Sphere

had stayed awake for the briefing.

  "Because," Ted said, "the atmosphere of the Earth is deadly. You don't realize it, but oxygen is a corrosive gas. It's in the same chemical family as chlorine and fluorine, and hydrofluoric acid is the most corrosive acid known. The same quality of oxygen that makes a half-eaten apple turn brown, or makes iron rust, is incredibly destructive to the human body if exposed to too much of it. Oxygen under pressure is toxic - with a vengeance. So we cut down the amount of oxygen you breathe. You breathe twenty-one percent oxygen at the surface. Down here, you breathe two percent oxygen. But you won't notice any difference - "

  A voice over a loudspeaker said, "We're starting to pressurize you now. "

  "Who's that?" Norman said.

  "Barnes," the voice said. But it didn't sound like Barnes. It sounded gritty and artificial.

  "It must be the talker," Ted said, and then laughed. His voice was noticeably higher-pitched. "It's the helium, Norman. They're pressurizing us with helium. "

  "You sound like Donald Duck," Norman said, and he laughed, too. His own voice sounded squeaky, like a cartoon character's.

  "Speak for yourself, Mickey," Ted squeaked.

  "I taut I taw a puddy tat," Norman said. They were both laughing, hearing their voices.

  "Knock it off, you guys," Barnes said over the intercom. "This is serious. "

  "Yes, sir, Captain," Ted said, but by now his voice was so high-pitched it was almost unintelligible, and they fell into laughter again, their tinny voices like those of schoolgirls reverberating inside the steel cylinder.

  Helium made their voices high and squeaky. But it also had other effects.

  "Getting chilled, boys?" Barnes said.

  They were indeed getting colder. He saw Ted shivering, felt goosebumps on his own legs. It felt as if a wind were blowing across their bodies - except there wasn't any wind. The lightness of the helium increased evaporation, made them cold.

  Across the cylinder, Ted said something, but Norman couldn't understand Ted at all any more; his voice was too high-pitched to be comprehensible. It was just a thin squeal.

  "Sounds like a couple of rats in there now," Barnes said, with satisfaction.

  Ted rolled his eyes toward the loudspeaker and squeaked something.

  "If you want to talk, get a talker," Barnes said. "You'll find them in the locker under the seat. "

  Norman found a metal locker, clicked it open. The metal squealed loudly, like chalk on a blackboard. All the sounds in the chamber were high-pitched. Inside the locker he saw two black plastic pads with neck straps.

  "Just slip them over your neck. Put the pad at the base of your throat. "

  "Okay," Ted said, and then blinked in surprise. His voice sounded slightly rough, but otherwise normal.

  "These things must change the vocal-cord frequencies," Norman said.

  "Why don't you guys pay attention to briefings?" Barnes said. "That's exactly what they do. You'll have to wear a talker all the time you're down here. At least, if you want anybody to understand you. Still cold?"

  "Yes," Ted said.

  "Well, hang on, you're almost fully pressurized now. " Then there was another hiss, and a side door slid open. Barnes stood there, with light jackets over his arm. "Welcome to DH-8," he said.

  DH-8

  "You're the last to arrive," Barnes said. "We just have time for a quick tour before we open the spacecraft. "

  "You're ready to open it now?" Ted asked. "Wonderful. I've just been talking about this with Norman. This is such a great moment, our first contact with alien life, we ought to prepare a little speech for when we open it up. "

  "There'll be time to consider that," Barnes said, with an odd glance at Ted. "I'll show you the habitat first. This way. " He explained that the DH-8 habitat consisted of five large cylinders, designated A to E. "Cyl A is the airlock, where we are now. " He led them into an adjacent changing room. Heavy cloth suits hung limply on the wall, alongside yellow sculpted helmets of the sort Norman had seen the divers wearing. The helmets had a futuristic look. Norman tapped one with his knuckles. It was plastic, and surprisingly light. He saw "JOHNSON" stenciled above one faceplate.

  "We going to wear these?" Norman asked.

  "That's correct," Barnes said.

