within a private spacecraft, his degeneration concealed by the gleaming white Beta-cloth layers.
Benacerraf and Rosenberg got into their own suits.
A half-hour later, when they were done, they studied each other. Their names were stitched on the chests of the shining white suits, and the NASA logo and the Stars-and-Stripes were proudly emblazoned on their sleeves; they wore bright blue overboots, blue gloves. In the bulky suits, hardly able to move in the cramped cabin, they looked faintly ludicrous, like three snowmen, Benacerraf thought.
Rosenberg checked his suit display, and the status of the Command Module from a control panel.
“For the record,” he said, “We have a go for vent.”
“Affirmative,” Benacerraf said. “We’re all sealed up. Go for vent.”
“All right.” Rosenberg closed a switch on the wall.
Vents in the base and apex of the Command Module opened up. There was a harsh hiss.
There was a muddy brown swirl around Benacerraf’s feet. The thick air of Titan was forcing its way into the lower-pressure cabin of Bifrost. She watched the little dials on the instrument panel, yellow and green and red, bright primary Earth colors. The smog of Titan dimmed them, washing the dials over in an orange-brown murk.
“Okay,” Rosenberg said. “Everything is go. We are just waiting for the cabin pressure to equalize with the exterior sufficiently to open the hatch…”
His voice is becoming stilted, Benacerraf thought. He’s speaking for the camera. For the history books.
The hiss died away.
Rosenberg checked his gauges. “That’s it,” he said. “One and a half bars; pressure has equalized. You should be able to open the hatch now, Paula.”
Her heart thumping, suddenly conscious of the camera on her, Benacerraf turned.
Apollo’s hatch was a rectangle, two feet high and three wide, behind the center couch of the cabin. There was a window in the middle of it, already stained with tholin smears.
Benacerraf pulled at the hatch’s single handle. She could hear the twelve locking latches click open. The hatch swung outward, easily.
The open doorway framed a rectangle of mud-brown ground, laced by some darker substance. The Command Module seemed to have sunk into the slush, almost to the depth of the door frame.
She looked back at Rosenberg, who was standing between the two couches, watching her. Angel still seemed to be unconscious, sprawled like a flaccid white balloon on the right-hand couch.
Rosenberg took a camera down off its bracket on the wall, and focused on her. He said, “You ready for your one small step?”
It was what Tom Lamb had once said to her, floating in the light of Earth, long ago.
“Let’s do it.”
To get out of the narrow hatch, Benacerraf had to turn around and crawl out backwards. Rosenberg, keeping the camera focused on her, guided her. “You’re lined up nicely. Come back towards me… Okay, put your foot down… you’re doing fine… A little more.”
At last she found herself with her head outside the conical hull of Apollo, one foot on the floor of the capsule, and the other resting on the edge of the hatch.
She looked around. It was dark.
Darker than she’d expected, like a late, murky evening. The Huygens images and Bifrost’s own monitors, light-enhanced, had fooled her.
The ground was a plain, slightly undulating, thick with slush. A reddish-brown color dominated everything, although swathes of darker material streaked the landscape. The Command Module sat squat, a metal tent on a muddy, empty plain. The slush must be deep, she thought; even here, at the center of Bifrost’s splash crater, no bedrock water ice was exposed.