  "Then we'll be going outside?" Norman said, feeling a twinge of alarm.

  "Eventually, yes. Don't worry about it now. Still cold?"

  They were; Barnes had them change into tight-fitting jumpsuits of clinging blue polyester. Ted frowned. "Don't you think these look a little silly?"

  "They may not be the height of fashion," Barnes said, "but they prevent heat loss from helium. "

  "The color is unflattering," Ted said.

  "Screw the color," Barnes said. He handed them light-weight jackets. Norman felt something heavy in one pocket, and pulled out a battery pack.

  "The jackets are wired and electrically heated," Barnes said. "Like an electric blanket, which is what you'll use for sleeping. Follow me. "

  They went on to Cyl B, which housed power and life-support systems. At first glance, it looked like a large boiler room, all multicolored pipes and utilitarian fittings. "This is where we generate all of our heat, power, and air," Barnes said. He pointed out the features: "Closed-cycle IC generator, 240/110. Hydrogen-and-oxygen-driven fuel cells. LSS monitors. Liquid processor, runs on silver-zinc batteries. And that's Chief Petty Officer Fletcher. Teeny Fletcher. " Norman saw a big-boned figure, working back among the pipes with a heavy wrench. The figure turned; Alice Fletcher gave them a grin, waved a greasy hand.

  "She seems to know what she's doing," Ted said, approvingly.

  "She does," Barnes said. "But all the major support systems are redundant. Fletcher is just our final redundancy. Actually, you'll find the entire habitat is self-regulating. "

  He clipped heavy badges onto the jumpsuits. "Wear these at all times, even though they're just a precaution: the alarms trigger automatically if life-support conditions go below optimum. But that won't happen. There are sensors in each room of the habitat. You'll get used to the fact that the environment continually adjusts to your presence. Lights will go on and off, heat lamps will turn on and off, and air vents will hiss to keep track of things. It's all automatic, don't sweat it. Every single major system is redundant. We can lose power, we can lose air, we can lose water entirely, and we will be fine for a hundred and thirty hours. "

  One hundred and thirty hours didn't sound very long to Norman. He did the calculation in his head: five days. Five days didn't seem very long, either.

  They went into the next cylinder, the lights clicking on as they entered. Cylinder C contained living quarters: bunks, toilets, showers ("plenty of hot water, you'll find"). Barnes showed them around proudly, as if it were a hotel.

  The living quarters were heavily insulated: carpeted deck, walls and ceilings all covered in soft padded foam, which made the interior appear like an overstuffed couch. But, despite the bright colors and the evident care in decoration, Norman still found it cramped and dreary. The portholes were tiny, and they revealed only the blackness of the ocean outside. And wherever the padding ended, he saw heavy bolts and heavy steel plating, a reminder of where they really were. He felt as if he were inside a large iron lung - and, he thought, that isn't so far wrong.

  They ducked through narrow bulkheads into D Cyl: a small laboratory with benches and microscopes on the top level, a compact electronics unit on the level below.

  "This is Tina Chan," Barnes said, introducing a very still woman. They all shook hands. Norman thought that Tina Chan was almost unnaturally calm, until he realized she was one of those people who almost never blinked their eyes.

  "Be nice to Tina," Barnes was saying. "She's our only link to the outside - she runs the com ops, and the sensor systems as well. In fact, all the electronics. "

  Tina Chan was surrounded by the bulkiest monitors Norman had ever seen. T
hey looked like TV sets from the 1950s. Barnes explained that certain equipment didn't do well in the helium atmosphere, including TV tubes. In the early days of undersea habitats, the tubes had to be replaced daily. Now they were elaborately coated and shielded; hence their bulk.

  Next to Chan was another woman, Jane Edmunds, whom Barnes introduced as the unit archivist.

  "What's a unit archivist?" Ted asked her.

  "Petty Officer First Class, Data Processing, sir," she said formally. Jane Edmunds wore spectacles and stood stiffly. She reminded Norman of a librarian.

  "Data Processing . . . " Ted said.